Questions About Tail Rotors.

[tDawe]

I know there was a link posted here at some point about tail rotor aerodynamics, but I can't find it, so I'm going to float a question I have about tail rotors, maybe someone can enlighten me.

 

 

1.) When I look at Sikorsky's S92 and UH60 the tail rotor is on the wrong side, but the blades still turn counter clockwise? Is there an aerodynamic advantage to turning the tail rotor around to the right hand side of the tail boom? Is there much difference between the tail rotor is acting as a "pusher" or a "puller"?

 

 

Thanks in advance to anyone who can enlighten me so I can sleep at night.

 

tDawe

[mtnhopper]

Good question, Idono maybe w&b? I'd be interested to here aswell

[mtnhopper]

Tdawe It could be the same as the 205s in the older non civilian machines the tr was on the oppiste side as the commercial machines it could be maybe a military thing beans how the uh60 is military and the s92 is now civilian ,But I'm probaly way off

[rotrhd1]

I know a guy who's used to be on a team of Bell disign engineers, and is now a pilot. I'll email him to try to get an informed answer.

 

Postulating out loud....

 

The tail rotor on the left side draws its air from around the vertical fin which may cause a disruption of smooth airflow. Putting the thing on the other side may give it more undisturbed airflow and therefore a tad more efficiency. It may also decrease the interferance of the main rotor vortices with a wind from the 10 o'clock position.

 

I believe having the tail rotor turn so the forward travelling (to the nose) blade is at the top helps with perfomance as this blade is moving upward through clean air outside of the downwash from the main rotor blades in the hover. Robinson changed their thinking in the transition from the R22 to the R44. R22 tail rotors spin clockwise (looking from the left side of the aircraft) and the R44's go the other way.

 

As a side note/question....

 

On the newer designs the manufacturers also canter the vertical fin to one side or t'other. Any ideas as to why this may be?

 

Regards

 

RH1

[shaggy]

I know a guy who's used to be on a team of Bell disign engineers, and is now a pilot. I'll email him to try to get an informed answer.

 

Postulating out loud....

 

The tail rotor on the left side draws its air from around the vertical fin which may cause a disruption of smooth airflow. Putting the thing on the other side may give it more undisturbed airflow and therefore a tad more efficiency. It may also decrease the interferance of the main rotor vortices with a wind from the 10 o'clock position.

 

I believe having the tail rotor turn so the forward travelling (to the nose) blade is at the top helps with perfomance as this blade is moving upward through clean air outside of the downwash from the main rotor blades in the hover. Robinson changed their thinking in the transition from the R22 to the R44. R22 tail rotors spin clockwise (looking from the left side of the aircraft) and the R44's go the other way.

 

As a side note/question....

 

On the newer designs the manufacturers also canter the vertical fin to one side or t'other. Any ideas as to why this may be?

 

Regards

 

RH1

<{POST_SNAPBACK}>

 

that is to add a vertical component to the thrust vector of the t/r. helps the machine lift more.

[Winnie]

Cleaner air maybe?

 

Shawn Coyle and Ray Prouty have both good explanations!

Will post more later!