airplane construction

Robert M. Gary wrote:
Mike wrote:
Hi,

I'm interested in learning more about airplane construction, say maybe a
Cessna 172. I know the basics of airframes and power plants, but what
I'm having a hard time finding is actual diagrams and depictions of the
actual assembly. For example, wing root connections, engine mounts,
supporting structures, etc. I imagine this might be available in a
mechanics manual, but I don't know where else to look. I've scoured the
Internet with no success.

When I saw how the wings are attached on a Cessna it almost made me not
want to fly one. Not much holding them on. Rational or not, I feel
better in turb in my Mooney knowing the entire cabin is sitting on the
one piece wing.

-Robert


I'm guessing that's why there's wing struts How many bolts secure the
wings to the fuselage?

--
Mike

Mike wrote:
Robert M. Gary wrote:
I'm guessing that's why there's wing struts How many bolts secure the
wings to the fuselage?

On the Cessna I don't remember how many "wing nuts" there were holding
the wing on, I just remember the very small area in which the wing
attaches to the body. There must be insane amounts of stress on that
small area of metal.

On the Mooney, there is but one single wing. The spar runs right under
the seats. No one has problems with wings coming off but the Mooney
design makes me more comfortable.

-Robert

Robert M. Gary wrote:

On the Cessna I don't remember how many "wing nuts" there were holding
the wing on, I just remember the very small area in which the wing
attaches to the body. There must be insane amounts of stress on that
small area of metal.

Most of the lift is transferred via the struts, not at the wing root (now
I'll be darned if I can remeber where I read that...). The wing basically
pulls on the strut, and the wing root only has to keep it from tipping one
way or another.

Anno.

Robert M. Gary wrote:
Mike wrote:
Robert M. Gary wrote:
I'm guessing that's why there's wing struts How many bolts secure the
wings to the fuselage?

On the Cessna I don't remember how many "wing nuts" there were holding
the wing on, I just remember the very small area in which the wing
attaches to the body. There must be insane amounts of stress on that
small area of metal.

On the Mooney, there is but one single wing. The spar runs right under
the seats. No one has problems with wings coming off but the Mooney
design makes me more comfortable.

-Robert

The 172 has a 7/16" bolt on the front spar attach, and a 3/8" at
the rear, IIRC without going downstairs and looking it up. Both are in
double shear. The bolt is stronger than the aluminum fittings, and the
fittings are much stronger than they look or need to be. The airplane
is rated for 3.8g positive, with 150% design limits beyond that, and I
can't remember the last time I heard of a 172 shedding a wing unless
the pilot tried to fly through a thunderstorm, in which case he'd have
died anyway. The stabilizer is weaker than the wing in many light
aircraft.
The struts are connected with 1/2" bolts in double shear.

The Mooney's one-piece wing spar is made of many smaller
pieces, all held together with tiny rivets. No stronger than the 172, I
bet. The Mooney's POH should give a g rating for the airframe.

Which reminds me: a friend recently told me of an accident in
the Southeastern US where a new Commercial pilot flew a Monney into a
thunderboomer at night. They found the wreckage scattered far and wide,
and the Mooney engineers that examined the bits and pieces estimated
that the aircraft experienced an upward acceleration of between 20 and
23 Gs. The passenger, complete with seat, went through the bottom of
the airplane and was found some distance behind the rest of the mess.
Even if the airplane had held together the occupants would have been
incapacitated or killed by the damage wrought by the acceleration.

Dan

wrote:
Robert M. Gary wrote:
Mike wrote:
Robert M. Gary wrote:

The 172 has a 7/16" bolt on the front spar attach, and a 3/8" at
the rear, IIRC without going downstairs and looking it up. Both are in
double shear. The bolt is stronger than the aluminum fittings, and the
fittings are much stronger than they look or need to be. The airplane
is rated for 3.8g positive, with 150% design limits beyond that, and I
can't remember the last time I heard of a 172 shedding a wing unless
the pilot tried to fly through a thunderstorm, in which case he'd have
died anyway. The stabilizer is weaker than the wing in many light
aircraft.

Agreed. I understand 172's are not falling from the sky, just an
emotional reaction to seeing what is actually holding the wings on. I
wonder what holds the wings on the C-177 if the struts old the wings on
the c-172.

The Mooney's one-piece wing spar is made of many smaller
pieces, all held together with tiny rivets. No stronger than the 172, I
bet. The Mooney's POH should give a g rating for the airframe.

The 3.8g limit you mention for the c-172 is just a function of the
certification category. Since the Mooney and the 172 share the same
category they are both 3.8g's with 150% minimum overdesign by
definition. Note sure what the actual structural limits are though. The
manufactors don't tell us the actual limits, just the certification
limits.

The Mooney is known for being amazingly strong though. Rememeber the
picture of the 201 coming off the line with several dozen people
standing on the wing? They flew that plane afterwards w/o problem. I
have a friend who survived a nasty accident in his 201 and credits the
steel tube cabin for saving his life.

Which reminds me: a friend recently told me of an accident in
the Southeastern US where a new Commercial pilot flew a Monney into a
thunderboomer at night. They found the wreckage scattered far and wide,
and the Mooney engineers that examined the bits and pieces estimated
that the aircraft experienced an upward acceleration of between 20 and
23 Gs. The passenger, complete with seat, went through the bottom of
the airplane and was found some distance behind the rest of the mess.
Even if the airplane had held together the occupants would have been
incapacitated or killed by the damage wrought by the acceleration.

Do you have a reference for this? A possible date range, the state if
happened in or something I can search on? I'd like to pull up the NTSB
on it.

