The Airmass Sunburst is an American ultralight aircraft that was designed by John Massey and produced in the early 1980s by Airmass, Inc. of Stillwell, Kansas, Personal Planes, Inc. of

Norwalk, Ohio Norwalk is a city in the U.S. state of Ohio and the county seat of Huron County. The population was 17,012 at the 2010 census. The city is the center of the Norwalk Micropolitan Statistical Area and part of the Cleveland-Akron-Canton Combined ...

, Double Star Engineering & Manufacturing, Inc. of

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

and Sterner Ultracraft based in Sterling Heights, Michigan. The aircraft was supplied as a kit for amateur construction.Cliche, Andre: ''Ultralight Aircraft Shopper's Guide'' 8th Edition, page E-38. 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 req ...

rules, including the category's maximum empty weight of . The aircraft has a standard empty weight of . It features a cable-braced

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 co ...

, an inverted

V-tail The V-tail or ''Vee-tail'' (sometimes called a butterfly tail or Rudlicki's V-tailGudmundsson S. (2013). "General Aviation Aircraft Design: Applied Methods and Procedures" (Reprint). Butterworth-Heinemann. p. 489. , 9780123973290) of an aircraft ...

, a single-seat, open cockpit,

tricycle landing gear Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle g ...

and a single engine in pusher configuration.Woltkamp, John A.; Carlos L. Blacklock and Dr. Jan Roskam
"Weight and Balance for the Airmass Incorporated Sunburst Model C Ultralight,"
November 1, 1983,

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

Report NASA-CR-175356 /

University of Kansas The University of Kansas (KU) is a public research university with its main campus in Lawrence, Kansas, United States, and several satellite campuses, research and educational centers, medical centers, and classes across the state of Kansas. T ...

report KU-FRL-6135-2 /

National Academies of Science The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

report NAS 1.26:175356, retrieved from NASA Technical Reports Server, September 13, 2021; also a
Archive.org
NOTE: Document at both locations includes a photocopy of the original manufacturer's description / equipment list / spec sheet for the Sunburst Model 'C'. The airframe 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 ha ...

tubing (mostly anodized). (On the Sunburst C, the wing spars and mixer assembly use 6061-TS stock, not anodized, with thicknesses of 0.058-inch and 0.049-inch.) Its span wing is supported by cables (on the Sunburst C: 3/32-inch and 1/8-inch plastic-coated, stainless steel cable) attached to an inverted "V"

kingpost A king post (or king-post or kingpost) is a central vertical post used in architectural or bridge designs, working in tension to support a beam below from a truss apex above (whereas a crown post, though visually similar, supports items above f ...

. (The Sunburst C's upper flying wires are not plastic-coated.) Sunbrust C fasteners are AN-aircraft grade standard hardware, with assorted plastic caps, plugs, saddles, and spacers. Wing and tail of the Sunburst C were originally surfaced with 3.9-ounce stabilized Dacron fabric. The control system is three-axis, with roll controlled by spoilers, using a

side stick __NOTOC__ A side-stick or sidestick controller is an aircraft control stick that is located on the side console of the pilot, usually on the righthand side, or outboard on a two-seat flightdeck. Typically this is found in aircraft that are equi ...

and pitch and yaw controlled by ruddervators. The pilot is accommodated on an open (fiberglas bucket) seat, without a windshield. 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 ...

features a steerable nose wheel and suspension on all three wheels (two large, one small, fiber-spoked wheels). The aircraft originally came without brakes, and was configured to allow the pilot to use his feet to hold the aircraft stationary on the ground under the engine's static thrust.Roskam, Jan, Ph.D. (

):
"Determination of the Static Performance of a Cuyuna CC Model UL-430RR Engine"
emoved from an Airmass Sunburst October 1, 1983,

Report NASA-CR-175354 /

report KU-FRL-6135-1 /

report NAS 1.26:175354, retrieved from NASA Technical Reports Server, September 13, 2021 The 2-cycle

Cuyuna 430 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, unda ...

engine of - with

recoil starter Rope start (also called pull start or ''rewind start'') is a method of starting an internal combustion engine, usually on small machines, such as lawn mowers, chainsaws, ultralight aircraft, small outboard motors and portable engine-generators. ...

