welding technique for clusters

On Sat, 21 Mar 2009 12:10:37 -0700 (PDT), wrote:

On Mar 20, 6:49*pm, Bob Hoover wrote:

Of course it matters, Harry. *EVERYTHING matters!


You can say that again.

One of the things that matters is getting the finish dimensions that
you started with. I've spent hours filing and shaping a fishmouth to
get that perfect fit, only to have the end off my tube off by 1/8"
once all the warping has finished. I've learned to minimize the
warping though. You should weld the fish mouth in 4 steps. First do
each side where the mouth reaches down the side of the non-cut tube.
As the metal shrinks, it will pull the mouth tighter into the non-cut
tube. You've welded on both sides, so the warping neutralizes
itself.


make yourself a shrink warping preventer. its a good welding exercise
in itself.

when you heat up the metal to red heat and let it cool it will shrink
and unless you prevent the longeron tube from moving it will develop a
bend.

my brother in law has a simple fixture that prevents the bend (he
being a life long expert welder)

you need a little solid section that will take a threaded hole across
it for a little jack screw like the screw up part of a common old "G"
clamp.
out each side you weld some scrap tube so that you end up with a long
straight tube with the little jacking screw transversely across the
middle.

mentally place this welded up tube bit on top of a fuselage longeron
tube with the jacking screw pointing at the longeron.
ok from each end of this tube bizzo you need some arms that go out
perpendicular from each end, then downward, then back under the fuz
tube, then a little bit that goes up toward the fuz tube. at the end
of this little upward bit you place an inch or so half length of tube
so that it will cradle the fuz tube.
the tube bizzo with the little cranked arms at each end are an
interesting welding practise exercise.

now to use it you straddle the joint and clamp it very very very
lightly to the longeron you expect to warp.
when you weld the cluster and the tubes are all red hot any over
clamping will of course warp the longeron so you need just the merest
holding clamping. as the cluster cools and wants to shrink bend the
longeron the little clamp will hold the tube straight.

brother in law came up with the idea years ago and has used it ever
since on his aircraft welding. works a treat.

dont bother painting it because the flame will burn the paint off

I'll see if I can find a photo of the ones I made.

Stealth Pilot

I'll see if I can find a photo of the ones I made.

Stealth Pilot- Hide quoted text -

- Show quoted text -

Stealth,

I know exactly what you're talking about. The clamps that held Wilbur
Wright's test "air plane" and flat plate to the bicycle-wheel-thingy
of the 1901 aerodynamic experiment are made that way (on a much
smaller scale).

For those of you that think airfoils are the subject of University
wind tunnels, Reynolds Numbers, and other such ilk, you may find it
interesting to know that good 'ole Wilbur Wright made his first
aerodynamic studies by mounting them on a bike wheel attached
horizontally to another bike. The apparatus's power source was only
rated at one "Orville", but that was sufficient to determine that
Smeaton's coefficient of air pressure was flawed. The follow-up tests
were run in a wind tunnel made of pine boards.

Harry

wrote in message
...
I'll see if I can find a photo of the ones I made.

Stealth Pilot- Hide quoted text -

- Show quoted text -

Stealth,

I know exactly what you're talking about. The clamps that held Wilbur
Wright's test "air plane" and flat plate to the bicycle-wheel-thingy
of the 1901 aerodynamic experiment are made that way (on a much
smaller scale).

For those of you that think airfoils are the subject of University
wind tunnels, Reynolds Numbers, and other such ilk, you may find it
interesting to know that good 'ole Wilbur Wright made his first
aerodynamic studies by mounting them on a bike wheel attached
horizontally to another bike. The apparatus's power source was only
rated at one "Orville", but that was sufficient to determine that
Smeaton's coefficient of air pressure was flawed. The follow-up tests
were run in a wind tunnel made of pine boards.

Harry

From a sign currently posted in their bicycle shop:

"Thousands of pages have been written on the so-called science of flying,
but for the most part, the ideas set forth, like the designs for the
machines, were mere speculations and probably ninety percent were false."

Wilbur Wright

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

wrote:
... The clamps that held Wilbur
Wright's test "air plane" and flat plate to the bicycle-wheel-thingy
of the 1901 aerodynamic experiment are made that way (on a much
smaller scale).

For those of you that think airfoils are the subject of University
wind tunnels, Reynolds Numbers, and other such ilk, you may find it
interesting to know that good 'ole Wilbur Wright made his first
aerodynamic studies by mounting them on a bike wheel attached
horizontally to another bike. The apparatus's power source was only
rated at one "Orville", but that was sufficient to determine that
Smeaton's coefficient of air pressure was flawed. The follow-up tests
were run in a wind tunnel made of pine boards.

Harry

Nice post!

BrianW

On Mar 24, 1:51*pm, wrote:

For those of you that think airfoils are the subject of University
wind tunnels, Reynolds Numbers, and other such ilk, you may find it
interesting to know that good 'ole Wilbur Wright made his first
aerodynamic studies by mounting them on a bike wheel attached
horizontally to another bike.
-------------------------------------------------------------------------

Roger that, Harry.

I don't know if you'll recall but you and I had an enjoyable exchange
on that topic some years ago.

I've always thought Oriville's 'How We Inveted The Airplane' one of
the best books I ever read. (I still havve a copy around here
somewhere.)

One of my dad's favorite terms for know-it-all airmen was to refer to
them as 'Orville's Flight Instructor.' This was soon reduced to:
"Another OFI... " and a shared grin.

I sure hate to see those days slipping away from me.

-Bob

On Wed, 25 Mar 2009 06:11:09 -0700 (PDT), Bob Hoover
wrote:

On Mar 24, 1:51*pm, wrote:

For those of you that think airfoils are the subject of University
wind tunnels, Reynolds Numbers, and other such ilk, you may find it
interesting to know that good 'ole Wilbur Wright made his first
aerodynamic studies by mounting them on a bike wheel attached
horizontally to another bike.
-------------------------------------------------------------------------

Roger that, Harry.

I don't know if you'll recall but you and I had an enjoyable exchange
on that topic some years ago.

I've always thought Oriville's 'How We Inveted The Airplane' one of
the best books I ever read. (I still havve a copy around here
somewhere.)

One of my dad's favorite terms for know-it-all airmen was to refer to
them as 'Orville's Flight Instructor.' This was soon reduced to:
"Another OFI... " and a shared grin.

I sure hate to see those days slipping away from me.

-Bob

been having a few people die around me lately. bit offputting. but I
steam on regardless.

I wannabe an active pilot at 99.
Stealth (just a wannabe :-) ) Pilot

On Tue, 24 Mar 2009 13:51:45 -0700 (PDT),
wrote:

I'll see if I can find a photo of the ones I made.

Stealth Pilot- Hide quoted text -

- Show quoted text -

Stealth,

I know exactly what you're talking about. The clamps that held Wilbur
Wright's test "air plane" and flat plate to the bicycle-wheel-thingy
of the 1901 aerodynamic experiment are made that way (on a much
smaller scale).


I went out in the workshop and after some searching found and
photographed my clamp.
I've posted the images on alt.binaries.pictures.aviation under a
header of welding aid 1 and 2. for some reason the text gets posted in
one post and the image in another.

the device works.

I reiterate that the "clamping" pressure is very light. only just
enough to hold it in place. too much clamping and you bend the
longeron in the opposite way to what you were trying to prevent.

Stealth Pilot