Helicopter control surfaces
Results 1 to 10 of 10

Thread: Helicopter control surfaces

  1. #1
    Senior Administrator PRB's Avatar
    Join Date
    Jun 2005
    Location
    MO (KSUS)
    Age
    58
    Posts
    9,160

    Helicopter control surfaces

    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.
    Attached Thumbnails Attached Thumbnails airfoil.jpg  
    - Paul

    Win7 x64 | GIGABYTE X79-UP4 | Intel Core i7-3820 Quad-Core 3.60 GHz | 16GB DDR3/1600MHz Quad Channel Memory | NVIDIA GeForce GTX 660 Ti 2GB 16X PCIe 3.0

  2. #2
    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.
    Attached Thumbnails Attached Thumbnails huey tail 2.jpg   huey tail 3.jpg  
    W7-64, 3GHz, 16GB Ram, GEForce 9400GT

  3. #3
    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.
    Fly Navy/Army (Ret. 2/2018)
    USN SAR
    DUSTOFF/ARMY PROPS

  4. #4
    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:
    The Model 204... tail boom was fitted with a tailplane to help keep the helicopter level in forward flight.

    Does that help answer the question?
    Pat☺
    Fly Free, always!
    Sgt of Marines
    USMC, 10 years proud service.
    Inactive now...

  5. #5
    SOH Staff .."Bartender" AussieMan's Avatar
    Join Date
    Jun 2005
    Location
    Woy Woy, NSW, Australia Zulu +11 AEDST
    Age
    73
    Posts
    3,450
    Or maybe being in Australia it appears upside down because we are down under .


    Cheers
    Pat


    "Some people might say that freedom is being alone in the bush with the only sounds being the murmurs from the birds ... but I believe freedom is at 5000 feet with no other sound than the engine roaring."- William Hutchison, a young man taken from us far too young (16).

  6. #6
    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
    Attached Thumbnails Attached Thumbnails images (8).jpeg  
    Matt
    FS Painter @ The Hangar

    AUSTRALIA

  7. #7
    Senior Administrator PRB's Avatar
    Join Date
    Jun 2005
    Location
    MO (KSUS)
    Age
    58
    Posts
    9,160
    Quote Originally Posted by AussieMan View Post
    Or maybe being in Australia it appears upside down because we are down under .
    That's it!
    - Paul

    Win7 x64 | GIGABYTE X79-UP4 | Intel Core i7-3820 Quad-Core 3.60 GHz | 16GB DDR3/1600MHz Quad Channel Memory | NVIDIA GeForce GTX 660 Ti 2GB 16X PCIe 3.0

  8. #8
    This has been an interesting topic. I had no idea myself.

  9. #9
    SOH-CM-2020
    Join Date
    Apr 2011
    Location
    Vale of the White Horse, UK
    Age
    82
    Posts
    1,456
    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.....

  10. #10
    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/
    Fly Navy/Army (Ret. 2/2018)
    USN SAR
    DUSTOFF/ARMY PROPS

Members who have read this thread: 0

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •