Cosmos Bison

French ultralight trike

Bison

Role  | Ultralight trike

Type of aircraft

National origin | France
Manufacturer  | Cosmos ULM
Status  | In production
Variants  | Cosmos Phase II

The Cosmos Bison, also called the Cosmos Bidulm, is a French two-seat, ultralight trike that is produced by Cosmos ULM. The aircraft is only supplied as a completed aircraft and is not available as a kit.[1]

## Design and development

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The Bison was designed to comply with the European Fédération Aéronautique Internationale microlight classification. It features a cable-braced hang glider-style high-wing, weight-shift controls, a two-seats-in-tandem open cockpit, tricycle landing gear and a single engine in pusher configuration.[1]

The aircraft wing is made from bolted-together aluminum tubing and covered in Dacron sailcloth. A number of different wings are available for the Bison. The wing is supported by a single tube-type kingpost and uses an "A" frame control bar. Optional equipment includes a cockpit fairing and wheel pants. Engines used are the 37 kW (50 hp) Rotax 503 and 30 kW (40 hp) Rotax 447 twin cylinder, two-stroke powerplants. The landing gear is cable-braced, which allows a folding design for ground transport or storage.[1]

The Bison was later developed into the Cosmos Phase II, by adding larger seats, new landing gear shock absorbers and a redesigned engine mount to reduce vibration. In 2012 the Bison remained in production alongside the Phase II and Phase III, offering a simpler, lighter and less expensive two seater than the newer models.[1]

## Specifications (Bison)

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Data from Bertrand[1]

General characteristics

* Crew: one
* Capacity: one passenger
* Wingspan: 10.6 m (34 ft 9 in)
* Wing area: 19 m2 (200 sq ft)
* Empty weight: 123 kg (271 lb)
* Gross weight: 400 kg (882 lb)
* Fuel capacity: 40 litres (8.8 imp gal; 11 US gal)
* Powerplant: 1 × Rotax 447 twin cylinder, air-cooled two-stroke aircraft engine, 30 kW (40 hp)
* Propellers: 2-bladed wooden

Performance

* Maximum speed: 85 km/h (53 mph, 46 kn)
* Cruise speed: 60 km/h (37 mph, 32 kn)
* Stall speed: 40 km/h (25 mph, 22 kn)
* Rate of climb: 2.5 m/s (490 ft/min)

## References

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1. ^ a b c d e Bertrand, Noel; Rene Coulon; et al: World Directory of Leisure Aviation 2003-04, page 97. Pagefast Ltd, Lancaster OK, 2003. ISSN 1368-485X

## External links

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* Official website
* Photo of a Cosmos Bison

* v
* t
* e

Cosmos ULM aircraft

Ultralight trikes|

* Bidulm
* Bison
* Echo
* Samba
* Phase II
* Phase III

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