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Well, Tracy and I had the same prop on our 2.17
drives and got essentially the same static rpm 5200 (although at times I have
gotten up to 5800 rpm - cooler mornings). Tracy informed me that with his
74x88 and 2.85 that his static went up to 6200 rpm. So I would expect the
same with the same prop. Tracy, however, felt a larger prop than what he
order might improve performance even more. So I ordered one that was 2"
longer 76x88 just to see.
If it turns out to be a bit too large, the prop
manufacture will trim it back to the 74 inches. It is a long
thing.
If it turns out that I produce the 6200 rpm
static (it will likely be slightly less than that with the longer prop), but if
I did - that would be an approx 25-30HP increase in power turning a much larger
prop. The increased torque from the 2.85 should provide sufficient torque
to twirl that hummer around 2100 rpm for take off. The prop of course will
turn slower with the 2.85 - but, slower and larger is supposedly more
efficient.
Apparently the thrust produced by such a large
diameter prop is considerable at low airspeeds and climb. Based on Tracy's
performance and my first hand observation of his take off it improves those
areas of performance considerably. Also, Tracy did not suffer any top end
lost in speed. Since, I normally cruise at 170 MPH IAS (just hate to burn
fuel at those prices) any potential lost of top speed is of no consequence to
me. I wanted something to get my butt off the ground and above the tree
tops quicker. It looks like this should do it.
I am suppose to get the gear box this coming
week. So need to order a new spinner for the prop and stop all this
messing around with a microchip and get back to REAL flying.
Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
Sent: Saturday, July 31, 2004 7:39
PM
Subject: [FlyRotary] Re: New Monster
Prop
Ed,
Congratulations
on the new prop, and soon to be 2.85:1 drive. It will be interesting to see what the
results are from the higher RPM’s.
What HP do you expect to make, and at what RPM ?
Steve
Brooks
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Ed Anderson
Sent: Saturday, July 31, 2004 4:00
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
New Monster Prop
Well,
Rusty
Eat
your heart out. Got my new monster prop from Performance Props
yesterday. Again, a beautiful piece of woodwork. Its about 8 1/2"
longer than my old prop. My heart skipped a beat as I was pulling the
new prop out of its shipping container as I happened to glance over at my old
prop sitting on the floor - when the thought hit me! Did I tell Clark
this one was conventional Rotation?????? Whew! was sure glad
to see the blades twisted the opposite of my old prop
{:>)
Got an
email from Laura who told me to ship $$ as they were shipping my modified gear
box to me next week. So timing is pretty good all the way around.
It
turns out the Prop is approx 1/4 thicker than my old prop - but I had a 1/4"
spacer so I'll be able to use the same prop bolts - rather than popping close
to $200 for a new set.
Well,
got to go wipe the dust off the new prop {:>)
Ed
Ed
Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
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