In the nasty, grimy, and generally unglamorous business of war, there is one type of combat that retains to this day the challenge, excitement and thrill of the ancient duels of feudal Europe and the legendary combats of Hector and Achilles, Aeneas and Turnus, and of the Horatii and Curiatii. Like the knights of old, the modern fighter pilot sets out to engage the enemy in “hand-to-hand” combat. Unlike the knights of old, his arena is the clear blue skies far above the battlefield.
The combat is both personal and impersonal. “Personal” because it deeply involves the individual skill and daring of the combatants. “Impersonal” because the duelists fight at long range and seldom get close enough to see the face of their opponent. Air-to-air combat has the character and glamor of a boxing or wrestling match—but in a detached scenario without personal contact.
Why is it important that we still have fighter aircraft in the Armed Services? Why do we still select the cream of our manhood, spend large sums of money on his training, equip him with the finest multimillion dollar fighter and set of weapons that technology can produce, and send him out to shoot down enemy aircraft in the time honored manner of the Eddie Rickenbackers, the Dave McCampbells, and the Pappy Boyingtons?
The reason is simple. The “Red Baron” scarf-and-goggles fighter duels of World War I were not just a circus stunt. Without Allied fighter opposition, the Germans would have been free to bomb and strafe Allied troops and installations at will, and the entire course of the war might well have changed. In World War II, a handful of Spitfires and Hurricanes and a few dedicated British pilots were decisive in the Battle of Britain. In both Europe and the Pacific, control of the air by fighter airplanes was critical to our ultimate victory. In Korea and in Vietnam, control of the air, though not strongly contested, has been equally important.
Are fighter airplanes obsolete in modern war? A brief reflection on the effect of Israeli fighter strikes on the outcome of the recent Arab-Israeli “Six Day War” will provide the answer. Fighters may well be decisive in modern conflicts—certainly, the lack of superior fighters and fighter pilots could lead to utter disaster.
Fighter Missions
Today’s Navy fighters have but one basic mission—to destroy enemy aerodynamic vehicles (manned and unmanned) which may be used by the enemy to interfere with our offensive operations, or to attack the Fleet. This mission is normally broken down as follows:
Air Superiority
Air-to-air engagement
Combat Air Patrol (TARCAP, BARCAP, RESCAP, etc.)
Escort of strike groups
Fighter sweeps
Delivery of air-to-ground ordnance
Fleet Air Defense Against Enemy
Bombers with air-to-surface missiles
Fighter bombers
Interceptors
Surface-to-surface missiles
The fighter-to-fighter engagements which are normally associated with gaining and maintaining control of the air may occur in many situations. Fighters are used on Combat Air Patrol missions over the target area (TARCAP)[,] at a particular geographic point as a barrier against penetration by enemy aircraft (BARCAP), or over a land or sea area where rescue operations are in progress (RESCAP). Fighters are also employed to escort strike groups and special detachments performing reconnaissance, early warning, or electronic countermeasures missions. In other situations, fighters may be used in suppression attacks against enemy antiaircraft gun sites or surface-to-air missile installations prior to or during a strike.
One of the most efficient ways of gaining air superiority is to destroy enemy fighters and attack aircraft on the ground (again, witness the Arab-Israeli war) or to make enemy airfield installations and runways unusable with strafing and bombing attacks. Fighter sweeps using guns and air-to-ground ordnance have proved ideal for this task.
The so-called Fleet Air Defense mission is little different from other tasks a fighter is required to perform. In this case the fighter is called an interceptor and performs its job of shooting down attacking enemy aircraft and aerodynamic missiles at a Combat Air Patrol station some distance from the task force, or is deck launched from the carrier to dash out to intercept the attacking aircraft and perform the same function.
In a combat situation, all enemy aircraft are “fair game” to a fighter pilot. Any and all tactics are legal—tricks, stealth, cunning, skill, maneuvers, concentration of forces, camouflage, countermeasures, decoys, or any other strategem that can be devised. All kinds of weapons are likewise legal—guns, rockets, short-range guided missiles, and long-range all-weather guided weapons. Ramming the enemy aircraft has also been tried, although this tactic is not strongly recommended by older fighter pilots. Obviously, there are many advantages in destroying enemy aircraft at a distance. Although this may take some of the “sport” out of the game, the end result can be equally gratifying and, in most cases, is much more efficient.
Designing a Fighter
How does one go about the complicated task of designing a new fighter? How does one determine a valid mission requirement for a new fighter so that it will have a long and useful life? It may sound a bit lofty, but one must really start with our State Department. In order to design the right fighter, one must have a deep understanding of the world geopolitical situation and of our grand national strategy and policy as related to other countries of the world, both friendly and unfriendly. One must also have an appreciation of the fact that although the United States may have productive, financial and technical superiority over other nations of the world, we represent only six per cent of the world’s population. Hence, our Armed Forces must rely on weapons of higher unit effectiveness to provide adequate backing to our national policies.
If our national policy were to retreat to “Fortress America” and to refrain from engaging in large or small conflicts through the world, one would obviously design a fighter optimized for the defense of the continental United States against enemy air attack. If our policy were to prepare for all-out war against a powerful unfriendly nation, one might design an entirely different fighter. And if our policy were to continue support of small underdeveloped countries in their fight against Communist aggression, one might design still another type of fighter. Since the “lead time” for designing, building, and deploying a new fighter may be five to seven years, the estimate of national policy must be made for many years into the future.
Once the most probable mission or missions have been determined for the new fighter, the next important step is to determine the critical part of the payload—the air-to-air weapons suit for the fighter. If the fighter were to be used primarily in close-in, air-to-air engagements, guns and short range “dogfight” missiles might be the choice. If the fighter were to be used in longer range encounters, all-weather air-to-air guided missiles might be called out. If the fighter were to be used for both functions, a combination of weapons would be in order.
The Concept Formulation/Contract Definition requirements of the Department of Defense, though cumbersome and lengthy, are designed to insure that the concept, mission, and payload of important new weapon systems such as fighters are clearly defined and accepted before development is initiated. Once this hurdle has been accomplished, one can then turn to the details of the design.
Fighter Design Characteristics
The sum of our experience in designing, building, and operating Navy fighter aircraft tells us that the following are important parameters for our fighters. No attempt has been made to list these in order of importance.
Deck Spot (deck space required)
Visibility
Performance
Speed
Rate of climb
Acceleration
Deceleration
Payload range
Loiter time
Combat time
Take-off and landing characteristics
Maneuverability
Wing loading
Buffet boundary
Roll acceleration
Roll rate
Time-to-turn
Weapons Suite
Flexibility
Carrier Suitability
Among people involved, the design characteristics of an “optimum” Navy fighter is a very controversial and explosive subject. However, there is general agreement that the “ideal” fighter should be the smallest, lightest, highest performance, and most maneuverable airplane that can be designed which satisfies Navy mission requirements for escort of strike groups, loiter time on Combat Air Patrol stations, and other fighter tasks. The “ideal” Navy fighter should also have the most effective and versatile air-to-air weapons and avionics systems that technology can devise and, particularly, have excellent carrier suitability characteristics and take up the minimum of space on the carrier deck (small deck spot). It is obvious that many of these desired characteristics are in direct opposition.
For example, high performance dictates large engines and high excess thrust combined with a small, low drag airframe. Such a fighter would have a comparatively small wing area (for low drag) and short range, but excellent acceleration, rate of climb and high speed performance.
In certain tactical situations, the ability to decelerate the airplane may be as important as acceleration. This can be accomplished with dive brakes or thrust reversers, but these devices add size and weight to the fighter.
Fighter pilots like good visibility from the cockpit for obvious reasons. Yet a large bubble canopy will increase the drag of an airplane and reduce its performance.
High maneuverability requires a low wing loading which allows high maximum lift and a high buffet boundary (the ability to pull high normal load factors or “g’s” in maneuvers and turns). Yet low wing loading requires a large wing area which increases drag and airplane weight and reduces acceleration and climb performance.
High roll acceleration and roll rate are required to change the direction of the airplane rapidly in maneuvers and can be obtained quite easily by proper design of ailerons, spoilers, or other roll devices. However, a more important parameter is the time required to turn a fighter through a given heading angle at any flight condition. Time to turn is strongly dependent on excess thrust and buffet boundary.
A Navy fighter that does not have sufficient internal fuel to carry out its various missions such as escort of strike aircraft and Combat Air Patrol may present severe operational problems to the Carrier Strike Force Fighters can be refueled in the air to extend their range but this requires tankers which must also be operated from the carrier or possibly from shore bases if they are available. Since carrier deck space is limited, each tanker on board means fewer attack and fighter aircraft for the real job of striking the enemy. Furthermore, tankers are very vulnerable to enemy action.
Fighter range and time on CAP station can also be extended by using external fuel tanks. However, external tanks increase airplane drag, take up valuable store stations and, if dropped on every mission, present a severe logistics problem to the carrier.
Deck cycle time (the time between launch and recovery of aircraft) is also an important consideration in sizing the fuel load of a fighter. A longer cycle time allows greater flexibility in operating and maneuvering the Carrier Task Force.
We also would like to have the most advanced and most lethal set of long and short range air-to-air weapons for our Navy fighter, with sufficient flexibility change weapons as the tactical situation might require. Each of these weapons requires sensors, fire control equipment, displays, and controls in the airplane. In addition, we need navigation, communication, identification, electronic countermeasures, and other avionics equipment to operate a fighter effectively.
Our requirements for comparatively large amounts of internal fuel, weapons, and avionics equipment all add size and weight to the fighter, at the expense of some performance and maneuverability, of course.
And last but not least, our Navy fighter must be carrier suitable. It must have provisions and structural strength for catapulting and arresting, and be capable of stable flight at low speeds for take-off and landing. Satisfactory low speed flight generally requires a large, thick, cambered wing while supersonic flight and high acceleration dictate a small, thin wing. High lift devices and a great deal of ingenuity are required to obtain good low speed characteristics without compromising the high speed performance of the fighter.
In summary, fighter design characteristics are not independent but are closely interrelated. With present technology, it is impossible to build a small, light, long range, extremely maneuverable, highest performance fighter that carries a large payload of avionics equipment and air-to-air weapons. The “optimum” design is always the finest compromise among these desired characteristics and equipments.
What have we learned? Naval aviation is over fifty years old. In this time we have built many aircraft—most were successful, some were failures. Each time we have made a mistake we have tried not to make the same mistake in future designs. Our present voluminous specifications for the design, structural strength, stability and control, carrier suitability, and other characteristics for naval aircraft have been built up over the years largely from the lessons we have learned on how not to design aircraft. Aside from this, one might ask what we have learned in a positive sense—that is, what makes a successful fighter?
Listed below are a few of the fundamental truisms for a good fighter. The list is by no means absolute or all inclusive.
(1) A fighter should be designed for a single, valid, well defined mission. Fighters designed to hazy operational requirements, or for more than one unrelated mission, have generally been doomed to failure before they were built.
(2) The design should be within the “state-of-the-art.” Attempts to make large technological “jumps” with untried and unproven designs in airframes, engines, or electronics have usually resulted in failure.
