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Gigax Sherpa

Comco Sherpa

 

gigaxsherpa


Hans Gigax developed his Sherpa using experience acquired with the earlier Microstar, the two machines sharing a similar configuration and technology. The Sherpa made its first flight as a single-seater in May 1982 and the two-seater took to the air in July of the same year. Since then both have been put into production by the West German Ikarus company, under which heading we give greater detail. Briefly, however, the Sherpas are provided with a cage where the tubes form a double triangular structure ensuting excellent rigidity whilst offering considerable passive security. The aircraft also exhibits the peculiarity of having been designed from the start to be usable either as a single-seater, with the seat fitted in the central position, or as a two-seater, its frame being large enough to be fitted either with a double bench seat or two separate seats, the pro-totype being equipped with a central stick.


Single-seat single-engined high-wing monoplane with conventional three-axis control. Wing has unswept leading and trailing edges, and constant chord; cruciform tail. Pitch control by elevator on tall; yaw control by fin-mounted rudder; roll control by one-third span ailerons; control inputs through stick for pitch/roll and pedals for yaw. Wing braced from above by kingpost and cables, from below by cables; wing profile double -surface. Undercarriage has three wheels in tricycle formation with additional tailskid; rubber suspension on nosewheel and suspension on main wheels. Push-right go-right nosewheel steering connected to yaw control. Optional brake on nosewheel. Aluminium-tube framework, without pod. Engine mounted at wing height driving tractor propeller.


A manufacturer of hang-gliders for many years, Ikarus has just acquired the licence to produce and sell the Sherpa designed by the Swiss Hans Gigax. The first Sherpa single-seater flew for the first time in May 1982 and Hans made the first flight with the Sherpa two-seater on the way to the amateur constructors convention at Brienne-le-Chateau in France at the end of July 1982.


The prototype used a Konig SD570 four- cylinder engine of 570cc, but this was abandoned on the commercial versions. Instead, Ikarus chose to fit its single-seater, the Sherpa I, with a twin-cylinder Hirth 263R 383cc engine developing 22hp. By February 1983, Ikarus had already delivered eleven machines and in March at the Friedrichshafen show the firm announced orders for 200 machines.


The Sherpa I options include electric starter (with alterna-tor and battery) and a package allowing the single-seater to be transformed into a two seater. This package contains a second seat fitted with belts, dual controls, and the Hirth 438cc engine and costs an extra DM2150.


Though very similar to the Sherpa I, the Sherpa II differs by the addition of a second seat, dual controls (on production models), structural reinforcements and a more powerful engine. Otherwise few changes are needed, as the Sherpa was designed from the outset to be a two-seater. The Sherpa II can be turned back into a single-seater in a few minutes and uses the Hirth 438cc engine developing 42hp. Following three pre-production models built during the first quarter of 1983, production started. A pod and instrument panel are optional.

Sherpa I
Length overall 16.2 ft, 4.95 m.
Height overall 9.3ft, 2.82m.
Wing span 34.4ft, 10.50m.
Constant chord 5.2 ft, 1.60 m.
Sweepback 0deg.
Tailplane span 9.8 ft, 3.00 m.
Total wing area 169 sq.ft, 15.7 sq.m.
Wing aspect ratio 7.0/1.
Wheel track 5.9 ft, 1.80 m.
Wheelbase 4.3 ft, 1.30 m.
Engine: Hirth 263R, 22hp at 4200rpm.
Propeller diameter 55 inch, 1.40 m.
Toothed-belt reduction, ratio 1.8/1.
Max static thrust 143 lb, 65 kg.
Power per unit area 0.13hp/sq.ft, 1.4hp/sq.m.
Fuel capacity 3.4 US gal, 2.8 Imp gal, 13.0 litre in main tank; 3.4 US gal, 2.8 Imp gal, 13.0 litre in res.
Empty weight 221 lb, 100 kg.
Max take-off weight 475 lb, 215kg.
Payload 254 lb, 115kg.
Max wing loading 2.81 lb/sq.ft, 13.7kg/sq.m.
Max power loading 21.6 lb/hp, 9.8kg/hp.
Load factors; +6.0, -3.0 ultimate.
Max level speed 56 mph, 90 kph.
Never exceed speed 68 mph, 110 kph.
Max cruising speed 50 mph, 80 kph.
Economic cruising speed 37 mph, 60 kph.
Stalling speed 24 mph, 40 kph.
Max climb rate at sea level 300 ft/min, 1.5 m/s.
Min sink rate 400 ft/min at 31 mph, 2.0 m/s at 50 kph.
Best glide ratio with power off 7/1.
Take-off distance 200ft, 60m.
Landing dis-tance 130 ft, 40 m.
Range at average cruising speed 93 mile, 150km.

Sherpa II

Engine: Hirth 263R, 22hp at 4200rpm.
Propeller diameter 55 inch, 1.40 m.
Toothed-belt reduction, ratio 1.8/1.
Max static thrust 143 lb, 65 kg.
Power per unit area 0.13hp/sq.ft, 1.4hp/sq.m.
Length overall 16.2 ft, 4.95 m.
Height overall 9.3ft, 2.82m.
Wing span 34.4ft, 10.50m.
Constant chord 5.2 ft, 1.60 m.
Sweepback 0deg.
Tailplane span 9.8 ft, 3.00 m.
Total wing area 169 sq.ft, 15.7 sq.m.
Wing aspect ratio 7.0/1.
Wheel track 5.9 ft, 1.80 m.
Wheelbase 4.3 ft, 1.30 m.
Fuel capacity 3.4 US gal, 2.8 Imp gal, 13.0 litre in main tank; 3.4 US gal, 2.8 Imp gal, 13.0 litre in res.

Engine: Hirth 276R, 42 hp at 4200 rpm.
Propeller diameter 63 inch, 1.60 m.
Toothed-belt reduction, ratio 1.8/1.
Max static thrust 232 lb, 105 kg.
Power per unit area 0.25 hp/sq.ft, 2.7 hp/sq.m.
Length overall 16.2 ft, 4.95 m.
Height overall 9.3ft, 2.82m.
Wing span 34.4ft, 10.50m.
Constant chord 5.2 ft, 1.60 m.
Sweepback 0deg.
Tailplane span 9.8 ft, 3.00 m.
Total wing area 169 sq.ft, 15.7 sq.m.
Wing aspect ratio 7.0/1.
Wheel track 5.9 ft, 1.80 m.
Wheelbase 4.3 ft, 1.30 m.
Fuel capacity 3.4 US gal, 2.8 Imp gal, 13.0 litre in main tank; 3.4 US gal, 2.8 Imp gal, 13.0 litre in res.
Empty weight 254 lb, 115kg.
Max take-off weight 662 lb, 300kg.
Payload 408 lb, 185
Max wing loading 3.91 lb/sq.ft, 19.1 kg/sq.m.
Max power loading 15.8 lb/hp, 7.1 kg/hp.
Load factors; +6.0, -3.0 ultimate.
Max level speed 50 mph, 80 kph.
Max cruising speed 44 mph, 70kph.
Economic cruising speed 37mph, 60kph.
Stalling speed 26mph, 42kph.
Max climb rate at sea level 400 ft/min, 2.0 m/s.
Min sink rate 400ft/min at 31mph, 2.0m/s at 50 kph.
Best glide ratio with power off 7/1.
Take-off distance 150ft, 45m.
Landing distance 115ft, 35m.
Range at average cruising speed 93 mile, 150 km.

 


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