please give some general formula for skin friction in terms of coefficient of drag, reynolds number etc.
2006-10-18 16:07:24 · 3 answers · asked by canard63 1 in Cars & Transportation ➔ Aircraft
Cf=(t sub W)/(1/2pV^2)
2006-10-19 03:16:01 · answer #1 · answered by Drewpie 5 · 0⤊ 0⤋
Surface finish has a lot to do with friction/drag.
The McDonnell Douglas MD-80's I use to build had an aluminum skin with a thin coat of highly polished surface called Alclad.
The American airlines planes we build had the best fuel economy, because the only paint they would get is a red/white/blue stripe along the cusp....the Alclad was super smooth, and without paint, they weighed less.....people think paint does not weigh that much, but pick up a 5 gallon bucket of paint, multiply that by how many gallons are needed to completely cover an airplane....then get back to me.
2006-10-19 13:08:17 · answer #2 · answered by strech 7 · 1⤊ 0⤋
Cd1/2pV2S. where:
Cd is the coefficient of drag
p is airdensity (Greek letter rho)
V2 is velocity squared
S is frontal surface area.
1/2pV2 is the formula for dynamic air pressure.
We have a coefficient of drag because we can't figure it out directly, we can only measure its effects. Rough skin will add to the coefficient. So will airflow interference (between wings and fuse for example).
2006-10-19 19:21:12 · answer #3 · answered by Anonymous · 0⤊ 0⤋