Data Point for Fairings speed increase

[czechsix]

Guys,

I know others have commented on how much speed an RV picks up when fairings are installed. Just for kicks though I took some data in my RV-8A without any fairings and then again with wheel pants, gear leg and intersection fairings installed. My data was taken with four-way GPS runs using one of the calculators on Kevin Horton's website (the advantage of the four-way run vs. three-way is that the spreadsheet gives you a sanity check to show how good/bad your data is).

Anyway, at 4000' density altitude, power set to 24 squared and mixture 50 ROP, I saw an 18 kt gain in TAS when when fairings were put on. I would imagine that the speed increase would be less in a taildragger since there are only two big gear legs/wheels to clean up. I wish now I'd taken some numbers at full power and lower altitude...I bet the speed increase would have been at least 20 kts. Even so I've told several of my spam-can buddies and they can't believe that fairings would make that much difference.

Cool!

--Mark Navratil
Cedar Rapids, Iowa
RV-8A N2D with O-360-A1A and blended Hartzell
Flying 29.2 hours now....