In addition to the three C-40s and ten C-40As ordered by the Air Corps in 1938, one additional plane was ordered and retained at the factory for modification to tricycle landing gear configuration. The plane was fitted with a fixed nose landing gear and a larger main landing gear with bigger wheels and tires.
After the plane was delivered in mid-1939, it was sent to Wright Field, Ohio, for installation of radio test equipment. The plane was used for performance testing of the tricycle landing gear configuration and evaluation testing of the radios. The C-40B was significantly slower than the C-40A primarily because of the fixed landing gear.
After less than one year of testing, the C-40B was converted to standard C-40A configuration. The nose landing gear was removed and the main gear was replaced with a smaller, standard retractable type. The remodification was completed in November 1940 and the plane, redesignated C-40A was used as a normal staff transport for a number of years.
Model 12 Electra Junior
Tricycle landing gear testbed
Designation not used
Impressed Electra Juniors
TECHNICAL NOTES: Engines: Two Pratt & Whitney R-985-17 radials of 450 hp each Maximum speed: Approx. 200 mph Cruising speed: 181 mph Range: 500 miles Service ceiling: 20,000 ft. Span: 49 ft. 6 in. Length: 36 ft. 4 in. Height: 9 ft. 9 in. Weight: 9,720 lbs. maximum gross weight Crew: Two (pilot and co-pilot) Passenger capacity: Five Serial numbers: C-40: 38-536 to 38-538; C-40A: 38-539 to 38-548; C-40B: 38-582; UC-40D: 42-22249, 42-38280, 42-38346 to 42-38352, 42-57504, 42-66386