(3) A successful fighter should have a large amount of excess thrust (or power) in the initial production airplanes. A high thrust-to-weight ratio not only gives excellent performance but allows for future growth.
(4) In the initial design of a Navy fighter, weight is the most important parameter. If weight can be kept within reasonable limits, chances of success are good. If weight increases drastically, nothing short of a complete redesign will save the airplane.
(5) “Good” fighters grow in weight during their life as new capabilities, equipment, engines, and weapons are added. “Poor” designs do not grow—they are terminated. Our subsequent modifications to a good basic design have produced our most successful fighters.
(6) The most critical single component in the design of a new fighter is the engine. Without a quantum engine improvement (higher thrust-to-weight ratio, and lower specific fuel consumption), it is impossible to build a significantly improved fighter for the same mission.
Assuming the same technology in engines and aerodynamics, a single purpose fighter can be built which will be superior in performance and maneuverability to a multi-purpose fighter (i.e., one that is designed to perform not only the fighter’s tasks but other unrelated missions such as close air support, reconnaissance, etc.). Similarly, a fighter with shorter range (less internal fuel) will have higher performance and agility than a longer range fighter. Hence, if we are forced by the tactical situation to fly long distances and engage enemy fighters over his territory, and if the enemy, with the same technology, chooses to design and build short range fighters, we can expect that his fighters will have somewhat higher performance and maneuverability than ours. In this “real world” situation, it is apparent that the outcome will depend strongly on the effectiveness and versatility of the air-to-air weapons carried by each fighter.
The puzzling problem of optimum fighter characteristics, weapons and appropriate missions is by no means new to our era. Since the days of the Langley, Navy operational and aircraft design personnel have wrestled with the well known compromises for a fighter between performance, armament, size, and maneuverability—as complicated by carrier suitability requirements, of course.
Fighter Development
The World War II Era
In the 1920s, the Navy’s carrier fleet was so small (consisting of the battle-cruiser hulled Lexington and Saratoga and the ex-collier Langley) that only a few airplanes could be accommodated. These airplanes had to perform all of the functions then required of Navy carrier aircraft—fighting, dive bombing, scouting and torpedo missions—and most airplane types performed more than one function. As more carriers were built (Ranger in 1934, Yorktown in 1937, and Enterprise in 1938), it became possible to develop more specialized airplane types. The scout-bomber class was developed and fighters became a separate type, although they were still designed to double as fighter-bombers.
As war rumblings increased in the late 1930s, Fleet commanders began to demand improved fighters. What they wanted, as simple as it may sound today, was an airplane “to fight other airplanes.” These fighters had to possess superior speed, maneuverability, and firepower.
In responding to these demands, the Bureau of Aeronautics was faced with several problems. Carrier aircraft had to be as small as possible in order to put the maximum number on each carrier. Experience showed, however, that fighter aircraft were likely to become larger rather than smaller unless each airplane was restricted to a certain type of mission. Specialization might make possible some reduction in size and permit a larger total number of aircraft per carrier.
The Bureau of Aeronautics considered the various tasks for a fighter and chose to investigate three—interceptors to protect the carrier, escorts for dive bombers and torpedo planes, and pickets to detect incoming attackers. The interceptor called for great speed and heavy armament at the expense of range; the escorts required sufficient range to accompany the bombers with reserve fuel for combat, and armament equal to that of the interceptor; and the pickets needed long range at the expense of armament and size. High speed and armament requirements precluded building an interceptor of smaller size than the escort fighter, and the two functions were combined. The picket, which seemed to offer the best opportunity for decreased size, was soon discarded because it was found impossible to design a small, long range aircraft for this function with any fighter characteristics worth mentioning. Furthermore, radar eventually replaced the picket or “scout” for detecting air attacks and the function was later abandoned.
In 1936, even before the concept of the Navy carrier fighter had completely crystallized, two important new airplane prototypes were started—the Grumman XF4F-1 (Wildcat) and the Brewster XF2A-1 (Buffalo). The first contract was let for the Chance-Vought XF4U-1 (Corsair) in 1938 and in 1941, scarcely six months before Pearl Harbor, work began on the Grumman XF6F-1 Hellcat. Derivatives of these prototypes were the backbone of our carrier operations in World War II in the Pacific. The Navy fighter, whose primary job was “to fight other airplanes,” emerged as a distinct and specialized type. Thirty years later we find little change in the basic idea.
F2A. At the time of our entrance into World War II, the Navy had to rely on the F2A-3 Buffalo and the F4F-3 Wildcat since these were the only carrier-based fighters in production. The XF2A-1 won the 1938 fighter competition mainly because it appeared as though there would be fewer production problems with the Buffalo than with the Wildcat. Drag clean-up tests in the NACA full scale wind tunnel at Langley Field led to changes that increased the maximum speed to over 300 mph, the first American fighter to reach this mark. However, later modifications to install essential equipment and to correct deficiencies increased the weight of the airplane to the point where wing loading became critical which drastically affected maneuverability and performance.
Leaking integral fuel tanks were a major problem. No satisfactory solution could be found short of a major redesign to install self-sealing tanks and the Navy decided to build the F4F in quantity production for the war. Number 503, the last F2A, came off the production line in the spring of 1942.
F4F. Although the series started with the XF4F-1 biplane, the F4F Wildcat was redesigned as a monoplane following wind tunnel tests to improve high speed performance. The first production model, the F4F-3, had a top speed of 315 mph and a ceiling of 33,500 feet. Built like a tank and highly maneuverable, the F4F-3 was powered by a Pratt and Whitney R-1830-76 Twin Wasp engine with a two-stage, two-speed supercharger. Performance and strength were lowered somewhat by the installation of protective armor and self-sealing tanks.
The urgency of war made it necessary to produce large numbers of Wildcats and to keep modifications to a minimum. After the Battle of Midway, the F4F carried the brunt of our carrier-based fighter offensive until the F6F began to arrive in the Fleet in early 1943. To increase production and allow Grumman to concentrate their efforts on the new F6F Hellcat, the Eastern Aircraft Division of General Motors began building the F4F as the FM-1 (F4F-4) and later the FM-2 (F4F-8). In all, General Motors produced almost 6,000 of a total of 8,000 Wildcats built.
In spite of attempts to minimize changes to the F4F, water injection, additional internal fuel tanks, and racks for bombs, rockets, and external fuel tanks were added. In the latter years of the war, most of the Wildcats were operated from Escort Carriers, insofar as possible, in missions that did not involve air-to-air combat with enemy fighters. In spite of its lack of performance, the Wildcat had a 7:1 kill ratio record against Japanese aircraft in the Pacific War.
The F4F-4 was one of the first Navy airplanes with folding wings. This change reduced the carrier deck space requirements for the airplane by almost one-half. The concept has turned out to be so important to naval aviation that it has been used in most carrier aircraft to this day.
XF5F. In the late 1930s the top speed of multi-engined bombers was approaching that of single engined fighters. In some quarters it was believed that two-engined carrier fighters would have to be built to maintain a speed superiority over bombers. As a result, Grumman suggested the twin engine XF5F-1, a radically new design that was started in 1938. The Bureau of Aeronautics held all other proposed two-engine designs in abeyance until the new XF5F-1 could be tested.
Grumman’s prototype, dubbed the Skyrocket because of its high speed and high climb rate (over 4,000 feet per minute), first flew in April 1940. A strange looking aircraft, the Skyrocket had twin rudders and a small fuselage that ended short of the wing leading edge. Engine cooling problems, landing gear troubles, and the lack of pilot visibility over the wing and engines doomed the project. Grumman proposed another twin engine design in the 1940 fighter competition which was developed as the F7F, and the F5F was dropped.
F4U. The design of the Chance Vought XF4U-1 was started in 1938 and the first flight occurred in 1940. An excellent basic design built around the Pratt and Whitney R-2800 engine, the F4U Corsair proved to be faster than any other airplane developed by the Navy to that time and a production order was immediately placed. The F4U had the distinction of being the first U. S. fighter to fly faster than 400 mph.
The unusual “inverted gull” wing design permitted the use of short, light weight landing gear with aft retraction and raised the forward part of the fuselage so that a 13-foot diameter propeller could be used. Poor lateral stability, unsatisfactory spin recovery characteristics, and various modifications needed for satisfactory service use delayed Fleet deliveries until October 1942. Because of certain carrier suitability problems involving oleo “bounce,” visibility from the cockpit, and directional stability on landing, most of the F4Us used in World War II were flown by the Marines from land bases.
The F4U established an enviable 11:1 kill ratio during the Pacific War. Rated high by the Navy because of its outstanding performance, the Corsair was produced by Brewster as the F3A and by Goodyear as the FG. The increased power of the R-2800 “C” engine (2200 hp) gave the F4U-4 a top speed of 445 mph. An attempt to further increase the power with the use of the R-4360 (3000 hp) engine in the F2G-1 resulted in failure, primarily because of unreliability and cooling problems.
Later models of the F4U were still procured after World War II to tide the Fleet over in the early days of jet fighter development. The Corsair was important in Korea where it was used in an attack role and as a night fighter using the APS-6 radar. Final phase out occurred in December 1955. In all, 12,570 Corsairs were produced over a period of almost 13 years—one of the longest production runs of any Navy fighter.
F6F. Started as insurance against the possible failure of the F4U, the F6F Hellcat was originally intended as a minimum modification to the F4F to install a larger engine, the Curtiss-Wright R-2600. However, once Grumman designers went to work, they evolved so many changes that an entirely new design was created. Using the Pratt and Whitney R-2800 engine instead of the R-2600, the F6F-3 became the production prototype. The F6F was first delivered to operational squadrons in January 1943 and saw combat in August 1943, scarcely six months after the F4U, although the design of the F4U was started three years earlier than the F6F.
About 4000 pounds heavier than the F4F, the Hellcat was much superior in performance, range, and military payload and became the backbone of our carrier operations during the war. Armed with six wing-mounted .50 caliber machine guns, the F6F could also carry external tanks and an assortment of bombs and rockets.
A night fighter version using the APS-6 radar became operational in 1944.
The F6F-5 version had further improvements including better streamlining, water injection for increased engine output, a flat windshield with a reflecting gun-sight, red instrument panel lights, spring tab ailerons, increased armor protection, and a strengthened tail. The F6F-5 eventually attained a top speed of 410 mph and a service ceiling of 39,000 feet. Over 12,000 Hellcats were produced by Grumman during the war years. The improved performance of the F6F and F4U fighters was primarily the result of the increased power of the larger R-2800 engine.
Over 75 per cent of all the enemy planes shot down by Navy pilots in World War II were destroyed by Hellcats. The exceptional 19:1 kill ratio is a tribute to the F6F’s rugged construction, protective armor, and self-sealing fuel tanks. By 1953, the F6F Hellcats were retired from operational use, being replaced by the improved F8F Bearcat.
Competition was keen between Grumman and Chance Vought with the F6F and F4U. This rivalry undoubtedly resulted in better aircraft from both companies. Modifications and improvements were developed, tested, and installed in production aircraft in unbelievably short times.
