P-51 flaps and wheel doors

Discussion in 'Other Mechanical Systems Tech.' started by Maxrobot1, Mar 7, 2010.

Tags:
  1. Maxrobot1

    Maxrobot1 Member

    Joined:
    Sep 28, 2009
    Messages:
    138
    Likes Received:
    7
    Trophy Points:
    18
    On P-51s,how long after engine shutdown would the hydraulic pressure drop allowing the main wheel doors to droop all the way down? Did the flaps droop also?
    This is a consideration in model building.
    Looking at photos, it seems that the wheel doors drop slowly but is it over a few hours time or a day or two?
     
  2. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    #2 FLYBOYJ, Mar 7, 2010
    Last edited: Mar 7, 2010
    Normally they shouldn't droop at all - if they do there is a bad check valve in the system or one or more actuators are allowing fluid to bypass.

    If you seen photos with the MLG doors and flaps down, maintenance personnel might be doing maintenance.

    In the landing checklist, you're supposed to raise the flaps after landing. I don't think operationally you had flap or MLG doors drooping, crew chief wouldn't put up with that. Mustangs being operated today don't have drooping flaps or MLG doors, at least the one I've seen.
     
  3. jimh

    jimh Active Member

    Joined:
    Feb 6, 2009
    Messages:
    310
    Likes Received:
    87
    Trophy Points:
    28
    Gender:
    Male
    Occupation:
    Flying
    Location:
    Ohio
    Home Page:
    There is a hydraulic "T" handle in the lower center console which is pulled after shutdown to release the pressure. It is at that point the flaps and gear doors drop. Seems every Mustang operator does it different, some taxi in with the flaps down, some up. It is prefered to have them up to prevent damage from loose gravel thrown up by the propwash. The main wheel doors are controlled by a sequencing valve and are shut after gear extention to provide undisturbed airflow into the scoop.

    jim harley
     
  4. GrauGeist

    GrauGeist Well-Known Member

    Joined:
    Aug 29, 2008
    Messages:
    15,196
    Likes Received:
    2,033
    Trophy Points:
    113
    Occupation:
    Public Safety Automotive Technician
    Location:
    Redding, California
    Home Page:
    Kind of like this, Jim?

    The photo shows the state of the flaps and wheel doors as the 'Stang was taxiing onto the ramp during the Collings Foundation's visit last year at Redding Airport (RDD)
     

    Attached Files:

  5. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    #5 FLYBOYJ, Mar 8, 2010
    Last edited: Mar 8, 2010
    Thanks Jim...

    The only Mustang operator I know personally keeps his flaps up as stated to prevent damage. BTW a sequencing valve (as used by other aircraft) will allow droop of the doors or other items it controls if defective as well.

    Here's one parked, flaps down, center MLG doors up

    http://www.vaq136.com/blaine/mustang-011b.jpg

    another one, everything down...

    http://www.vaq136.com/blaine/mustang-003b.jpg

    From WW2, P-51 A&B, Doors and flaps up

    http://www.wwiivehicles.com/usa/air...ng/north-american-p-51a-p-51b-mustangs-01.jpg
     
  6. beaupower32

    beaupower32 Well-Known Member

    Joined:
    Jun 10, 2007
    Messages:
    1,840
    Likes Received:
    41
    Trophy Points:
    48
    Location:
    Lancaster, California
    Here is a WW2 bird with the doors down.
    [​IMG]


    Is going to end up being a personal preference on how you want your mustang to look.
     
  7. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    I think it’s more operational - If I was crew chief I'd want everything down for maintenance and inspection. It’s also a good idea to keep the system exercised ensuring that o rings and packings have fluid under pressure on them. Additionaly this would also reveal any "creap" in the system as first mentioned.
     
  8. beaupower32

    beaupower32 Well-Known Member

    Joined:
    Jun 10, 2007
    Messages:
    1,840
    Likes Received:
    41
    Trophy Points:
    48
    Location:
    Lancaster, California
    I was refering on how he might have wanted his model to look. But I agree with you 100%, I would want a little bit of pressure still built up in the system to keep everything good.
     
  9. drgondog

    drgondog Well-Known Member

    Joined:
    Jun 28, 2006
    Messages:
    7,359
    Likes Received:
    561
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Executive, Consulting
    Location:
    Scurry, Texas
    This is correct. The 51 has a hydraulic accumulator that pressurizes to 1000psi (IIRC) fed by the engine. When the engine shuts down it no longer powers the accumulator but most of the time the pressure was not bled away after taxi and park unless some maintenance was being performed on the hydraulic system.

    The emergency system bypasses the accumulator and enables the gear and door to drop by gravity.

