<snips>

Nix that. Brain fade. That only works for big props. I looked at

some

prelim

designs. The biggest problem is that the prop winds up being stalled

over a

large percentage (like all) of the blade at static conditions. There

is

plenty of power to spin it up. It just stalls and stirs up the air.

The

thing doesn't "hook" up until at least 100 mph. That doesn't give me

the

warm fuzzies. Maybe I am looking at this wrong, but my preliminary

numbers

don't look promising for a fixed pitch version. Large portions of

the

blade

would be stalled at climb speed. What's the secret? How did you

arrive

at

the graph? Give us a good design treatise here Vance.

Monty

Do I have the source code to this program Vance?

PRPLRIT3.BAS
Prplrit3.bas
PRPLRIT5.BAS
prplrit5.bas
Prplritf.bas
Prpsiz.bas


Paul Lamar

Yes - but I do not remember why there is a 3 and a 5 the version that I

have

been using is just plain PRPLRIT and it has some engine curves in it
I think I gave you truncated vesions to make them more self explanitary
the prpsiz is for a first rough cut sizing and the iterative programs

step

through rpm and flight speed , predicting thrust and power required
The constant speed is not handled automatically - you just keep
running narrow speed ranges with pitch changes at fixed blade
widths, and smooth out the steps - the theory behind this
program is in my web page vjaqua.tripod.com
Vance

Monty, can you handle BASIC?

Paul Lamar

Why soitanly (as curly would say).  But I haven't programmed anything since
the wonderful spreadsheet revolution. I used to have a Qbasic compiler, but
with the move and all, I'm not sure exactly where it is. Do you have an
executable file?

Monty

OK try this one. I have no idea what it does.

Paul Lamar
 
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