, forced-air cooling, and dual capacitive-discharge ignition - is mounted under the wing. It drives the pusher propeller through an extension shaft. The Sunburst C was supplied with a 54"x27" laminated, 2-ply birch-wood propeller. A study by the

, for

, found a Sunburst's Cuyuna UL-430RR engine to have thrust ranging from 10 pounds at ground idle to 208 pounds maximum in flight. In static testing, the report said: "...fuel consumption ranged from about 1.0 Ibs/Hr at idle to 18 Ibs/Hr at 2600 RPM and, from there, increased to 35 Ibs/Hr at 2810 RPM." Construction time from the factory-supplied assembly kit was estimated at 30 hours. The aircraft can be disassembled and stored in a bag suitable for car-top ground transportation.

Operational history

A number of Sunbursts suffered structural failures that resulted in fatal accidents (reportedly involving cable breakages killing four pilots). The cause was traced to cable attachment brackets that were made with rough holes that over time in service sawed through the cable thimbles and caused the flight cables to break. This was addressed by replacing the brackets. In service, the propeller extension shaft suffered from vibration issues that caused failures of the engine output shaft. This was addressed by the use of a vibration dampening shaft coupler made from rubber. In 1982, designer Massey piloted one of his Sunburst ultralights across the English Channel, as part of the 1982 London-Paris ultralight race. Starting in January, 1983, the University of Kansas, sponsored by NASA, initiated several different analytic studies of various aspects of an Airmass Sunburst Model 'C', with the reports published by NASA in the public domain.Blaclock, Carlos L., Jr.; and Jan Roskam
"Summary of the Weight and Balance, and The Drag Characteristics of a Typical Ultralight Aircraft,"
'' SAE Transactions,'' Volume 93, Section 4: 840772––841109 (1984), pp. 718-733 (16 pages),

SAE International SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internatio ...

, retrieved from JSTOR.org, September 14, 2021

Production history

Airmass

The ''Sunburst'' and two-seat ''Sunburst II'' were designed by John Massey, and originally produced by Airmass, Inc. in the Kansas City suburb of Stillwell, Kansas. Following a series of fatal crashes, the craft was modified. A Sunburst Model 'C' was also produced by Airmass, and studied extensively in 1983 by the University of Kansas for NASA.

Personal Planes, Inc.

The design was acquired by Personal Planes, Inc. (owned by James Bender and Robert Blackman), the operator of the Norwalk-Huron County Airport in

."Norwalk’s airport loses its operators Thursday,"
Aug. 27, 1983, in "Blast from the Past: The top stories in the ''Norwalk Reflector'' on Aug. 27, 1983," republished Aug 27, 2020, '' Norwalk Reflector,'' retrieved September 13, 2021Lewis, Dave
"Airport Deal isn't off the ground,"
Ohio], October 26, 1983, '' Sandusky Register'', p. 19", OCR text transcript, retrieved from NewspaperArchive.com, September 13, 2021 The design was marketed as the ''Sunburst V.'' In April, 1983, the company's chief pilot, Robert Burger, was killed in the crash of his ultralight,Lewis, Dave
"Ultralight Pilot Dies in Crash ,"
April 28, 1983, '' Sandusky Register'' p. 1," OCR text transcript, retrieved from NewspaperArchive.com, September 13, 2021obituary: "Robert Burger, Collins,"
Ohio], April 28, 1983, '' Sandusky Register'' p. 6", OCR text transcript, retrieved from NewspaperArchive.com, September 13, 2021 and by July, 1983, the company had announced plans to dissolve the business.

Double Star Engineering & Manufacturing, Inc.

In the autumn of 1983, the design was acquired by Double Star Engineering & Manufacturing, Inc., of Texas, and marketed as the ''Lone Star'' (single-seat) and ''Double Star'' (two-seat).

Sterner Ultracraft

In the spring of 1984, Double Star merged with Sterner Ultracraft, of Sterling Heights, Michigan (owner: Bob Sterner), who resumed production of the two Double Star company models, and a third, the Star Fire (along with Sterner's own unrelated Sky Walker design). By early 1985, Sterner Ultracraft had ceased operation.

Variants

* Sunburst (original aircraft, as described above) * Sunburst C (referenced as test subject in series of NASA-sponsored research tests by University of Kansas) * Sunburst II (two-seater) * Sunburst V (improved model, with early post-fatality fixes, as produced by Personal Planes, Inc.) * Lone Star (version produced by Double Star Manufacturing & Engineering, Inc., and Sterner Ultracraft) * Double Star (two-seat version produced by Double Star Manufacturing & Engineering, Inc., and Sterner Ultracraft)

Specifications (Sunburst)

References

{{reflist

External links

Photos of an Airmass Sunburst in flight and on ground
from Barnstormers.com, September 12, 2021.
Video introduction to the Sunburst
1980s United States ultralight aircraft Homebuilt aircraft Single-engined pusher aircraft