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 Aircraft flight control system, conventional three-a ...

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 exist outside of the United States. In most countries, ultralights are a class of aircraft. A completely different legal concept is valid within the USA. The FAA makes explicitly clear that ultralight vehicles are not air ...

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 struts, which act in ...

high wing A monoplane is a fixed-wing aircraft A fixed-wing aircraft is a heavier-than-air aircraft, such as an airplane, which is capable of flight using aerodynamic lift. Fixed-wing aircraft are distinct from rotary-wing aircraft (in which a r ...

, a single-seat,

conventional landing gear Conventional landing gear, or tailwheel-type landing gear, is an aircraft Landing gear, undercarriage consisting of two main wheels forward of the Center of gravity of an aircraft, center of gravity and a small wheel or skid to support the tail ...

and a single engine in

tractor configuration In aviation, a tractor configuration is a propeller-driven fixed-wing aircraft with its engine mounted with the propeller in front, so that the aircraft is "pulled" through the air. This is the usual configuration; the pusher configuration ...

. The aircraft is made from bolted-together

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium 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 struts, which act in ...

. A single aluminum tube acts as the

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

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 engine, single-cylinder, two-stroke aircraft engine, that was built by Rotax, BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.Raisner, William: ''LEAF catalog'', pages 6-105. Leading Edge ...

and the

Cuyuna UL II The Cuyuna 430 and Cuyuna 340 are a family of two-stroke, twin-cylinder piston snowmobile engines that were redesigned to serve as ultralight aircraft powerplants.Cuyuna Development Company: ''Cuyuna Engines'', Cuyuna Development Company, undat ...

. The aircraft may be flown with an open cockpit or with

zipper A zipper (N. America), zip, zip fastener (UK), formerly known as a clasp locker, is a commonly used device for binding together two edges of textile, fabric or other flexible material. Used in clothing (e.g. jackets and jeans), luggage and oth ...

ed sailcloth cockpit enclosure panels installed for cold weather flying. The controls are conventional three-axis and include a

center stick A centre stick (or center stick in the United States), or simply control stick, is an aircraft cockpit arrangement where the control column (or joystick) is located in the center of the cockpit either between the Aviator, pilot's legs or between ...

, 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 aroun ...

s. The

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...

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