The National Airplane and Motor Company of Billings, Montana developed this National engine for their Bluebird airplane, which was certified as Group 2-465 in 1934. The engine was not certified, but was tested and received the unapproved engine specification calibration rating No. 4-8.
O-91 -- {4.0 / 3.625 / 91.1} / {101.6 / 92.1 / 1493}
2cyl; National 35; 30hp@2150rpm, 35@2400, 37@2600; 1934-36; Wt = 105#; TC = none.
Single-ignition engine.
Ae39; J9.
Applications: (US) National Bluebird C-3 (LP-1).