Schweizer SGM 2-37
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| SGM 2-37 | |
|---|---|
| Type | Motor glider |
| National origin | USA |
| Manufacturer | Schweizer Aircraft Corporation |
| Designed by | Leslie Schweizer[1] |
| Maiden flight | 1982 |
| Introduction | 1982 |
| Retired | USAF service: April 2003[2] Still in civil use |
| Primary user | United States Air Force Academy - 9 |
| Produced | 1982-1988 |
| Number built | 12[1] |
| Unit cost | USD$70,000 (1983 base price) |
| Developed from | Schweizer SGS 1-36 and 2-32 |
The Schweizer SGM 2-37 is a two-place, side-by-side, fixed gear, low wing, motorized glider.[1][3]
A total of twelve were produced between 1982 and 1988, including nine for the the United States Air Force Academy, which designated it the TG-7A. The TG-7A was retired from USAFA service in April 2003.[1][2][4]
The basic airframe was later developed into the SA 2-37A and B covert surveillance aircraft.[5]
Contents |
[edit] Background
Schweizer had flown a Schweizer SGU 1-19 as a motor glider in 1946 without putting the design into production. [6]
Later the company carried out a design study of a motorglider designated as the Schweizer 1-30, but no examples were built. A single motorglider prototype, the Schweizer 2-31 was completed, but no further motorgliders were built by the company until 1982.[7][8][9]
[edit] Development
The SGM 2-37 was designed at the request of the USAF for use at USAFA, in both the powered and glider trainer role.[3]
To save both money and development time the aircraft used a number of existing aircraft components:
- Nose, cowling and engine installation adapted from the Piper PA-38 Tomahawk[2]
- Wings adapted from the Schweizer SGS 1-36 Sprite, including extensions to bring it from the Sprite's 46.2 feet to 59.5 feet and leading edge cuffs to improve stall characteristics[2]
- Tail from the Schweizer SGS 2-32[2]
The design was intended to be available as a civil aircraft as well as a military aircraft. The USAF version was delivered with a Lycoming O-235-L2C 4 cylinder aircraft engine of 112 hp. The civil version offered the same engine or an option of a Lycoming O-320 of 150 hp or a Lycoming O-360 of 180 hp.[2][3]
The aircraft is of all metal aluminum monocoque construction. The engine cowling is made from fiberglass and plastics are employed in some of the nonstructural components.[2]
The 2-37 features a 27 cu ft baggage compartment behind the side-by-side seating. The aircraft does not have flaps, but instead has top-and-bottom wing-mounted balanced divebrakes, similar to other Schweizer glider designs.[3]
Performance includes a cruise speed of 114 mph while burning 4 US gal per hour with the O-235 engine. The 17.9 aspect ratio wing provides a glide ratio of 29:1 and a minimum sink speed of 3.16 feet/sec (0.96 m/s).[1][3]
[edit] Certification
The SGM 2-37 was certified by the Federal Aviation Administration under type certificate G1NE on March 22, 1983.[10]
The 2-37 type certificate is currently held by K & L Soaring of Cayuta, New York. K & L Soaring now provides all parts and support for the Schweizer line of sailplanes.[10][11]
[edit] Variants
- SA 2-37A
- The SA 2-37A is a two seat special mission surveillance aircraft built for the Central Intelligence Agency and US Army and equipped with a Lycoming O-540-B powerplant of 235hp (175kW) and first flown in 1982 and eight.[12]. The US aircraft register records six SA-2-37As, including four belonging to Vantage Aircraft Leasing with serial numbers as high as 8. All are in the experimental exhibition category.[13].
- SA 2-37B
- The SA 2-7B is a development of the 2-37A equipped with a Lycoming TIO-540-AB1AD powerplant of 250 hp. The aircraft is optimized for covert surveillance missions and carries FLIR and electronic sensors. It has a 500 pound (231 kg) sensor payload in a 70 cubic foot fuselage bay. With a fuel capacity of 99 Gallons (374.8 litres) it can remain on station for up to 12 hours. Gross weight is 4300 lbs (1950 kg).[5] The US aircraft registry records four SA 2-37Bs, all owned by Schweizer Aircraft. All are in the experimental Research and Development category.[14]
- TG-7A
- United States Air Force designation for the SGM 2-37.
