How to measure takeoff and landing distances

[Cubonaut875]

I tried out an intersting way to measure takeoff and landing distances, I thought I would share it with everyone. I placed a white line on my tire, measured the distance it takes for one revolution, set up a GoPro camera on my strut and recorded the takeoff and landing. I downloaded to my IMovie software, slowed it down and counted the number of revolutions and multiplied it by the distance of one tire revolution. Worked great, here's the YouTube video link:


http://youtu.be/ngs7hFfrT9M

[steveinindy]

OK, this gets my vote for the best idea on the forum recently. I wish I'd have thought of it! Thanks for sharing and that's a really nice airplane.

[Ron Blum]

Great use of the video camera for flight testing!

If you put distance marks on the runway, you can calibrate the distances, too! Regretfully this method doesn't work if the brakes are applied. In fact, that (when brakes are applied) is how anti-skid braking systems are evaluated/tuned (difference between wheel speed/distance and GPS speed/distance).

You can also use the video camera for ground airspeed calibration, lag calibration, airborne airspeed calibration, etc. It's an awesome tool ... and even more useful if you know the frame rate.

Please email me at fly-in-home@att.net The video of your local airports has made me homesick for Illinois. I grew up in Washington. It looks like your home airport is Mount Hawley ... my oldest brother still lives in Alta.

Great Job! Thanks, Ron

[Frank Giger]

How many iterations at different air densities did you perform to get a baseline for adjustment?

[Antique Tower]

When I worked at Lockheed, we did some STOL work on a modified C-130.

We mounted a .410 shotgun near the mains, pointed straight down and wired to the squat switch.

Loaded it with chalk-filled shells. They shot directly at the runway. Then we went out there with a tape and measured it....

[steveinindy]

When I worked at Lockheed, we did some STOL work on a modified C-130.

We mounted a .410 shotgun near the mains, pointed straight down and wired to the squat switch.

Loaded it with chalk-filled shells. They shot directly at the runway. Then we went out there with a tape and measured it....

Somehow, I just don't see the FAA being too thrilled about that idea among a bunch of homebuilders. Still a neat idea that I would not have thought about.

[Cubonaut875]

This is the first try, It will be iintersting to see how things change with practice and weather/runway changes.
How many iterations at different air densities did you perform to get a baseline for adjustment?

[Cubonaut875]

That - would make a great video!
When I worked at Lockheed, we did some STOL work on a modified C-130.

We mounted a .410 shotgun near the mains, pointed straight down and wired to the squat switch.

Loaded it with chalk-filled shells. They shot directly at the runway. Then we went out there with a tape and measured it....

[Ron Blum]

Years ago, we designed a paint ball gun to do something similar for Vmcg testing. OEMs want way the heck too much data, and we decided that the gun would overheat ... and never used it. On hidesight that was probably a good idea anyhow. We would have lost paint splotches within paint splotches of various runs ... and the Airport Authorities would have had an issue, too.