airplane construction

Jim Macklin wrote:
Understand that bolts used in aircraft construction are not
"hardware store" items. The steel and the tolerances for
aircraft grade fasteners are better than hardware store
Grade 8 bolts. Beech uses bolts in tension to hold the wing
on the Bonanza, Baron and King Air models. When there is a
crash, the bolts are rarely broken. But if the bolts are
not properly installed and maintained, corrosion can weaken
the bolts causing them to break.

Cessna uses a bolt installed in shear through fittings like
you fingers meshed. This is called "double shear" and as
long as the bolt is a snug fit in the hole the bolt can hold
more load than the airplane is designed to experience.
But a bolt in tension is stronger than a bolt in shear.


"george" wrote in message
ups.com...
|
| Bill Watson wrote:
|
| The more you know the more you can do.
|
| Nothing like assembling a sailplane, loading it full of
water and
| bombing down a ridge at red-line for a few hours.
|
| Then you just pull the wings and tail back off and
trailer it home.
|
| the size of those pins/bolts that hold the wings on
should attract the
| attention of any pilot not used to rigging sailpanes :-)
|


Here's a good illustration/animation on "double shear" connections:
http://www.ijee.dit.ie/OnlinePapers/...ted_double.htm

--
Mike

Matt Whiting wrote:
Jose wrote:

I'd have to pull out my AISC manual to be sure, but I believe that a
bolt in double shear has more capacity than in tension. If you are
comparing single shear to tension, then I agree with you.


What is "double shear" and "single shear"?

It refers to the number of planes in shear. Think of the rivet in a
scissors. There is one shear plane where the two halves of the scissors
meet and are held together by the pin/rivet.

Now think of a sandwich of three pieces of metal held together with a
bolt or pin or rivet. There are now two planes that are in shear and
thus you have twice as much shear resistance of the outer two pieces of
metal are pulled one direction and the middle piece is pulled another
direction.


Matt

Here's a good illustration/animation:
http://www.ijee.dit.ie/OnlinePapers/...ted_double.htm


--
Mike

Here's a good illustration/animation on "double shear" connections:
http://www.ijee.dit.ie/OnlinePapers/...ted_double.htm

Thanks. It's a way to spread the shear load.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

Matt Whiting wrote:


Cessna uses a bolt installed in shear through fittings like
you fingers meshed. This is called "double shear" and as
long as the bolt is a snug fit in the hole the bolt can hold
more load than the airplane is designed to experience.
But a bolt in tension is stronger than a bolt in shear.

I'd have to pull out my AISC manual to be sure, but I believe that a
bolt in double shear has more capacity than in tension. If you are
comparing single shear to tension, then I agree with you.

Matt

That's right. The 70% figure refers to single shear.

I made a mistake on the Grade 8 bolt head marking. It has six
radial marks, not five. Five is a Grade 7, not a common bolt. The
grades go clear to Grade 16, IIRC.

Dan

Robert M. Gary wrote:
wrote:
Robert M. Gary wrote:
Last summer, Texas/Louisiana neighborhood, I think. The
details were in the story, not the time and place.



The only Mooney fatal I could find in the SE last summer was this one
http://www.ntsb.gov/ntsb/brief.asp?e...31X01061&key=1

Perhaps that's the one?? The report is only preliminary but doesn't
mention whether the pilot was with the aircraft or not.

-Robert

That's likely it. The report gives no details whatever of the
condition of the wreckage; perhaps that's forthcoming.

Dan

Aircraft grade bolt have many standards, more to do with
heat-treating and plating and tolerances on the thread and
shank fit and finish. Aircraft hardware is a detailed
study all to itself.



wrote in message
oups.com...
|
| Matt Whiting wrote:
|
|
| Cessna uses a bolt installed in shear through fittings
like
| you fingers meshed. This is called "double shear" and
as
| long as the bolt is a snug fit in the hole the bolt
can hold
| more load than the airplane is designed to experience.
| But a bolt in tension is stronger than a bolt in
shear.
|
| I'd have to pull out my AISC manual to be sure, but I
believe that a
| bolt in double shear has more capacity than in tension.
If you are
| comparing single shear to tension, then I agree with
you.
|
| Matt
|
| That's right. The 70% figure refers to single shear.
|
| I made a mistake on the Grade 8 bolt head marking.
It has six
| radial marks, not five. Five is a Grade 7, not a common
bolt. The
| grades go clear to Grade 16, IIRC.
|
| Dan
|

Jim Macklin wrote:
Understand that bolts used in aircraft construction are not "hardware
store" items. The steel and the tolerances for aircraft grade fasteners
are better than hardware store Grade 8 bolts. Beech uses bolts in
tension to hold the wing on the Bonanza, Baron and King Air models. When
there is a crash, the bolts are rarely broken.

Well, Beech used to use bolt in tension on the King Air. But a bunch of them
had their wings fall off.

Now they use bolts in shear.

Karl
N185KG

I have not looked at a recent King Air, but I think that
they still use the traditional Beech bath-tub fitting and
tension bolts.


"karl gruber" wrote in message
...
|
| Jim Macklin wrote:
| Understand that bolts used in aircraft construction are
not "hardware
| store" items. The steel and the tolerances for
aircraft grade fasteners
| are better than hardware store Grade 8 bolts. Beech
uses bolts in
| tension to hold the wing on the Bonanza, Baron and King
Air models. When
| there is a crash, the bolts are rarely broken.
|
| Well, Beech used to use bolt in tension on the King Air.
But a bunch of them
| had their wings fall off.
|
| Now they use bolts in shear.
|
| Karl
| N185KG
|
|