The Ultra-Fab Sundowner, also called the Sundowner Convertible, is an American
ultralight aircraft
Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with ailer ...
that was designed by Bob Leinen and produced by
Ultra-Fab. The aircraft was supplied as a kit for
amateur construction.
[Cliche, Andre: ''Ultralight Aircraft Shopper's Guide'' 8th Edition, page E-39. Cybair Limited Publishing, 2001. ]
Design and development
The aircraft was designed to comply with the US
FAR 103 Ultralight Vehicles
Ultralight aircraft in the United States are much smaller and lighter than ultralight aircraft as defined by all other countries.
In the United States, ultralights are described as "ultralight vehicles" and not as aircraft. They are not requ ...
rules, including the category's maximum empty weight of . The aircraft has a standard empty weight of . It features a
strut-braced
In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in ...
high wing
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
, a single-seat,
conventional landing gear
Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...
and a single engine in
tractor configuration.
The aircraft is made from bolted-together
aluminum
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
tubing, covered in
Dacron
Polyethylene terephthalate (or poly(ethylene terephthalate), PET, PETE, or the obsolete PETP or PET-P), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods ...
sailcloth. Its span wing is supported by "V" struts and
jury struts
In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in ...
. A single aluminum tube acts as the
fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
keel and supports the tail at the aft end, the wings in the middle and the engine at the front. The engines supplied include the
Rotax 277
The Rotax 277 is a , single-cylinder, two-stroke aircraft engine, that was built by BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.Raisner, William: ''LEAF catlog'', pages 6-105. Leading Edge Airfoils, 1995.
Development
The ...
and the
Cuyuna UL II. The aircraft may be flown with an open cockpit or with
zippered sailcloth cockpit enclosure panels installed for cold weather flying. The controls are conventional three-axis and include a
center stick, adjustable rudder pedals and full-span
aileron
An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...
s. The
landing gear
Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
has aluminum torsion suspension on all wheels and the tailwheel is steerable.
The aircraft was introduced just as the ultralight market in the US became saturated and demand collapsed. As a result, even though the Sundowner had many innovative features, it was not a commercial success.
Specifications (Sundowner)
References
{{reflist
External links
Drawing of the Sundowner
1980s United States ultralight aircraft
Homebuilt aircraft
Single-engined tractor aircraft