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  Aircraft History, Specification and Information
Fairchild KR-21
1930 Fairchild KR-21 - N107M
1930 Fairchild KR-21 - NC107M (sn 1011)
Photo taken Aug. 11, 2011
Independence State Airport - Independence, OR - USA (7S5)
Photo © Marcel Siegenthaler

The Kreider-Reisner Challenger (later the Fairchild KR series) was an American utility biplane aircraft designed and produced by the Kreider-Reisner Aircraft Company, which was later taken over by the Fairchild Aircraft Company.


The C-2 Challenger was the first commercial aircraft developed by the Kreider-Reisner Aircraft Company. The Challenger was a conventional mixed-construction biplane with a fixed tailskid landing gear. It had two open tandem cockpits for a pilot (at the rear), and passenger (forward) and was powered by a 90 hp (67 kW) Curtiss OX-5 inline engine. A number of variants were built designated the C-3 Challenger and C-4 Challenger which had detailed differences and different engines fitted. Late in 1928 the company introduced a new and slightly smaller design designated the C-6 Challenger.

In 1929 the company was bought by the Fairchild Aircraft Company who continued the production of the C-4 as the Fairchild KR-34 and the C-6 as the Fairchild KR-21. Although not built by Fairchild the C-2 was re-designated the Fairchild KR-31.

To act as an engine test-bed a KR-21 was modified to use a Fairchild 3-690 engine (later named Ranger) and changes were made to the wing and landing-gear geometry. The modified aircraft was known as the Fairchild KR-125. In 1931 a similar aircraft without the geometry changes but with a Ranger engine was sold under the designation KR-135.


  • C-2 Challenger
    Initial production version, later KR-31.
  • C-3 Challenger
    C-2 with detail and engine changes.
  • C-4 Challenger
    C-2 with detail and engine changes, later KR-34
  • C-6 Challenger
    Smaller version of C-2, later KR-21.
  • KR-21
    Re-designation of the C-6.
  • KR-31
    Re-designation of the C-2.
  • KR-34
    Redesignation of the C-4
  • KR-34CA
    1930 attack aircraft version of the C-4C
  • KR-35
    Re-designation of the C-4.
  • KR-125
    One KR-21 modified to an engine test bed for the Fairchild 6-390.
  • KR-135
    Production version of KR-21 with in-line engine.

Specifications (Fairchild KR-21B)

Length: 22 ft. 7 in.
Height: 9 ft. 0 in.
Empty Weight: 1,015 lbs.
Gross Weight: 1,550 lbs.
Wingspan - Upper: 27 ft. 0 in.
Wingspan - Lower: 24 ft. 6 in.
Total Wing Area: 193 sq. ft.
Fuel Capacity: 23 gal.
Oil Capacity: 3 gal.
Cruising Range: 350 miles
Cruising Speed: 98 mph
Maximum Speed: 123 mph
Service Ceiling: 15,000 ft.
Climb: 755 fpm
Price at Factory: $4,525
Engine: 125 hp., Kinner B5 (R-440), 372 cubic inch, 5-cylinder radial

Last updated April 15, 2012
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Fairchild KR-34".
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