On Tuesday, October 20, 2020 at 12:02:17 PM UTC-4, Tango Whisky wrote:
40 kts corresponds to 20.58 m/s. (20.58 m/s) ^2/3 doesn't make any sense unit-wise, and the numerical result would be 7.36.
My Ventus cM touches down at 40 kts and has a hydraulic disc brake which works pretty well. Stopping distance without hitting the nose on the ground (on grass) is 170 m.

Ah, I see the problems. You've made a mistake in the order of operations AND I've made a typo. The exponential resolves before the division so it's not v^(2/3). However, even worse is the typo: the equation is (v^2)/12.Â*

Derivation is heÂ*https://gist.github.com/kubark42/61a...e0f6e7abefe643

Despite the typo, the calculation was correct for your plane 20^2/12 = 33.33m. Please do note that this calculation is meaningless beyond giving how much the tailwheel moment limits you to before you tip forward onto your nose.

However, your real-world 170m distance supports my theory that for modern glass planes the limiting factor is not the weight distribution between the main and tail wheels.