P-51 flaps and wheel doors

[Maxrobot1]

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?

 

[FLYBOYJ]

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?

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.

 

[jimh]

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

 

[GrauGeist]

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)

 

[FLYBOYJ]

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

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

 

[beaupower32]

Here is a WW2 bird with the doors down.

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

 

[FLYBOYJ]

Here is a WW2 bird with the doors down.

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

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.

 

[beaupower32]

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.

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.

 

[drgondog]

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

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'.

 

[Maxrobot1]

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.

 

[davparlr]

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

I like this picture showing the differences between the P-51B and the A.

 

[bobbysocks]

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

 

[FLYBOYJ]

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

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?"

 

[jimh]

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

 

[FLYBOYJ]

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

From my little time around Mustangs I don't see stepping on the flap or the fillet without eventually cracking either one

 

[drgondog]

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?"

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.

 

[FLYBOYJ]

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.

 

[drgondog]

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.

Ditto here on the non slip tape inside of the inboard flap.

 

[bobbysocks]

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.