Rotor Blade Tip Temperature
Rotor Blade Tip Temperature
(OP)
Does anyone here know if the blade tips on helicopters get hot due to aerodynamic heating? Alternately does anyone here know a good reference for how to estimate how hot they get? I understand aerodynamic heating starts to become significant at Mach .8 or so. Does anyone have a formula for the way to calculate this heating effect?
Thanks for any help
LloydofDSS
Thanks for any help
LloydofDSS
RE: Rotor Blade Tip Temperature
At Mach=1, To/T1=1.2
Starting at 300 Kelvin, the temperature would rise to 360 K.
This effect is not very significant until much higher Mach numbers.
An interesting college exercise I remember was to start with the melting point of aluminum and feed that backward through the equation to find the aircraft's top speed, then to compare the result to the Concorde.
Steven Fahey, CET
"Simplicate, and add more lightness" - Bill Stout
RE: Rotor Blade Tip Temperature
RE: Rotor Blade Tip Temperature
"An interesting college exercise I remember was to start with the melting point of aluminum and feed that backward through the equation to find the aircraft's top speed, then to compare the result to the Concorde."
That is an interesting excercise. What was the result? I gather the russians are sticking to Mach 1.8 for precisely that reason.
Mart
RE: Rotor Blade Tip Temperature
Thanks for the info, that was very helpful.
RE: Rotor Blade Tip Temperature
Yes, I didn't state explicitly that I was using Mach 1 for a maximum tip speed, even though they are almost always less than that.
Graviman,
The exact resulting Mach number escapes me, but the point of the exercise demonstrated that above a certain speed, aluminum cannot be used for a leading edge, and titanium must be substituted (for extra cost). For higher and higher speeds, increasingly resistant materials are required, until you reach the ludicrous point of gluing millions of brittle 12 inch thick tiles all over your shuttle.
Sorry Lloyd, I've totally sidetracked your thread now.
Steven Fahey, CET
"Simplicate, and add more lightness" - Bill Stout