I am somewhat savvy on helicopter dynamics, having been flying the R/C versions since 1982, but there is one thing I haven't been able to figure out...

Quite a few full-scale helos, including but not limited to the UH-60 Blackhawk, have tilted tail rotors. Why? What is the reasoning behind this "feature"?

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This message has been edited. Last edited by: benny6,

tailrotor authority determines hovering performance at altitude.

I have mostly owned/flown Bell aircraft and Sikorsky S-76 and Aerospatiel SA-15. Can't really answer your question directly but it may be the lift mentioned above.

quote:

...helicopter aerodynamics...

Ahhhhh....hahahahahahahahahahahahahahahahahahahaha

-fixedwingaircraftmaintenancemonkey



But to answer, the moment (tilting force and yaw in a forward pitch and lateral roll) induced by the main rotor torque, is offset with angled tail rotor. It is sort of like trimming a fixed wing aircraft. (Or as some recip aircraft had offset in the engine mounting to help counteract the torque and asymmetrical thrust.)

quote:

Originally posted by sigmonkey:

some recip aircraft had offset in the engine mounting to help counteract the torque and asymmetrical thrust.

Yup. The V-Tail's engine centerline is not parallel to the airplane's longitudinal axis, for the reasons that you cite. It is offset so that the thrust provides a slight yaw to starboard, to counter the port yaw produced by P-factor and torque.

I know nothing of helicopter dynamics. Flew all over Southeast Asia in the things and see them flying every day from the Navy training base nearby, but the more I look at them, the more mystified I am. I am convinced there is an element of black magic involved.

quote:

Originally posted by sigmonkey:

quote:

...helicopter aerodynamics...

Ahhhhh....hahahahahahahahahahahahahahahahahahahaha

-fixedwingaircraftmaintenancemonkey

Now, now Mr. Monkey, even a cinder block has an aerodynamic profile. A terrible aerodynamic profile, but an aerodynamic profile nonetheless.

quote:

Originally posted by Sig2340:


Now, now Mr. Monkey, even a cinder block has an aerodynamic profile. A terrible aerodynamic profile, but an aerodynamic profile nonetheless.

Is that the thought behind the F4?

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This message has been edited. Last edited by: benny6,

quote:

Originally posted by MikeinNC:

quote:

Originally posted by Sig2340:


Now, now Mr. Monkey, even a cinder block has an aerodynamic profile. A terrible aerodynamic profile, but an aerodynamic profile nonetheless.

Is that the thought behind the F4?

With enough thrust you can get a brick to fly.

quote:

Originally posted by sigmonkey:

quote:

...helicopter aerodynamics...

Ahhhhh....hahahahahahahahahahahahahahahahahahahaha

Yeah, yeah.... I know. Helicopters do not fly; they beat the air into submission!

quote:

Originally posted by sigmonkey:
-fixedwingaircraftmaintenancemonkey


But to answer, the moment (tilting force and yaw in a forward pitch and lateral roll) induced by the main rotor torque, is offset with angled tail rotor. It is sort of like trimming a fixed wing aircraft. (Or as some recip aircraft had offset in the engine mounting to help counteract the torque and asymmetrical thrust.)

Thanks... that makes sense!