Helicopter control surfaces

[PRB]

I shot this pic last week at the RAAF Amberley Aviation Heritage Centre It's a UH-1 tail surface. Notice anything interesting? They screwed it on upside down! I've seen lots of helicopters, including H-1s, but I have never noticed this detail before. After a bit of Googling, it seems that the idea was to impart a nose up (tail down) force when the ship was moving forward because getting these things to move forward involves "pushing the nose down" and the designers wanted the tail surface to counteract this tenancy. The other interesting bit about this pic is that in this particular case, the surface is angled such that it would impart a nose down force. Is the tail surface on the H-1 movable? Can it be trimmed? If it is "trimmable", it seems they could have achieved the same effect with a "neutrally" shaped cross section, rather than an upside down airfoil. Very interesting.

 

[aeromed202]

Actually, if I remember from my modelling days, I think this is correct. I always thought it was positioned to account for the rotor downdraft. I found a couple of examples of different positions so it might be set for a particular airframe.

 

[Victory103]

Good catch and one can review aerodynamics to determine the purpose of the "synchronized elevator" on the Huey. I have not flown a UH-1 yet, but the H-60 stabilator moved to help maintain a level flight attitude and control-ability.

 

[PhantomTweak]

From Wiki: The UH-1H also features a synchronized elevator on the tail boom, which is linked to the cyclic control and allows a wider center of gravity range.

Also, from Airvector.net: [FONT=&quot]The Model 204...[/FONT][FONT=&quot] tail boom was fitted with a tailplane to help keep the helicopter level in forward flight.
[/FONT]
Does that help answer the question?
Pat☺

 

[AussieMan]

Or maybe being in Australia it appears upside down because we are down under .

 

[jeansy]

Nothing wrong with the picture as its correct

Its like that to keep the tail down to in flight otherwise with the pitch of the blades and helo it wouldnt fly level

 

[PRB]

Or maybe being in Australia it appears upside down because we are down under .

That's it!

 

[Moses03]

This has been an interesting topic. I had no idea myself.

 

[Dev One]

Interesting to see the negative angle of the aerofoil (sorry airfoil?) relative to the boom (fuselage) centreline (waterline/datum) there must be one h*ll of a downwash there from the rotor.....

 

[Victory103]

To that more info from the leader in the strake and improved kit to B204/205 models (civ UH-1):
https://www.blraerospace.com/products/fastfin-for-bell/