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So it's possible to buy fixed pitch propellers which are either optimised for takeoff or for top speed. I guess most airplanes have a compromise.

Considering a training aircraft like a Cessna 152, what would be the difference in Ground Roll and Total to Clear 50ft obstruction between different props?

As an example the Ground Roll and Total to Clear 50ft Obstruction at 20 deg C for a weight of 1670 lbs at Sea Level is listed as 755 and 1390 feet respectively. How much numerically would they change with different props?

Please note this is just a hypothetical question. I'm not in the market for propellers!

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    $\begingroup$ Between a cruise prop and climb prop, takeoff performance will generally improve about 15-20% with the climb prop vs the cruise. $\endgroup$ – John K Jan 7 at 4:52
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With my old VariEze (not a training aircraft; in the same power class as the Cessna 152 but lighter and with much higher wing loading) I had a cruise propeller and a climb propeller that I could exchange on the ground with about 30 mins of work. I measured ground roll at max gross weight and calm wind to be around 1500' with the cruise prop and 1100' with the climb prop. I could usually get around 1500 fpm climb with the climb prop and 1000 fpm with the cruise. Cruise speed was 10 to 15 kts slower with the climb prop depending on altitude; you'd usually have to throttle back quite a lot to avoid exceeding redline RPM.

The difference in takeoff performance is more dramatic when a constant-speed (variable pitch) prop is compared to a fixed-pitch prop. I'm presently in the process of upgrading my Lancair 360 from a cruise/climb compromise fixed-pitch prop to a constant speed and I expect that to decrease the ground roll to less than half the current 1500'. I'll report back with data once it's flying.

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    $\begingroup$ Why would the takeoff performance of a constant speed prop be any better than a fixed pitch climb prop that is optimized for take off RPM? $\endgroup$ – Mike Sowsun Jan 7 at 4:57
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    $\begingroup$ @mikesowsun The constant-speed prop can go to finer pitch than the climbiest of remotely-practical climb props. This gives you significantly more thrust for the earlier portion of the takeoff run while the aircraft is below flying speed. $\endgroup$ – pericynthion Jan 7 at 5:01
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    $\begingroup$ The CS prop runs at redline the entire time so you are getting full rated power for the entire takeoff roll. Even a climb prop has to either be pitched to keep RPM below redline at low speed. If you pitch it fine enough to get redline at the start, you have to reduce power as soon as you are rolling to keep from overspeeding. $\endgroup$ – John K Jan 7 at 5:01
  • $\begingroup$ @pericynthion +1 for "climbiest" $\endgroup$ – StephenS Jan 7 at 19:49

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