Fighters in Other Roles
As Japanese airpower weakened, there were less demands for fighters in strictly a fighting role. However, since the possibility existed that heavy concentrations of enemy fighters would be encountered, large numbers of fighters were maintained on our carriers. The proportion of fighters assigned to carriers steadily increased from 25 per cent in 1942, to 50 per cent in 1944 and 70 per cent in 1945.
Navy fighters were soon adapted to the light attack role. The structural strength we had insisted upon for fighters was a decided advantage when these airplanes were used as light bombers starting in 1943. Fighters were not as efficient as dive bombers or torpedo planes for these purposes, but fighter versatility proved to be a marked advantage during the war.
Fighter Lessons from WW II
A few of the lessons concerning the design, production and employment of Navy fighters in World War II are listed below:
Armor, self sealing tanks, and, above all, firepower proved to be more important than the last increment in speed, ceiling, and maneuverability.
Pilot training, air-to-air tactics, and our ability to concentrate forces were decisive factors.
Small size is important for a fighter. Folding wings allowed more aircraft to be operated from each carrier. Aircraft built originally as fighters could be easily converted to the attack role. Our fighters performed nearly as well as our best dive bombers in this role.
In wartime, fighters grew in weight rapidly as equipment and armament were added. Engines were continuously uprated in horsepower to compensate for the weight increases.
All Navy fighters used in World War II were started before the war. We were unable to design, produce, and deploy a new fighter during the war years. Rapid modification of existing designs proved to be the best route. Attempts to accelerate new designs by telescoping and overlapping development and production simply wasted time and money.
Large numbers of development, test and evaluation aircraft were needed to test out new modifications before production installation. At times during 1944, over a hundred fighter airplanes were assigned to these projects.
A requirement evolved for a night and all-weather fighter.
A limit was reached on the size and horsepower of the reciprocating engine. With the R-4360 it appeared as though we had gone beyond the optimum size.
The ability of the U. S. to outproduce the enemy in fighters was a major factor in the outcome of the war.
F7F. Started in June 1941 at about the same time as the F6F, the F7F could be considered a follow-on development from the F5F. The F7F Tigercat was the first twin-engined airplane designed for carrier use and the first to use tricycle landing gear. Built originally as a single seat airplane with R-2600 engines, the F7F was finally developed with R-2800-22W engines. The airplane could carry a variety of weapons and ordnance including four 20mm wing mounted cannon, four .50 caliber machine guns in the nose, a torpedo, two 1000 pound bombs or external tanks. Maximum speed was 429 mph.
Since the Marines needed a twin-engined two-place night fighter, the Bureau of Aeronautics accelerated work on the F7F. By reducing the size of the main fuel tank, space was provided for a second cockpit for the radar operator. If a single seat day fighter was needed, the original range could be restored by installing an auxiliary fuel tank in the second seat. The Tigercat was produced principally in the night fighter version.
The F7F never saw action in the Pacific War, arriving on Okinawa the day before the surrender of the Japanese on 14 August 1945. The F7F-4N model was modified specifically for carrier operations. However, because of landing strength problems, emergency barrier provisions, and poor single engine approach characteristics, the airplane was never deployed from a carrier.
XF5U. Another twin engine fighter development of this era was the Chance Vought XF5U-1, a military version of the Vought-Sikorsky flying wing. The unusual design, started in the spring of 1942, had wings with the chord nearly equal to the span, giving the airplane the appearance of a “flying flapjack.” Design studies showed the possibility of a maximum speed in excess of 500 mph with a minimum speed well under that for contemporary fighters. The decision was made to develop and test a flying prototype before proceeding with production.
However, many problems were encountered with the airplane. A special sandwich material, balsa covered with an aluminum alloy, was used to overcome rigidity problems with the large, unsupported wing surface. Engine and propeller controls were still greater problems. The articulated propellers which “flapped” as well as rotated and the interconnecting drive system between engines could not be made to work satisfactorily and the project was finally cancelled in 1948. Progress in jet engines made the concept and the airplane obsolete.
F8F. The design of the F8F Bearcat (started in 1943) was the culmination of all we had learned in building high performance, propeller driven fighters. Smaller than the Wildcat with more power than the Hellcat, the F8F was an attempt to build a higher performance, more maneuverable fighter than any in the Japanese inventory. The F8F was conceived as the smallest fighter that could be built around the R-2800-34W engine and a 13-foot, four bladed propeller. It had specially constructed wing tips which would break off cleanly if overstressed. If only one wing tip separated, the other was blown off automatically by an explosive charge to maintain aircraft stability. This feature was later eliminated from the F8F.
Electronics, armament, and fuel capacity were kept to a minimum to save weight. The electronics “suit” of the first models consisted of a VHF communications set and an ARN-6 low frequency receiver. Armament was four .50 caliber machine guns with provisions for two 1000 pound bombs, a drop tank, and four 5-inch rockets. Later models of the Bearcat had an improved engine with a variable speed supercharger. Photographic and night fighter versions were produced.
The Bearcat was famous for its short take-off, high rate of climb, high performance, and small, uncomfortable cockpit. In 1945, it established a climb record to 10,000 feet in one minute and 34 seconds after a take-off run of 115 feet. Maximum speed at sea level was 425 mph.
The F8F was the last of our prop fighters although the F4U was retained in the inventory for almost three years after the F8F was retired. In all, over 1,200 Bearcats were produced.
The Jet Fighter Era
Wartime developments in gas turbines were of great interest to the Navy since the turbojet engine promised great increases in fighter speed, altitude, and rate of climb. Jet propelled flight became a reality in Germany in 1939, in Italy in 1940, and in England in 1941. In 1942, the United States flew its first jet airplane—the Army Air Force’s YP-59A. The appearance in 1941 of the German prototype Messerschmitt 262 forecast the day when all fighter aircraft would eventually be jet powered. The United States took the threat seriously and contracts were let with Allis Chalmers, Westinghouse, General Electric, and the Turbo Engineering Corporation to develop models based on British designs and to originate their own.
However, many problems were foreseen in operating jet aircraft from carriers, some equally as difficult as the original problems encountered in the 1920s of adapting military aircraft to carriers. Turbojet aircraft required large quantities of jet fuel and tricycle landing gear for an efficient design. Long take-off runs were impossible on carrier decks, making necessary the use of larger and more powerful catapults. Higher landing speeds meant stronger arresting gear and engines. Larger and heavier fighters were predicted for the future.
The advent of jet propulsion, advances in aeronautics and aircraft design, and the dream of supersonic flight started a proliferation of fighter developments in the middle 1940s that has not been repeated since and will probably never be seen again in this country. The era lasted until the late 1950s. Five major aircraft companies were involved, each developing a series of all-jet fighter models—Chance Vought, Douglas, Grumman, North American, and McDonnell. Over a dozen basic models of new fighters were produced, all with many modifications or “block improvements.” In addition, many experimental fighters were developed which never reached the production stage.
Noting that until the F-14 was begun in 1968, the Navy had not started development of a new operational fighter since the F-4 in 1954, one might ask the question as to why we developed (and were allowed to develop) so many new fighters in the late 1940s and 1950s. The answer has many facets.
The war was then fresh in people’s minds and there was a desire to keep a strong Navy technical and production base for the development of new fighters. During this period it was considered desirable to operate a number of carrier fighter types and no real limit was placed on the number of models that could be started. There was an underlying philosophy that it was less expensive to develop two or more new prototypes and select the best of these for quantity production through competition than to establish a monopoly with one contractor for a new fighter and modify and remodify the design until it was satisfactory. In addition, the technology of aerodynamics and turbojet engines was expanding rapidly. With each advance, new fighters were proposed which would go farther, faster, and higher.
The Ryan FR. One of our first approaches in the new jet fighter era was a composite airplane powered by a combination of a reciprocating engine and a jet propulsion unit. It was hoped that such an airplane would combine the best features of each powerplant—the reciprocating engine for take-off, cruise, and landing and the extra thrust of the jet for high speed, rate of climb and ceiling for combat.
The Navy needed a new high performance fighter that could be operated from escort carriers to replace the F4F. After a competition, the first contract was let for the XFR-1 with the Ryan Aeronautical Corporation in 1943. The design was a single seat, low wing, tricycle gear monoplane incorporating a proven reciprocating engine, the R-1820-72W, and the General Electric I-16 turbojet with 1,600 pounds thrust. Intakes for the tail jet were located in the wing roots. The FR-1 Fireball was one of the first Navy airplanes with a laminar flow wing, a flush riveted exterior, and all metal control surfaces. Four .50 caliber machine guns and racks for four 5" rockets and either two 1000-pound bombs or two 150 gallon drop tanks could be installed. Top speed with prop only was 295 mph and with the turbojet added was 404 mph.
Originally intended for combat, by January 1945, a total of 700 production FR-1s had been ordered. However, at the end of the war production was cancelled and only 69 were delivered. Flight tests revealed many weaknesses. Longitudinal stability was marginal in all configurations and worse in the power approach condition. Engine cooling was inadequate, problems arose because of improper flush riveting procedures, and tails were under strength. In spite of a vigorous program to correct deficiencies, the FR-1 was never considered acceptable for service use and all aircraft were retired from the active inventory in 1947.
A modification of the FR-1 became the Navy’s first turboprop airplane. The XF2R-1 was powered by a General Electric TG-100 turboprop engine and an auxiliary I-16 jet in the tail. Development work on the XF2R-1 and the TG-100 was stopped when it became apparent that successful jet powered fighters would be developed.
Design studies of a pure jet fighter were begun by the Navy in December 1942. At the same time, the Navy was engaged in a cooperative research program with the Army and the National Advisory Committee on Aeronautics in an attempt to solve the many aerodynamic and structural problems connected with flight at transonic and supersonic speeds. Many methods were used to gain information and data. Full scale airplanes were “droned” and dived at high speed under radio control. These dives were not only limited to the speeds that operational airplanes could stand but frequent failures of the radio-control system complicated the procedure. Models were also mounted on the upper surface of wings of full scale airplanes for test, but this procedure was again limited by the maximum speed of the parent airplane. High and low speed wind tunnel tests also were used extensively. Subsonic wind tunnel tests provided meaningful data only up to about nine-tenths the speed of sound while supersonic tunnels were useful at speeds well above the speed of sound. At that time, wind tunnel facilities and techniques which would provide valid data in the transonic speed range were not available.
It soon became apparent that the only way to solve many of the problems of flight at transonic and supersonic speeds was to actually build full scale airplanes of radical design and test them. The joint high speed research program yielded dramatic results. In 1947, the official world speed record was raised to 650 mph by the Navy Douglas D-558-1 and in 1948 to 670 mph by the Air Force F-86. By the end of 1948, the Air Force had announced that its high speed research airplane, the X-1, powered by a Reaction Motors engine developed by a Navy contractor, had reached a speed of Mach 1.06.
In the summer of 1944, the Bureau of Aeronautics decided to hold its first fighter competition since 1940. Although eight contractors expressed interest, four withdrew, leaving McDonnell, Grumman, Chance Vought, and North American in the field. The best proposal of each contractor was selected for development, with the exception of Grumman, where people and facilities were still fully occupied with fighter production for the war. The Bureau of Aeronautics selected a McDonnell design, the FD-1, for production and the XF2D-1 for further development of a more advanced fighter. Other designs which resulted from this competition were the North American XFJ-1 and the Chance Vought XF6U-1.
