This question of "warp drive" props on V W engines keeps coming up and I saw this answer on [AirVW] from Hal Hadaller which I thought covered the question very well.
Posted - Saturday, 02/03/07 11:53 am Regards Myron (Dan) Freeman Indpls, Ind. 46203 USA mfreem...@indy.rr.com ----- Original Message ----- From: Hal Hadaller To: ai...@yahoogroups.com Sent: Saturday, February 03, 2007 11:24 AM Subject: Re: [AirVW] warp drive props? Most plastic or metal props resonate. They also have hubs that are seperate of the prop. All this can/will create severe torsional vibrations and ultimate failure if this occurs. The resonances are a function of the rpm and the overall balance/imbalance of the system including the crankshaft, drive system and propeller. The higher the moment of inertia the worse the problem can become. These type props are not recommended for a VW engine. They have also caused failure of Lycoming engines which have really heavy duty crankshafts. The propeller on certified engines are mated with the particular engine and the FAA does not allow much for variation of the factory setup. When I say mated, they are "tuned" for the inherent resonances of the engine and propeller. Some aircraft have restrictions on running a certain bands of rpm as this could cause failure. The VW case and crankshaft are inherently weaker than Lycoming/Continental engines. Thus only w Need I say more? I should also add, that the aerodynamic pitch off all producers of props are different. You can't test one type on an engine and then learn anything about the pitch required on another type of prop. The diameter also makes a huge difference. The shape of the outer section of the Warp drive blades are completely different than about any wood propeller. It is a good thing that you are asking these questions now as it is indicative that you need to do some serious research and studying. In your case, I would only recommend the tried and proven. Even making your own HUB is a big risk. Don't take these risks unless you are prepared for disastrous results. It takes a large investment and a huge amount of testing to overcome the risks envolved. And most or us do not have these sorts of resources. Your Designated inspector may not even approve of some of these things if he believes flight safety is envolved. Hal ----- Original Message ----- From: JEFFREY D WALIN To: Air VW Sent: Friday, February 02, 2007 9:59 PM Subject: [AirVW] warp drive props? Hey, I wanted to ask about the Warp Drive props....I read somewhere that they had been 'linked' to crankshaft failures in VW's. Is there any truth to that? I am building a flywheel drive Type 4. I will have my own design prop hub, and will use a 4340 forged stroker crankshaft. I want to use a Warp Drive ground adjustable to find the best performance, then buy a Sensenich all wood prop. Anyone see anything I should look out for? Jeff [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] __._,_.___ Messages in this topic (3) Reply (via web post) | Start a new topic Messages | Files | Photos | Links | Database | Polls | Calendar Change settings via the Web (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe Recent Activity a.. 7New Members Visit Your Group SPONSORED LINKS a.. Aircraft engine maintenance b.. Aviation c.. Recreation d.. Aircraft engine overhaul e.. Aircraft engine repair New web site? Drive traffic now. Get your business on Yahoo! search. Y! GeoCities Create a Web Site Easy-to-use tools. Get started now. Yahoo! Groups Start a group in 3 easy steps. Connect with others. . __,_._,___
