Where do main pin holes come from?

On Nov 1, 6:59*pm, wrote:
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

those fairy's are really boring too...........

Brad

On 11/1/2010 7:10 PM, Darryl Ramm wrote:
On Nov 1, 4:15 pm, Greg 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...

Polyurethane, it says. One hopes that in their new paint booth they
have a healthier system.



Darryl

I have replaced a wing on; Libelle, K-21, ASW-20 and G-103. The only
one that fit without re-bushing was the Grob because their fittings
are jig set and the aft lift pin can move laterally. On the K-21 we re-
set only one bushing and held the wings in place with both main wing
pins inserted..................rotated them every 15 minutes to insure
they would come out when dry!
Looking good Bob, did you glue in an uncut bushing and then cut the
wings apart after the epoxy set?
JJ

On Nov 2, 6:33*am, JJ Sinclair wrote:

*...Looking good Bob, did you glue in an uncut bushing and then cut the
wings apart after the epoxy set?

Thanks, JJ!

No, we inserted our bushings in pairs with the separation lines
between the spars. It did get a bit of epoxy between the pin and the
bushing, and the first removal was a bit hard. But after cleaning the
pins and bushings with acetone and re-lubing them, the pins slid
straight in.

Bob K.

On Nov 1, 6:08*pm, Martin wrote:
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.

Yes, that looks exactly right! Thank you!

Here's the Wikipedia page:

http://en.wikipedia.org/wiki/Aermacchi_MB-326

Bob K.

On Mon, 1 Nov 2010 18:59:20 -0700 (PDT), wrote:
[snip]

Answer to your question is that those holes come from the wing pin
hole fairy. What an easy question.

Dang! I thought it was done with explosives.

rj

On Nov 2, 8:28*am, Ralph Jones wrote:

Dang! I thought it was done with explosives.

The stuff I used for the bearing blocks in the spar where the pins go
is tough freakin' stuff, and made a mess of just about every sort of
drill bit we threw at it.

So, yeah, we did toss around the idea of det cord or shaped charges.
But sanity prevailed in the end.

Thanks, Bob K.

On Nov 2, 3:57*pm, Bob Kuykendall wrote:
On Nov 2, 8:28*am, Ralph Jones wrote:

Dang! I thought it was done with explosives.

The stuff I used for the bearing blocks in the spar where the pins go
is tough freakin' stuff, and made a mess of just about every sort of
drill bit we threw at it.

So, yeah, we did toss around the idea of det cord or shaped charges.
But sanity prevailed in the end.

Thanks, Bob K.

the landlord nixed the idea of using explosives.............I better
stop before echelon gets me!

Brad