The McDonnell Jet Fighters
FH. In the later years of World War II, most of the Navy’s aircraft producers were completely occupied in the mass production of airplanes for the war effort. Jet engine developments in this country by Westinghouse and General Electric had reached the point where it appeared feasible to build and operate all-jet carrier airplanes. The contract for the Navy’s first turbojet fighter was given to the young McDonnell firm of St. Louis in January 1943. This airplane was to be used to determine the requirements for carrier-based jet fighters.
Although the design originally proposed for the XFD-1 (the designation was later changed to the XFH-1 to avoid confusion with Douglas models) had six small axial flow turbojets in the wings, the final design used two Westinghouse-designed J30-P-2A engines built by Pratt and Whitney. These engines had 1,600 pounds of thrust and were imbedded in the wing roots. The XFH-1 Phantom first flew in January 1945 and became the first Navy all-jet airplane to operate from a carrier. A total of 61 were produced.
In the design of the XFH-1, a strong effort was made to keep the airplane as simple as possible to avoid the difficulties of combining a radically new airplane with a new concept in propulsion. The mission specified for the single-place, low wing Phantom was combat air patrol over or near the carrier. Armament consisted of four .50 caliber guns in the nose. A flush mounted 295 gallon drop tank could be installed to extend the range.
The FH-1 was the first Navy airplane to reach a maximum level flight speed in excess of 500 mph. Service ceiling was above 41,000 feet. The airplane could be operated from a carrier satisfactorily and maintenance requirements were low. However, the Phantom was underpowered, as were most of our first jet aircraft, and had limited utility because of its restricted range and endurance. It was accepted for service use by the Navy as an interim jet fighter until such time as an improved fighter became available.
F2H. The F2H Banshee series were based largely on the original FH-1 design. Additional fuel was added to increase the range. Thinner wings and larger J34-WE-30 engines of 3,150 pounds thrust were installed to improve the performance. Design of the XF2H-1 was started in March 1945 with first flight in January 1947. In all, 894 F2H fighters were built including photographic and night fighter versions.
Many improvements were made in the performance and effectiveness of the Banshee as various models were introduced. The F2H-3, for example, was the first Navy fighter to use power boosted controls. Improved engines made it possible for the Banshee to set an altitude record of 52,000 feet in August 1949, an amazing feat for that time period. These progressive changes and additions to the original Banshee raised the gross weight from 14,000 pounds in the F2H-1 to more than 20,000 pounds in the F2H-3. Banshees were used as escort fighters, fighter bombers, and reconnaissance aircraft in the Korean War. However, because of the Mach limitations imposed by straight wings, little attempt was made to engage the MIG-15 fighters in air-to-air combat.
F3H. A completely new design started in 1949, the XF3H-1 was developed through a competition as a single engine, single place, guns-only interceptor. Later the design was adapted to the all-weather interceptor mission using the Sparrow III guided missile system. The first F3H-1 Demons used the Westinghouse J40-WE-8 engine rated at 11,300 pounds in afterburner. However, the J40 had many development and reliability problems and never did develop specification thrust. The Allison J71-A2 engine was substituted in later production airplanes. F3H models had a fully powered control system for elevator, rudder, and ailerons.
The Demon became our first line, all-weather, Fleet air defense interceptor. Many of the problems with the F3H stemmed from the engine. Not only was the airplane underpowered, the J71 had troubles with compressor stalls and exhaust nozzle controls. In heavy rainstorms, compressor and turbine blades “grew” and the engine case shrunk to the point where complete engine seizure could take place.
The Demon was our first operational guided missile fighter. In addition to the Sparrow III missile system, the airplane carried four 20 mm guns and racks for air-to-air and air-to-ground rockets, bombs, or drop tanks. Fleet deliveries of the F3H Demon started in August 1951, with a total production of 519.
F4H (F-4). With eleven years of experience in designing and building Navy carrier jet fighters, McDonnell Aircraft started work on a new design in 1954 which was to become the world famous F-4 Phantom II fighter. The airplane was originally planned as the F3H-G (later the AH-i), a single place, J65 powered, long range, high speed attack aircraft with four 20 mm guns and eleven external store stations for ground attack weapons. However, the Navy decided that it needed an improved all-weather, Fleet air defense interceptor more than a supersonic attack airplane. After many changes to the basic design and layout, the detailed specification was signed in July 1955 and the designation of the airplane changed to F4H-1.
As finally conceived, the F4H Phantom II was a single purpose, two-place, all-weather interceptor armed solely with the Sparrow III missile system. Guns and other armament were deliberately omitted from the design. The most advanced turbojet engine available at that time was called out for the airplane—the General Electric variable geometry J79 engine with a thrust-to-weight ratio of 4.5 and markedly improved fuel consumption characteristics over previous engines. This so-called “rubber engine” has variable compressor inlet guide vanes and variable stator blades in the first six stages of the compressor. Blade angles are scheduled as a function of engine speed and compressor inlet temperature. These features plus a variable area exit nozzle allow the engine to be operated efficiently over a wide range of engine outputs with excellent thrust response to throttle movement.
First flown in May 1958, the F-4 is a low wing design with wing leading edge and trailing edge flaps, ailerons, and spoilers for lateral control, and speed brakes mounted under the wings ahead of the trailing edge flaps. The elevators are all-movable surfaces with 23 degrees of negative dihedral for proper alignment with the airflow in the tail area and to alleviate pitch up problems at high angles of attack. The airplane has two independent flight control power systems and extensive redundancy in many of the other aircraft systems for increased reliability. The F-4A and F-4B models have the Aero-1A airborne missile control system, the APQ-72 radar, and an infrared search set. The F-4B and subsequent models were modified to carry Sidewinder air-to-air missiles and external racks for drop tanks, air-to-ground ordnance, or nuclear weapons. On attack missions, the F-4 can carry up to 16,000 pounds of external stores.
Preliminary tests of the F-4A and F-4B revealed deficiencies in the cockpit, the control system, the engine, the avionics installation, and the missile system. Like most complicated aircraft, initial production units showed poor maintainability and low reliability of engines, systems and components. However, most of these problems were corrected early in the program through an intensive effort by the Navy and the contractor.
The F-4 represents a vast improvement over previous all-weather Navy fighters in performance, missile control system effectiveness, multi-mission capability, and armament versatility. Airplane flying qualities and controllability are generally excellent throughout most of the flight envelope. The superior airplane performance (in excess of Mach 2) and the long range detection and lock-on ability of its missile control system make the Phantom II an ideal airplane for air defense of the Fleet against attacking aircraft. Although the addition of the Radar Intercept Officer increased the size and weight somewhat over what it might have been as a single place fighter, the division of tasks between the pilot and the RIO allows fuller use of the operational capabilities of the weapon system in the all-weather intercept. In visual air-to-air engagements, the additional man in the airplane has also proved valuable in spotting enemy aircraft and in keeping track of friendlies.
In a fly-off competition in early 1958 between the single engine, single place, high performance F8U-3 and the twin engine, two place F-4A for a new Fleet air defense fighter, the Navy selected the F-4A primarily because of improved target detection and enhanced weapon system effectiveness with a full-time radar operator aboard.
The F-4 Phantom II has been produced in many models (F-4A through F-4M) for the Navy, Marine Corps, and Air Force, and the British Royal Navy and Royal Air Force. Succeeding models have used uprated engines and many improvements have been made to the radar, fire control system, and avionics equipment in the airplane. The Navy F-4J model has the AWG-10 weapon control system with a pulse doppler radar which allows long range detection and tracking of targets against a sea or land background, a feat not possible with previous systems. The British F-4K and F-4M models use the Rolls-Royce Spey engines with over 20,000 pounds thrust each. A reconnaissance version of the F-4 has also been produced for the Marines and the Air Force.
By 1970, about 3600 Phantom II fighters of all models have been built. The total number produced by McDonnell might reach 5000 before the production is finally terminated as the Navy F-14 and the Air Force F-15 fighters are introduced in the mid-1970s. A production run of this magnitude over a period of almost 20 years is positive evidence of the excellence of the design. The success of the Phantom II can be attributed to advanced engines, high thrust-to-weight ratio, capacity for growth and improvement, and the fact that it was originally designed as a single purpose airplane. Our failure to develop a superior fighter as a replacement for the F-4 has also contributed to the success of the Phantom II.
Phantom IIs have established a total of 15 world records in speed, altitude, and rate of climb, many of which are still unbeaten. Speed records have been set for the Los Angeles to New York run and the 3 kilometer, 100 kilometer, and 500 kilometer courses. In addition, a world’s absolute speed record was set at 1606.3 mph for the 15/25 kilometer course. (This record was later broken by the YF-12 and the Russian MIG-23 Foxbat fighters.) Eight official world time-to-climb records and two altitude records were also established by the Phantom II.
Chance Vought Jet Fighters
F6U. Following the start of the McDonnell FH-1 in January 1943, the Navy began its second jet fighter development by a contract for the XF6U-1 in December 1944 with the Chance Vought Division of United Aircraft. A conventional straight wing, blunt nose fighter with tricycle landing gear and wing tip tanks, the F6U-1 Pirate used a single Westinghouse J34-WE-30A turbojet with afterburning, the first afterburner turbojet engine used in a Navy fighter. Maximum thrust with afterburner was 4100 pounds. Construction of the airframe was of Metalite—two thin sheets of aluminum alloy bonded to a balsa wood core.
Although the F6U-1 had generally acceptable flying characteristics, its performance with or without afterburner was extremely low and considerably inferior to that of current prop fighters in service. Furthermore, the afterburner in the first engines was so unreliable that it had to be replaced after about 8 minutes of operation. After evaluation by the Navy, the 33 F6U-1s which were built, were retired from service and never reached operational squadrons. The F6U-1 was so underpowered that it was recommended that the airplane “not be used for any purpose involving flight unless the pilot is experienced and the conditions favorable.”
F7U. The most radical aircraft design of the period was the Navy’s first swept wing aircraft, the XF7U-1 Cutlass, a single-seat, tailless airplane using two Westinghouse J34-WE-42 engines with 4850 pounds of thrust each in afterburner. Fully powered ailevators (combined elevators and ailerons) on the outer wing panels provided longitudinal control when actuated together and lateral control when actuated differentially. Directional control came from manually operated rudders located on the trailing edges of the 38 degree swept wings. At rest, the Cutlass had a nose-high attitude with a long strut for the nose wheel, a feature necessitated by the requirement for a high angle of attack for the wing during take-off and landing. Full span slats on the wing leading edges provided increased lift at low speeds.
After an industry-wide competition, design work started on the experimental XF7U-1 in June 1946 and the first prototype flew in September 1948. Like most of the Navy’s first jet fighters, the XF7U-1 was greatly underpowered (the engines failed to produce specification thrust), and the airplane met none of its performance guarantees. The powered control system was plagued with operating and reliability problems and the unique aerodynamic design had many stability and control deficiencies, particularly at high Mach numbers. The XF7U-1 remained an experimental prototype.
