Facetmobile

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The Facetmobile (properly, FMX-4 Facetmobile) is a homebuilt aircraft designed by Barnaby Wainfan, a well known professional aerodynamicist and homebuilt aircraft expert.

The FMX-4 Facetmobile in flight

While only one Facetmobile prototype was produced, it has become well known due to its unique nature. The aircraft is somewhat of a cross between a lifting body and flying wing configuration - the whole aircraft is one low aspect ratio wing: a flat, angular lifting shape. Particularly notable is that the aircraft's shape is formed of a series of 11 flat surfaces, somewhat similar to the body of the F-117 Nighthawk jet strike aircraft, but without separate wing structures. The Facetmobile was designed prior to the public disclosure of the F-117 aircraft shape, and Wainfan claims that the visual similarity is coincidental, with very different engineering reasons (the F-117 uses flat panels for stealth technology, the Facetmobile for ease of construction). ^[1]

1 Design
- 1.1 Shape
- 1.2 Structure
2 Specifications
3 Media coverage
4 Current status
5 Derivatives
6 Models
7 References
8 External links

[edit] Design

The Facetmobile is a unique design in many ways. ^[1] ^[2]

[edit] Shape

As noted above, the Facetmobile is a unique airfoil shape, but is generally similar to some other generally low aspect ratio delta wing light aircraft, such as the Dyke Delta models JD1 and JD2, the Hatfield LB1 and LB3, and the ARUP 2.

The FMX-4 Facetmobile shape forms 11 flat planes, plus two wingtip rudders. Three flat shapes form the bottom of the aircraft (slightly inclined front, flat middle, and sharply raised back), and eight form the top (one large downwards sloping rear section, one thin nose section, and three inclined side panels per side). The wing section is an 18% thickness ratio, much thicker than the typical 12-15% thickness of normal light aircraft wings.

[edit] Structure

The facetmobile structure is 6061 aluminum round tubes, joined together by rivetted gussets, and covered in a fabric covering.

[edit] Specifications

General characteristics

Crew: 1
Length: 19 ft 6 in (5.95 m)
Wingspan: 15 ft (4.57 m)
Height: ()
Wing area: 214 ft² (19.9 m²)
Empty weight: 370 lb (168 kg)
Loaded weight: 740 lb (336 kg)
Powerplant: 1× Rotax 503 DC Fixed, 46 hp (34 kw)

Performance

Maximum speed: 96 knots
Cruise speed: 80 knots
Stall speed: 33 knots ()
Rate of climb: 750 ft/min ()
Wing loading: 3.45 lb/sq ft ()

[edit] Media coverage

Media coverage for the Facetmobile design and related concepts has been extensive. Coverage includes:

Life on the Facet Track, Kitplanes magazine, February 1995. Reprinted online at [1]
Other print coverage includes articles in:
- KITPLANES: 9/93
- KITPLANES: 2/95 (above)
- KITPLANES: 3/95
- Sport Aviation: 10/94
- Experimenter: 10/94
- Air Progress: 1/95
- Air Progress: 2/95
- Flying: 10/94
- Pacific Flyer: 2/94
- Model Builder: 10/96
- Flight (Air Age): Nov/Dec 1996
- Volare Sport (Italy): 10/94
- Aero Revue (Switzerland): 6/95
- Aircraft Illustrated (UK) 5/95
- Contact Issue #71
- Popular Science: January 2005

[edit] Current status

The prototype FMX-4 Facetmobile crashed on October 13, 1995, after an in-flight engine failure. The aircraft landed at low speed into a barbed wire fence which caused extensive skin, engine, and some structural damage, though there was no injury to the pilot (Barnaby Wainfan). As of 2006, the aircraft has been partially repaired but not flown again.

[edit] Derivatives

Wainfan has proposed two derivative aircraft based on the FMX-4 Facetmobile.

FMX-5 Facetmobile, a larger 2-seat design using the same aluminum tube and fabic construction.
An unnamed similar 2-seat design using advanced flat composite panel construction.

^[3]