Explanation please; Figure 4-42, 43.14-1B

Figure 4-42 "Streamline tube splice using round tube" - obviously they
inserted a round tube into the streamlined tube. Can anyone explain
the rest of the drawing? What's being shown in the top perspective? -
thanks, Mike

On Mon, 27 Aug 2007 11:14:18 -0700, mhorowit wrote:

Figure 4-42 "Streamline tube splice using round tube" - obviously they
inserted a round tube into the streamlined tube. Can anyone explain
the rest of the drawing? What's being shown in the top perspective? -
thanks, Mike

see the left hand cross section. that shows the setup.

you have a diagonal cut across the streamline tube, this allows access
into the streamline tube at that point.
there is a slot cut into the sides of the streamline tube extending
from the diagonal cut along the streamline tube in both directions for
at least 1 1/2 times the streamline tube chord. the slot has rounded
ends.

you select an appropriate length of tube and fishmouth the ends.
you need to panel beat the ends down a little so that it fits into the
streamline tube. the round tube should be a neat fit in the slot in
the streamline tube.
once you have the round tube fitting into the entire length of the
slot (by percussive persuasion, panel beating etc) you assemble the
three components together
you then weld the two steamline tubes together as indicated by the
hachure on the drawing.then you rosette weld the round tube to the
streamline tube along the edges of the slot.

personally I think they've drawn the length of the round tube a little
short. this may give welding problems that can be obviated by making
the round tube a little longer.

I hope that makes it clearer.

Stealth Pilot

On Aug 28, 7:10 am, Stealth Pilot
wrote:
On Mon, 27 Aug 2007 11:14:18 -0700, mhorowit wrote:
Figure 4-42 "Streamline tube splice using round tube" - obviously they
inserted a round tube into the streamlined tube. Can anyone explain
the rest of the drawing? What's being shown in the top perspective? -
thanks, Mike

see the left hand cross section. that shows the setup.

you have a diagonal cut across the streamline tube, this allows access
into the streamline tube at that point.
there is a slot cut into the sides of the streamline tube extending
from the diagonal cut along the streamline tube in both directions for
at least 1 1/2 times the streamline tube chord. the slot has rounded
ends.

you select an appropriate length of tube and fishmouth the ends.
you need to panel beat the ends down a little so that it fits into the
streamline tube. the round tube should be a neat fit in the slot in
the streamline tube.
once you have the round tube fitting into the entire length of the
slot (by percussive persuasion, panel beating etc) you assemble the
three components together
you then weld the two steamline tubes together as indicated by the
hachure on the drawing.then you rosette weld the round tube to the
streamline tube along the edges of the slot.

personally I think they've drawn the length of the round tube a little
short. this may give welding problems that can be obviated by making
the round tube a little longer.

I hope that makes it clearer.

Stealth Pilot

Wow. Thanks for the explanation. Is there any supplimental text that
augments 43.13 i.e.gives a text description like you provided? - MikeH

On Aug 28, 4:10 am, Stealth Pilot
wrote:

personally I think they've drawn the length of the round tube a little
short. this may give welding problems that can be obviated by making
the round tube a little longer.
-------------------------------------------------------------------

Roger that.

The cited 1.5C is the accepted MINIMUM. In practice I believe you'll
find the PRACTICAL minimum to be 1.5C + B (ie, 3C + 2B for the
insert's total length). This reflects the fact that the fishmouthed
ends tend to absorb heat more quickly. To keep from having to chase
the weld-pool you'll find it best to have the full diameter of the
doubler under the end of the notch.

Also, because stresses in the streamlined tube will cause the material
to spring out of position once you've created the notches, this is one
of those cases where you'll need lots of clamps & tack-welds to
maintain alignment. Note the recommended eighth-inch gap along the
diagonal. I believe you will find this too is a minimum.

Finally, while TIG does fine for the tacking, you'll probably have
less trouble if you do the weld with O/A. If TIG is used for the
whole job you're liable to get some cracks on the LE side of the
groove unless you can bring the whole thing up to red heat and allow
it to cool in still air. (O/A pretty much guarantees the whole damn
thing heats up.)

-R.S.Hoover

On Tue, 28 Aug 2007 04:33:14 -0700, mhorowit wrote:

On Aug 28, 7:10 am, Stealth Pilot
wrote:
On Mon, 27 Aug 2007 11:14:18 -0700, mhorowit wrote:
Figure 4-42 "Streamline tube splice using round tube" - obviously they
inserted a round tube into the streamlined tube. Can anyone explain
the rest of the drawing? What's being shown in the top perspective? -
thanks, Mike

see the left hand cross section. that shows the setup.

you have a diagonal cut across the streamline tube, this allows access
into the streamline tube at that point.
there is a slot cut into the sides of the streamline tube extending
from the diagonal cut along the streamline tube in both directions for
at least 1 1/2 times the streamline tube chord. the slot has rounded
ends.

you select an appropriate length of tube and fishmouth the ends.
you need to panel beat the ends down a little so that it fits into the
streamline tube. the round tube should be a neat fit in the slot in
the streamline tube.
once you have the round tube fitting into the entire length of the
slot (by percussive persuasion, panel beating etc) you assemble the
three components together
you then weld the two steamline tubes together as indicated by the
hachure on the drawing.then you rosette weld the round tube to the
streamline tube along the edges of the slot.

personally I think they've drawn the length of the round tube a little
short. this may give welding problems that can be obviated by making
the round tube a little longer.

I hope that makes it clearer.

Stealth Pilot

Wow. Thanks for the explanation. Is there any supplimental text that
augments 43.13 i.e.gives a text description like you provided? - MikeH

that is one of the beauties of R.A.H. ask and you can be helped.
sometimes you can ask and get no replies.
sometimes if you held the tube to the flames it would be welded and
annealed in the one set of responses. :-)

veedubber is one of the guys I look forward to. Wannntttajjjja and
Weir as well.

never drop your guard though. I could have been wrong.
Stealth Pilot