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Hi Chris,
With Sam's original prop, he got around 5000 rpm max
static. May have been as high as 5100 but ranged around 4800-5000
rpm. When He put my 74x88 Performance Prop on he got as high as 6100 rpm
one time but each time got at least 6000 rpm.
Measure your chord at its widest point - mine is 5 1/2",
Sam's was around 8" - not the whole story on a prop, but can be an indication of
whether your prop is close to one end of the spectrum or the other
Ed
Sent: Sunday, October 03, 2010 9:37 PM
Subject: [FlyRotary] Re: Sam Hodges Prop area
Comparison
Ed,
I
have the same Catto prop and mine is marked 76x88. I didn’t get more than
5000 RPM max static either. To be honest, I didn’t look at the max RPM
while airborne, I was too busy looking at the temp, and I pulled the power back
as soon as I could. I hope to fly again with the new radiator in a few
weeks, and should be able to get new data. What were Sam’s numbers Max
static with the CATTO and with your prop?
Thanks,
Chris
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed
Anderson
Sent: Sunday, October 03, 2010 10:46 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Sam Hodges Prop area
Comparison
Just doing a
rough back of the envelope calculation comparing Sam Hodges prop (8" cord)
to my prop (5 1/2" cord) and assuming the two props blade profiles were similar,
Sam's prop would have approx 45% more prop area trying to push the air back than
my prop. Small wonder his engine was groaning trying to spin it up to 6000
rpm.
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