I called warp drive and talked to them. They were great! They corrected my bad measurment technique and are sending me the instructions, tools and torque values to fully enjoy my ground adjustable Warp Drive product.
I called warp drive and talked to them. They were great! They corrected my bad measurment technique and are sending me the instructions, tools and torque values to fully enjoy my ground adjustable Warp Drive product.
Wheels,
I have a 68" 3 blade square tip Warp Drive prop. I've always measured my pitch from the tip of each blade but my degrees are always different than I hear about here. Did they tell you to measure somewhere other than the tips?
Steve Wilson
Huntsville, UT
Kitfox 85DD
912A / 3 Blade Taper Tip Warp Drive
Convertible Nosewheel & Tailwheel
SkySteve's SPOT Page
SkySteve's You Tube Videos
Mine is 11.5 at the tip.
Nick W
IV 1200
912Ul
Warp Taper Tip
Mine is at 9.5 at the tip. Rotax 912A 80 hp. Cruise 92 mph @ 5000 rpm, 100 mph @ 5400 rpm. Off the ground in 350-400 ft. The elevation is 4500-5000 MSL. Empty weight 670#
Steve Wilson
Huntsville, UT
Kitfox 85DD
912A / 3 Blade Taper Tip Warp Drive
Convertible Nosewheel & Tailwheel
SkySteve's SPOT Page
SkySteve's You Tube Videos
No, they said the tips. I said I was measuring 6" in with a digital micrometer. That gives me more surface area on the flat side for my level. They thought that was fine. When I remeasured last night with their technique, I found only one blade out, but its really out. 5 degrees. So I'll give it a shot today on the ground run with the tools I have. Probably won't fly until I see the tools from warp drive, but I am thinking I can make the vibration go away. I have calibrated torque wrenches and all the numbers.
The prop pitch is probably fine now. the vibe went away except at some midrange points and a little more than I like at WOT so I am investigating plugs, and balance. If I can't get it cleaned up with that I will check the clips in the carbs but the vibration is 80 percent bette now that the blades are so close in pitch.
On a related topic...I was trying to balance my 3 blade Whirlwind that has a carbon graphite spinner and plate. Are there any caveats for drilling through the spinner plate (type of drill bit, edge distance, dont do it all???) to put balancing weights?
Ok, the pitch is set. The blades are within about a tenth of a degree. the balance is good with the low mid and full throttle points being smooth as silk. I am seeing 5200 static and 5800 at cruise. The plane is doing well. I'll send pix this week, or next, you have all helped me put together a plane that came to me in boxes. I can't thank you enough.
Wheels
I got the vibration back and when I checked the blades, one of them was out by nearly 4 degrees again. Wow! I reset the pitch, re torqued to specs, rechecked the pitch, rechecked the torque, I'll test it tomorrow and I'll send it off if it slips out of pitch. Any other suggestions.
Make sure you are torquing the hardware properly. If you have self locking nuts you may not have accounted for running torque. If this is the case the resultant torque will be less then it is supposed to be.
To get the correct torque add the running torque to the actual torque. Example: An AN4 bolt/nut (1/4"-28) has a torque range of 50-70 in-lb., if the running torque was measured to be 5 in-lb then the final torque would need to be 55-75 in-lb. Personally I would take it up to the high end of 75 for a propeller, especially if the blades have been slipping. If you torqued it to 50 without accounting for running torque the actual torque applied to the bolt/nut would only be 45.
Running torque is the amount of torque it takes to overcome the friction for a bolt turning in a hole or a a self locking nut turning on the bolt/stud. You can find running torque by using a torque wrench and measuring what it takes to make it turn.
Phil Nelson
A&P-IA, Maintenance Instructor
KF 5 Outback, Cont. IO-240
Flying since 2016