-Robert

wrote:
Robert M. Gary wrote:
Mike wrote:
Robert M. Gary wrote:
I'm guessing that's why there's wing struts How many bolts secure the
wings to the fuselage?
On the Cessna I don't remember how many "wing nuts" there were holding
the wing on, I just remember the very small area in which the wing
attaches to the body. There must be insane amounts of stress on that
small area of metal.

On the Mooney, there is but one single wing. The spar runs right under
the seats. No one has problems with wings coming off but the Mooney
design makes me more comfortable.

-Robert

The 172 has a 7/16" bolt on the front spar attach, and a 3/8" at
the rear, IIRC without going downstairs and looking it up. Both are in
double shear. The bolt is stronger than the aluminum fittings, and the
fittings are much stronger than they look or need to be. The airplane
is rated for 3.8g positive, with 150% design limits beyond that, and I
can't remember the last time I heard of a 172 shedding a wing unless
the pilot tried to fly through a thunderstorm, in which case he'd have
died anyway. The stabilizer is weaker than the wing in many light
aircraft.
The struts are connected with 1/2" bolts in double shear.

The Mooney's one-piece wing spar is made of many smaller
pieces, all held together with tiny rivets. No stronger than the 172, I
bet. The Mooney's POH should give a g rating for the airframe.

Which reminds me: a friend recently told me of an accident in
the Southeastern US where a new Commercial pilot flew a Monney into a
thunderboomer at night. They found the wreckage scattered far and wide,
and the Mooney engineers that examined the bits and pieces estimated
that the aircraft experienced an upward acceleration of between 20 and
23 Gs. The passenger, complete with seat, went through the bottom of
the airplane and was found some distance behind the rest of the mess.
Even if the airplane had held together the occupants would have been
incapacitated or killed by the damage wrought by the acceleration.

Dan


Thanks for the insight, Dan. I never knew that about the C172 (or should
I say high-wing?). Definitely learned a few more things today.


--
Mike

"Robert M. Gary" wrote in message
oups.com...

Mike wrote:
Hi,

I'm interested in learning more about airplane construction, say maybe a
Cessna 172. I know the basics of airframes and power plants, but what
I'm having a hard time finding is actual diagrams and depictions of the
actual assembly. For example, wing root connections, engine mounts,
supporting structures, etc. I imagine this might be available in a
mechanics manual, but I don't know where else to look. I've scoured the
Internet with no success.

When I saw how the wings are attached on a Cessna it almost made me not
want to fly one. Not much holding them on. Rational or not, I feel
better in turb in my Mooney knowing the entire cabin is sitting on the
one piece wing.

-Robert


Try standing at the back of an empty 757, on a positioning leg. I could
swear that you can see the fuselage gently flex as it flies- a bit like a
fish going through water.
Now that does scare the sh1t out of you.

Chris wrote:
"Robert M. Gary" wrote in message
oups.com...
Mike wrote:
Hi,

I'm interested in learning more about airplane construction, say maybe a
Cessna 172. I know the basics of airframes and power plants, but what
I'm having a hard time finding is actual diagrams and depictions of the
actual assembly. For example, wing root connections, engine mounts,
supporting structures, etc. I imagine this might be available in a
mechanics manual, but I don't know where else to look. I've scoured the
Internet with no success.
When I saw how the wings are attached on a Cessna it almost made me not
want to fly one. Not much holding them on. Rational or not, I feel
better in turb in my Mooney knowing the entire cabin is sitting on the
one piece wing.

-Robert


Try standing at the back of an empty 757, on a positioning leg. I could
swear that you can see the fuselage gently flex as it flies- a bit like a
fish going through water.
Now that does scare the sh1t out of you.



I certainly believe that. I was on a flight out west a while ago, and I
guess the pilot realized he was going to overshoot the centerline on the
turn to final, so he/she banked more suddenly than usual. Definitely
heard the flex, that's for sure .

--
Mike

Ummm.. re" things that move..float or fly..."

Those that don't bend or flex, - break..



Dave



On Wed, 10 Jan 2007 16:41:32 -0500, Mike wrote:

Chris wrote:
"Robert M. Gary" wrote in message
oups.com...
Mike wrote:
Hi,

I'm interested in learning more about airplane construction, say maybe a
Cessna 172. I know the basics of airframes and power plants, but what
I'm having a hard time finding is actual diagrams and depictions of the
actual assembly. For example, wing root connections, engine mounts,
supporting structures, etc. I imagine this might be available in a
mechanics manual, but I don't know where else to look. I've scoured the
Internet with no success.
When I saw how the wings are attached on a Cessna it almost made me not
want to fly one. Not much holding them on. Rational or not, I feel
better in turb in my Mooney knowing the entire cabin is sitting on the
one piece wing.

-Robert


Try standing at the back of an empty 757, on a positioning leg. I could
swear that you can see the fuselage gently flex as it flies- a bit like a
fish going through water.
Now that does scare the sh1t out of you.



I certainly believe that. I was on a flight out west a while ago, and I
guess the pilot realized he was going to overshoot the centerline on the
turn to final, so he/she banked more suddenly than usual. Definitely
heard the flex, that's for sure .

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.

Robert M. Gary wrote:
Mike wrote:
Hi,

I'm interested in learning more about airplane construction, say maybe a
Cessna 172. I know the basics of airframes and power plants, but what
I'm having a hard time finding is actual diagrams and depictions of the
actual assembly. For example, wing root connections, engine mounts,
supporting structures, etc. I imagine this might be available in a
mechanics manual, but I don't know where else to look. I've scoured the
Internet with no success.

When I saw how the wings are attached on a Cessna it almost made me not
want to fly one. Not much holding them on. Rational or not, I feel
better in turb in my Mooney knowing the entire cabin is sitting on the
one piece wing.

-Robert