Although similar in planform to the XF7U-1,1 the F7U-3 was a completely redesigned, larger and heavier airplane. Design changes were included in an attempt to correct many of the deficiencies of the XF7U-1. Two Westinghouse J46-WE-8B afterburner engines were to power the airplane, but because of engine delays, the F7U-3 was first flown with J35 engines. Air-to-air armament consisted of four Mark 12 20 mm guns located above the engine air intakes and a fuselage rocket pack with 32 2.75 inch folding fin rockets. Two wing pylons were installed which could carry bombs, special weapons, or other ordnance. A total of 305 F7Us were produced as day fighters (F7U-3), photographic airplanes (F7U-3P) and Sparrow I missile fighters (F7U-3M). The F7U-3 was retired from the active inventory in 1957.
Although the F7U-3 was considered suitable as a bombing, rocket, or gun platform up to speeds of Mach .92, stability characteristics above this speed were unsatisfactory. The low radius of action of 138 miles, limited endurance, excessive maintenance required for the complicated airplane systems, and large size for carrier deck handling made the F7U-3 generally unsuitable as a carrier-based fighter compared with other Navy jet fighters of that period.
The F7U-3 was considered to be a peculiar airplane to fly, requiring special indoctrination of pilots before flight. After certain types of stalls, the airplane would progress into a “post-stall gyration” which was followed by maneuvers which were wildly different from the “normal” spins of most aircraft. Furthermore, the unusual tailless design (the F4D and F5D were similar) had characteristics that are generally incompatible with very low and very high speed flight—fundamental requirements of all Navy fighters. For example, at low speed the ailevators at the wing trailing edges deflect upwards to attain the high wing angle of attack needed for high lift at low speeds, an action exactly opposite from that of landing flaps used on most aircraft. However, deflecting the ailevators upward tends to reduce the lift on the wing at the very flight condition where highest lift is required. At high speeds, the center of pressure of the wing moves aft and the ailevators must again be raised to trim the airplane, which increases the drag of the airplane at the very condition where minimum drag is desired. Because of these and other unusual characteristics, the tailless design has been abandoned for Navy fighters in favor of more conventional planforms.
F8U (F-8). In 1952, an industry-wide competition was held for a new, high performance, carrier-based day fighter with the mission of maintaining air superiority during fair weather over the task force and over hostile target areas. Eight contractors submitted proposals. Chance Vought won the competition with their XF8U-1 design.
The F8U Crusader was an attempt to design the smallest, lightest, and simplest fighter around the most powerful and efficient engine available. The engine selected was the Pratt and Whitney J57-P-4 turbojet with 16,000 pounds thrust in afterburning. In the design of the supersonic F8U, the contractor took full advantage of the lessons learned and systems developed in his previous jet fighter designs—the F6U-1, F7U-1 and F7U-3. In order to improve pilot visibility and reduce the fuselage angle at low speeds, a unique hydraulically-operated, two position, variable incidence wing was used. The airplane also had an advanced, fully powered control system, many components of which had been developed and perfected on the F7U. Armament consisted of four 20 mm guns and a fuselage mounted rocket pack with 62 2.75 inch folding fin rockets. Later, the rocket pack was removed and fuselage mounts for Sidewinder or Zuni 5-inch rockets were added.
The first flight of the XF8U-1 occurred in March 1955, just 21 months after design work was started. Fleet deliveries began in March 1957, less than four years from go-ahead and precisely on the schedule laid out at the beginning of the program.
An excellent basic design with few major problems, the Crusader has been produced in many models from the F-8A (F8U-1) through the F-8E. Uprated engines, new radars, improved fire control systems, new equipments, wing racks for air-to-ground ordnance or external fuel, and many other improvements have been added in successive models. A total of 1261 Crusaders were built including photographic versions and 42 F-8Es purchased by the French for their carriers Clemenceau and Foch. A tribute to the success of the Crusader was the decision to modernize and “remanufacture” almost 500 F-8s as F-8Hs through F-8Ms to extend the life of these airplanes through the mid-1970s. These Crusaders will be operated principally from Essex Class attack carriers which are planned for phase out in the same time period.
The F-8 Crusader has the distinction of being the first airplane to cross the United States at an average speed greater than the speed of sound, winning the Thompson Trophy for this achievement. The Crusader also established a national speed record in 1956 with a speed of 1015 mph over a 15 kilometer course. Used extensively for escort missions and fighter sweeps over Vietnam, the Crusader with its Sidewinders and guns is credited with 56 per cent of the total kills by Navy fighters in the war.
The Navy provided funds to Chance Vought for the development of the F8U-3 as part of a competition with the McDonnell F4H-1 to select the Navy’s next generation all-weather Fleet Air Defense interceptor. The F8U-3 was a new design using a single J75-P-6 turbojet with 26,000 pounds of thrust in afterburner and incorporating many of the design features of the original Crusader including a single cockpit and the two position wing. Two large ventral fins were added for directional stability at high speeds. The ventrals were moved to the horizontal position for clearance with the ground during take-off and landing. Boundary layer control was added for flaps and ailerons to increase lift at low speeds.
The fire control and radar functions of the F8U-3 were automated extensively so that the high speed, all-weather intercept could be handled by the pilot alone. Both Sparrow III and Sidewinder missiles could be carried. Take-off weight was about 40,000 pounds with four Sidewinders. The F8U-3 had excellent flying qualities and was probably the highest performance fighter ever built in this country. A stabilized maximum speed was never reached. On high speed runs, the airplane was still accelerating quite rapidly at Mach 2.3 where runs had to be discontinued because of temperature limits of the canopy, airframe, and engine.
The fighter competition between the F8U-3 and the F4H-1 was finally decided by a “fly-off” evaluation of each airplane as an all-weather interceptor. In spite of the superior performance and excellent flying qualities of the F8U-3, the Navy selected the F4H primarily because of its increased reliability with two engines and the conviction that a pilot and Radar Intercept Officer would be more effective in the all-weather intercept problem than a single pilot, particularly in an electronic countermeasures environment.
North American Jet Fighters
The XFJ-1 Fury, first flown in September 1946, was the first of a series of four basic models of Navy jet fighters produced by North American Aviation. A total of 1,148 FJs were produced over a period of 17 years, the last FJ-4B being retired from operational use in September 1962.
A single engine, single seat, low wing monoplane with short stubby straight wings and tricycle landing gear, the FJ-1 was the first American jet fighter to use a single straight ram duct with a nose intake. This same basic arrangement was used successfully in many other fighters such as the F-86, F-84, and F-8 Crusader. The FJ-1 incorporated the 4000-pound thrust Allison J35-A-2 engine and was the fastest tactical fighter in the world in 1947. The airplane had a level flight speed of 480 knots and reached an unheard of Mach number of .87 in a dive. The FJ-1 was considerably superior to the FH-1 and F6U-1 in performance and had better take-off, climb, and high Mach performance than contemporary Air Force fighters such as the F-84 and F-80C. Although designed for six nose mounted .50 caliber machine guns, the 33 FJ-1s accepted by the Navy had no armament, and were used for jet indoctrination and carrier qualification only. The FJ-1 was the first Navy jet fighter to be operated from a carrier in squadron strength and the first to use wingtip tanks, but was discontinued in favor of other designs that looked more promising.
North American first proposed the famous F-86 fighter to the Air Force as a new straight wing design adapted from the FJ-1. However, as German aerodynamic and wind tunnel data on swept wings became available following World War II, North American proposed a swept wing version to the Air Force, which later became the F-86, and a similar design to the Navy. Since initial limited data showed that stalling speeds of swept wing fighters would be too high for the carrier limitations then existing, the Navy chose to go with the straight wing F9F and F2H. Later, in 1951, as more data became available which showed that stalling speeds of swept wing fighters were not too high for carrier operations, the Navy awarded a contract to North American for the development of the FJ-2.
The FJ-2 was basically an Air Force F-86E modified for carrier operations as a single seat day fighter. The FJ-2 had a General Electric J47-GE-27 engine of 6090 pounds thrust, four Mark 12 20 mm guns in the nose, and the Aero 10B armament control system. Other design features included folding wings, automatic wing leading edge slats, fuel dump provisions, irreversible (fully powered) controls with artificial feel for the horizontal tail and ailerons, and a conventional rudder. Maximum speed at sea level was 587 knots and the service ceiling was 39,100 feet. Although prototypes of the FJ-2 were built in Los Angeles, production of the FJ-2 and later models was turned over to the Columbus plant.
An improved version, the FJ-3, incorporated the Curtiss-Wright J65-W-2 Sapphire engine with 7200 pounds thrust. Although the FJ-2 and FJ-3 were used operationally by both the Navy and the Marines, the utility of these aircraft was limited by short radius and deck cycle time even with wing tanks installed. Another undesirable feature of both airplanes was the sensitivity of the longitudinal control system which could easily lead to rapidly divergent, pilot induced oscillations of the aircraft in the pitch plane.
Most of the deficiencies of the FJ-1, FJ-2, and FJ-3 were corrected in the FJ-4 model. Almost a completely new design, the FJ-4 had a larger and thinner wing, more thrust, a fully powered control system, and four wing racks for fuel tanks, rockets, or bombs. Additional internal fuel was carried in the wings to increase the radius of action and the carrier cycle time. Further control system improvements, more effective dive brakes, and two additional wing racks were added in the FJ-4B model. The FJ-4B was operated mostly in a light attack role.
The North American FJ series is an example of how performance and flying qualities can be improved by successive modifications to a good basic design. More powerful engines were installed in each "block improvement” which increased performance measurably. Significant improvements were also made to the cockpit, control system, stability, and payload capacity.
Douglas Jet Fighters
F3D (F-10). The F3D-1 Skyknight was designed from the start as an all weather fighter with the mission of destroying high performance bombers which might attack the Fleet or advanced bases. A two-place (side by side), twin engine, mid-wing monoplane with tricycle gear, the Skyknight was originally intended to use the Westinghouse J46 turbojet engines with 4200 pounds thrust. However, development problems delayed the J46 and Westinghouse J34 engines of 3250 pounds thrust were substituted in the aircraft. Design work was started in April 1946 with first flight in March 1948. A total of 268 F3Ds were built.
The Skyknight was our first fighter with a truly advanced fire control system and Airborne Intercept Radar (APQ-35). The system was designed for both search and automatic firing of its four 20 mm guns. Bombs, rockets and other armament could also be carried on wing racks. Because of the requirement for a large radar dish, large quantities of bulky electronic equipment, and a radar operator in addition to the pilot, the F3D was a comparatively large and heavy airplane (take-off gross weight 26,750 pounds). An escape chute was provided in lieu of ejection seats to save weight in the design.
The Skyknight was used in Korea by the Navy and Marines as a night fighter and has the distinction of being the first jet fighter to shoot down another jet aircraft at night. The F3D-2 used uprated J34-WE-3 engines of 4080 pounds thrust which gave the airplane a top speed of 480 knots and a combat radius of 543 nautical miles in the clean configuration. Although the F3D had problems with ineffective speed brakes, inadequate stall warning, low aileron control effectiveness, and poor high Mach characteristics, the otherwise excellent flying qualities of the airplane made it a stable gun platform at normal operating speeds. However, because of insufficient thrust, the acceleration, rate of climb, ceiling, and maximum speed of the F3D were considerably less than contemporary jet fighters.
