Abstract :
Every airplane flies to reach velocity and altitude flying in climbing
condition are determined by aircraft performance on the engine and effect by
altitude. This research for determine the effect of altitude on air fuel ratio,
specific thrust, specific fuel consumption, thermal efficiency, propulsive efficiency
and overall efficiency in turboprop engine 250-B17F. Knowing value of specific
fuel consumption in turboprop engine 250-B17F on ideal and real condition, and
to know specific fuel consumption value is the smallest with the effect on altitude
at 2000 ft, 4000 ft, 6000 ft and 8000 ft on real condition in climbing conditions.
The method used is method calculations , which calculations use software
"Mathcad" and "Microsoft Excel ". To begin the calculation it is necessary to
have some data parameters input that have been obtained from reference
and data plane Grob 120 TP-A. The parameters are to find the smallest specfici
fuel consumption value in climbing condition starting from 2000 ft , 4000 ft. 6000
ft, and 8000 ft, with an elevation interval per 2000 ft.
The result of this research is using comparison of altitude analysis with
ideal and real condition, until got difference ideal and real condition values
specific fuel consumption at 2000 ft, 4000 ft, 6000 ft, and 8000 ft. Value specific
fuel consumption at 2000 ft is 0.575 decrease at 8000 ft value is 0.485, real at
2000 ft is 1.138 decrease at 8000 ft is 0.832. On the smallest in climbing condition
of altitude at 8000 ft with value is 0.811(lbm / hr) / lbf