The Sandlin Goat is an American parasol wing, single-seat, ultralight

glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...

that was designed by Mike Sandlin and is provided in the form of technical drawings for amateur construction.Bertrand, Noel; Rene Coulon; et al: ''World Directory of Leisure Aviation 2003-04'', page 55. Pagefast Ltd, Lancaster OK, 2003. ISSN 1368-485X

Design and development

The Goat first flew on 1 February 2003. The aircraft was designed as a

monoplane 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 ...

development of the

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

Bug. Like the Bug it is intended to be an inexpensive and easy-to-fly three-axis-controlled aircraft similar to a primary glider, although the designer terms it an ''airchair''. The Goat has an empty weight of under and so qualifies to be flown under the United States

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 ...

regulations and does not require registration or a pilot license. The aircraft is made available as technical drawings, not plans, to allow potential builders to study them. Sandlin makes his computer assisted design drawings available free of charge as downloads in

.dxf AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange Format) is a CAD data file format developed by Autodesk for enabling data interoperability between AutoCAD and other programs. DXF was introduced in December 1982 as part of AutoCA ...

.dwf Design Web Format (DWF) is a file format developed by Autodesk for the efficient distribution and communication of rich design data to anyone who needs to view, review, or print design files. Because DWF files are highly compressed, they are sma ...

and

.gif The Graphics Interchange Format (GIF; or , see pronunciation) is a bitmap image format that was developed by a team at the online services provider CompuServe led by American computer scientist Steve Wilhite and released on 15 June 1987 ...

formats and has explicitly released them to the

public domain The public domain (PD) consists of all the creative work A creative work is a manifestation of creative effort including fine artwork (sculpture, paintings, drawing, sketching, performance art), dance, writing (literature), filmmaking, ...

. The Goat 1 drawings consist of 71 sheets. The designer considers his aviation activities a hobby only. The aircraft is predominately made from bolted-together

aluminium 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. I ...

tube and covered with heat-shrunk

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 ...

fabric. The

wing rib In an aircraft, ribs are forming elements of the structure of a wing, especially in traditional construction. By analogy with the anatomical definition of "rib", the ribs attach to the main spar, and by being repeated at frequent intervals, form ...

s are made from

fiberglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...

rod and

epoxy resin Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also coll ...

over Styrofoam. It has a span wing supported by lift struts and

jury strut 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 c ...

s or, alternatively, cable bracing. Controls are conventional three axis, with the

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 and

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

controlled by a center stick and

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

controlled by pedals. The landing gear is a fixed monowheel gear. The pilot sits on an open cockpit seat without a windshield and is secured with a four-point harness. The aircraft is designed to be car-top transportable and can be assembled by one person. The Goat is designed to be launched by aerotow behind an ultralight aircraft,

auto-tow Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is al ...

winch-launch Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is al ...

or by rolling it down a slope. It is flown for

soaring Soaring may refer to: * Gliding, in which pilots fly unpowered aircraft known as gliders or sailplanes * Lift (soaring), a meteorological phenomenon used as an energy source by some aircraft and birds * ''Soaring'' (magazine), a magazine produced ...

and is not recommended for aerobatics.

Operational history

One Goat was flown on a cross-country flight of more than that exceeded .

Variants

;Goat 1 :Initial version, first flown 1 February 2003, with "V" lift struts and

s that fold onto the wing for transport. Landing gear is a monowheel. Drawings are still available. ;Goat 2 :Lighter-weight version, with a kingpost and

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

cable-bracing in place of struts and push-pull tubes eliminated in favor of cables. Landing gear is a monowheel. Drawings no longer available as it has been replaced by the Goat 4. ;Goat 3 :Short-wing version, with "V" lift struts and jury struts similar to the Goat 1, plus a higher-speed

airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...

. Drawings are still available. ;Goat 4 :Standard-wing version, uses the cable-braced Goat 2 wing with Goat 3 nose and tail. Drawings are still available.

Specifications (Goat 1)

References

External links