The F3D (now designated the F-10) has been used for years with great success as a test bed for the development and testing of new radars, missile systems, and electronic equipment. An electronic countermeasures version has also been used extensively by the Marines in the Vietnam War.
F4D. The F4D-1 Skyray was conceived as a high speed, all-weather point interceptor to be deck launched from the carrier for defense of the Fleet. A radically new design started in December 1948, the Skyray was a single place, single engine, low aspect ratio wing, tailless fighter optimized for high climb performance and maneuverability. (The combat wing loading was only 31 pounds per square foot—about one-third that of current jet fighters.) Fleet deliveries began in 1956 with a total of 421 aircraft produced. The F4D was retired from operational units in 1964.
A new fire control system, the Westinghouse Aero 13F, was installed in the F4D. Armament consisted of either four 20 mm guns or four 2.75-inch folding fin rocket packs. Four Sidewinder missiles were installed in later models. Two 300 gallon external fuel tanks could also be carried to extend the range and endurance of the aircraft.
Not only did the Skyray have many stability and control problems stemming mostly from its new and unusual tailless design, three different engines were used in the airplane before the design was frozen. The F4D was originally designed for the ill-fated Westinghouse J40 turbojet. Since the development of the J40 was delayed, the J35 was substituted in the first prototypes. When the J40 ran into serious difficulties, the' decision was made to switch to the new Pratt and Whitney twin-spool J57-P-8 engine with 16,000 pounds thrust. Like most new and advanced jet engines, the J57 had development problems—compressor stalls both at high altitude and at low speed wave-off conditions, and afterburner blowout and relight problems at high altitude. In addition, the radically new aircraft design had many stability problems including large longitudinal trim changes at transonic speeds and strong adverse yaw at low speed in the landing configuration. In all, eight years elapsed from the start of the design to the delivery of the first F4D to the Fleet.
Although the F4D had limited usefulness as a Fleet interceptor because of its short combat radius, the airplane, with the J40 engine, set a world’s record for the 3 kilometer straight away course (753 mph) and the 100 kilometer closed circuit course (728 mph). Time to climb records were also established with the J57 engined F4D for all altitudes up to and including 15,000 meters.
In the brilliance of retrospect, however, the F4D should probably never have been committed to production. A better plan might have been to use the F4D as a development prototype and produce the improved F5D at a later time in quantity for Fleet use as an all-weather interceptor.
F5D. Similar in planform and design to the F4D, the F5D incorporated changes which corrected many of the major deficiencies which plagued the F4D Skyray. Additional fuel, a thinner wing, a larger vertical fin, and other design refinements gave the F5D a maximum speed of about Mach 1.5, a combat radius of 360 nautical miles, and a ceiling of over 53,000 feet. Started in November 1953 with first flight in April 1956, only four prototype F5Ds were built. Production was cancelled primarily because the higher performance F8U-3 and F4H-1 projects were progressing so satisfactorily.
Grumman Jet Fighters
Grumman’s entry into the Navy jet fighter field stemmed from a competition for a new jet night fighter held in 1945. Douglas and Grumman won the competition. Douglas proceeded with the design and production of the F3D. Grumman started work on the XF9F-1, the forerunner of the long line of Grumman Panther and Cougar fighters that began with the F9F-2 and extended through the F9F-8 and F9F-8T. The last F9F was finally retired from an operational squadron in 1960.
While all other Navy jet fighters used axial flow engines, the F9F series used turbojets with centrifugal flow compressors. These engines were based on the Rolls-Royce Nene design and were produced by Pratt and Whitney as the J42 and J48 series and by the Allison Division of General Motors as the J33 series. The principal disadvantage of the centrifugal flow jet engine is its large cross sectional area compared with that of an axial flow engine. For a fighter, a large diameter engine means a larger frontal area and higher drag. Performance suffers.
One of the turbojet engines available for the XF9F-1 design was the Westinghouse 24C engine with 3000 pounds thrust. In order to obtain the desired performance, four of these engines were considered necessary for the XF9F-1. Problems arose in designing a suitable wing installation for the four turbojets and as a result the Navy cancelled the requirement for the XF9F-1.
F9F-2/5. Grumman then proposed the straight wing F9F-2 Panther as a single seat, high performance day fighter with a single fuselage-mounted J42-P-8 Nene engine of 5000 pounds thrust. The XF9F-2 first flew in November 1947. Armament consisted of four 20 mm guns in the nose. All of the straight wing F9Fs had non-jettisonable wing tip tanks, ejection seats, and pressurized cockpits.
The F9F-3 model used the alternate Allison J33-A-8 engine of 4600 pounds thrust, but since the F9F-2 proved superior in performance, all F9F-3s were converted to F9F-2s. The improved Allison J33-A-6 engine was planned for the F9F-4 model, but these were later absorbed in the contract for F9F-5s using the more powerful Pratt and Whitney J48 engine with 7000 pounds thrust. A total of 1388 F9F-2/5 fighters were produced.
The performance of the straight wing F9F Panthers was limited by low rate of climb, low limiting Mach number, excessive maneuvering control forces, and instability as a gun platform at high speeds. The Panther series were also limited in range and endurance for low altitude missions and were unsuitable for all weather operations. However, at medium and low speeds, the aircraft had excellent maneuverability, high rate of roll, and good stability for gun or rocket firing. These characteristics and its excellent maintainability made the straight wing F9Fs a suitable airplane for the transition of squadrons from props to jets and for certain combat operations including close air support missions, escort, and armed reconnaissance.
Although the F9F-2s were the first Navy jet fighters to see combat in Korea, they were large, heavy, and underpowered compared with enemy fighters such as the MIG-15. Because of their lack of performance, Panthers were used to escort strike groups although little attempt was made to engage enemy fighters in air-to-air combat. The straight wing F9F-2/5 fighters were retired from active service as the swept wing Cougars were introduced.
F9F-6/8. Developed directly from the F9F-5, the F9F-6 Cougar had an uprated J48-P-8 engine of 7,250 pounds thrust, a new wing with 35 degrees of sweep, enlarged flaps and leading edge slats, wing fences, and plate-type spoilers in place of ailerons for lateral control. Tip tanks were not used in the Cougar series. The XF9F-6 first flew in September 1951 and first squadron deliveries started in November 1952.
The F9F-7 used the Allison J33-A-16A engine with only 6,350 pounds thrust. Because the F9F-7 was inferior in performance to the F9F-6, most of the F9F-7 airplanes were either converted to the J48 engine or sent to Reserve squadrons.
The final version of the Cougar series was the F9F-8 which had its first flight in December 1953. This model had a new and larger wing, a longer fuselage, and increased fuel capacity. The F9F-8 had fully powered longitudinal and lateral control systems and a manually controlled rudder. Improvements were incorporated which corrected many of the stability and control problems of the F9F-6 such as low dynamic lateral directional stability, low buffet boundary, and poor transonic speed characteristics. The final model of the Cougar series was the two-place F9F-8T which is still used as a flight and instrument trainer. A total of 1,985 Cougars were produced.
Like the straight wing F9Fs, the swept wing Cougars also lacked thrust and had inferior speed, rate of climb, and ceiling compared with other contemporary U. S. and enemy fighters. The maximum level flight speed of the Cougar was less than 600 knots.
XF10F-1. Navy jet fighters of the late 1940s and early 1950s were considerably larger and heavier than propeller driven fighters (such as the F8F Bearcat) principally because of the large quantities of jet fuel that had to be carried for adequate range and endurance. In addition, high thrust turbojet engines were not available and most jet aircraft of this period were underpowered by today’s standards. Swept wing designs, required for high speed performance, also had high take-off and landing speeds. The Navy’s approach to handling swept wing jet aircraft of larger size and weight was the steam catapult, higher capacity arresting gear, and the angled deck carrier. Other approaches were also tried.
Design work on the variable sweep wing XF10F-1 was started in 1947. The airplane was the Navy’s second attempt to develop a swept wing combat fighter, the first being the XF7U-1 started in 1946. Studies by the Navy and Grumman showed that a variable geometry airplane could provide good stability and control at low speeds for carrier operations with wings forward and improved high speed performance with the wings swept back.
Several configurations were considered including a variable incidence wing for improved pilot visibility on take-off and landing without high fuselage angles, and a variable sweep wing for good high and low speed performance. The final design selected was a wing that actually translated and rotated. From the straight position for low speed flight, the wing center section moved slightly forward and rotated downward as the wings were swept to an angle of 42 degrees for high speed flight. The XF10F-1 was powered by the J40-WE-8 engine of 11,600 pounds thrust and was to have a maximum speed of 634 knots and a combat radius of 658 nautical miles.
A major problem in the XF10F-1 design was not the variable sweep wing but the longitudinal control system. The airplane had a high “T” tail with the pilot manually controlling a small delta surface which produced the forces that moved the basic slab tail. The concept had been tested and it had been demonstrated that the required forces were produced. However, the dynamic problems could never be solved. In addition, the J40 engine ran into serious difficulties and never achieved its design thrust output. The Navy cancelled further work on the design in favor of other developments such as the F3H-1 that promised improved performance. Except for research airplanes such as the X-5, variable sweep was not tried again until the days of the F-111.
F11F. The F11F-1 Tiger, originally designated the F9F-9, was an attempt to get the maximum possible performance from an airplane based on the original F9F-2 design. Design work started in 1953. However, the F11F turned out to be a totally new design with a thinner wing and an “area rule” fuselage for improved high speed performance.2 The airplane was a single place, swept-wing day fighter and used the Curtiss-Wright J65-W-18 engine with afterburner. Maximum speed was Mach 1.1 and the combat ceiling with military thrust (without afterburner) was 41,400 feet.
The F11F-1 was seriously delayed by engine development problems and was short legged as a day fighter. Only 201 were produced and the airplane was retired from operational use in 1961. A version with much improved performance, the experimental XF11F-1F Super Tiger, used the advanced J79-GE-7 engine with 17,000 pounds thrust and had exceptional performance, maneuverability, and flying qualities both at subsonic and supersonic speeds. Maximum level flight speed was almost Mach 2. However, the Super Tiger was never produced in quantity, mainly because a major redesign would have been required to increase the fuel capacity for adequate range and endurance and also because of the fact that it was over-shadowed by the success of the F8U design.
The F11F-1 concluded a 27-year period of continuous production of Navy fighters by Grumman which started with the XFF-1 in 1931. During this period, Grumman produced 19,702 Navy fighters.
Jet Fighter Summary
In the twelve years following the start of development of the Navy’s first jet fighter (the McDonnell XFH-1 in January 1943), the Navy produced a proliferation of fighter designs and models. Some were successful, others unsuccessful. A few new and radically different designs were tried such as the variable geometry F10F and the swept wing, tailless F4D and F7U. None of these unusual designs worked out well. With the exception of the F-4 and possibly the F-8, all of the jet fighters we produced in quantity were underpowered, though probably not in relation to other contemporary fighters. Our program to develop superior carrier based jet fighters that would fly farther, faster, and higher than prop fighters was primarily paced by the turbojet engine developments, and improvements in jet engines came slowly.
