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N82HB
11-06-2010, 08:15 AM
We just brought back a IV with a 912 and a taper tip warp drive prop. It is pitched way to fine and I am wondering where we should try on this beauty. I have the nice protractor for setting it; I just don't know what angle to set. Any suggestions? I have the same prop on my airplane, but I have the S engine so that setting won't work.
Thanks,
Kelly

Dave S
11-06-2010, 10:33 AM
Kelly,

Our series 7 has the 912ULS and warp tapered tip.

The ultimate advice is going to come from Warp. I called them up on this issue with my eng/prop combo and they said that the minimum is 10 degrees and the max 15 degrees at the tip.

I originally pitched it to 12 at the tip, found out that was a little too short legged - hurt the cruise a bit. Then went to 14 - that was a bit to far the other way. (Note Rotax recommends no less :eek: than 5200 RPM @ full throttle - like on takeoff.)

13 degrees worked out about right with 5200 at best angle of climb and balanced with a decent cruise. It is going to matter how heavy the plane is too. I set up with 13 with approx 1400# which is about where I fly most of the time with full fuel and a passenger.

Each person has a performance level in mind when they set this up - some would pitch less to get max HP at max allowable RPM - in my case - the fox climbs just fine for my use @ 13 and I'd rather have a better cruise.:)

Of course - the ideal would be a constant speed.....but....$

Sincerely
Dave S
KF 7 Trigear
912ULS Warp Tapered tip

catz631
11-06-2010, 03:46 PM
Kelly,
I have a Warp drive prop with the nickel leading edge taper tip as you do. It is hanging on the wall as I replaced it with a Kiev prop. The Kiev has worked out to be much smoother and solved my engine run on problems at shutdown,but I digress.
The pitch angle is dead on on the Warp(5200rpm @WOT) and if you would like I will measure it and give you the angle. You will probably have to vary it a bit but at least it will give you a start. My cell # is 850-304-7371 if you would like to call. I could give you the measurement at whichever point on the blades you would like. I have the warp protractor but have never had to use it and am more familiar with the Kiev protractor.
Dick Maddux
Fox 4
912UL

N82HB
11-06-2010, 05:56 PM
Dick,
For reproducibility I like to be on the widest part of the blade when measuring. I have been using the outboard end of the straight portion of the blade when measuring. If you wouldn't mind measuring it for me that would be great!
I would really appreciate the help; having a good place to start would be fantastic.
Thanks again,
Kelly

Monocock
11-07-2010, 01:50 AM
Kelly

I have just been through this on my Mk 5 that I have taken a GSC off and put a Kiev on.

I have a 912s and the angle recommended to start with by Kiev was too fine. I gradually pitched it up by 1 degree at a time and re-tested the static after each re-pitching. I eventually got to 5200 which is where I like the static to be (some say it is too high but I would rather have get up and go performance than max possible cruise). As she unloads in the climb she goes to 5400 which is good by me.

I would suggest you gradually pitch it up until you can see 5200. It is easy if you have a protractor. There are lots of different types but I would strongly recommend using the one specifically designed for your prop as they all take the angle measurement in different places on the prop's length which is normally where the pitch is most measurable. Out of them all I prefer the GSC pitch tool as it is completely foolproof and as long as you have gravity where you live (how many Kitfoxes are there on the moon?!) then you can get the blades pitched very accurately. It is just a shame the GSC blades aren't all the same shape though !!:(

catz631
11-08-2010, 05:42 AM
Kelly,
I have the prop pitch angles for you. I took the prop off the wall and layed it on a flat table. The first measurement was taken where the trailing edge of the prop starts to taper toward the leading edge .This point pretty much coincides with the start of the nickle leading edge on my prop. When you lay the protractor across the blade( scale and bubble level below the blade) the nickle and wide portion of the trailing edge align with each other. The angle at that point with the bubble centered is 17 degrees. The angle at the very tips(flush with the tip) is 10 degrees.(for ref.)
As mentioned earlier ,this prop pitch gave me 5200 at WOT accelarating to about 5400 prior to rotation. It was "dead on' for my use.
Hope this gives you a good starting point,let me know how it works.
Dick Maddux
Fox 4
912UL

N82HB
11-08-2010, 11:58 AM
Thanks a lot Dick!
If our paths cross I sure owe you a good cup of coffee. I'll be looking for a reason to get down there and pay you back. Thanks for taking the time.
Kelly

cap01
11-08-2010, 04:46 PM
kelly , i made it to the hangar and checked the book . i was off a bit . i have it set at 10 dgrs but that is about 2 inchs in from the tip ,i have the tips painted and am using one of the stripes as a ref .

jtpitkin06
11-08-2010, 11:31 PM
I'm a bit confused on this thread. Is everyone on the same page with the same diameter prop with the same taper and number of blades?

John Pitkin
Greenville, TX
SS7 in build.

cap01
11-09-2010, 12:39 AM
i think your correct john , there are some apples and oranges here . but i think a person could get an idea of a place to start and maybe save a couple failed attempts .

catz631
11-09-2010, 05:03 AM
Kelly,
Happy to do it ! That's what we are here for...to help each other out.
John brings up a good point that I overlooked. I had assumed that you and I have the same dia Warp taper tip prop with nickle leading edges for the 80 hp engine. I think we do and are talking apples and apples. If not at least it is a starting pitch as Chuck mentioned
Dick

N82HB
11-12-2010, 09:58 AM
This prop measures at 15 degrees using the same method as Dick mentioned 17. I was going to increase it one degree at a time, so I figure there is a good chance I have saved myself one adjustment. Thanks.
I have been away for a bit; I have started teaching a night class and my schedule has been screwed up enough I haven't been on the forum.
Between having flown this other airplane home last week and starting my new class I hadn't flown my own in about 2 weeks (Crazy). I took care of that yesterday! I feel better now.
Moving into a new house and selling a T-hangar that I now need to move out of has caused the schedule to be crazy lately.
I am ready to see some snow though. Skis are dusty!
Kelly

N82HB
11-25-2010, 09:26 AM
I finally got the airplane out for a test hop. 17 degrees, as Dick mentioned was really close. I was turning about 5250 static; I will fly it a couple of more times and then see what I think. Currently, I am thinking 17.5 degress is where I am going next.

I am rebuilding doors right now so I had to fly sans doors. It was 26 degrees!!! I froze to death, but I had to know. I think I'll be happy to get the doors back on over the weekend.

Thanks to everyone for the help,
Kelly