Microlighters

My trike was damaged in hanger (doors blew down) and had to replace one of the prop blades. It is a NC prop and was done professionally by the manufacturers. I now have a vibration from 5400rpm and higher. When I measure the distance from the prop blade tips to the trike’s body, there is a slight difference. How serious is this and how do I fix it. I was advised to use spacers as thin as coke tin and torque nuts back to 8nm. Any advice or professional procedures I should take.

Peter

I have a 62" 3 blade warp on my trike and one of my blades runs out of track by 2-3mm, I contacted warp drive to ask there advise and was told its within limits and to a certain extent the are self aligning as the blade spins-centrifugal force,

Does it need balancing? and how much out of track is it.

Nick.

Well I presume that it was balanced when one blade was replaced (Nigel from NC Props). It is out by about 5mm. My problem is that the AP that replaced and test flied my trike, did not pick it up; neither did the person who did my anual 4 months later. Only after I told him he explained how to correct it. So maybe it is not bad enough to worry.

Hi,

Five mills is quiet a lot, Have you checked the pitch? if its different to the other two it will cause a lot of vibration and might also be part of the 5mm diff in tracking.

This is a problem. You need to check the prop for balance. If you find it out then rebalance it yourself or send it back to the manufacturers

Balancing is a simple process. Your prop hub should have a hole in it. Measure this hole and go to a pharmacy or plastics supplier or your medicine cabinet and see if you can find a tablet tube with the same size. The top of the tablet tube should be bigger. Drill a tiny hole in the exact center on the bottom of the tube and insert a piece of string and tie a knot to prevent the string from slipping out. Then insert the tube through the hub from the side that normally faces forward, i.e. the side with the rounded profile on the prop blades. Now suspend the prop in a wind free environment so it hangs parallel to the ground with the flat rear surfaces of the blades facing up.

if the prop is balanced, then it will hang perfectly parallel to the ground. If not the heavier blades will hang lower. Now using a spray can of clear laquer spray, spray the back of the highest blade. keep doing this on all the blades until the prop is perfectly parallel. I often use a little round spirit level guage that you use to level fridges with, Camping shops supply them, to make sure it is completely accurate. I put this on the hub as close to the center as possible so as not to affect the balance too much.

Secondly you need to make sure that the tracking is as near as dammit, 1 or 2mm maximum

I will try this and let you know. Thanks