Photograph:
An Ascender on display at the Queensland Air Museum at Caloundra, QLD (David C Eyre)
Country of origin:
United States of America
Description:
Single-seat ultralight sport aircraft
Power Plant:
One 26 kw (35 hp) Cuyuna 430R two-cylinder, two-stroke, converted Snowmobile engine
Specifications:
- Wingspan: 10 m (32 ft 8 in)
- Length: 5.12 m (16 ft 8 in)
- Wing area: 16.07 m² (173 sq ft)
- Cruising speed: 89 km/h (55 mph)
- Stalling speed: 40 km/h (25 mph)
- Rate of climb: 305 m/min (1,000 ft/min)
- Service ceiling: 5,486 m (18,000 ft)
- Range: 193 km (120 miles)
- Fuel capacity: 19 litres (4.17 Imp gals)
- Empty weight: 98 kg (215 lb)
- Loaded weight: 250 kg (551 lb)
History:
Pterodactyl in the United States produced a number of ultralight aircraft for the sports aircraft market and these included the Ptraveller, the Pfledge and the Ascender II. The Ptraveller was a high-wing braced canard wing aircraft developed in the early 1980s, the wing being able to be folded down for transport on the roof of a car, or for hangarage. It had rudders at the wing tips which controlled roll and yaw and the canard handled pitch control. It had large wheels and a bungee suspension on the undercarriage for rough strip operations. The three variants were the Ptraveller; Ascender II + with a strengthened airframe, a fibreglass springrod undercarriage and reduction drive; and the Ascender II + 2 which was a two-seat training variant.
In recent years the Ascender has been marketed by DFE Ultralights Inc of Vanderbilt, Pennsylvania. Models include the II, III, IIIB and IIIC, the latter being a heavy duty variant of the IIIB. The latter could also be fitted with a “sidecar” for two-seat operation. An advanced model was the PTiger, with a fibreglass pod for the pilot.
While developing the Pterodactyl Pfledge flying-wing ultralight in the late 1970s, designer Jack McCormack experimented with a number of possible engines, early test flights using a German-made Sachs engine, but the high exchange rate and long lead times meant other engine options needed be looked at. The designer then settled on a converted snowmobile engine produced by the Cuyuna Development Co and in 1979 this was modified with a crankcase extension, an additional main bearing, lowering the compression ratio using an additional head gasket, and substituting a smaller 32 mm (1.26 in) Mikuni carburettor. The original snowmobile engine produced 30 kw (40 hp). Lowering the compression ratio not only de-rated the engine, but also made pull-starting easier and allowed it to run on lower-octane regular fuel. The resulting engine was thus de-rated to produce 22 kw (30 hp) at 5,500 rpm.
The aircraft was marketed in Australia by Ultralight Flying Machines of North Balwyn, VIC, and a few examples were imported. Australian aircraft have been registered under AUF/RAA rules and include 10-0628, 10-0092, 10-0657, 10-0665, 10-0111, 10-1025, 10-0178, 10-0270, 10-0203, 10-0311, 10-0462, 10-0467, 10-0523 and 10-0657. An example has been placed on display at the Queensland Air Museum at Caloundra.
The type was very popular in New Zealand, with at least 40 examples being imported. Ptravellers registered have included: ZK-FCU (c/n MAANZ124) and Ascenders have included ZK-FCB (c/n MAANZ116), ZK-FCE (c/n MAANZ093), ZK-FCG (c/n MAANZ097), ZK-FCZ (c/n MAANZ123), ZK-FER (c/n MAANZ197), ZK-FES (c/n MAANZ182), ZK-FEV (c/n MAANZ183), ZK-FEZ (c/n MAANZ191), ZK-FFE (c/n MAANZ194), ZK-FFH (c/n MAANZ189), ZK-FFI (c/n MAANZ195), ZK-FFQ (c/n MAANZ199), ZK-FFR (c/n MAANZ200), ZK-FFU (c/n MAANZ205), ZK-FRY (c/n MAANZ412), ZK-UPU (c/n MAANZ321) and ZK-PAY (c/n BRW-1). A Ptiger was registered as ZK-MIH (c/n MAANZ082).
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