Im giving a little update on the information I have now concerning the prop change I made recently. I wrote on a previous email that I removed my Prince p-tip 52X54 due to vibrations and replaced it with a loaner from William Wynne. The Sensich I currently have on is a 54X52 and runs very smoothly. It is a great prop and has good climb and cruise numbers but has too little pitch for the rpms I want. But, again, it is a loaner until I perform the turbo change. Upon further analysis of the Prince prop that I removed I do want to make a couple things clear. The vibrations that were being felt on the prop and the tracking problem I had were not anything to do with the manufacturing or how the prop was built. The vibration started soon after the airplane had been tied down improperly at an airport. Straps were tied around the prop itself and then to the ground. (very strong winds required this). When the straps were removed there was a section of trailing edge that was broken off from the straps. It was repaired but I believe there have been more problems internally with that prop so I have removed it from service. I had over 200 hours of flying time on it and it did a great job. I had good cruise numbers and smooth performance with it. Ihave flewn with other Prince props and never had any problems and have had excellent service from Lonnie Prince. He called today when he heard that I had had problems with the prop and was concerned for my saftey and wondered whether there was a defect but I assured him it was outside damage that caused the problem. It isnt every prop maker that would call you personally to check up on his product and I appreciate the fact that he did. I would fly behind another Prince prop again with no problems. His props are CNC'd and are outstanding. There are many good prop manufactures out there.
Perhaps my prior note seemed to pick on the prop makers but I really wanted to stress to you builders to not be cheap and to buy a high quality prop. You get what you pay for. Prince makes a great prop - but not cheap - Sensnich makes a great prop - but not cheap. Spend the extra money for a good prop guys. I can only talk about these two makers because that is all I have tested. I will be testing a Sterba prop on the turbo installation to get some numbers and then testing with a Sensnich and a Prince to get more information. I will have to buy a good prop - and maybe two.... I appreciate those who have lent me props to do the testing to get some good numbers for you guys. We are all learning in this game boys (and girls) and the more information we learn, the better. Another aspect about props and engine is vibration. The vibration that cause me to investigate the prop was very slight. A pilot behind an 0200 or VW may never have noticed what I noticed. I have a lot more experience and time behind the corvair engine and know what a "right" feel should be. When the vibration analysis was performed Arnold said that the vibration was typical for most certified engines and props but that the majority of vibration came from the damaged prop. It was a very slight vibration and only at some rpm settings but something that I could tell was not right. Sorry to say that I dont believe more pilots could pick it up because many dont pay attention or or not entuned to their engines....again this takes time and experience to develop. Many wait util something breaks but a lot of these issues can be caught ahead of time if you develop those skills. We have seen people flying on five cylinders (out of six) that thought their engine were running smooth...compared to an 0200 yes but not for a corvair. Learn what "right" is and then it is easier to learn when things are going wrong. Maybe this helps - I sure hope so...See you all at Sun N Fun...... Bill and N41768
