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Aviation History
1956
1956 - 1454.PDF
606 FLIGHT, 12 October 1956 FLYING THE G 82 Handling Characteristics of Fiafs Jet Trainer By VICO ROSASPESJA EARLY last year I had the opportunity of flying the FiatG 82 at a time when it was still experimental and in theflight-test stage. It was, incidentally, the first aircraft in which I exceeded 1,000 km/hr (620 m.p.h.) and, even at thatearly stage, I was favourably impressed with its safety and with its maximum and stalling speeds. Since that time a number of G 82s have been built in the Fiatfactories at Turin and these have now been assigned to the jet training schools of the Italian Air Force, where they are flowntogether with T-33s. By virtue of this I recently had a further opportunity to fly the G 82 at the Jet Centre at Foggia when Iwas carrying out an attachment as a reserve officer and flying a number of modern jet fighters. The configuration of the G 82 is well known. It is a low-wingmonoplane with two seats in tandem for instructor and pupil, and is powered by a Rolls-Royce Nene. It has a retractablenosewheel undercarriage, slotted flaps, powered ailerons and fixed tailplane. A tail-braking or anti-spin parachute is mounted abovethe jet efflux, and a large, perforated dive brake extends from under the fuselage. A pair of 0.5in machine guns are mountedunder the top decking of the nose section. Panels which expose these also give access to communication radio and A.D.F., whilea landing light shines through a plastic panel under the nose cone. Rockets, bombs and tanks can be carried on under-wing pylonsin addition to small tip tanks. Most controls, together with a gyro gun-sight, are installed in the front cockpit and clearlyarranged on canted panels. Other switches and indicators are distributed along sloped lateral consoles and on a central panelextending downwards between the pilot's legs. The instructor's cockpit contains a less comprehensive, but equally well laid out,range of dials and controls. The cockpits are pressurized and air conditioned and while, in some G 82s, Martin-Baker Mk 2automatic ejection seats are fitted, other machines have one or two Martin-Baker Mk 4 lightweight seats. Arguments in favourof tandem or side-by-side seating were carefully considered by the designers, and the tandem arrangement was chosen in orderto give the pupil, who would by the time he flew the G 82 already have considerable flying experience, a sense of independence fromhis instructor. Noteworthy characteristics of the G 82 are that its handlingqualities are similar to those of modern jet fighters. Yet its wing loading is not excessive and landing and take-off runs aretherefore short and manceurvability in flight is good. The air- brake is efficient, and does not give an untoward pitching momentwhen extended. Boundary-layer fences on the wings, placed in the area influenced by the ailerons, give good low-speed behaviour.The aircraft's endurance is sufficient to allow really useful training flights at fairly high speeds. Visibility is equally good for bothinstructor and pupil and equipment is modern and compre- hensive, giving maximum comfort and safety. The ejector seatsare automatic, and the canopies are automatically jettisoned by pneumatic rams at each hinged section. Armament installations,including machine guns, rockets, bombs, cin6 gun-camera, and reconnaissance camera, are easily interchanged and maintained.Accessibility for maintenance has been particularly carefully studied and engine-changing is straightforward. The aircraft'sultimate load factor is 15. From the pilot's seat the visibility is very good in all directions.Some 7,500 r.p.m. are sufficient to get the aircraft moving; and half this power is enough to maintain taxying speed and to turn.Precise steering with the brakes is easy. For take-off, trim is set at neutral. Directional control duringthe ground run is excellent and, if the nosewheel is lifted at 80 kt, the aircraft is airborne in only about 700 yards of groundrun. The undercarriage retracts rapidly, speed builds up smartly and good manoeuvrability is immediately apparent in all threeaxes. Initial rate of climb is about 3,500ft/min