    About 9/10 pics of a 51 will have the wheel doors in the 'up' position.. as you noted the flaps are 'pilot's preference'.
     
  10. Maxrobot1

    Maxrobot1 Member

    Joined:
    Sep 28, 2009
    Messages:
    138
    Likes Received:
    7
    Trophy Points:
    18
    I guess an A/c all bombed up and ready to go after an engine check would have flaps and doors up. The same for one that has just landed after a flight/mission. However for one that was parked for a while - anything goes.
    North American craft like B-25s and F-86s also had bigger gear doors close after the gear was extended.
     
  11. davparlr

    davparlr Well-Known Member

    Joined:
    Mar 23, 2006
    Messages:
    2,934
    Likes Received:
    105
    Trophy Points:
    63
    Occupation:
    retired avionics engineer
    Location:
    Southern California
  12. bobbysocks

    bobbysocks Well-Known Member

    Joined:
    Feb 28, 2010
    Messages:
    3,809
    Likes Received:
    181
    Trophy Points:
    63
    Location:
    Pennsylvania
    I think a lot of it had to do with the work that was going to be done to it at the time the photo was taken. you never let too many places where birds or other critters could climb inside open. the flaps were down for ease of getting into the aircraft. after you laced into you G-pants put the heavy clothing on...thick boots...may west and chute you needed help climbing in. here is a link to bud andersons site where he has a ton of pics.

    Photographs
     
  13. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    #13 FLYBOYJ, Mar 8, 2010
    Last edited: Mar 8, 2010
    On the Mustang? You sure about that?

    Bill?

    Edit - I seen some of your photos with a red "box" on the inboard portion of the flap - "Step Here" or "No Step?"
     
  14. jimh

    jimh Active Member

    Joined:
    Feb 6, 2009
    Messages:
    310
    Likes Received:
    87
    Trophy Points:
    28
    Gender:
    Male
    Occupation:
    Flying
    Location:
    Ohio
    Home Page:
    Hey Grau...thats the way...in fact that is me in the backseat! we just arrived from Concord. way cool. I've seen some Mustangs with a step built into the left inboard flap, I am pretty sure this is a post war mod. The original "Step Here" stenciling points toward "elephant ear" fillet on the inboard trailing edge of the wing. This is weak spot that doesn't take long to start cracking if repeatedly stepped on. We load our passengers by using the left landing gear as a ladder onto the wing.

    Jim Harley
     
  15. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    From my little time around Mustangs I don't see stepping on the flap or the fillet without eventually cracking either one
     
  16. drgondog

    drgondog Well-Known Member

    Joined:
    Jun 28, 2006
    Messages:
    7,359
    Likes Received:
    561
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Executive, Consulting
    Location:
    Scurry, Texas
    Joe - There was no SOP other than do not step on the flap. I have climbed on board from main gear wheel to leading edge of wing and from trailing edge of wing - with flaps up and down, but mostly up.

    I would say I 'got in' 90% from inboard trailing edge with flap up.
     
  17. FLYBOYJ

    FLYBOYJ "THE GREAT GAZOO"
    Staff Member Moderator

    Joined:
    Apr 9, 2005
    Messages:
    23,202
    Likes Received:
    786
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Aircraft Maintenance Manager/ Flight Instructor
    Location:
    Colorado, USA
    Thanks Bill, I figured if anyone is going to know for sure it would be you.

    Just for the record folks - unless there is a step provision on the flap, you NEVER step on a flap - PERIOD!

    The only mustang I ever got into belonged to Joe Thebault. I went up a stepstool at the training edge he had some antil slip tape along the inboard portion of the wing from I remember.
     
  18. drgondog

    drgondog Well-Known Member

    Joined:
    Jun 28, 2006
    Messages:
    7,359
    Likes Received:
    561
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    Executive, Consulting
    Location:
    Scurry, Texas
    Ditto here on the non slip tape inside of the inboard flap.
     
  19. bobbysocks

    bobbysocks Well-Known Member

    Joined:
    Feb 28, 2010
    Messages:
    3,809
    Likes Received:
    181
    Trophy Points:
    63
    Location:
    Pennsylvania
    yep you are right. i remember my dad telling me he stepped on the left tire and up. what gave me vapor lock of the brain was not less than 3 days ago i was following a stream of u-tube videos and came across a really cool one. of course i didnt save it...but it was of ground crew servicing the planers and the flight getting ready to go out. it was all 51s and in this particular video they went up from the rear...may just for show's sake?? then it showed how one of the crew would lay on the left wing and marshal the plane as it taxied. it bugs me now that i cant find it...but that kind of entry wasnt normal practice.
     
Loading...

Share This Page