- RG-8A
- In US Coast Guard service the SA 2-37 is designated RG-8A, indicating Glider, Reconnaissance.[15]
[edit] Marketing
The SGS 2-37 was marketed by the company as being suitable for the following roles:[3]
- Sailplane trainer
- Powered aircraft trainer
- Glider towplane (with larger horsepower engine option)
- Private touring aircraft
- Surveillance
- Aerial Inspection
[edit] Reception
Soaring, the journal of the Soaring Society of America, described the SGM 2-37 as:
| “ | Very versatile, very promising, very expensive[3] | ” |
The publication's review noted that the USD$70,000 base price did not include a feathering propeller, gyro instruments, wheel fairings, long range fuel tanks or other optional extras.[3]
[edit] In use
There were nine aircraft still registered in the USA in April 2008. Current owners include the Tuskegee Airmen National Historical Museum and designer Leslie E. Schweizer.[16]
[edit] Specifications (SGM 2-37)
Data from Sailplane Directory[1], USAFA[2], Soaring magazine November, 1983[3] & FAA Aircraft Type Certificate G1NE[10]
General characteristics
- Crew: two in side-by-side seating
- Length: 27 ft 6 in (8.5 m)
- Wingspan: 56 ft 6 in (18.14 m)
- Height: 7 ft 8 in (2.4 m)
- Wing area: 195.7 ft² (18.18 m²)
- Airfoil: Wortmann Fx 61-163
- Empty weight: 1200 lb (544 kg)
- Loaded weight: 1850 lb (839 kg)
- Useful load: 650 lb (295 kg)
- Max takeoff weight: 1850 lb (839 kg)
- Powerplant: 1× Lycoming O-235-L2C aluminum fixed pitch, 112 hp (84 kW)
Performance
- Never exceed speed: 135 mph (219 km/h)
- Maximum speed: 135 mph (181 km/h)
- Cruise speed: 112 mph (181 km/h)
- Stall speed: 48 mph with divebrakes closed (78 km/h)
- Range: 230 mi (372 km)
- Service ceiling 14,000 ft (4300 m)
- Rate of climb: ft/min (m/s)
- Wing loading: 9.45 lb/ft² (46.15 kg/m²)
[edit] References
- ^ a b c d e f g Activate Media (2006). SGS 2-37 Schweizer. Retrieved on 2008-06-03.
- ^ a b c d e f g h United States Air Force Academy (May 2008). TG-7A. Retrieved on 2008-05-26.
- ^ a b c d e f g h i j Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 131. Soaring Society of America, November 1983. USPS 499-920
- ^ Federal Aviation Administration (June 2008). FAA Registry. Retrieved on 2008-06-03.
- ^ a b Schweizer Aircraft Corp (2006). Reconnaissance Aircraft: SA 2-37B. Retrieved on 2008-06-03.
- ^ Schweizer, Paul A: Wings Like Eagles, The Story of Soaring in the United States, page 120. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3
- ^ Smithsonian Institution (2004). Directory of Airplanes. Retrieved on 2008-05-03.
- ^ Federal Aviation Administration (May 2008). FAA Registry Make/Model Inquiry Results. Retrieved on 2008-05-27.
- ^ Savetz Publishing (2008). SCHWEIZER 2-31 Profile. Retrieved on 2008-05-27.
- ^ a b c Federal Aviation Administration (September 2007). TYPE CERTIFICATE DATA SHEET NO. G1NE. Retrieved on 2008-05-26.
- ^ K & L Soaring (undated). K & L Soaring, LLC. Retrieved on 2008-04-05.
- ^ World Aircraft Directory (undated). Schweizer SA 2-37A. Retrieved on 2008-06-03.
- ^ Federal Aviation Administration (June 2008). Make / Model Inquiry Results. Retrieved on 2008-05-03.
- ^ Federal Aviation Administration (June 2008). Make / Model Inquiry Results. Retrieved on 2008-05-03.
- ^ Stoll, Alex (September 2001). Schweizer RU-38A Twin Condor. Retrieved on 2008-06-04.
- ^ Federal Aviation Administration (April 2008). Make / Model Inquiry Results. Retrieved on 2008-04-29.
[edit] External links
- Photo of a USAFA TG-7A (SGM 2-37) motor glider
- Photo of a USAFA TG-7A (SGM 2-37) motor glider
- Photo of SA 2-37A reconnaissance aircraft
- Photo of SA 2-37B reconnaissance aircraft
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