Grass Strip Guys: How High?

[SkySteve]

For those of you who fly out of or maintain grass strips, is there a correct grass height? There are some common sense things, of course, like keeping it low enough for prop clearance, but is there a particular length of grass that just "feels right"? If so, what is it?

[Pilot4Life]

SkySteve,
Because I have that kind of time right now, I just scanned through some advisory circulars (AC 150/5300-13A Airport Construction & AC 150/5370-10 under Turf Establishment) and didn't find any recommended or required lengths. Just in case you thought to look at the FAA side, I'm not finding anything regulatory or recommended. Probably for liability reasons! Happy Hunting!

[kmach]

I remember seeing somewhere? that the grass should be kept axle height or lower.
The taller it is, there is definitely more surface drag.

I cut my grass when it gets around 8" , its cut height is around 2 1/2 "s .

This cut height depends on the type of grass, some do not handle being cut too short.

[avidflyer]

My runway extends out past the yard for 1400', so I mow it when I do the lawn. Some parts grow better than others, so it's often different hights, but lower the better for resistance I would say. I suppose my mower is set about 2 1/2" also. Jim Chuk

[av8rps]

I know this is contraban here on the Kitfox forum, but here is a good picture of me landing my brand X on my runway (that I don't live near so I never cut it). You can't see my large Maule pneumatic tailwheel in the long grass, and my 850 tires are about at the half way point. So it is pretty long for most people. But landing in grass this long presented no problems whatsoever. In fact I think it is softer than a regular runway that is cut to a more normal 3 inch height. The only negative I noticed was getting weeds hung up on my tailwheel to rudder springs. (I have a new tailwheel now that doesn't use rudder springs so even that's not a problem now).

The takeoff was uneventful as well. I used less than 300 ft of the 2450 available without even trying. So if brand X does it, so will our Kitfoxes.

With all that said, I would avoid grass longer than this mostly because I'd be concerned about grass getting wrapped around things and causing some braking effect you might not want.

I used to fly my early Avid Flyer on the tall and narrow motorcyle tires out of any old 3 to 4 ft high hayfield and never had issues except for having to always clean grass wrapped around things. But the tires we all like to use today tend to be short and fat, so I don't think they would work as well in that long of a grass.

[SkySteve]

Perfect. Good real life info from all. I'm more concerned with what works good vrs what some gov'nt agency desires.

[jonstark]

I've got 1000' of OVC mix. That's Orchard, Vineyard and Clover. They spread by rhisome and lay down pretty smooth. They aren't "clump" grasses that come up in tufts which get wider with time but make a really bumpy runway.

I'm pretty partial to landing on a putting green when it's green and lush but 6-8 inches of dry grass is sure fine by me!

jon

[SkySteve]

Jeff,
Understood....in a theoretically way, of course.

[SkySteve]

Chris,
Amen brother!

[SkySteve]

jon,
Yes, dry is gooood!