Kohler Alpha
{{Short description|American rglider}}
{{Use mdy dates|date=May 2022}}
{{Use American English|date=May 2022}}
| {{Infobox Aircraft Begin
| name=Alpha | image=Kohler Alpha N4702G.jpg | caption=Kohler Alpha }}{{Infobox Aircraft Type | type=Glider | national origin=United States | manufacturer= | designer=Spud Kohler | first flight=1965 | introduced=1965 | retired= | status= | primary user= | more users= | produced= | number built=One | developed from= Schreder Airmate HP-11 | variants with their own articles= }} |
The Kohler Alpha is an American, mid-wing, V-tailed, FAI Open Class single seat glider that was designed and built by Spud Kohler of Cleveland, Ohio.{{Cite web|url = http://www.sailplanedirectory.com/PlaneDetails.cfm?PlaneID=160|title = HP-11 Airmate HP Aircraft, LLC|accessdate = 19 May 2011|last = Activate Media|year = 2006|url-status = dead|archiveurl = https://web.archive.org/web/20110820205029/http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=160|archivedate = 20 August 2011}}Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 45. Soaring Society of America November 1983. USPS 499-920{{Cite web|url = http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=4702G|title = Make / Model Inquiry Results|accessdate = 19 May 2011|last = Federal Aviation Administration|authorlink = |date=May 2011}}
Design and development
Kohler built the Alpha in 1965 as a development of the Schreder Airmate HP-11. He used the wings from the HP-11 and combined this with a newly designed fuselage and tail. Kohler expressed the opinion that a sailplane's performance is mostly determined by its wing, while the fuselage imparts character to the design. The fuselage that he designed must have contributed to the performance, though, as the Alpha has a glide ratio two points higher than the HP-11 with the same wing.
The Alpha fuselage is made from wood, with some fiberglass components incorporated. The fuselage uses a circular cross-section from nose to tail, with the diameter varying from the {{convert|12|in|cm|0|abbr=on}} diameter at the tail to a {{convert|24|in|cm|0|abbr=on}} diameter at the cockpit. The HP-11 wing is of all-metal and features a 26:1 aspect ratio, a {{convert|52|ft|m|1|abbr=on}} wingspan and a NACA 65 (3)-618 airfoil. The v-tail is removable by first removing the tailcone and then withdrawing two pins. The controls are adapted from a Piper PA-24 Comanche. The landing gear is a retractable monowheel and a tail skid. The tail skid was later replaced with a tail wheel.
Operational history
The Alpha had a number of owners and, according to Federal Aviation Administration registry records was most recently transferred to the Jimmy Doolittle Air & Space Museum at Travis Air Force Base, in Solano County, California. The museum does not currently indicate the aircraft is part of their collection, nor is it on display.{{Cite web|url = https://www.travis.af.mil/Units/travisairmuseum/|title = Travis Air Museum|access-date = 19 May 2011|last = Travis AFB|year = n.d.|url-status = live|archive-url = https://web.archive.org/web/20110725212532/http://www.travis.af.mil/units/travisairmuseum.asp|archive-date = 25 July 2011}}{{Cite web|url = http://www.jimmydoolittlemuseum.org/html/exhibits.html|title = The Exhibits|accessdate = 14 May 2011|last = Jimmy Doolittle Air & Space Museum|authorlink = |date=May 2011}}
Specifications (Alpha)
{{Aircraft specs
|ref=Sailplane Directory and Soaring
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|span ft=52
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|wing area sqft=104
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|aspect ratio=26:1
|airfoil=NACA 65 (3)-618
|empty weight kg=
|empty weight lb=420
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|gross weight lb=650
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|glide ratio= 39:1 at {{convert|60|mph|km/h|0|abbr=on}}
|sink rate ms=
|sink rate ftmin=129
|sink rate note= at {{convert|55|mph|km/h|0|abbr=on}}
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|wing loading lb/sqft=6.25
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