Saturday, July 05, 2008


My Skytec starter has problems..... test flying has stopped.

With about 6 hours on the engine, flight test progress has ground to a halt. At the end of a very satisfying day of testing (4th July) I filled the tanks, went to start the engine to taxi back to the hangar to be confronted by an awful sound from the starter. I was not aware of any kick back which, looking back through the Vansairforce archives, appears to be frequently the demise of rather too many Skytec starters .

As you will see from the first four pictures, the starter motor is hardly overlapping, or meshing, with the starter ring. Just the tops of the teeth appear to be in contact. This is witnessed by the very slight wear on the starter ring. I am not sure if this poor meshing is the cause of the problem or a result. (A result of what I don't know.)

The engine is an O-320 from Aerosport Power. Its a Skytec LS starter with dual P-mag ignitions, a two blade MT prop, and an Odyssey battery. Until now every start has been very easy and immediate with no sign of a problem.

To me it looks as though the whole base of the starter is too thick and the little sprocket wheel is positioned too far from the starter ring around the flywheel. An alternative explanation is the starter motor bracket has deformed and it has bent away. I have to say though I can see no sign of deformation.

It is wired as Skytec suggest here. This, plus the dual P-mags, I would have thought would protect it from any kickback problems, though I do not in fact think that was the cause.

All the teeth are on the flywheel, but as you can possibly see in the last two pictures there is some damage to the corners.

It has been hard to get things moving this having happened late on a Friday in the UK. I am trying to be patient and not think too badly with the suppliers involved.

The primary questions that run through my head are:

1) Why did this happen (after just 6 hours - perhaps 20 starts.)?
2) Why will a replacement unit be any better?
3) Will Aerosport Power and Skytec get me back in the air quickly or slowly?

Postscript - 8th July '08
Well Aerosport Power sure came through on this one. On the 7th thy had a Skytec NL model and toothed ring shipped, and as I write I see FedEx have just cleared it through Stansted Airport. Soon be here.

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