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Caproni A-21 Calif




Designed by G. Ferrarin and L. Sonzio, the original A-21, the prototype of which made its first flight on 23 November 1970, was a high performance two-seat version of the A-14, from which it differed in having a slightly longer fuselage widened to accommodate two in luxurious side-by-side seating.

This version was succeeded by the A-21S, which held four world records for two-seaters; among these is the Class D2 speed record for women over a 300km closed circuit, set up on 18 August 1974 by Adele Orsi and Franca Bellingeri in an A-21S at a speed of 60.73mph.
Caproni Vizzola Calif A-21 S
The cantilever mid wings have a wide constant chord centre section and tapered trapezoid outer panels, and are all-metal; the three-piece all-metal main spar is supplemented by two auxiliary spars in the centre section and one in each outer panel, the downturned wing tips being of glassfibre. The trailing edge flaps/spoilers can act as air brakes when deflected to 89 downwards, and as camber-changing surfaces between ±8°; the plain ailerons are differentially-operated. The forward fuselage is a glassfibre/foam plastics semimonocoque structure with a load-carrying light alloy frame, and the rear fuselage is a thin boom of all metal stressed skin construction. The distinctive high aspect ratio fin and rudder is all-metal, and has the all-moving metal tailplane and elevator, which both have glassfibre tips, mounted on top; the tailplane trim is spring-adjusted. The mechanicallyretractable twin main wheels have rubber-incompression shock absorbers and a brake, and there is a fixed steerable tailwheel, as well as a small wheel in each downturned wing tip. The two pilots have dual controls under a rearward-sliding two piece canopy, and sit in luxury seating equivalent to the best light plane standards.


Over 100 A-21S Califs had been built, production of a third batch of 54 being ordered by January 1980.


With 66.9 feet of wingspan, the A-21SJ is the only production turbojet-powered sailplane in the world. It offers side-by-side seating and all-metal construction. The engine retracts into the fuselage just aft of the cockpit. Cruise speed is 124 mph and climb is 945 fpm. On 36 gallons of fuel, range is about 217 miles, with a ceiling of 43,300 feet. Takeoff run requires only 1,181 feet. Up to 90 percent of the parts between the sailplane and the motorglider are common to both, so the glider can be transformed easily into a jet glider, even in retrofit. The landing gear for both aircraft features dual main gear that retract into the undercarriage. Two small wheels are built into the wingtips. The wing is all-metal with a single spar, stressed skin, and fiberglass tips; the wing is fitted with top-hinged, differentially operated ailerons plus lower-hinged, aerodynamically balanced flaps/spoilers. The fuselage has a monocoque forward section of fiberglass with a load-carrying lightweight alloy structure. The tailboom is an all-metal stressed-skin unit ending in an all-metal single-spar tailplane.

Caproni (which built its first glider in 1908 at Vizzola Ticino, Italy) produced the first A-21 (designed by Carlo Ferrarin and Livio Sonzio) in 1970, and within two years had collected four world multi-place sailplane speed and distance records with it. A 2-place all-metal ship with a fiberglass forward fuselage, the A-21 was followed into production by the slightly improved S model. The ship features a roomy side-by-side cockpit and widely spaced retractable twin landing wheels. Aft-hinged brakes on the lower surface, and these, with large flaps (which deflect to +89 degrees) limit speed in a vertical five to 188 kph / 102 kt / 117 mph. The T-tail is all moving. A steerable tail wheel and water ballast were optional.

The Calif A-21S was produced im a small-series produced (6 aircraft) at the Gomolzig Flugzeug und Maschinenbau.

The Italian construction offers good performance (comparable to Janus C) and good flying characteristics, giving the aircraft a broad range of applications reaching from advanced training and guest flights up to performance flights. Only for competition flights in the double-seater class, it is exceeding the 20-meter definition by a few centimeters.

The A- 21S cost approximately 20000 Marks less than a Duo Discus and features a fixed tailplane.

The A-21JA self launch jet model is a 2 place, side by side all metal sailplane. Forward fuselage is glass fibre. Dual, manually retracting undercarriage. Fixed tail wheel. Rudder pedals adjustable. Both seats adjustable. Extremely powerful trailing edge flap / brakes. Flaps have a thermal setting, cruise setting and fully variable down for landing. Automatic control hook up. No manufacturers fatigue life limit. A very high quality structure, built by an aircraft manufacturer not a glider manufacturer. It was well and truly "state of the art" in 1974.


First flying in late January 1972, the A21 J jet version added a SERMEL TR18 100 kp thrust (220 lb) jet engine. The span was reduced from 22.87 to 20 m, and overall length increased from 7.27 to 8m. The tare weight (equipped) is reduced from 484 to 434 kg. The engine is mounted in the lower part of the fuselage, behind the seat, the ejection of gas under the fuselage. The volume of wing and fuselage tanks hold 160 litres of kerosene. The engine is started with a compressed air bottle.


