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HAWK21M
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LG Shearpin Load

Mon Dec 27, 2004 7:20 pm


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What would be the Max load the MLG Trunnion link Shear pin would withstand prior to Shearing in the Above case.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
JetMechMD80
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RE: LG Shearpin Load

Tue Dec 28, 2004 12:50 pm

Hi MEL,

I was not aware that the MLG Trunnion bolts were designed to shear. I have never heard them called anything but Trunnion bolts. And having pulled quite a few in my "C" check days, I can say that they are very beefy bolts. Not sure why you would want them to shear. Normally something designed to shear is done to prevent catastrophic damage. It seems in this case, you are going to cause it by shearing. JMO.
"I get along great with nobody"~ Billy Idol
 
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HAWK21M
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RE: LG Shearpin Load

Tue Dec 28, 2004 3:36 pm

The B737 Classics have the Fwd Trunnion to the Drag strut of the Main Gear attached by a Shear pin/Shear bolt [Painted yellow].Also each Trunion Attachment end has shearing provision.
The purpose is on experiencing heavy load the same would shear to prevent further & more structurally critical damage to the Wing surface during an Accident.
Thats the reason when there is a major Incident or Accident involved on a B737 the MLG collapses.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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HAWK21M
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Joined: Fri Jan 05, 2001 10:05 pm

RE: LG Shearpin Load

Tue Dec 28, 2004 3:36 pm

The B737 Classics have the Fwd Trunnion to the Drag strut of the Main Gear attached by a Shear pin/Shear bolt [Painted yellow].Also each Trunion Attachment ends have shearing provision.
The purpose is on experiencing heavy load the same would shear to prevent further & more structurally critical damage to the Wing surface during an Accident.
Thats the reason when there is a major Incident or Accident involved on a B737 the MLG collapses.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
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HAWK21M
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RE: LG Shearpin Load

Tue Dec 28, 2004 4:21 pm



From the AMM.
Shaded the concerned areas.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
AUAE
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RE: LG Shearpin Load

Tue Dec 28, 2004 9:53 pm

You can estimate the load with a little information.

Lets just assume that the trunion (or shear pin if you want to calculate that) is hollow. So if you were to look at a cross section of the trunion, it would be 2 concentric circles. To find out how much shear strength the trunion would have at that one cross section, calculate the area between the two circles.

pi(r2^2 - r1^2) where R2 is the greater radius

Then take the shear strength of the material and multiply it by the area. Lets assume that the steel has a shear strength of 100 ksi and the area is 10 sq in. Then the shear strength is 1000 k lbs or 1000000 lbs. Just an example on how to calculate single shear loading. Impact loading is different, some else want to tackle that one?

Shawn
Air transport is just a glorified bus operation. -Michael O'Leary, Ryanair's chief executive
 
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HAWK21M
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RE: LG Shearpin Load

Fri Dec 31, 2004 2:31 pm

How is it with other Models from the Shear pin Point of View.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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