Hi Dave, Try Googling 'vw warp drive failure' There have been numerous prop shaft failures.
Basically as I understand it any difference in the lift of each of the blades can cause horrendous vibration and a vw crank cannot take it - not sure if this applies to revmasters. Wooden props are the best solution for vws. Generally in uk vw engines are limited to 3400 revs to keep prop tip speed below 0.7 mach - your prop tip speed at 120mph @ 5000ft is 0.76 mach. A further problem with 3 blade props is they are smaller, so they are less efficient as a lot of prop wash hits the cowling. I think you should be looking for a prop that gives you around 3100rpm static, 3400 max level. Probably something like 56/46 2 blade wood -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. Dave Dunwoodie <ddunw...@fnwusers.com> wrote: Hi again everyone, I have more questions! Revmaster hasn't responded to my questions, but Warp Drive has. So I'm making a little progress! Here's a brief history. The airplane is a standard KR2 with spring gear and brakes. Beyond those changes, it appears to be plans-built. It is fitted with a Revmaster 2100D and a Warp Drive 3-blade prop, square tip, 52" diameter. I am soliciting suggested RPM settings, pitch settings, etc. I note that the Revmaster charts stop at around 3300 RPM, but that the curve is still rising at that 80HP point. Daryl at Warp Drive suggested that I should be looking at perhaps 3500-3600 RPM ??? He said that if I want to "slow it down" to 3000 RPM, some pitch adjustments might be appropriate. So I guess I'll ask for the simple information now, and then the detailed stuff later! What would be the redline for the 2100D ? What would be the best takeoff RPM setting ? What would be the best cruise RPM ? (And dozens more questions like that)... On the prop, what would be the best pitch, at least to start from ? Has anybody worked climb against cruise performance and developed some suggestions for pitch settings ? Any information and/or suggestions for this engine/prop combo would be most appreciated. The aircraft has 118 hours logged with this combo, but very little performance data is documented. The original tachometer had the redline at 3500 RPM, however Warp Drive is suggesting the 3500-3600 range for normal operations, so I'm wondering now. I am trying to develop a POH and also determine some do-not-exceed markings, etc., so any experience in these areas would really help. Thanks, Dave._____________________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
