REFLECTOR: grass strips

[gapax2000 at juno.com]

Doug,   I am currently based at a well maintained 3300x150 foot grass field. There are approx 75 planes based here and I have always wanted to keep the option available of remaining at this strip where I have based an American Yankee for the past 20 years. When I originally purchased my SEFG kit in 2003, the first question I asked Scott Baker was "what do I need to do to keep the option open of operating off a grass field?". Although he nor the Velocity Factory endorsed flying off grass, Scott did give two recommendations in order to even have a chance of operating off grass. The 1st was to install the larger XL nose wheel and the 2nd was to install a 3 blade MT CS propeller, both of which I did.   Now, 10 years later, the 1st flight of my SEFG was on 2-1-13 and I'm 25 hrs into the 40 hr test phase. Although limited, I hope I can offer what experience I have gained so far. I am trying to break-in a 0SMO lycoming IO360 with chrome cylinders so my main flights have been to take off, fly greater than 75% power for one or two hrs maintaining acceptable engine temps and then return to the field and land. The landings on grass have been a pleasure being easy on the gear, tires, breaks, and the airframe as a whole. I have only had to apply the brakes once on roll out. I've always thought that landing would be the difficult part to master but on grass it's the takeoff that's the real challenge. To date I've aborted 3 takeoff attempts due failure to rotate. It feels like the nose is being pushed into the ground and all acceleration stops at around 50 kts. It feels like you just ran into a sand pit and everything bogs down. Once this happens you know there's no way the nose is going to rotate no matter how long the runway. I've had this occur with W&B in the 1st flight box and at the aft CG limit ( tire pressure at 45 psi in nose / 55 psi in mains, trim set, and 2700 RPM at start of takeoff roll ). Aggressively "pumping" the elevator sometimes helps and or backing off the throttle a couple hundred RPM's seems to help lighten the nose. I believe this is all due to the nose tire drag on the turf surface. The faster you go the more nose wheel drag is generated and the more the thrust drives the nose down which causes more drag. My plane actually sits about 1.5 degrees nose high after installing the Mishler nose wheel lock which should actually make it easier to rotate. I had always heard that the main negative concern with pushers operating off grass was from FOD to the prop. Well so far after 25 hrs my prop is showing moderate leading edge erosion from sand and only one 1"x1/8" ding toward the tip of one blade (has been repaired) that was received while making a fuel stop at a hard surface runway. This doesn't seem to be isolated to just me as I have recently read several other pusher pilots relating similar experiences with difficulty rotating on grass.   Anyway, as much as I'd love to stay at my grass strip, I don't enjoy struggling with the physics of taking off on grass and will be moving to a hard surface runway where not only the landings but the takeoffs have been an enjoyable experience.    Garry PaxtonSEFG flying 25 hrs321-354-5109Bob White Field X-61Zellwood, Florida 
---------- Original Message ----------
From: "Douglas Holub" <douglas.holub at gmail.com>
To: <reflector at tvbf.org>
Subject: REFLECTOR: grass strips
Date: Sat, 25 May 2013 00:16:27 -0400


There's a cool little airport just three miles from where I live and I'm thinking about hangaring the Velocity there.  But it's a grass strip, just 2700 feet long.  Is there a special technique for taking off from grass?  Maybe I should take some weight off the nose by pulling back on the stick a little while I'm accelerating? Of course, I'm worried about FOD to the prop.  I know some of you regularly fly out of grass strips. Any advice?  (We have this discussion every now and then, but I guess I don't pay that much attention unless it applies to me.) Doug Holub 
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