Runway Grass Height?

[TXFlyGuy]

What would be considered the normal max height for the grass on a runway, for normal daily operations? 3"? 4"? We are cutting this to 3.5" now. The runway is 3000' X 150'.
Any thoughts?

[humptybump]

It may be personal preference and the type of aircraft operating off the grass runway.

My runway is shorter than yours so I cannot afford an extended takeoff roll due to rolling resistance. Higher performing aircraft and aircraft with constant speed propellers have less of an issue.

I cut the runway to 2" and the taxiways to 2.5".

Remember, your cut height is the shortest it will be. Depending on how frequently you mow and how fast the grass grows you can easily see grass 1.5" taller than your mowing height.

[Piper J3]

Depends on the airplane. Tailwheel is far more tolerant of tall grass than nose wheel. Also 6" wheels are better than 5". The 65hp Cub I had could handle tall weeds. My 12 likes short dry grass or it's not happy.

[TXFlyGuy]

There will be a C-150, Piper 140, plus two tail draggers. All based at this airport. I would post photos, but it is not easy here.
So based on the response so far, 4" is the definite max?

[pa38112]

Tall grass does not make that much difference on take-off performance. The main reason to keep it well maintained are to keep staining on your prop and wheel pants to a minimum. I cut mine at 2-1/2" once a week.

[brad walton]

It also depends on the type of grass, which may be related to your geographic location. TS07 in Cypress,Texas is Bermuda grass cut very short, maybe one inch and maintained like a golf fairway. In the northern regions, it is going to be something like blue grass which must be cut longer

[TXFlyGuy]

The grass is a wide variety...on the last 1000' (17), it has a lot of coastal Bermuda. The first 1000' is rye, weeds, and broad leaf grass. The middle 1000' is rye, tall fescue, and broad leaf grass plus various weeds.

The north end slopes a bit, so does not retain enough moisture to support Bermuda. The very south end is relatively flat, holds moisture well, thus the Bermuda that is doing well on that end.

It looks awesome when mowed...I will go to some trouble, see if we can post a photo or two.

[Toobuilder]

Originally Posted by TXFlyGuy

It looks awesome when mowed...I will go to some trouble, see if we can post a photo or two.

Fixed that for ya.

If the image exists anywhere on the web, just add [img] before the address and [/img] at the end.

[TXFlyGuy]

Thanks! Here are a couple more...

[M McGraw]

I agree with the people that say a high performance aircraft and larger wheels makes grass length less important.
I normally keep mine at 3 to 3.5 inches and I can't tell the difference when it is at 5 inches. However, my subsoil is mostly hard clay and the grass is not very thick. I went into a field in Florida with nice thick 5 inch grass and a sandy subsoil and I aborted my first takeoff thinking the engine was not producing. Type of soil is really more important. Soft soil probably holds moisture better and would allow you to mow shorter without harming the grass.