P-40, comin' at yer!

Mike · **Joined:** Tue May 04, 2004 8:54 am **Posts:** 3331

A beautiful autumn afternoon in the Sonoma valley today. Chris Prevost was out and about enjoying his recently-restored P-40N

APG85 · **Posted:** Sun Nov 15, 2009 3:57 am

Sweet!

Steve Nelson · **Posted:** Sun Nov 15, 2009 6:17 am

Beautiful! But isn't is supposed to have a shark mouth on it? <ducks for cover>

SN

Django · **Posted:** Sun Nov 15, 2009 10:43 am

Cool! Great photos.

warbirdguy · **Posted:** Sun Nov 15, 2009 12:36 pm

Thanks for sharing the cool photos!

Lynn Allen · **Posted:** Sun Nov 15, 2009 10:28 pm

And don't forget the Ober Stripes..........

hang the expense · **Posted:** Mon Nov 16, 2009 12:13 am

Some really nice photos.Thanks for posting.

rreis · **Joined:** Tue Aug 04, 2009 4:42 pm **Posts:** 441

sorry for being ignorant, but shouldn't it retract in sync?

Speedy · **Posted:** Mon Nov 16, 2009 12:03 pm

rreis wrote:

sorry for being ignorant, but shouldn't it retract in sync?

Oh, but that's one of the best parts about the P-40...they DONT retract in sync. The first one is almost all the way in the well before the second one even rotates.

warbird1 · **Joined:** Fri Sep 21, 2007 6:25 pm **Posts:** 2760

Speedy wrote:

rreis wrote:

sorry for being ignorant, but shouldn't it retract in sync?

Oh, but that's one of the best parts about the P-40...they DONT retract in sync. The first one is almost all the way in the well before the second one even rotates.

Now that I think about it, I don't know of any W.W. II fighters who's hydraulically-actuated gear retract in sync. Are there any? Hopefully, one of the more technically-minded maintainers can correct me if I'm wrong, but I don't believe there is enough hydraulic pressure with those older systems to retract them in sync. It is too much demand on the system.

JDK · **Posted:** Tue Nov 17, 2009 5:07 am

Nice pics, Mike!

As I understand it, sequential rather than parallel process is part of the way these hydraulic systems work - as Warbird 1 wrote, if you look closely, many of the hydraulic retraction systems of the W.W.II era do this - certainly every P-40 I've seen acts like this.

Regards,

bdk · **Joined:** Sun May 02, 2004 1:16 am **Posts:** 11324

P-40 gear is locked down by an over center link that is hydraulically actuated so one will "pop" before the other depending on whichever has the least friction to overcome in the system. They are loaded overcenter in flight when extended due to the airflow. Once gear #1 is unlocked the airflow helps to retract it and relieves the hydraulic pressure somewhat so the second gear won't unlock until the gravity force to raise gear #1 into the wheel well exceeds the pressure required to unlock gear #2. At that point, gear #1 may actually drop out of the well a bit as the airflow blows back gear #2, once again relieving some of the pressure demand. After that it pretty much is just a battle against gravity and the uplock hook.

If you look at 51fixer's Bald Eagle gear trunnion thread you can see how the Mustang has a door latch type arrangement. There really isn't any significant load on the downlocks after takeoff and the gear on a Mustang aren't so much affected by the airflow to retract and extend, although large yaw angles can have an affect due to the spade doors mounted on the gear.

On a T-6 the downlocks are mechanically actuated by rods from the gear handle, but otherwise operate like the Mustang's.

rreis · **Joined:** Tue Aug 04, 2009 4:42 pm **Posts:** 441

thanks all for the insight

hang the expense · **Posted:** Wed Nov 18, 2009 2:57 am

Mike wrote:

A beautiful autumn afternoon in the Sonoma valley today. Chris Prevost was out and about enjoying his recently-restored P-40N

Man,somebody needs to get after that toe out. :axe:

JDK · **Posted:** Wed Nov 18, 2009 5:26 am

There you go bdk, spoiling it with accurate technical explanations. :lol:

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P-40, comin' at yer!

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