P337 Intercooler Flight Test Comparison

[Bob Cook]

Kevin

HP = FF < losses (fricitional and otherwise).

Fuel flow is the only way to determine actual hp unless you work backwards knowing the Inlet air temp and using that to calc density altitude. Even that is tricky.

You can only assume you are accurate at two points; 1) full throttle take off, and cruise leaned to peak or thereabouts and then resorting to the engine mfg. charts.

The fact you are cooling the inlet air temp does NOT give you more hp, it provides you with better combustion characteristics. You still need the correct fuel/air mixture to maximize efficiency.

Get out the sliderule......... errr..... calculator! or, you run the engine within its temperature limits avoiding pre-ignition or detonation.

During world war II they used water and/or water methane injection to get emergency hp.
Limits ? strickly temps.
How much additonal hp ? > was theoretical based solely on density altitude from charts.

Compare the POH fuel flow leaned to peak and work backwards, using the correct rpm scale, you can see where the MP would be if there was no intercoolers. The difference is what the intercooler is contributing the performance. The amount of hp (%) remains the same for the given fuel flow.

GMAS ?? comments

Bob