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.