The prop clearance on my plans-built, KR-2 with Diehl tri-gear and Great Plains 2180 VW and 52x52 prop is 9-1/2 inches. Tony Bengalese recommends 9-inches in his book Firewall Forward. I made a wheel-barrow landing on my first flight; I bent the nose strut and the swivel bolt plus trashed the nose wheel fairing. Did not have a prop strike. I taxied about half mile back to the hangar and shut down before I found I had bent something. I still had 7 inches prop clearance. I have since replaced the nose strut and the swivel bolt assembly and got back the 9-1/2 inches prop clearance.
Had I made that first flight starting out with 7 inches prop clearance, I am certain I would have had a prop strike and probably trashed the VW. Tony has passed, but he is still helping me. Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ------------------------------ > Paul Visk wrote: > >> Can someone tell me the distance between the bottom of the firewall and >> the center line of a corvair engine? I might have a 56x60 prop. I need >> to know how long the nose and main gear needs to be so I don't make >> rumble strips down the runway. > > See the image at the bottom of > Can someone tell me the distance between > the bottom of the firewall and the center line of a corvair engine? I > might have a 56x60 prop. I need to know how long the nose and main gear > needs to be so I don't make rumble strips down the runway. You need one > more measurement to make to get your number, crank centerline to the > bottom of the case, but that should be easy for you.. The 8.25" number is > bottom of firewall to bottom of case. > > A 56" prop is pushing it, somewhat. I started out with a 52" prop, then > went to 54" props (and I killed one of those in a deliberate nose-low > landing), and after a lot of experience went to a 56" prop, but you need > to keep the tail low and be cognizant that there's not a lot of room for > the prop clearance out front... > > Mark Langford ------------------------------ Also I have heard that you need 4" prop clearance in a level position. Put your engine up high enough to get that figure, Virg ------------------------------ More is better! I will bet that someone will come up with facts rather than our supposition, Virg Ain't this a great forum ? On 1/3/2014 9:37 AM, Pat and Robin Russo wrote: > I was under the impression that nine inches was recommended/required > clearance.