prop clearance

[Jim Morris]

What is about the minimum prop clearance permisable on a stunt ship. Mostly fly off asphalt, sometimes grass. this is with tail on wheel.

[Andrew Borgogna]

Jim
Having just had a prop clearance issue this past weekend I would say at least 1 to 2 inches with the planes center line parallel to the ground.  I clipped both ends of a wood prop on take off and the engine kept running.  This was on asphalt, the vibration really rattled the plane and lead to damage to one of my wheel pants on the next flight.  I didn't realize the screw holding the wheel pants on came loose and the it rotated 90 degrees and caught the ground on landing.  Minor problem, but it ended my flying for the day.
Andy

[Bill Gruby]

Prop clearance would probable be whatever you are comfortable with. I have to agree with Andy, my comfort range is 1 1/2" in asphault, on grass it is a little less, grass being a little more forgiving. Again bottom line here is how you feel.

"Billy G"   

[RandySmith]

What is about the minimum prop clearance permisable on a stunt ship. Mostly fly off asphalt, sometimes grass. this is with tail on wheel.

HI Jim

The normal Minimum ..if there is such a thing...is  1 inch on concrete  1.5 inches on grass, That is with the plane level, not sitting back on the tail wheel

Randy

[Crist Rigotti]

HI Jim

The normal Minimum ..if there is such a thing...is  1 inch on concrete  1.5 inches on grass, That is with the plane level, not sitting back on the tail wheel

Randy

That's what I shoot for.  Listen to Randy.

[Jim Morris]

Thanks guys, I guess Im going to have to remake the gear legs for my Avanti. I only have a little less than 1 in. with tail on wheel. 12" prop. Like to be able to go with a little more prop if needed.

[Randy Powell]

I've had as little as an half inch. But sooner or later (probably sooner) you will buzz the prop on take off. This is a real problem on low slung classic planes. Go with Randy. At least an inch on pavement and an inch and a half on grass if you want consistent takeoffs without damaging props.

[Bill Little]

geeezzzzzzzz, Randy Smith!  you'uns never told us'uns that before!!!  Now I will probably grind down some props because of it!  I have been a'thinkin' that 1/2" was ok!  Really.............  bad thing is that up ' til now, I haven't had a prop problem, now you done gone and jinxed me..............  but then, I haven't even measured it a lot of the time...........when you only get a couple dozen flights a year, there doesn't seem to be too many problems.......    

[minnesotamodeler]

Thanks guys, I guess Im going to have to remake the gear legs for my Avanti. I only have a little less than 1 in. with tail on wheel. 12" prop. Like to be able to go with a little more prop if needed.

You could just go to bigger diameter wheels; or a 3-blade prop with a little less diameter.

[don Burke]

I think a good rule of thumb is to have the prop tip no lower than the main gear axle with the airplane at zero degrees (level flight attitude).  More of course would give a safety margin.