Propeller Theory and Practice--Limited Data, Sorry

[carlmill]

Hi,

I have a 2+ month old Legend Cub with the Continental O-200 and the Sensenich 72" ground adjustable prop. I've mostly been running it with the 46" pitch cartridge but recently tried the 50" cartridge.

Here is the, so far, limited data @ 75 degree temp:

46 vs 50
rpm with 60 mph climb 2525/2300
rpm full power level 2750+/2600
true speed at 2400 rpm 92/98

First the Theory part: I realize that speed vs pitch change will be very non-linear and will need testing with various power, prop pitch, altitude variations to determine the point of diminishing return as far as trading off climb/runway length is concerned. My question is, will variations in climb rpm, max rpm, and fuel flow per a particular rpm be more linear with prop pitch change than speed? I'm trying to interpolate/extrapolate with limited data

Now the Practical: In June I plan to put this Cub on Baumann 1500's. How much will the additional float drag reduce the above rpm #'s with the 46" pitch? In other words, should I be ordering a 44" cartridge?

Thanks,

Carl

 

[DaveG]

 

[JimC]

 

[DaveG]

 

[JimC]

 

[newcub]

 

[carlmill]

 

[DaveG]

 

[carlmill]

 

[DaveG]