The engine maximums[1] authorized in the aircraft airworthiness certificate of NC 13359 at the time of the accident[2] were as follows:
| Press Alt. | In. Hg. | R.P.M | H.P. | |
|---|---|---|---|---|
| Take-off 1 min. | 35½ | 2200 | 550 | |
| Maximum except take-off | Sea level | 35 | 2200 | 550 |
| Maximum except take-off | 8,000 feet | 33 | 2200 | 550 |
When the manufacturer sought an Approved Type Certificate for Wasp S1H1-G engines in 1934, the usual tests were run. During these tests the engine was operated continuously for 50 hours at an average of 35.6 inches manifold pressure, at 2200 r.p.m., and at an average of 556 h.p., without in any way adversely affecting the engine.
The airplane was equipped with Hamilton Standard, constant speed, hydromatic, full-feathering propellers.
- ↑ Aircraft engines are designed to produce a given horsepower under continuous operation. This normal rated maximum horsepower can be exceeded for short periods without affecting the safety of operation or the service life of the engine. However, if an engine is operated at this higher horsepower for any continuous period of time, excessive temperature will be developed in the cylinder head, valves, pistons, etc., which may result in a failure of any one of these parts or seriously reduce the service life of the engine. Accordingly, engine operation limitations are specified by the Civil Aeronautics Administration in the operation record attached to the aircraft airworthiness certificate of each airplane. These limitations are expressed in terms of maximum permissible (a) manifold pressure measured in inches of mercury, (b) revolutions per minute, and (c) horsepower.
When an engine is operated with a constant speed propeller, as were both engines on the airplane involved in the accident, the manifold pressure alone is used to gauge the horsepower output. - ↑ See Appendix A for a history of the engine limitations for NC. 13359.
