In a message dated 99-12-29 20:12:33 EST, [EMAIL PROTECTED] writes: > Horse power and RPM are related, no increase in rpm > no increase in horse power.
This is true, but the relationship is complex in the fixed pitch prop world. The "standard" prop for a particular engine/airframe combination is chosen to get full rated power at rated RPM. If you put a climb prop on, you allow the engine to run closer to rated RPM and hence closer to rated power while climbing. If you level off with this package and set the throttle for rated RPM, you will be producing less than rated power. (If you allow the engine to exceed the redline, you may or may not be able to make rated power at some higher RPM. It's hard to say. Without increasing the carburation on the C-75, rated power is the most you can hope to get. If you reduce the pitch or diameter of the prop to get the RPM up, you'll find that when you get it to turn 2575 in level cruise, your prop pitch will be finer than the "standard" C-85 prop. You are essentially forced to use a "lower gear" to get the engine speed up. By increasing the size of the carb but retaining the coarse prop, you've got a C-85 with a cruise prop. Can you achieve the specified static RPM for your airframe with a C-85? If not, your plane is technically not airworthy. On the other hand, if you can make 2575 RPM in level flight with that prop, you're getting more than 85 hp out of the engine. (And the FAA frowns on that too.) Clear, huh? BTW, out of curiosity, what kind of paperwork did you have to file for the venturi change? John __________________________________________________________________________ ______ To unsubscribe from this list please send mail to [EMAIL PROTECTED] _____________________________________________________________ Get your favorite topic delivered daily. http://www.topica.com/t/11
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