ABSTRACT
This paper presents an experimental method for determining the maximum power
obtainable from an aircraft diesel engine derived from the automotive field. Several
tests were performed to estimate the real values of pressure and thermal loads on the
piston and head. The simple and original method described in this paper made it
possible to define two constants for the description of the engine-performanceenvelope.
Maximum allowable pressure on the piston and the head was evaluated with
computer simulation. Two different indicator cycles of the same engine (in the
automotive and aircraft version) were analyzed to extrapolate three constants that
define the engine family:
• The contributing factor of compression (the exponent of the polytrophic curve n)
• The contributing factors of combustion (a constant and an exponent)
These contributing factors were examined and quantified separately.
The paper is composed of two parts: the first part highlights the ultimate loads on
critical engine parts while the second details the method for the extrapolation of the
ultimate power output value. Successive experimental tests performed on the engine
confirmed the simple method described herein.