During this period we successfully mated the high speed, swept wing jet fighter to the aircraft carrier by introducing the steam catapult, the angled deck, improved arresting gear, and the Fresnel Lens carrier optical landing system. Advances in the science of aerodynamics led to the design and construction of low drag airframes and thin wings suitable for transonic and supersonic flight. High lift devices such as flaps, slats, leading edge droops, and boundary layer control were introduced to allow these same high speed airframes to be flown safely at low speed for take-off and landing. Fully powered control systems were developed to provide the large forces needed to deflect control surfaces at high speeds. Synthetic “feel” systems were also perfected to provide the proper feedback to the pilot from the control system to allow safe and controllable flight throughout the flight envelope.
Of the many Navy jet fighter designs produced in the late 1940s and 1950s, the Navy chose to retain two as primary Fleet fighters—the F-8 day fighter armed with Sidewinders and guns for use on Essex class carriers, and the F-4 all-weather interceptor with its Sparrow and Sidewinder missiles for operation from Midway class and larger carriers. Phantoms can be operated from Essex class carriers but only at lighter gross weights and with favorable wind-over-the-deck conditions. In addition, considerable damage to the flight deck has resulted in attempting to operate the heavy F-4s from these smaller carriers. These and other considerations have led to the decision to operate F-4 fighters from larger and newer carriers only.
Both the F-4 and F-8 are outstanding designs which are ideally suited to Navy fighter missions. Both have subsequently been modified to deliver air-to-ground weapons to augment the attack capability of the carrier task force in situations where air superiority has been attained. From this point of view, the F-4 and F-8 are not true fighter-bombers as built and used by the Air Force and other nations of the world whose fighter-bombers were designed from the start as multi-mission aircraft.
The Fleet Air Defense Problem
One of the principal means available to the United States for projecting power throughout the world in support of national objectives is the Navy’s attack carrier striking force. In carrying out its many types of offensive missions, it is obvious that the carrier task force must be able to gain air superiority in the areas of conflict and defend itself from enemy attack. Without the power to accomplish the latter, the carrier task force cannot stay to accomplish its primary task—air strikes against the enemy.
It should be remembered that the Navy has developed many jet fighters whose primary mission was defense of the Fleet against enemy attack. The F3D, F4D, F2H, F3H, F4H and many others have been designed and built for this function.
One of the primary concerns is the possibility of a concentrated enemy air attack on the Fleet. Such an attack could consist of high speed enemy bombers escorted by long range fighters. The bombers would probably be armed with long range air-to-surface guided missiles and the attack might be made in conjunction with a submarine or ship launched attack with guided surface-to-surface missiles. We could also expect that the enemy would make full use of electronic countermeasures techniques in such a situation.
In addition to Fleet air defense, our fighter/interceptor aircraft must be able to perform the many other functions required of Navy fighters—escort of strike aircraft, fighter sweeps, combat air patrol and air-to-ground missions. Navy fighters must have sufficient range to accompany attack aircraft to and from the target and enough endurance to loiter for long periods on combat air patrol stations. When over the objective area, our fighters must be able to defeat enemy fighters both in a long-range air-to-air missile exchange and in a close-in “dogfight” situation using guns and short range missiles.
F6D. As long ago as the early 1950s the Navy made detailed studies to determine the most effective airborne system for defense of the carrier task force against the enemy threat. The Eagle-Missileer concept was developed from these early analyses. The studies showed that the best system could be obtained by trading off aircraft speed for radar and missile system performance—putting the performance into the airborne missile instead of the airplane. This concept was examined by many analysis groups. The consensus was that the Eagle-Missileer would provide the most effective and cost effective way to provide air defense of the Fleet for its intended operational era.
Thus the Missileer aircraft (later designated the F6D) became the launching vehicle for the Eagle missile. Missileer was conceived as a subsonic, long endurance aircraft capable of remaining on combat air patrol station for extended periods of time to destroy attacking aircraft with long range missiles. The F6D was designed for a large, high powered (5 kilowatt output and a five-foot radar dish), pulse doppler radar that allowed air targets to be tracked in background clutter. The missile control system had track-while-scan and multishot capabilities, meaning that it could search through a large volume of airspace, track several targets at the same time and guide several missiles toward different targets simultaneously. Missileer was to carry six long range Eagle missiles, each weighing about 1,400 pounds and having a range in excess of 70 miles.
Since the missile, fire control system, and radar were the high-risk, long lead time components for Eagle-Missileer, a contract was first awarded to the Bendix Corporation for the development of these items in December 1959. Douglas was selected as the winner to design and build the next generation Fleet air defense interceptor—the F6D. The F6D-1 was to be a conventional, subsonic, carrier based monoplane powered by two Pratt and Whitney TF30-P-2 turbofan engines (no afterburner) of 8,250 pounds thrust each. Although it had been recognized from the start that the Eagle-Missileer would be used only for the Fleet air defense mission, the entire program was cancelled in early 1961, ostensibly because the airplane was too slow and the system too single purpose. However, the technical feasibility of several critical subsystems of the missile control system was successfully demonstrated before the program was cancelled.
F-111B. As a result of a Department of Defense study to review the entire tactical air problem for the 1962-1971 period, the decision was made in mid-1961 to build a single variable geometry TFX airplane to fill the fighter requirements of the Air Force and the Navy. The Air Force needed a new tactical fighter-bomber to replace its F-105 Thunderchiefs—a plane that could act both as an air superiority fighter, and as a long range strike bomber. The Navy desired an airplane that could loiter at slow speeds for long periods on a combat air patrol station or could be deck launched as an interceptor to dash out at high speeds to engage enemy raids. In spite of the widely divergent requirements of the Air Force and Navy the decision was made to procure a common fighter for both services, compromising requirements as necessary until a single airplane could result. The Air Force and Navy models were to have a maximum of structural commonality to reduce costs.3
To some, this course appeared feasible, primarily because of research and wind tunnel tests performed by NASA on variable sweep wings. The advantages of such a design were that the wing could be put forward for low speed flight during take-off and landing and for efficient performance at loiter speeds, and be swept back for low drag in high speed flight. A new engine, the TF-30, our first afterburning turbofan, was to be used in all TFX airplanes.
With the cancellation of Eagle-Missileer and the start of the bi-service TFX program, the Navy again re-studied its requirements for advanced fighter/interceptor aircraft to replace the F-4 in the mid-1970s. As a result of these studies, the requirement evolved for the AWG-9/Phoenix system to be installed in a TFX type of airplane for Fleet air defense. The AWG-9/Phoenix system retained most of the functional features of the Eagle-Missileer (pulse doppler, track-while-scan, multi-shot system) while backing off on such characteristics as radar power, dish size and missile range to reduce size and weight and to make the system compatible with a supersonic aircraft of the TFX type. The AWG-9/Phoenix system was to be the sole air-to-air armament of the Navy TFX.
The original concept of the Navy version of the TFX (F-111B) was a fighter that would perform both the air superiority and Fleet air defense missions. However, as the program proceeded, the F-111B developed many problems, primarily stemming from weight growth to over 80,000 pounds, and it soon became apparent that the airplane could never be the advanced fighter that the Navy needed. Not only would it not fill our requirements for a new fighter, but operation from carriers would be marginal at best. When it became clear that performance difficulties could not be overcome, Congress stopped funding the F-111B and the program was terminated. At this point, the Navy had no new fighter under development to replace its obsolescent F-4 and F-8 aircraft.
Much has been written and spoken about the difficulties encountered in the bi-service TFX program and no attempt will be made here to discuss the details. However, a recount of a few of the primary lessons learned (and re-learned) may be in order in the hope that some of the major mistakes may not be repeated in future programs.
Both the Air Force and the Navy participated in the conception, design and development stages of the F-111 program—each service with its own requirements. The resulting design was compromised by two entirely different missions, each a challenging one in its own right. This is not the type of problem that can be solved by excellent management.
Both the F-4 and A-7 were uncompromised during development by the requirements of another service and were designed to a single important mission. Experience has shown that this has always been the surest path to excellence in that mission. When the Air Force showed interest in these airplanes, it was allowed considerable latitude in tailoring the basic designs to fit its own requirements. Both services were able to modify the designs in subsequent models to improve performance and add additional capabilities.
When a set of requirements for an airplane cannot be met within the state-of-the-art, no amount of management attention can solve the technical problems that follow. The solution to these problems, if there is a solution, comes from a few critical technical people who are many echelons down in the organization.
In the F-111 program, the greatest optimism for the success of the program was not in the Air Force or the Navy but came mostly from organizations outside the decision-making chain of command. High level management personnel received an overly optimistic technical projection.
Once more we re-learned the fundamental theorem that to build an effective carrier aircraft, we must be annoyingly narrow minded and tenaciously uncompromising about the carrier environment. This is a prime go/no-go Navy parameter regardless of anticipated mission performance.
The Threat
In recent years the Russians have been quite busy developing new and advanced aircraft—particularly fighters and interceptors. In the July 1967 Domodedovo Air Show, the Soviets flew six new fighters plus major “block improvements” of three previous models. Two of these fighters, the Foxbat and Flagon A, are estimated to have performance comparable to the F-4 at most altitudes, but higher top speeds and ceilings. In the last 15 years, the Soviets have introduced at least 20 new fighter prototypes, not all of which went into production, however. They have introduced either a new or an improved fighter into their operational inventory at the rate of almost one per year, showing a pattern of regularity and continuity in their fighter development which is unequalled anywhere in the world, particularly in the United States. (In contrast, the Navy F-4 is the only new U. S. fighter introduced into service since 1961.) The Soviets have undoubtedly recognized that air superiority is essential for any type of military operation whether a local conflict or all-out war.
In the 1950s, the Russians concentrated on building higher and higher performance, short-range day fighters armed with guns only. However, in the 1960s they have followed our lead and turned to longer range fighters equipped with all-weather guided missile systems and complex avionics equipment. Most of their latest fighters appear to have improved armament and fire control systems. Fiddler, Foxbat, and Flagon A have large radomes which undoubtedly house advanced radars for use in firing all-aspect, all-weather, long range air-to-air guided missiles.
Soviet fighter developments are not our only problems. The Soviets have developed many other weapon systems obviously designed to attack the Fleet. Their Badger and Blinder bombers can launch various types of guided air-to-surface missiles at ranges in excess of 100 miles. In addition many types of advanced surface-to-surface guided missiles have been developed and deployed by the Soviets. These weapons can be quite accurate and deadly, attested to in the Israeli Eilat incident, and can be launched from submarines, surface ships, and shore installations. The threat of Soviet advanced fighters and improved weapon systems to attack the Fleet is serious now, and will become even more severe in the future.
F-14. In the fall of 1967, Grumman submitted an unsolicited proposal to the Navy concerning a possible replacement for the ailing F-111B. The proposal suggested that a new, advanced, part titanium airframe could be built at low risk using the existing TF30-P-12 engines, the AWG-9/Phoenix system and the other avionics developed for the F-111B. Furthermore, it was proposed that a follow-on improved fighter could use the same airframe but an “advanced technology” engine and improved avionics when these were developed and became available, thus providing a follow-on high performance air superiority fighter with minimal redesign and cost.
