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This is the second in a series of reports °n the aircraft expected to compete for the U.S. Air Force-U.S. Navy Joint Primary Training Aircraft System (JPATS).
Northrop and Embraer believe a reengined Tucano that can operate at altitude without compromising the basic aircraft’s fuel efficiency or mechanical simplicity is just what the U.S. Air Force and Navy are looking for in a primary trainer.
The two companies signed an agreement in May 1992 to offer the aircraft as
a candidate for the Joint Primary Aircraft Training System (JPATS). [See “The JPATS Contenders,” Proceedings September 1992, pages 90-91.]
Given that all of the contenders probably will meet the basic service requirements, “We think it is going to be a cost competition . . . and this turboprop is the answer,” John Boivin, Northrop’s deputy program manager for training, said. The team has selected Quintron Corporation, of Chantilly, Virginia, which is producing simulators for the Air Force’s T1A Jay- hawk multiengine trainer, to produce the JPATS simulators. Boivin expects to exploit existing modular, transportable personal-computer technology for the training system—“We’ll subcontract to make maximum use of emerging technology,” he said.
The Super Tucano EMB-312H (Tucano H) will have a Pratt & Whitney Canada PT6A-68/1 engine with 1,600 shaft horsepower (shp)—more than doubling the power of the 750-shp PT6A-25C on the basic EMB-312A (Tucano A) that is used as a trainer by several air forces. Great Britain uses yet another version, designated the Tucano T. Mk 1, with a 1,100- shp Garrett TPE331-12B and a four-bladed propeller.
Two Super Tucano prototypes are under
PT6A-68/1
Weight: Takeoff weight................ 6,952 poor'
Performance: Maximum level speed...................... O'
337 miles per hour
Rate of climb....................................................... Over 4,0*
feet/minute
Range.................................................................... 1,000
Endurance............................................................ 4.5 ho0r
Powerplant: 1600 SHP Pratt and Whitney
The proof-of-concept aircraft’s 1,600- ship engine gives it a red-line speed of 290 knots; the actual Tucano H should do 330. The raised backseat provides excellent visibility for the instructor. This low pass should bring back memories for World War II fighter pilots.
construction at Embraer’s Sao Jose dos Campos facility in Brazil; the first flight is scheduled for February. Should the Northrop-Embraer team win the JPATS competition, Embraer would build the airframe and do subassembly work in Brazil, while Northrop would perform the final assembly in the United States
Embraer has built a single proof-of-con- cept aircraft with the 1,600-shp engine to evaluate the airframe’s ability to handle the extra power. I flew this version from the civil airport at Manassas, Virginia, with Northrop test pilot Jim Sandberg while the aircraft was on a tour of U.S. bases with a standard Tucano A. The most noticeable external differences between the two aircraft are the five-bladed propeller and the stretched fuselage on the proof-of-concept aircraft. It has a short plug forward of the cockpit and a longer one aft that add a total of 4.5 feet to the aircraft’s length and maintain the proper center-of-gravity. The new aircraft also has ventral fins.
I flew from the rear cockpit to get an instructor’s perspective. The cockpit layout is standard, and the aircraft is equipped with a circular angle-of-attack gauge and an indexer with fast, on-speed, and slow chevrons—tentative JPATS requirements specify these instruments. Strapping in is somewhat tedious—two leg restraints on each leg below the knee and various harness, lap-belt, g-suit, and oxygen-radio connections. Sandberg said that the team plans to simplify things in the two prototypes, but commented that it was the best inverted-flight restraint system he had used. Rudder pedals adjust with a hand- crank on the lower instrument panel and the seat height is adjusted electrically.
The aircraft has a Martin-Baker Mk. 10 zero-zero ejection seat with command selection, but the team has yet to select a seat for the actual Tucano H. We launched with a full internal fuel load of 1,140 pounds. The aircraft has an automatic fuelbalancing sensor designed to keep wing tanks within 25 pounds of the same weight.
The availability of the Tucano A made it possible to get in a little formation flying on the way out to the working area. We briefed for a section takeoff followed by some formation work with Northrop Chief Test Pilot Paul Metz and reporter David Harvey, on assignment for Avionics Magazine, in the lead EMB-312A.
The brief then called for us to split up for individual high work before returning : to the field for touch-and-gos.
Starting the aircraft is straightforward: turn the battery on, hit the start switch, and move the throttle from cut-off to idle as the engine accelerates through 13%. We ! used an external power source rather than the battery, as the aircraft was on a heavy demonstration schedule. Sandberg handled the radios while I went through the sim- pie post-start checks, ending up with half- I flaps and takeoff trim set.
Taxiing the aircraft was easy, even in the somewhat restricted parking space near the hangar; I moved the throttle to the taxi position, added a little power, checked the brakes, and we were on our way. The stepped-up rear cockpit provides good visibility over the front-seater and the nose of the aircraft. The aircraft’s swiveling nose wheel is linked mechanically to the
Ventral fins and a lengthened fuselage are hallmarks of the reengined Tucano.
rudder pedals, and the system provided good control—
®ore than adequate to maneuver in tight spaces on a crowded training command ramp. Eliminating a separate nose-wheel steering hydraulic system is a real plus, m my opinion, not only for maintenance but for safety—
The chance of a hard-over command is very, very low,”
,s the way Sandberg put it.
