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Prometheus 1

EFF (ENTWICKLUNGSGEMEINSCHAFT FOR FLUGZEUGBAU DER AKADEMISCHEN FLUGGRUPPE)

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Prometheus 1, HB-2020, takes off from Olten-Gheid on the 12th August, 1972. Source : VGC New Spring 2015, Photo: Erich Gandet

Ce projet est issu d’un programme lancé en 1970 par des membres de l'Akademische Fluggruppe (AFG) de Zurich. Parmi eux on trouve T. Bircher, un des principaux constructeurs du Diamant, A.Schiller, qui a entièrement conçu et réalisé le FS-1, P. Senn, qui a construit un Weihe et réparé de nombreux planeurs et D. Favarger, responsable de la Technische Abteilung de l'AFG. Afin de mener à bien ce projet, ils ont fondé l'EFF (Entwlcklungsgemeinschaft fur Flugzeugbau : Groupe d'étude et de construction aéronautique)

The Prometheus 1 was an experimental powered sailplane, based on the airframe of the FFA Diamant 18. Design and construction began in late 1970, and the aircraft flew for the first time on 21 June 1971, powered by a 176 lb (80 kg) Microturbo Eclair II turbojet engine. This had been later replaced by a more powerful TRS 25 engine.

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EEF Prometheus 1 powered sailplane
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Fligth Archives 1972 - Prometheus I
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Caractéristiques du Prometheus I

ManufacturerFFA
Modified byEFF
TypeJet glider
First flight21 june 1971
Nb. built1 with Eclair II
Crew1

Power plant

EngineMicroturboEclair II
Count1
TypeTurbojet
Max ratings  80 kg225 lbs

Dimensions

Span18,00 m59.05 ft
Length7,56 m24.80 ft
Height1,35 m4.43 ft
Areasft²
Aspect ratio 22,5

Weights 

Empty290 kg639 lb
Crewkglb
Fuel81,8 llb
Enginekglb
WaterballastKglb
Max. permissible 500 kg1102 lb

Performances 

Vne - Max. speed270 km/168 mph
Max crusing speed at S/L210 km/h130 mph
Max eco. speed at S/L170 km/h106 mph
Vs - Stall speed flaps up80 km/h50 mph
Vs - Stall speed flaps down68 km/h42.5 mph
Max. rate of climb at S/L180 m/mn591 ft/min
Service ceiling11 000 m36,100 ft
Range> 250 km> 155 miles
Best gliding ratio28:1
Landing distance from 50 ft50 m164 ft
Take off distance to 50 ft150 m492 ft
G limits+-

General description

Wings, Fuselage, tail units and landing gear are coming from an original Diamant 18.

Power Plant

One 264 lb (120 kg) st Microturbo TRS 25 turbojet, mounted on a pylon above the wing center-section.

Total fuel capacity 

Fuel in two 8-75 Imp gallon (40 litre) wing tanks and one 0.4 Imp gallon (1.8 litre) fuselage tank. 

Total : 17.9 Imp gallons (81.8 litres). 

Oil capacity 

0.11 Imp gallons (0.5 litres).

Dimensions and areas

Wing span18,0 m59 ft 0.5 in 
Wing aspect ratio22,5
Length overall 7,56 m24 ft 9.5 in 
Height over tail4 ft 5 in 1,35 m
Tailplane span9 ft 6,25 in 2,90 m