PDA

View Full Version : Warp Drive pitch settings



the Drew
06-03-2009, 03:45 PM
Does anyone know where I can find the proper pitch setting for said prop and Rotax 912 ULS for the Kitfox 7? I am not getting near the static RPM that I should, and want to start checking with the prop pitch. Thanks in advance.


Kenny

SkyPirate
06-03-2009, 05:26 PM
2 blade or 3? tappered tip or square?

the Drew
06-03-2009, 07:10 PM
It is a three blade, and the ends are squared.

SkyPirate
06-03-2009, 07:52 PM
if I remember right ..Slyfox ..(Steve) was using a warp 3 blade on a 912,..he has switch out to a Medium IVO now ,..but he would have better numbers for you .

Mine was a 3 blade tappered tip on a 582 E box ..set at 12 degree's
450 ASL..average temp 80 F.

from what your saying you have too much pitch on your prop,..it takes very small increments in degree change to change RPM's with the warp,.. if your less then 500 RPM from your desired RPM,..I'd go 1/2 degree changes until you reach what your looking for ..it's a little time consuming with the warp..
but it will take less time with small adjustments then with big ones going back and forth on changes.

the Drew
06-04-2009, 03:20 AM
Thank you Slyfox.

I rechecked my settings last night, and I was set at 16 deg. I don't even know where that # came from. I was only getting 3300 rpm or so. I've reset the pitch to 10 deg. and will see what I get later this morning.

Dorsal
06-04-2009, 03:42 AM
Please post your results, I have the same set-up and I am about ready to run the engine.

JimS
06-04-2009, 07:07 AM
I run the three blade nickel leading edge warp on my 912. Upgraded from a 582 and last summer flew with the warp wide tip. Sent it back to Warp this winter and had the tips tapered. Gained 6-7 mph in cruise and climb remained the same if not slightly better. The motor runs noticibly smoother also. Don't know what my prop is set at as I just use a bubble protractor and adjusted to get 5500-5600 on takeoff. In cruise I'll set 5000-5100 and see 105 mph which for my Model IV is the top of the green. 3.5 gph.

JimS

SkySteve
06-04-2009, 08:00 AM
I run the Warp Drive medium, square tip on my 912A (80hp) at 8.5 degrees.

Dave S
06-05-2009, 04:35 PM
Kenny,

If any doubts - might want to call up the warp drive folks at 251-609-0969; or e-mail them at warpdrive@gnt.net

I found these folks very knowlegeable and helpful with specific applications.

Provide them with your prop's serial number and the engine - they'll give you the working range for the pitch setting.

At any rate, if you are pulling 3800 rpm- the pitch is probably a little radical.

Reality is a person needs a staring point then will probably fine tune from there. I started with a mid range pitch setting and worked up to somewhat of a cruise setting.

My understanding is that the square tip will pick up RPM quicker once the airplane is moving than the taper tip will and they do behave a little differently.

Sincerely,

Dave S:cool:
K7 trigear - warp tapered tip & rotax 100 hp

the Drew
06-06-2009, 10:08 AM
I did call Warp Drive and they told me 11-13 deg. I also talked to John McBean at Kitfox Aircraft. He measures at a different location than the tip, but his setting correlated exactly to the Warp Drive setting measured at the tip.

Fess-up time. I am using the Grand Rapids EIS system. As I was re-reading everything, I found a small hidden paragragh which stated that the EIS must be calibrated for the 912. So out to the hangar I go with book in hand and follow through all their steps (not really that many) to check the calibration. It was not set correctly. I made the correction, and now have all kinds of RPM.

My pitch setting ended up at 13 degrees, measured a the tip. 5380 RPM static full power.

On another happy note, we passed our airworthiness inspection this morning.

Dave S
06-06-2009, 10:41 AM
Hey Kenny,

That is great news. There is that little thing about instrument calibration - those of us who responded obviously made some assumptions about the original reported indicated RPM; but you got 'er now!

FYI - I sort of decided through experimenting that measuring a few inches in from the tip and interpolating the difference between the protractor reading and the pitch the tip is supposed to be set at helped a bit with the accuracy of the setting from one blade to the next - since I have the tapered tip - it seemed a bit awkward trying to get a consistent reading from blade to blade at the tip since there is such a short chord to work with - figured that would be less of an issue with the non-tapered blade anyway.

Really great hearing you got the airworthiness certificate - that is a major milepost to your progress.

Do good on that first flight now!:)

Sincerely,

Dave S
k7 Trigear
912 ULS Warp

wadeg
07-16-2009, 10:17 PM
Have you flown yet and if so, how do you like the 13 degrees setting on your prop. Might reduce my pitch to help me get down steeper. At idle it really wants to keep going and going. Would love to get it to the point where I can "cut and plop".

the Drew
07-17-2009, 07:58 AM
I have flown and find like you, that at idle power, it carries me too far. What would you suggest if anything? Perhaps reducing to around 11.5-12? Aside of that, it's got plenty of scoot, and having a blast.

wadeg
07-21-2009, 10:42 PM
Reduced my prop to 11 and tried it out. I like the sling-shot acceleration on takeoff and the ability to bring it down really fast. Cruise is slower. At 5300 I was getting about 105. I might try 11.5 out. 12 was just a little too much pitch for me I think.
I did notice that at 5300 in cruise it was a little rougher with the pitch at 11 than it was at 12. Anyone notice a difference? Using a digital level so got the pitch within .1 degrees for each blade so I don't think I have a aerodynamic imbalance. Sure wish LSA would allow for in flight variable pitch!

Slyfox
07-22-2009, 09:08 AM
sounds like you have a rotax, if it's the 912, do what I did and lower the idle down a half turn on the stops. This puts the idle down to about 600rpm. Eeeek you say, well if you are on it right, you can pull the throttle all the way back on decent and have a nice little brake. As you are flairing to land push the throttle slightly in and you now have a normal idle. I've done this for hundreds of hours it it works real slick. On shut down you run around 2000rpm and than kill the switches and pull back on the throttle, makes a nice smooth shut down. On start up, I run without the mags on for a few seconds to circulate the oil, I don't do any pre turning of the prop but a few turns to make sure it's not oil locked and than start it mags off for about a count of 6 at least while watching the oil pressure. Than I pull the throttle all the way back, it's usually already there and turn the mags on, than slowely increase the throttle and a nice start up. With my 912uls, if I don't do this it will lock up because of compression stroke and fire. I guess my little battery isn't enough. But starting with throttle closed off, idle 600rpm remember, it starts fine. Even in the winter, in that period, I run throttle closed with about 6 seconds with choke on, mags off, than mags on throttle closed, choke off, fires right up. Sounds complicated, but not really, my lycoming is much more work.

kitfox812
11-13-2009, 02:27 AM
Hi

I have a SS 7 / 912uls with the same problems. My prop is a Powerfin 3 blade. My takeoff RPM does not get above 4700 till about halfway down the runway then it starts climbing above 5000 depending on my departure angle. After numerous pitch changes, I ended up with a pitch that tops out at around 5600 WOT when level. I can still get off in 150 ' or less and climb at 1000 fpm right after liftoff but I hate to be lugging down the engine.

Rich