The flight controls are also mechanical, rather than hydraulic. Trim is electric, as on most jets, and a Chinese-hat switch on the stick controls aileron and elevator trim. The rudder- trim switch, a horizontally mounted toggle, is conveniently located on the front side of the throttle. It operates the way you would expect it to—if the ball is °ut to the left, toggling left will put it back *n the center. “The aircraft is built around Pushrods, bellcranks, and cables,” Sandberg said. The flaps operate electrically; only the landing gear and speed brakes are powered by the aircraft’s hydraulic system. The wheel brakes operate on their °Wn independent hydraulic system.
The outside air temperature was 81 ° but the cockpit was cool with the canopy closed and it was comfortable with my °xygen mask on. The aircraft was e<3uipped with an on-board oxygen generating system (OBOGS), also a JPATS requirement. Neither the Tucano A nor the Proof-of-concept aircraft is pressurized, hut the prototypes will get pressurization to meet the JPATS requirements.
The winds were light and, once on the runway and cleared for takeoff, I lined up °n Harvey’s starboard side. We ran up the engines, looked each other over, Harvey dropped his hand, and we rolled. He cracked the nose at 70 knots and we were nirborne at 80 knots. Although I had prac- t'ced reaching for the gear and flap handles without looking at them, in the event Jbatted only 50%; I got the gear handle, hut Sandberg had to get the flaps for me.
1 he flap handle is in an awkward location relative to the throttle, as other pilots have commented, and the team plans to repo- S|tion it in the prototypes.
I had stayed on bearing throughout the and managed to do so once airborne—but I was over-controlling and our hght path was a cross between a pilot-induced oscillation and a sine curve until I eased out and settled down. I figured they ^ould be waiting for me on vulture’s row.
The aircraft has a selectable automatic rudder-trimmer that integrates torque and airspeed to set a rudder position. Although the tricycle landing gear has eliminated much of the ground-looping tendencies associated with big-engined tail-draggers, under the JPATS concept this aircraft could be the first aircraft most students have ever flown. Accordingly, the automatic rudder-trimmer may be an important item in early stages of training.
The aircraft actually does not have a lot more power than the Navy T-28B, which had a 1,425-hp Wright R1820-86. But, although there were periods when students started from scratch in the T-28B, most got about 30 hours in the 225-hp T-34B before stepping into the larger aircraft. Sandberg pointed out that reduced-power takeoffs are an option until the student has become accustomed to the aircraft.
This illustrates one of the concerns facing the turboprop contenders: they need a big engine to get the high-altitude performance specified in the tentative requirement, but they also need an aircraft that the average beginning flight student can handle. Jet contenders have the performance, but they also tend to be more complicated, and thus more expensive to operate than the turboprops.
We climbed out heading for R-6608A, the restricted air space over the Marine base at Quantico, Virginia. Harvey began a series of turns and I flew a rather loose parade—I was conscious of the aircraft’s long nose and that big prop out at the end of it. I did some cross-unders, and once I had the aircraft trimmed properly, it handled well and had a good, solid feel.
At a climb speed of 150 knots we had a 4,300-feet per minute (fpm) rate of climb passing through 10,000 feet, and were still maintaining 3,200 fpm passing
through 15,000 feet.
We levelled off at 17,000 feet and Harvey began some steep turns at about 60° angle of bank. I slid out to the cruise position, and found the aircraft responsive as I slid inside the turns when he reversed. Many of us get a chance to continue flying after we retire, but rarely do we get a chance to fly formation—it was over too soon.
We split up to do a stall series and some acrobatics, and Harvey and Metz slid back to keep us in sight. We dropped down to about 12,000 feet to give us plenty of airspace. I rolled the aircraft, did a couple of easy wingovers, and then set up for the stalls. Power back, nose up, and the stall came at about 78 knots; the aircraft entered increasing buffet, but there was no tendency for a wing to drop. With gear and flaps down, the stall came at about 72 knots. The stall is characterized by buffet, but there is no definite break.
In both cases, 1 eased the nose position, added power, picked up the optimum angle-of-attack—and the aircraft climbed out of the stall. The big engine was a real help. With gear and flaps down, I eased the power back, rolled into a 20° bank, and pulled the aircraft into an approach- turn stall. The ailerons were fully effective as I leveled the wings, eased the nose position, and added power—once again, the aircraft lost very little altitude and began climbing out of the stall.
I set up for a loop at 12,000 feet and 200 knots and picked up 4gs. We went over the top at about 14,500 feet and 100 knots; the airplane does not use up a lot of air space doing maneuvers. Sandberg told me that on one demonstration flight he was given a block of air space from 10,000 to 15,000 feet between the five and ten nautical-mile fix along a VORTAC radial and had no problem performing loops and spins within the block. The anti-g system worked fine, and after a half-Cuban eight, I kept the aircraft heading downhill and picked up 280 knots. This aircraft is red-lined at 290, but the goal for the production models is 330 knots.
