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Old Feb 03, 2010, 01:49 AM
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awmeade's Avatar
S-u-A, UK.
Joined Jan 2003
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Don't forget that the speed difference, in hydraulics, is usually due to there being a larger surface area for the oil to act on one side of the piston compared to the other.

The side with the actuator rod ("rod end") of course loses out, as it has the diameter of the rod itself to reduce surface area. The "base" end of the ram, when actuated, is usually fastest - unless of course it is compensated in another way. More surface area = greater pressure = faster movement.

hth,

Andy.
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Old Feb 03, 2010, 02:07 AM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Quote:
Originally Posted by barneybdb View Post
On many aircraft the bomb bay door closing speed is deliberately slowed to give maintainers a chance to drop to the ground when they are working in there and the d-head wireless fitter working in the cockpit hits the wrong switch. Yes, I am talking from personal experience.
I think that is a very plausible explanation....

Of course I don't think I would want to be working under the plane and have somebody hit the control to open them either....

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Old Feb 03, 2010, 06:21 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Ilkley, West Yorkshire, UK
Joined Nov 2008
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Quote:
Originally Posted by awmeade View Post
More surface area = greater pressure = faster movement.
Isn't the pressure the same? But the same pressure operating on a greater surface area gives a greater force

Just posted for pedantic fun!!!
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Old Feb 03, 2010, 06:41 AM
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Joined Aug 2007
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Quote:
Originally Posted by awmeade View Post
Don't forget that the speed difference, in hydraulics, is usually due to there being a larger surface area for the oil to act on one side of the piston compared to the other.

The side with the actuator rod ("rod end") of course loses out, as it has the diameter of the rod itself to reduce surface area. The "base" end of the ram, when actuated, is usually fastest - unless of course it is compensated in another way. More surface area = greater pressure = faster movement.

hth,

Andy.
In the case of the B-36 bomb bays, the doors are closed by extension of the hydraulic actuator i.e., pressure acting on the full-face side of the piston. Applying what you've said above would have them opening slowly and closing quickly.
Not picking, just saying.

Myself, I think it's forces of gravity along with the possibility of a flow restrictor on the up side.
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Old Feb 03, 2010, 07:26 AM
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raipe's Avatar
Finland
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551 Posts
Quote:
Originally Posted by awmeade
The side with the actuator rod ("rod end") of course loses out, as it has the diameter of the rod itself to reduce surface area. The "base" end of the ram, when actuated, is usually fastest - unless of course it is compensated in another way. More surface area = greater pressure = faster movement.
Isn't it the other way around? The end with the rod has a smaller surface area = smaller volume = less oil (or air) needed to fill it. And with the same oil flow the "smaller side" fills quicker. And that brings us to: more surface = greater force = slower movement.

Wouldn't physics be sweet if greater force would equal faster movement
Raipe
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Last edited by raipe; Feb 03, 2010 at 07:29 AM. Reason: Edited the pressure part due to re reading colonel blinks post
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Old Feb 03, 2010, 07:33 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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About the bomb bays,
My data on the full scale B-36D-II Featherweight Configuration states that the doors being articulating stay in a self state as somewhat locked. Gravity will not open the doors. They will only drop open about 6". It then goes to say that the door need an minimal force to over come the slip stream of air on the fuse skin. It also states that to prevent buffeting that the aft lower gun turret door needs to be open. It does not specify a time, but it states that caution should be used when operating on the ground as the open sequence is faster than the close sequence. It also states that in the emergency procedures that the hydraulic hand pump must be pumped until the light for door open is eliminated showing that in fact the door has been pumped to it's full open state.

DAG
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Old Feb 03, 2010, 10:53 AM
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When this beauty eventually flies, I have to see it. Please let us know.
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Old Feb 03, 2010, 01:30 PM
Put a bigger motor on it!
gtfreeflyer's Avatar
Costa Mesa, CA
Joined Feb 2007
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One of the coolest things to me about seeing the B36 at the AF museum is that you could get under it and stick your head up in the bomb bay.

Now DAG, not to side track you or anything, but how cool would that be if you had a flight line stand for this bird so people could do the same! Either that, or park it over a huge mirror so you can show off those awesome bomb bays! lol
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Old Feb 03, 2010, 06:09 PM
Use the 4S Luke
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USA, TX, Euless
Joined Aug 2003
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As far as bombs - the B-36 was no doubt designed around the largest nuke in the arsenal bt I have read where it was also capable of carrying severla different size of conventional bombs. Probably to make it more useful. Surely the air cylinders could be made to resemble one of the conventional bomb packages. Along that route, you could install a full complement of 'air bombs' increasing scale looks as well as air volume.
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Old Feb 03, 2010, 07:13 PM
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Tennessee
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Quote:
Originally Posted by feathermerchant View Post
As far as bombs - the B-36 was no doubt designed around the largest nuke in the arsenal bt I have read where it was also capable of carrying severla different size of conventional bombs. Probably to make it more useful. Surely the air cylinders could be made to resemble one of the conventional bomb packages. Along that route, you could install a full complement of 'air bombs' increasing scale looks as well as air volume.
T\

The B36 was designed long before the first nuke to carry convential bombs to Europe from bases in the US.
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Old Feb 03, 2010, 11:23 PM
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Joined May 2004
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Hi Dag!
Been on the road for ten days
Got weathered in at Albuquerque NM, so a stayed with a buddy and we went to the Atomic Museum there.
Out back is a real nice B-29 in good condition. I asked them if I could buy it!
LOL!
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Old Feb 04, 2010, 05:37 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,802 Posts
The first design of the B-36 goes back to 1940. The Nukes size were designed around the largest plane at the time, the B-36. The MK17 was designed as the biggest nuke that could be lifted by a plane, the B-36. It was designed around what bombs were being dropped on Germany, the 500 pound bomb would do the best job and you could cram 136 of them into the B-36. The B-36 was designed because the US was worried that England would fall, but the British had no fear and showed them what real flying was all about.

DAG
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Old Feb 04, 2010, 05:43 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Here is what I got done last night. Video to follow of testing.

DAG
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Old Feb 04, 2010, 06:29 AM
London RC Project
BrotherBloat's Avatar
London
Joined Apr 2009
357 Posts
ooooh - looking forward to see that gear hatch operate. cool stuff! :]
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Old Feb 04, 2010, 09:06 AM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
5,802 Posts
Gear door test.

Convair B-36D Main Right Gear Door Test.avi (2 min 50 sec)


DAG
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