hydroplane formula?

[splash]

I tried googling this but didn't get what I was hunting for. I can't remember the formula for the speed at which a tire will hydroplane at. It is close to something like this tire pressure x 7/9??? Is this correct? Maybe a 3 in the mix somewhere? Any help out there? Thanks.

 

[Jfk-Pilot]

for take off its 8.7 times the square root of the main wheel tire pressure, and for landing its 7.7 times the square root of the main wheel tire pressure

 

[///AMG]

I've always heard 9x SQRT [tire pressure]. Is the difference in factor you heard between T/O and landing to account for less weight following fuel burn (and thus a lower minimum hydroplaning speed for a lighter aircraft) ?

 

[Cessnaflyer]

I've always heard 9x SQRT [tire pressure]...

Same thing I've heard.

 

[bLizZuE]

8.6 is the official, but 9 gets you close.

I have never heard different figures for takeoff or landing however.

 

[African_Swallow]

Here's what the AFH has to say:

http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-4of7.pdf

 

[ProudPilot]

So... nothing about it? That's about right for the FAA.

 

[granlistillo]

I think on the gleim it is 8.52 x sqrt of tire pressure in psi. If you are taking the atp test.

 

[African_Swallow]

So... nothing about it? That's about right for the FAA.

:insane:

Page 8-34; formula only works for dynamic hydroplaning.