Where do main pin holes come from?

Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

On 11/1/2010 4:07 PM, Bob Kuykendall wrote:
Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24


Interesting to compare your technique with the way it is done at Jonker
Sailplanes:

http://www.jonkersailplanes.com/factorypictures8.htm

That's a good way to make a one-off homebuilt. In production, they use
a jig to make sure the parts are interchangeable.


Nov 1, 7:07*pm, Bob Kuykendall wrote:
Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

On Nov 1, 4:07*pm, Bob Kuykendall wrote:
Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

Bob,

Your design for the parts and the tooling is simply
amazing............I tacked in the rear lift pin tube yesterday
evening. This AM Doug and I pulled the wings off and put them back on
a couple of times and they slid right in just like the real thing. We
finished the day by shear taping in the rear tube.

Tomorrow the shop gets cleaned up and we head home.

Brad

On Nov 1, 4:07*pm, Bob Kuykendall wrote:
Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

The video must have cut off before the obligatory "oh sh!@ that's the
wrong spot" comment from the person doing the drilling to the owner of
the glider. That's got me more than once.

Darryl

On Nov 1, 4:44*pm, Martin wrote:
That's a good way to make a one-off homebuilt. In production, they use
a jig to make sure the parts are interchangeable.

Yes, interchangability is a definite concern. But I didn't want to
invest mondo dollars in locking down all of the interfaces until we'd
finished one ship and made sure it all works. The tooling that I did
build to ensure interchangability at the lift pin interfaces is shown
in this Update on my Web site:

http://www.hpaircraft.com/hp-24/update_1b_nov_10.htm

It is similar in function to that used by Jonkers, except that as you
observe it does not embody the locations of the main pin bores.

Also, as I understand it, a lot of European ships aren't really all
that interchangable. In fact, I don't know of a factory that would
send you an entire brand new wing and guarantee that it would mount
right up to an existing fuselage and opposite wing without at least
some drilling or adjustment.

What I've heard and read is that if you need to replace an entire wing
they want to handle the fitment either at the factory or at their
authorized service shop. And what they'll probably do there is either
start with a blank spar stub and match-drill it to the good wing, or
go ahead and bore out the bushings in the good wing and match drill
and re-bush both of them together.

And either of those techniques would guarantee "interchangability" for
the ship at hand.

Thanks, Bob K.

On Nov 1, 4:45*pm, Brad wrote:
On Nov 1, 4:07*pm, Bob Kuykendall wrote:

Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

Bob,

Your design for the parts and the tooling is simply
amazing............I tacked in the rear lift pin tube yesterday
evening. This AM Doug and I pulled the wings off and put them back on
a couple of times and they slid right in just like the real thing. We
finished the day by shear taping in the rear tube.

Tomorrow the shop gets cleaned up and we head home.

Brad

Sounds great, Brad!

Bob K.

Btw, those two seat jet trainers at Mojave look like Impalas. They
are Aermacchi MB-326 built under license in South Africa. The
National Test Pilot School operates a few of them.

On Nov 1, 8:10*pm, Bob Kuykendall wrote:
On Nov 1, 4:44*pm, Martin wrote:

That's a good way to make a one-off homebuilt. In production, they use
a jig to make sure the parts are interchangeable.

Yes, interchangability is a definite concern. But I didn't want to
invest mondo dollars in locking down all of the interfaces until we'd
finished one ship and made sure it all works. The tooling that I did
build to ensure interchangability at the lift pin interfaces is shown
in this Update on my Web site:

http://www.hpaircraft.com/hp-24/update_1b_nov_10.htm

It is similar in function to that used by Jonkers, except that as you
observe it does not embody the locations of the main pin bores.

Also, as I understand it, a lot of European ships aren't really all
that interchangable. In fact, I don't know of a factory that would
send you an entire brand new wing and guarantee that it would mount
right up to an existing fuselage and opposite wing without at least
some drilling or adjustment.

What I've heard and read is that if you need to replace an entire wing
they want to handle the fitment either at the factory or at their
authorized service shop. And what they'll probably do there is either
start with a blank spar stub and match-drill it to the good wing, or
go ahead and bore out the bushings in the good wing and match drill
and re-bush both of them together.

And either of those techniques would guarantee "interchangability" for
the ship at hand.

Thanks, Bob K.

I put 2 wings together on an ASW-19 which were 100 serial numbers
apart and the only thing I had to do was
shim the lift pins.
But it don't always go that way.
Answer to your question is that those holes come from the wing pin
hole fairy. What an easy question.
UH

On Nov 1, 4:15*pm, Greg Arnold wrote:
On 11/1/2010 4:07 PM, Bob Kuykendall wrote:

Where do those big holes in the spars of composite gliders come from?
You know, the ones where they put the bushings that you insert the
main pins through?

Somebody with a big drill drills them.

http://www.youtube.com/watch?v=FZ3rISscO2I

Thanks, Bob K.

http://www.hpaircraft.com/hp-24

Interesting to compare your technique with the way it is done at Jonker
Sailplanes:

http://www.jonkersailplanes.com/factorypictures8.htm

Impressive looking jig, but it also looks like they are using filter
respirators for what they are spraying the wings with, which looks
like a topcoat. Wonder what they are spraying...

Darryl