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Performance and Operational Characteristics of a Python Turbine-propeller Engine at Simulated Altitude Conditions

The performance and operational characteristics of a Python turbine propeller engine have been investigated over a range of engine operating conditions at simulated altitudes from 5000 to 40,000 feet in the NACA Lewis altitude wind tunnel . For the performance phase of the investigation, a single cowl-inlet ram pressure ratio was maintained and independent control of engine speed and fuel flow was used to obtain a range of power at each engine speed.

Engine performance data obtained at a given altitude could not be used to predict performance accurately at other altitudes by use of the standard air pressure and temperature generalizing factors.

Specific fuel consumption based on shaft horsepower decreased as the shaft horsepower increased at a given engine speed. At a given altitude condition and turbine -inlet total temperature, there was an optimum engine speed at which maximum shaft horsepower was obtained. At a given engine speed and turbine-inlet total temperature, a greater portion of the total available energy was converted to propulsive power as the altitude increased.

Windmilling starts were made at altitudes up to 40,000 feet; the minimum true airspeed required for successful windmilling starts increased as the altitude was raised. In general, the engine control prevented large overshoots or undershoots of engine speed during starts, accelerations, and decelerations.

Document ID
Acquisition Source
Glenn Research Center
Document Type
Other - Research Memorandum
Carl L. Meyer
(Lewis Flight Propulsion Laboratory)
Lavern A. Johnson
(Lewis Flight Propulsion Laboratory)
Date Acquired
August 16, 2013
Publication Date
February 6, 1952
Subject Category
Aircraft Design, Testing and Performance
Aircraft Propulsion and Power
Report/Patent Number
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
Engines - Armstrong-Siddely Python Turbo-Propeller (Brit )
Wind Tunnel Tests - LFPL - High-Altitude (20')
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