FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1983
1983 - 1930.PDF
DEFENCE Caproni will bid for RAF trainer Caproni Vizzola will respond to Royal Air Force Air Staff Target (AST) 412 to replace Jet Provost basic trainers from 1989 onwards, re ports Mike Gaines from Malpensa. The Italian company believes that its C.22J light weight jet trainer has sufficient performance to fulfil the RAF's requirements while providing low initial costs and lower running costs than any of the other types so far offered. The C.22J is small, weigh ing only 2,7671b at maximum take-off weight and spanning just over 30ft. The aircraft is powered by two Microturbo TRS-18s, giving a total thrust of 5721b, or a thrust loading of 4-831b/lb at MTOW. The C.22 was designed for side-by- side seating, and Caproni would prefer to retain that layout, but AST.412 requires the target aircraft to have a tandem cockpit, internally as similar as possible to that of the BAe Hawk. The RAF also specifies a single turbine engine. Caproni's chief designer, Carlo Ferrarin, has drawn up a tandem cockpit design for the C.22, but points out that the present laminar-flow design contributes towards the C.22's performance and a tandem layout could also affect stability. "If I increase the nose length, then I've got to redesign the tail. I also have to move the main gear stow age around." Caproni is quite prepared to make the neces sary changes to land the 155-aircraft RAF contract, but points out that the aircraft's cost will rise accord ingly to reflect the extra design, development, and test work necessary. And the two engines? Caproni seems convinced that the RAF did not have such tiny powerplants as the TRS- 18 in mind when it specified a single engine for AST.412. Should the RAF insist on one engine, there are no rated engines yet available that could produce the required thrust together with TRS-18's low weight, simplicity, and, above all, low cost and high reliability. "And the TRS-18 is easy to work on. No trouble to change, it takes about 20min and one man can lift it in or out." But Caproni would like to see future engines in this class devoted to better specific fuel con sumption. "We don't need to climb like an F-16, but more endurance is always good for a trainer." At present Caproni has two C.22Js flying, and a static fatigue-test specimen is almost ready to be put through its paces. The camouflaged first prototype has around llOhr on the clock, while the red, white, black, and silver second proto type, I-GIAC, has accumu lated 190hr and is working towards FAR certification, expected in late March or early April next year. The latter aircraft is built to pro duction standard, but one or two minor changes might be made. One is the addition of electric aileron trim; another possibility is a change from manual to electrically oper ated airbrakes. Apart from the cockpit and engines arguments, can the C.22J meet AST.412's performance requirements? On paper it seems that most can be met, a couple are marginal and one, the minimum stalling speed, needs working on. The C.22J stalls at 73kt clean, and the RAF specifies 60kt gear down. This problem is not insur mountable, says Caproni. Altering the flap profiles and perhaps adding leading-edge slats will bring the stall down to the required airspeed. The C.22J was designed to meet FAR.23 stall requirements for twin-engined aircraft, dic tated by problems on take-off, says Caproni. Caproni is still working through the AST.412 docu ment. One specification is brakes-off to 15,000ft in 7min at maximum take-off weight. "I think we meet that", says chief test pilot Paolo Barberis, "but I'm going to check it out tomorrow. I see no problem with either that or the descent criteria. [15,000ft to 2,000ft and circuit speed in 4min without exceeding 15° pitch down]. I am not sure about the fuel reserves after the speci men double mission. We might have to work on that one a little, but no big prob lems." Flight understands from sources other than Caproni that AST.412 specifies two consecutive general handling sorties without refuelling. After the second sortie the aircraft must be capable of carrying out a 120 n.m. diversion at best range altitude and land with 10 per cent of total fuel remaining. Another endurance criterion is a one-hour low-level mission at maximum power followed by the 120 n.m. diversion and 10 per cent fuel remaining. Sitting on the pan at Malpensa airport, the C.22J is dwarfed by a Navajo some yards up the ramp, and posi tively eclipsed by a TWA Boeing 747 across the way. Walkround is quick and simple, aided by being able to see all top surfaces except the tailplane, but needing a deep crouch to check out the gear. Lightweight glider-type backpack parachutes are usually worn, but 'GIAC's pair are due for routine packing, so we have to settle for bulkier military backpacks which are heavier and do not fit the reclined seats as well. Enter ing the aircraft is easy and no steps are required. Settling into the left-hand seat, I am reclined at an angle with my feet at about the same level as my chest. This gives good g tolerance; the C.22J is designed for +7/-3-5g, although 'GIAC is cleared only to 5g with two on board, pending certification. AST.412 calls for +6/-3g. 'GIAC's present fit has the standard six flying instru ments grouped on the right of the panel, with engine instru ments to the left with a second ASI. Avionics are stacked in the centre; two VHF comms boxes, two VORs and, to the left, a DME and, below that, an SSR transponder with alti tude encoder/warner. The engine instruments take the form of an easily read block of six "palm tree"-type parameter indicators with light bugs travelling up or down. Fuel contents and flow rate are digitally displayed on a compound instrument. All instruments and indicators are clear and easy to read. The two throttles are mounted towards the front of the centre console within easy reach of either pilot. The airbrake selector is just to the rear and right of the throttles, while the gear and flap switches are mounted on the panel in front of the throttles. I am 5ft 9in tall and of medium build, Paolo is about the same. I find the cockpit comfortable while wearing flying suit, parachute, and lightweight headset, but there would not be a lot of space if one had to wear an immersion suit, LSJ, a military flying helmet, and a parachute/ survival pack. At present C.22J emergency egress consists of canopy jettison, invert, and fall clear. A rocket-assisted system of the Stencel Ranger/Yankee type could be fitted, says Caproni. Paolo demonstrates the simple start sequence — battery on, left-hand master switch, and press the engine start button. We have 5201b of fuel, the tip tanks are empty. Number one starts smoothly, fuel flow establishes at 801b/min, and EGT climbs momentarily to 800° then backs off to 450° at 52 per cent. The right hand engine is equally easy to start. Noise level is low, and conversation is possible without either of us using or removing the head sets. As the engines start a CAPRONI C.22J- LEADING DATA Length (ft/in) Height (ft/in) Span (ft/in) Wing area (ft2) Empty wt (lb) Max TO wt. with tip tanks (lb) Max TO wt, no tip tanks (lb) Wing loading (lb/ft2) Max dive speed-Vd (kt) 20:6 6:2 30:2 82 1,605 2,767 2.502 30 325 Max operating speed-Vmo (kt) Max structural cruise speed-Vc (kt) Max level speed-Vh (kt) Stall speed-flaps-down power off-Vso (kt) Rate of climb, sea level (ft/min) Service ceiling (ft) Max range at 25.000ft (n.m.) Endurance (hr) 300 260 280 73 1,814 29,500 650 3 5 1082 FLIGHT International, 22 October 1983
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