up to over 20,000ft. During the climb at 100 per cent power, with nountoward rise in j.p.t., I tried the static longitudinal stability, observing correct increases in stick force with speed, and thedynamic stability, noting a quick damping of longitudinal oscilla- tions with stick both free and fixed. At 20,000ft I tried stalls in the landing, powered-approach,cruising and gliding configurations, with accelerations of 1, 1.5 and 2 g. I also made three turns of a spin. Stall warning is good,beginning with strong airframe vibration at about 130 kt increas- ing in intensity down to 110 kt I.A.S. Below this speed the G 82dropped its nose straight to an angle of about 50 to 60 deg; recovery was immediate. In order to spin I had to reach stalling speed and apply pro-spin rudder when the nose dropped. Entry into the spin was difficult and the first two turns were irregular. Rates of rolland turn varied to begin with, the first revolution taking about 5 sec. Recovery could be effected at any moment simply bycentering the rudder, because the G 82 had to be held in the spin. Application of forward stick is not desirable during spinrecovery because the aircraft does tend to go into an inverted dive. Spinning with the tip tanks attached is perfectly safe. I determined the minimum trim speeds in the landing,powered-approach and overshoot configurations with satisfactory results. As for spiral stability, the manoeuvre margin was clearlypositive in the powered-approach and cruising conditions. At 38,000ft, with the aircraft trimmed, I noted that it retained excel-lent static and dynamic stability in accelerated manoeuvres in a power-on, clean configuration at various speeds and with up to3 g. The response to rapid corrections was also good. Decreased ambient temperatures did not cause any friction in trim and flyingcontrols; and centering and break-out forces remained normal. Pressurization, air conditioning and heat distribution, and de-icingwere very good. The oxygen bunkers (of the American demand- regulator type) were very easy to see and the valves came readilyto hand. I also tried compressibility effects at various altitudes. At30,000ft there were no effects up to 0.83 Mach when slight air- frame vibration began, increasing up to 0.89 Mach when theycould be felt on the stick as well. There were no other symptoms and no tendency to drop a wing, although a slight nose-uptendency, caused by the static stability qualities of the aircraft, occurred as the speed increased. This could be easily trimmedout. Deceleration could be achieved either by extending the airbrakes, which had no adverse effects at 0.89 Mach, or bypulling the stick back and achieving 4 to 5 g. The G 82 remained easv to control at the top of its Mach range. The highest straieht-and-level speed at 20,000ft is 910 km/hr.Best endurance at 20.000ft and 275 kt T.A.S. is 2 hr 40 min, or 2 hr 45 min at 30,000ft at 329 kt T.A.S. At the latter height andsoeed fhe best range is 865 nautical miles. The service celling (400ft/min) is 41,000ft. Aerobatics are easy to perform and theaircraft is stressed for all types of manoeuvre. The G 82's excellent stability makes it a good platform for firing and bombingas well as for photographic reconnaissance. FIAT G82 Rolls-Royce Nene 2/21 or 4'21 * R-R. Nene 2/21 R-R. Nene 6/21 Total weight 13,7801b Span 38ft 9.5in Wing area 270.6 sq ft Take-off thrust 5,000 1b 5,400 Ib Maximum speed 490 kt 500 kt Stalling speed 100 kt 100 kt Maximum Mach number 0.88 0.88 Range, with normal tankage, at 29,530ft at - 313 kt T.A.S. allowing for take-off, climb and descent 620 nautical miles Time of climb to 19,700ft 5 min 30 sec 4 min 30 sec „ ,, ,, 29,530ft 10 min 30 sec 8 min 15 sec Service ceiling (400 ft/min) 41,000ft 42,600ft Take-off run 2,130ft 1,970ft Landing run 2,790ft 2,790ft Normal fuel capacity 386 Imp. gal N.B.—Two 66 Imperial gallon tip-tanks will increase the quoted range; and further tanks can be carried on the under-wing pylons. There are attachments for eight 5tn HVAR rockets under the wings and, as alternatives to bombs of up to 500 Ib, the main pylons can carry 0.5in machine-gun packs or 2.75in rocket packs.
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