The Bowlus SP-1 Paperwing was an American high-wing cantilever monoplane, single-seat,
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 in 1928 and completed by
William Hawley Bowlus William Hawley Bowlus (May 8, 1896 – August 27, 1967) was an American designer, engineer and builder of aircraft (especially gliders) and recreational vehicles in the 1930s and 1940s. Today he is most widely known for his creation of the worl ...
on January 1, 1929. The SP-1 was Bowlus' sixteenth glider, and was test flown at
Lindbergh Field
San Diego International Airport , formerly known as Lindbergh Field, is an international airport northwest of Downtown San Diego, California, United States. It is owned and operated by the San Diego County Regional Airport Authority.. US Federa ...
in San Diego in January, 1929. Later tests were also made from hillsides near
Bonita, California
Bonita (Spanish for "Beautiful") is a census-designated place (CDP) in southern San Diego County, California, nestled between the cities of Chula Vista, National City, and San Diego. The population was 12,538 at the 2010 census.
Geography
...
in April, 1929. SP-1 received identification mark "493" from the United States Department of Commerce and was one of the first licensed gliders in the United States. Many refer to the Bowlus SP-1 as the first sailplane of U.S. design and construction.
Design and development
The SP-1 received two nicknames, the first "Old Number 16" as the sixteenth Bowlus glider, and "Paperwing" because its
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 ...
webs were fabricated from craft paper. The ribs of both the rudder and the elevator were also made with paper webbing. Otherwise the aircraft was predominantly wood and doped
aircraft fabric
Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as are ...
. The aircraft originally had a span wing with a USA 35-A
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.
...
with conventional aileron control and landing wheels for the rough dirt surface at Lindbergh Field. The wing was later redesigned to include tip-ailerons, extending the wingspan to . The aircraft achieved a very low empty weight for its size of and a matching low wing loading as well.
Operational history
Bowlus flew the SP-1 in several regional glider meets in southern California including two at
Pacific Beach, California and one at
Redondo Beach, California
Redondo Beach (Spanish for ''round'') is a coastal city in Los Angeles County, California, United States, located in the South Bay region of the Greater Los Angeles area. It is one of three adjacent beach cities along the southern portion of Sa ...
in 1929. On October 5, 1929, Bowlus established a new U.S. soaring endurance record in SP-1 above the cliffs at
Point Loma, California
Point Loma (Spanish: ''Punta de la Loma'', meaning "Hill Point"; Kumeyaay: ''Amat Kunyily'', meaning "Black Earth") is a seaside community within the city of San Diego, California. Geographically it is a hilly peninsula that is bordered on the w ...
near the
Old Point Loma Lighthouse with a flight of 14 minutes and 10 seconds. On October 19, 1929 Bowlus extended this to 1 hour and 21 minutes, to make the first soaring flight over 1 hour duration in the US. SP-1 was used for glider instruction at the Bowlus Glider School in San Diego. Many of the first licensed glider pilots in the U.S. learned to fly in SP-1.
Variants
The Bowlus SP-1 sailplane served as a prototype for a series of other Bowlus designs, first with the Bowlus SP-D, then the Bowlus model "A" and S-1000. Only the single SP-1 sailplane made use of paper ribs, all subsequent Bowlus sailplanes used completely wood and fabric construction. The latter designs also used a larger 60 foot wingspan and were the type used by
Charles A. Lindbergh
Charles Augustus Lindbergh (February 4, 1902 – August 26, 1974) was an American aviator, military officer, author, inventor, and activist. On May 20–21, 1927, Lindbergh made the first nonstop flight from New York City to Paris, a distance o ...
and
Anne Morrow Lindbergh
Anne Spencer Morrow Lindbergh (June 22, 1906 – February 7, 2001) was an American writer and aviator. She was the wife of decorated pioneer aviator Charles Lindbergh, with whom she made many exploratory flights.
Raised in Englewood, New Jers ...
to establish their glider licenses in 1930. Bowlus later used a Bowlus model A sailplane design to set several other endurance records, while student Jack Barstow used a Bowlus model A to set an unofficial world record for glider endurance of 15 hours and 13 minutes at Point Loma in 1930.
Many variants patterned from the Bowlus SP-1 through Bowlus S-1000 series were constructed, including the ''Silver King'' by Harland Ross, and the ''Nighthawk'', a sailplane flown by William A. Cocke to a world endurance record of 21 hours 34 minutes in 1931. The ''Nighthawk'' is in the collection of the Los Angeles County Museum of Natural History and was, for a time, displayed at the Santa Monica Museum of Flying.
Aircraft on display
*
San Diego Air & Space Museum
San Diego Air & Space Museum (SDASM, formerly the San Diego Aerospace Museum) is an aviation and space exploration museum in San Diego, California, United States. The museum is located in Balboa Park and is housed in the former Ford Building, ...
– Bowlus SP-1 (replica)
*
Wings of History Museum
Wings of History is an aviation museum in San Martin, California. It is a nonprofit organization that operates using donations and membership dues.
The museum also has a restoration shop, library, and Propeller (aircraft), propeller shop.
Hangar ...
– Bowlus S-1000 (317W; original) in storage
Specifications (SP-1)
See also
References
{{William Hawley Bowlus aircraft designs
1920s United States sailplanes
Aircraft first flown in 1929