Question re F6F Hellcat's Wing-Flap Operation

Discussion in 'Other Mechanical Systems Tech.' started by BSquared18, Jul 8, 2014.

  1. BSquared18

    BSquared18 New Member

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    Hi,

    For a flight-sim build I'm doing of the Hellcat: I notice in diagrams of the F6F's cockpit that there is a toggle switch shown for operating the wing flaps. Does that mean that the flaps are either up or down, with no intermediate (half-down) position? Or does the pilot flip the toggle switch off again when the flaps have reached the desired position? Or is there more than one way to activate the flaps?

    Thanks,
    Bill
     
  2. N4521U

    N4521U Well-Known Member

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    Well Bill............... I found this on a flight sim forum......... Hope it helps, from Bill

    F6F flap operations ((( References are from the : "Pilots Handbook of flight operations", for F6F-3 and F6F-5 aircraft. )))
    -------------------------
    General Description:
    COMPRESSION SPRINGS:
    Flap operations is "controled", by "compression spring" action. This is done once the flaps are extended
    ( push straight back out ) and the airspeed is in correct perimeters. It is totaly automatic from a speed of
    93 kts - 106 mph ( 50 deg full deflection ) to
    150 kts- 172 mph ( 5 deg deflection ) or
    170 kts- 195 mph ( 0 deflection ).
    (( note one mile =5280 ft, one knot = 6080.20 ft ( old navy measurment ) (standard as used WWII )
    ----------------------------
    HYDRAULICS:
    Flaps are "deployed out or retracted in" hydraulicaly. when commanded by pilot or "automatic retract/extend airspeed switch is activated". Hydraulic pressure extends flaps out horizontaly or retracts into the trailing edge of the wing. Other than extending out the area of the wing no flap aerodynamic action has been performed by this operation.
    ----------------------------
    ACTIVATION: ELECTRICAL/ MECHANICAL.
    When the pilot wants the flaps to operate he does so with an "electric two way switch". It selects flaps up, or flaps down. If selected down all the rest of the operation is automatic and controled by airspeed and the action of the "compression springs".
    ----
    A second way of accuation is with a manual switch on the "Hydraulic control valve". Again two selections , flaps up or down. Again the operations becomes automatic varying by airspeed and the action of the "compression springs".
    ---
    As long as the pilot input is for flaps down with either the "elect two way switch" or the "hydraulic control valve" the flaps will will "extend" or "retract" out or into the wing at 170 kts ( 195 mph ) to reduce drag at the higher speeds or for use at lower speeds.
    This is controled by a "auto retract airspeed switch". this is in the wing installed in parallel with the pitot air speed system of the plane. It activates any time the plane reaches 170kts sending hydraulic pressure to the flap extend/retract actuators.
    ===========================
    This is a far more effiecient system then most other fighters of the time. Other planes had specific positions or flap settings creating excessive drag or possible failure if certain speeds were not adheard to. They also required close attention by the pilot to ensure damage to his craft, he didnt depart flight, or make himself volnerable due to improper flap settings. This was all solved with the compression spring auto flap system in the Hellcat.
    ==============================
    SUMMARY:
    A. pilot activates flaps with electric switch or hydraulic switch.
    B. at 170 KTS or below the hydraulic system controled by the speed sensor/switch extends flaps out form the wing.
    C. Compression springs ensure the flaps are positioned automaticaly to the most efficient angle from 0 to 50 degrees depending on the airspeed of the plane.
    D. If speed increases over 170 kts or pilot activates switch to retract the flaps they will hydraulicaly retract back to the wing.
    NOTE: The flap switch can be activated at "any speed". The flaps will deploy and begin operations automaticaly at the correct speed.
    ==============================
    Hope this was interesting or useful
     
  3. BSquared18

    BSquared18 New Member

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    #3 BSquared18, Jul 9, 2014
    Last edited: Jul 9, 2014
    Thank you. Very helpful. That's a lot of work on your part.

    I have a couple of Pilot's Handbooks from WW2 for the Hellcat (shhh, they are "Restricted" and are not to fall into enemy hands, so don't let the government know I have them :) ) and missed that information. I've copied and pasted into my notes what you posted.

    The challenge will be to see how closely X-Plane can model things like automatic extension and retraction.

    (Correction: I see now there is mention of partial deflection.)

    Bill
     
  4. stona

    stona Well-Known Member

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    It's in the hand books.

    [​IMG]

    Steve
     
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