The Navy studied this proposal in great detail and analyzed the effectiveness of the proposed design in comparison with possible alternate aircraft for all Navy fighter/interceptor missions. The results of the studies looked so favorable for the proposed new fighter that an industry-wide competition was held. Grumman won the competition and the development contract for the F-14 fighter was let in February 1969.
The F-14 is a phased development program carefully designed to produce the best fighters in the shortest time with minimum risk. Experience has shown that the highest risk and longest lead time items for a new advanced fighter are the engines and the avionics suit including, of course, the armament systems and countermeasures equipment. The first model of the F-14 program, the F-14A, will use the existing TF30 engine now operational in the F-111 and A-7 airplanes. The TF30 is our first afterburning turbofan and has many advanced features including low fuel consumption at cruise and loiter speeds. The F-14A will also have the AWG-9/Phoenix system which is in the advanced stages of development and test—a program which has been highly successful to date. This system is believed to be the most effective and advanced air-to-air missile system m the world today. Detailed studies have concluded that the AWG-9/Phoenix is more than twice as effective as single shot systems (such as Sparrow) against air targets.
The F-14A is a two-man tandem design with ejection seats and a variable sweep wing. Advanced construction techniques and the use of titanium will save airframe weight. Structural strength will be provided for speeds in excess of Mach 2. In addition to Phoenix, the F-14 will also be able to carry Sparrow, Sidewinder, and the M61 20 mm gun. This weapons suit will allow a great deal of flexibility in tailoring the weapons to the tactical situation. The F-14A will have enough internal fuel to escort A-6 and A-7 attack aircraft on most long range strike missions without tanking and will be capable of air combat over the target.
The F-14A is not in any sense a “warmed-over” F-111B. It will be a new airplane—smaller, lighter, higher performing, much more effective than the F-111B; and with better fighter performance than the F-4. Because of the fact that the engines and avionics are completely developed, the Navy has a great deal of confidence in the success of the program. The F-14A will become operational in 1973.
The second step in the F-14 development program will be a block improvement, the F-14B. This model will use the same airframe and avionics as the F-14A, but will incorporate the “advanced technology” engine currently funded and under joint development by the Air Force and the Navy. The new engine will have a 75 per cent improvement in thrust-to-weight and reduced specific fuel consumption over current engines because of its advanced design features and high turbine inlet temperatures. The advanced engine will be installed in production F-14 aircraft as soon as it has passed qualification tests. Contractors bidding on the F-14A were required to design their airplanes for installation of the new engine with a minimum of airframe modification.
The “advanced technology” engine will give the F-14B extremely high performance as an air superiority fighter with a minimum of cost, redesign, and risk. The F-14B will have high maneuverability, high rate of climb, high turn rate, and rapid acceleration because of its high thrust-to-weight ratio—a fighter pilot’s airplane.
The F-14C is the third step in the F-14 fighter program. This model will have the same airframe and engines as the F-14B but will incorporate an advanced electronics system which is now in development. This electronics suit will take advantage of the latest techniques in micro-miniaturization and solid state electronics and should be smaller, lighter, more reliable, and more versatile than previous systems.
In summary, the Navy’s F-14 program has been carefully designed to provide a fighter with outstanding performance and flexibility, both in missions and weapons. The F-14 will be an optimized combination of speed, acceleration, maneuverability, and radius of action, including a fire control system with multiple weapon options. It has been designed from inception to grow in performance as technology permits and is ideally suited for the Navy fighter missions of air-to-air combat, sweep, escort, combat air patrol, and all-weather intercept for many years into the future.
Fighter Weapons
In World War II, the primary armament of our fighters was the .50 caliber machine gun. With six of these guns, our F6F and F4U fighters had significantly superior firepower to Japanese fighters. Toward the end of World War II, we started arming our fighters with 20 mm guns of increased range and lethality. Air-to-air rockets, such as the 2.75-inch folding fin rocket, were also added to increase the firepower of the fighter. Guns and rockets were our principal air-to-air weapons in Korea. Since that time, the Navy has concentrated on the development of guided missiles as a primary armament of Navy fighters because of their larger warheads and increased effectiveness at long range, compared to unguided rockets and guns.
The infrared-seeking Sidewinder missile was developed in the mid-1950s. This weapon has proved so reliable and so lethal that advanced versions are still in use today and will probably be used for many years to come. In the same period, work was underway on the long range, all-weather Sparrow missile designed to home on reflected radar energy from the target aircraft. Later, the pulse doppler Sparrow was developed for the F-4J and the multi-shot Phoenix system for the F-14 to further increase the range, effectiveness, and firepower of the weapon systems of these fighters.
Experience shows that the optimum air-to-air weapon for a fighter depends on the particular tactical situation at hand. Since Navy fighters must be able to defeat enemy aircraft in a variety of tactical environments in conflicts ranging from all-out war to local brush fires, a spectrum of air-to-air weapons and the flexibility to change loadings appears to be the only answer. The weapon suit of the new F-14 fighter has been designed to allow this flexibility.
Several foreign countries, such as England, France, Israel, and Russia, have armed many of their fighters with larger caliber machine guns such as the 30 mm French Defa gun and the British Aden. The effectiveness of this weapon in certain tactical situations was clearly demonstrated during the brief Arab-Israeli war of 1967. With the advantage of complete surprise and flawless planning, Israeli fighter-bombers destroyed most of the Arab Air Force and a great deal of their rolling stock by strafing with 30 mm guns—ideal fighter weapons for this particular situation. However, one might reflect a bit further on this incident. If the Arabs had not been taken by surprise and if their fighters were airborne and armed with effective long-range air-to-air guided missiles, the entire outcome of that war might have changed drastically.
Development Programs
With the exception of the Navy F-14 and the Air Force F-15 now in the preliminary stages of development, the United States has not introduced a new fighter since the F-4 became operational in 1961. The fine Navy aircraft contractor design teams of the 1940s and 1950s have largely been dispersed and much of the best aeronautical talent has left the aircraft industry for other fields such as space, electronics, and computers. Superior aircraft designs are the product of a very few competent and experienced design engineers who gain their competence only by the act of designing and building new airplanes. In recent years there have been so few new aircraft programs of any type in this country that the U. S. aircraft industry as a whole is rapidly losing its capability to design and build new, superior aircraft, particularly fighters. We should have a planned national program to develop new aircraft of all types at regular intervals or stand the chance of losing world leadership in this field. (The Soviets have such a program.)
Competition
One possible way to improve our aircraft industrial competence is through the construction of competitive prototypes for a new design and a “fly-off” competition to select the winner. Besides ensuring the continuation of design expertise, bona fide competition somehow creates incentives that cannot be duplicated by sophisticated contractual documents with strict guarantees or by elaborate management systems. With our present system, too much money is spent on paper studies that are largely worthless.
Engines
All of our experience in developing new fighters has emphasized the basic fact that the engine is the critical component, and that without an improvement in the engine (higher thrust-to-weight ratio, smaller size, and improved specific fuel consumption) it is generally impossible to build a better fighter for a given mission. We should have a continuing, well funded program for the development of improved engines, components, accessories, and materials for engines. Similarly, increased effort should be made in applied research in basic aerodynamics and in improving various components of aircraft—control systems, auxiliaries, high lift devices, new construction materials and fabrication techniques for fuselages, wings, and tails.
Guns
Our aircraft gun program has been neglected and under-funded for years. We should either develop more effective and reliable aircraft machine guns or procure some of the excellent designs available in European countries. We also need a short-range “dogfight” guided missile with better maneuvering capabilities than our present missiles.
Planned Modification Program
Our experience tells us that an excellent fighter is generally obtained by improving a good basic design. It has seldom been possible to obtain fully acceptable performance and stability characteristics in the first prototype of a new fighter. At times, several modifications may be required to eliminate the deficiencies. The improvement process could be expedited by setting aside sufficient funds for major and minor improvement modifications as soon as a new airplane can be made available to the contractor. Such a program would cost millions, but in the long run it would save far more than it costs.
Design Details
Many of the problems encountered with service aircraft are the result of poor detail design of mechanical and structural parts. A contributing factor to this problem is the fact that experienced mechanical engineers of aircraft companies are promoted to higher management positions sooner or later, leaving the design of detail parts to the youngest and least experienced engineers. Perhaps the Navy should set up a small group of mature mechanical engineers to keep an eye on mechanical details during the construction and assembly of a new airplane. A collection of photographs and descriptions of design details that have given trouble, together with modifications that are satisfactory, also might help to avoid repeating the same mistakes in design.
Evaluation Team
Above all, the Navy should keep intact and even strengthen its unique team of aircraft design evaluation engineers in the Naval Air Systems Command. The competency of this team is a primary reason that the Navy has been able to produce superior aircraft in the past. To lose this competency would mean great problems in the future.
Testing Facilities
With the increasing complexity of modern fighters, particularly in avionics and weapon systems, it is also essential that the Navy retain and strengthen its field activities engaged in the test, evaluation, and development of aircraft and their systems. Without these activities, there is little way to detect deficiencies early and ensure that corrective measures are taken by the contractor.
And last, but by no means least, our new generation of expensive and complicated fighters will require much more training of pilots, Radar Intercept Officers, line and maintenance personnel than has ever been done in the past. Our plans should be made accordingly.
Résumé
In World War II, in Korea, and in Vietnam, the enemy has always had smaller, higher performance and more maneuverable fighters than ours. Yet in the Pacific phase of World War II, Navy fighters gained a 14:1 kill ratio over Japanese fighters. In Korea, the Air Force F-86 fighters had a published kill superiority of 10:1 over the higher performance, more maneuverable MIG-15. In Vietnam our kill ratio advantage has been about three to one against the improved, highly maneuverable MIG-17 and MIG-21. Superior tactics, protective armor, self-sealing tanks, more effective armament, and better pilot training have been the primary reasons for our success.
We have devised fighter tactics which maximize the superior features of our aircraft and avoided, where possible, those situations which are tactically disadvantageous. We have added armor plate and other protection to our fighters even though these measures increased airplane size and weight. We have improved armament systems by adding radars, fire control equipment, guided missiles, and countermeasures devices, again at the cost of an increase in fighter size and weight. We have added internal fuel for sufficient range to carry out the missions required of Navy fighters. At the same time we have maximized the performance and maneuverability of our fighters. The resulting designs are always a delicate compromise among many parameters but they always have the same goal—the finest Navy fighter weapon systems that technology will allow.
[signed] C. O. Holmquist
The author is deeply indebted to VADM W. A. Schoech, USN (Ret.), RADM A. B. Metsger, USN (Ret.), Captain Walter S. Diehl, USN (Ret.), Mr. F. M. Gloeckler, Mr. G. A. Spangenberg, Mr. Lee M. Pearson and Mr. Fred Locke, Jr., for their kind advice and counsel in the preparation of this article.
1. XF7U-2 was proposed but it was never designed or built.
2. The “area rule” fuselage has been used in most subsequent high speed fighter designs.
3. The Navy and Air Force have different mission requirements for fighters and must necessarily operate in different environments. The Navy operates fighters from carriers against land targets and must protect the carrier from attack. Air Force fighters operate from land bases in strikes against close and distant targets. The varying missions and environments dictate different design requirements for fighters for the two services.