I recently bought a Mk 5 that has a 912s installed. I am summarising my prop experiences as I thought it might help others who are looking to change props this winter.

When I bought the aircraft it had a 68 inch GSC ground adjustable on it. I just could not get the engine to stop vibrating, especially in the 3500 - 4500 rpm range. I tried everything from carb sync'ing, checking the mountings right through to balancing the prop dynamically. But, still she vibrated like hell. We eventually worked out what it was and realised that the tracking had moved from 1/16 inch error on one blade when it was installed to half an inch error within 6 hours of flying!!! There was nothing we could do to put this amount of error right and the blade just seemed to get more and more out of track the more I flew.

As a last resort I tried a friend's Kiev to do some ground run-ups with. It was remarkable how smooth it ran, right through the power range. So, I ordered one and installed it last week.

Setting it up was easy and within an hour we had a static of 5,200 rpm. I flew her for the first time with it installed yesterday and it was like a different aircraft. Smooth as silk and very responsive. The climb rate is 1400 fpm and 100 kts is easy at 5,000 rpm. 4400 rpm (or will I get deleted from this forum for suggesting such a low cruise power) gives 75 kts.

The prop wasn't too expensive and the dealer was really helpful. I have to get a spacer to be able to fit the spinner/backplate but will just wait for this to arrive.

All in all I can highly recommend the Kiev. I know I have only done a couple of hours with it but so far, so good.