We zoom-climbed up to 12,000 feet and set up for some spins. The proof-of-concept aircraft is restricted from negative-g flight because of engine gear box limitations, so we were limited to upright spins. Entry was standard: power back, nose up to 20° above the horizon, then full back- stick and rudder in the direction of spin at
Northrop-Slingsby T-3A On Schedule
All contract-award protests have been denied, and the Northrop Worldwide Air Services/Slingsby Aviation Limited of Great Britain team is set to deliver the first T-3A enhanced flight screener to the U.S, Air Force this November. The aircraft will replace the service’s T-41 Cessna, in use for many years to screen prospective pilots. “We plan to start putting students through a 21.5-hour syllabus beginning in June 1994,” Brigadier General J. O. McFalls, the Air Training Command's Deputy Chief of Staff for Operations, said.
The Air Force is on contract for the first 38 of a total projected buy of 113 aircraft. Much of the aircraft will be of U.S. origin, according to Lieutenant Colonel Michael Uecker, T-3A program manager at the Aeronautical Systems Center. It will have a 260-horsepower Lycoming engine, Collins avionics, and will be assembled by Northrop personnel at
Hondo, Texas. Air Force Academy cadets will undergo training at Colorado Springs, while those officers commissioned through the Reserve Officer Training Corps
(ROTC) or Officer Training School (OTS) will fly the aircraft at Hondo. Successful candidates will solo and fly acrobatics before going on to tanker/transport or bomber/fighter training. ROTC and OTS candidate attrition during T-41 screening to date has been 16.2%, while Academy attrition has averaged about 6%. The Academy cadets fly the same syllabus, but spread over a longer period, McFalls said.
Given the pressure for joint training, and the potential savings generated by washing out marginal students early, the T-3A enhanced flight screener program has obvious implications for the Navy.
B. M. Greeley, Jr.
The Air Force’s new T-3A enhanced flight screener is a reengined version of the Slingsby Firefly.
the stall—and hold what you’ve got. The aircraft rolled, pitched about 70° nose down, and entered an auto-rotative spin. After three turns, I neutralized stick and rudder, and the aircraft recovered immediately. I brought the nose up to the horizon, added power, and we zoomed back up for another series.
The aircraft’s excess power translates to less time lost climbing back to altitude—we lost about 2,500 feet in the spin, but gained it all back in the zoom and were ready to go again—a capability that T-34C instructors would appreciate. This time I spun the opposite direction with the same results. The aircraft will recover hands off, Sandberg said, but tends to tuck and unload; because of the negative-g restriction, we left that for the prototype.
We headed back for a down-wind entry to the landing pattern at Manassas. The JPATS specifications do not require the aircraft to be stressed for carrier landings, but it is possible to fly optimum angle-of- attack, constant airspeed approaches until flaring for touchdown. I lowered the gear and full flaps and picked up the optimum angle-of-attack, which translates to 95 knots indicated air speed, at the abeam position. Stall speed in the landing configuration is 73 knots, so there was plenty of margin. Manassas has a visual approach-slope indicator and, although high at the 90° position, I rolled wings level in the groove fairly close to on-speed and on-glide slope. I eased the power over the numbers, flared, and we touched down at about 82 knots. Of course, you can fly 110 knots on downwind, 100 knots on base, and then 95 knots on final to more closely approximate an Air Force approach.
The constant-airspeed approach has obvious advantages for Navy and Marine Corps student pilots, although some might contend that it is the last few seconds of a carrier approach that are critical, and that flaring teaches future carrier pilots bad habits. On the other hand, many Navy and Marine Corps students who flew similar approaches in T-28s in basic training have gone on to complete advanced jet training carrier qualification successfully. On balance, it appears a good compromise.
In any event, the decision has been made, carrier qualification during basic training will end in the Navy when the T- 2Cs are phased out, and students will go aboard ship for the first time during advanced training in the T-45A Goshawk.
We shot two more full-flap landings and then set up for a no-flap, 130-knot pattern, which can be used to simulate an approach in a higher-speed aircraft. Sandberg characterized it as something the services might want to demonstrate in the latter stages of primary training before students transition to jets. “It gives them a look at a higher approach speed and greater rate of descent,” he said.
We shot two of these, rolled out, and taxied clear of the duty. We shut down after a 1.1-hour flight, just a bit shorter than a typical training command precision acrobatic sortie, having burned 566 pounds of fuel according to the digital counter.
The folks on vulture’s row did not disappoint us, but then, they never do after such spectacular takeoff performances. I felt OK, though; as the old RAF saying goes—if you can’t take a joke, you shouldn’t sign up.
Lieutenant Colonel Greeley is an associate editor at Proceedings. He flew A-4s throughout his career, which included service in Vietnam and duty as operations officer of an advanced jet training squadron flying TA-4Js. He commanded VMA-223, an A-4M squadron, prior to his retirement in 1982.