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I replaced my GSC with a Warp Drive which I just installed, but am at a loss as to what pitch to start with. Here is my set up.
Kitfox 3, 85 mph cruise, 90 mph VNE
1990 Rotax 912 80 hp.
New prop: Warp 70" 3 blade, tapered tip, nickel leading edge.
Any suggestions. Guidelines. Words of Wisdom?
Ralph
What did Warp Drive suggest? Darrell is real easy to talk to there, and is very knowledgeable about his props. JImChuk
I talked to Darryl at length when I ordered, but forgot to ask where to start for a setting, thought I would hit the brain trust.
Ralph
Ralph,
Darryl originally gave me a range to start with of 10-15 degrees at the tip and suggested a midrange for the same prop on our ULS to start....for your 3 with the 80 horse being a little lighter and a little less HP.......I doubt that it would be much different...to be on the safe side - go a little less. I started with 12, experimented with 11 and ended up @ 12.5 which gave a nice balance between best ROC and cruise.
If in doubt, I'd second giving Darryl a call again.
I run mine at 11.5 degrees measured at the tips.
One thing I noticed with the Warp taper tip is that the airfoils in the tapered section are not really very precise. (They're hand ground.) I therefore started measuring pitch at the 75% point to get the blades more even. (And no, I can't tell you off the top of my head what I'm running for my 100hp IV. My guess as to your pitch is 11.5 - 12 degrees at the tip.)
Guy's comment about measuring the pitch angle in from the tip on the warp tapered tip is spot on......I developed the procedure of initially setting at the tip on one blade at the recommended angle for starting reference, then measuring inboard (where the pitch will increase compared to the tip) and using that point to measure from on all blades thereafter - much more precise. There is less measuring variation inboard a bit where the blade is wider.
I want to thank everyone that took the time to answer my questions. I have also contacted Daryl at Warp Drive by email and asked... where to measure, what angle to start with and recommendations if I want to paint the tips. His answers are as follows:
We recommend doing the initial pitch setting at the very tip of the blade.
As long as you are consistent from blade to blade, it does not matter where
the pitch is measured. Our recommendation at the tip of the blade is around
11 - 12 degrees for this size of prop on the 912UL engine. This should
allow for a static RPM of around 52 - 5300. If you are interested in more
take-off and climb performance initially you could back the pitch down to 10
degrees for a starting point.
The finish on the blades is a flat black lacquer paint. You can use any
type of paint, even as simple as an enamel spray can for painting the tips.
It is best to mask off the area you wish to paint, then keep the number of
passes with the spray can as close as possible so you keep them in balance.
I have since set the angle starting at 11 degrees and as soon as I have time and the weather cooperates, I will do a static RPM check.
Ralph
Well I'll respectfully disagree with Warp as to where to measure pitch. As to painting, I painted the whole forward face of my prop with urethane, then sanded smooth and polished and dynamically balanced.
Guy, your prop looks great.
The placement of the protractor really doesn't matter.. as long as you place it in the same relative position on each blade. The difference of comparing that angle set between aircraft will be dependent on the same placement. Due to blade twist, the angle used at the tip will be different than the angle used 6 inches from the tip, for comparson purposes.
Ralph