A21 J


In 1976 the first prototype of the A- 21J was purchased by Lockheed to be used in a research program conducted in cooperation with the Mississippi State University. The experiments concerned inter alia the effects of wind, dust, insects and rain on some wing sections, as well as measures and vortex noise rappport the fuselage. In the initial test phase, the A- 21J was towed to the appropriate altitudes.


The J was succeeded by the A-21SJ, which first flew in May 1977 and was based on the production A-21S sailplane. The main difference between the A 21A and A 21 SJ is the positioning of the 198 lb st Microturbo TRS 18-046 turbojet engine. In remains in the fuselage behind the pilot, but now in the top position. Its air intake is by a removabe NACA inlet located on the back of the fuselage. The ejection of the exhaust is by a nozzle opening on each side of the fuselage. The A-21SJhas a metal fuselage with fiberglass monocoque forward sectrion surrounding aluminum load-carrying structure; all metal wings and tail with minor fiberglass fairing.
Caproni Vizzola Calif A-21SJ
Up to 242.5 lb of fuel is carried in fuselage and wing tanks, and there is a starter/generator and batteries for in-flight and ground starting. Apart from the engine the A-21 SJ is very similar to the A-21S, but has larger mainwheels and tailwheel. Two A-21SJs had been completed by May 1979 and five more were being built. One A-21SJ was being tested with a more powerful Microturbo TRS 18 jet of 242.5 lb st.


Prototype A21J
Span: 20 36 m
Length: 7 84 m
Height: 1.919 m
Wing area: 16,19 m²
Wing loading: 39.8 kg / m²
Maximum weight: 644 kg
Max speed: 255 km / h
Climb speed: 63 km / h


Wing Span: 20.38m / 66.9ft             
Wing Area: 16.91sq.m / 174.3sq.ft
Empty Weight: 436kg / 961lb            
Payload: 208kg / 459lb
Gross Weight: 644kg / 1420lb             
Wing Load: 39.8 kg/sq.m / 8.16 lb/sq.ft
Airfoil: Wotmann FX-67-K-1 70/60-126     
Aspect ratio: 25.65     
L/DMax: 43 at 105 kph/ 56 kt/ 65 mph        
MinSink: 0.61 m/s / 2.0 fps / 1.18 kt

Engine: Sermel TRS 18, 220 lb.         
Seats: 2.
Wing loading: 8.91 lbs/sq ft.             
Wing aspect ratio: 25.
Gross: 1,543 lbs.             
Empty: 957 lbs.
Useful: 586 lbs.                 
Max airspeed: 162 kts.
Rough-air speed: 162 kts.                 
Stall: 41 kts.
Lift / drag: 43 at 63 kts.             
Sink: 1.97 fps at 49 kts.
Fuel: 236 lbs.                 
Length: 26 ft 3 in.
Wing  span: 65 ft 7.5 in


Glide ratio: 1:43 at 58 kt / 1:42 at 60 kt.     
Never Exceed Smooth Air: 138 knots
Max Rough Air: 91 kts                
Stall: 34 /38 knots
Climb rate: 650 ft/min            
Ceiling: 30,000 ft
Power Cruise: 115 kts


Engine: turbojet, 100kg/220 lb Thrust     
Wing Span: 20.38m / 66.9ft
Wing Area: 16.19sq.m / 174.3sq.ft         
Empty Weight: 436kg / 961lb
Payload: 208 kg / 459 lb             
Gross Weight: 644kg / 1420lb
Wing Load: 39.8kg/sq.m / 8.16lb/sq.ft         
Aspect ratio: 25.65
Airfoil: Wotmann FX-67-K-1 70/60-126     
L/DMax: 43 at 105 kph/ 56 kt/ 65 mph
MinSink: 0.61 m/s / 2.0 fps / 1.18 kt


Wingspan: 20.38 m / 66 ft 10.5 in
Length: 7.84 m / 25 ft 4.5 in
Height: 1.61 m / 5ft 8.5 in
Wing area: 16.19 sq.m / 174.3 sq.ft
Aspect ratio: 25.65
Wing section: Wortmann FX-67-K-170/60-126
Empty weight: 436 kg / 961 1b
Max weight: 644 kg / 1,420 lb
Water ballast: None
Max wing loading: 39.8 kg/sq.m / 8.15 /b/sq ft
Max speed: 156 mph / 138 kt / 255 km/h
Stalling speed: 34 kt / 63 km/h
Max aero-tow speed: 87 mph
Min sinking speed: 1.97 ft/sec at 53 mph / 46 kt / 85 km/h
Best glide ratio: 43:1 at 65 mph / 56.5 kt / 105 km/h
A-21 SJ
 Span: 66 ft 10.25 in
 Length: 25 ft 4.5 in
 Height: 5 ft 3.5 in
 Wing area: 174.3 sqft
 Aspect ratio: 25.65
 Empty weight: 1,164 lb
 Max weight: 1,781 lb
 Max level speed: 143 mph (power on)
 Max rate of climb: 787 ft/min (sea level, power on)
 Take-off run: 985 ft (power on)








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