Mitchell Nimbus
{{Short description|American glider}}
{{Use mdy dates|date=May 2022}}
{{Use American English|date=May 2022}}
| {{Infobox aircraft begin
| name=Nimbus | image= | caption= }}{{Infobox aircraft type | type=Glider | national origin=United States | manufacturer= | designer=Don Mitchell | first flight=1954 | introduced=1956 (Nimbus III) | retired= | status=Production complete | primary user= | more users= | produced= | number built= | developed from= | variants with their own articles= }} |
The Mitchell Nimbus is a series of American, single-seat, high-wing gliders that was designed by Don Mitchell in the 1950s. Mitchell is also well known for his ultralight Mitchell Wing A-10 and U-2 designs.{{Cite web|url = http://www.sailplanedirectory.com/PlaneDetails.cfm?PlaneID=247|title = Nimbus III Mitchell|accessdate = 4 April 2011|last = Activate Media|year = 2006|url-status = dead|archiveurl = https://web.archive.org/web/20120405061614/http://www.sailplanedirectory.com/PlaneDetails.cfm?PlaneID=247|archivedate = 5 April 2012}}Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 15. Soaring Society of America, November 1983. USPS 499-920
Design and development
The Nimbus series was designed as an attempt to combine a high aspect ratio wing with a thin airfoil section to produce a fast cross country sailplane.
The first Nimbus prototype used a Göttingen airfoil, which resulted in lower than expected performance. It first flew in 1954.{{Cite web |title=J2mcL Planeurs - Fiche planeur n° |url=https://www.j2mcl-planeurs.net/dbj2mcl/planeurs-machines/planeur-fiche_0int.php?code=969 |access-date=2022-05-20 |website=www.j2mcl-planeurs.net}} The Nimbus III, introduced in 1956, employed an FX-05-191 airfoil and this greatly improved performance. The Nimbus III is constructed entirely from wood and incorporates a three-piece wing, with a center section and removable wing tips. Rib spacing is 6 inches and the plywood leading edge extends to 83% of the chord.{{cite journal|last=Swierkowski|first=Vic|title=Nimbus III|journal=Soaring|date=May–June 1956|volume=20|issue=3|pages=17, 19}}
Operational history
The original Nimbus's fuselage was severely damaged at the May 1954 NCSA Soaring Meet during a cross country flight and as a result the Nimbus II was rushed to completion to be ready for the US National Soaring Contest in 1954 at Lake Elsinore, California. The Nimbus II was completed in time and Dr. J.B. Sawyer flew it to 15th place. He was forced to withdraw from the contest after the 5th day when he let go of the controls in flight and the glider pitched up steeply. After landing it was discovered that the elevator attach bracket was bent and they were unable to repair it at the contest. Sawyer went on to fly the Nimbus II on a 230-mile flight at a 1955 glider meet in Lincoln, California. He also soared it to over {{convert|20000|ft|m|0|abbr=on}} in Minden, Nevada during the summer of 1955. At the 1956 US National Contest in Grand Prairie, Texas the Nimbus III was flown by Vic Swierkowski and won the Design Contest. The Nimbus II was also flown at the Nationals by Sawyer in 1956 and actually out-scored the Nimbus III.{{cite journal|title=21st National Story|journal=Soaring|date=September–October 1954|volume=18|issue=5|pages=5}}{{cite journal|last=Barnaby|first=Captain R.S.|title=23rd Annual US National Soaring Championships|journal=Soaring|date=September–October 1956|volume=20|issue=5|pages=13–19}}
Nine Nimbus III kits were produced by Mitchell and of these, four were reported as having been completed. In April 2011 there was one Nimbus III on the US Federal Aviation Administration registry.{{Cite web|url = http://registry.faa.gov/aircraftinquiry/AcftRef_Results.aspx?Mfrtxt=&Modeltxt=NIMBUS+III&PageNo=1|title = Make / Model Inquiry Results|accessdate = 18 April 2011|last = Federal Aviation Administration|authorlink = |date=April 2011}}
Variants
Aircraft on display
- National Soaring Museum – Nimbus III{{cite web|url=http://www.soaringmuseum.org/collection.html |title=Sailplanes in Our Collection |accessdate=26 February 2011 |last=National Soaring Museum |year=2011 |url-status=dead |archiveurl=https://web.archive.org/web/20110516142717/http://www.soaringmuseum.org/collection.html |archivedate=16 May 2011 }}
Specifications (Nimbus III)
{{Aircraft specs
|ref=Sailplane Directory and Soaring
|prime units?=imp
|genhide=
|crew=one
|capacity=
|length m=
|length ft=
|length in=
|length note=
|span m=
|span ft=40
|span in=0
|span note=
|height m=
|height ft=
|height in=
|height note=
|wing area sqm=
|wing area sqft=106
|wing area note=
|aspect ratio=14.7:1
|airfoil=FX-05-191
|empty weight kg=
|empty weight lb=450
|empty weight note=
|gross weight kg=
|gross weight lb=670
|gross weight note=
|more general=
|perfhide=
|max speed kmh=
|max speed mph=
|max speed kts=
|max speed note=
|cruise speed kmh=
|cruise speed mph=
|cruise speed kts=
|cruise speed note=
|stall speed kmh=
|stall speed mph=
|stall speed kts=
|stall speed note=
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=
|never exceed speed note=
|g limits=
|roll rate=
|glide ratio=39:1 at 66 mph (106 km/h)
|sink rate ms=
|sink rate ftmin=144
|sink rate note=at 44 mph (71 km/h)
|lift to drag=
|wing loading kg/m2=
|wing loading lb/sqft=6.4
|wing loading note=
|more performance=
|avionics=
}}
See also
References
{{reflist}}
{{Don Mitchell aircraft}}
Category:1950s United States sailplanes