The Mitchell Nimbus is a series of

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, single-seat,

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 wings. A monoplane has inherently the highest efficiency and lowest drag of any wing config ...

gliders that was designed by Don Mitchell in the 1950s. Mitchell is also well known for his

ultralight Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with aile ...

Mitchell Wing

A-10 The Fairchild Republic A-10 , also infamously known under the nickname , is a single-seat, twin-turbofan, straight-wing, subsonic attack aircraft developed by Fairchild Republic for the United States Air Force (USAF). In service since 19 ...

and U-2 designs.Said, Bob: ''1983 Sailplane Directory,

Soaring Magazine ''SOARING'' is a magazine published monthly as a membership benefit of the Soaring Society of America. It was first published in 1937. The headquarters is in Hobbs, New Mexico. The magazine's article topics include safety issues and accounts of i ...

'', 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 The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...

wing with a thin

airfoil An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more Lift (force), lift than Drag (physics), drag. Wings, sails and propeller blades are examples of airfoils. Foil (fl ...

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. 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 tip A wing tip (or wingtip) is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft. Because the wing tip shape influences the size and drag of the wingtip vortices, tip design has produced a diversity of sha ...

s. Rib spacing is 6 inches and the plywood leading edge extends to 83% of the chord.

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

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. 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

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. He also soared it to over in

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during the summer of 1955. At the 1956 US National Contest in

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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. 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

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registry.

Variants

;Nimbus I :Initial version with a Göttingen airfoil ;Nimbus II :Improved version ;Nimbus III :Improved version with an FX-05-191 airfoil.

Aircraft on display

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– Nimbus III

Specifications (Nimbus III)

References