Steve, Are the tube ends cluster welded together also or is the only
connection via that slot? Thanks, Dick
"Steve Beaver" wrote in message
...
The Sukhoi 26/29/31 aerobatic a/c use a system similar to the one you
describe. A plate is welded on the outside and the inside of the cluster
but
there is a slot, about 1/16 in wide and 4 or 5 inches long cut in the
plate
exactly in line with the center of each tube. It is through this slot that
the welds are made between the plate and the tubes.

The tubing on the Sukhoi is VN02 stainless, not 4130 but it is an
interesting piece of design.

"Dick" wrote in message
. com...
Other than a weight consideration, what concern is there with replacing
a
typical fuselage tube cluster (all legs in the same geometric plane)
with
a
half circle plate where the slotted end legs are slide onto and then
welded?

Kind of like a bridge with it's clip angles on I-beams. Then the
diagonals
and other bridge members are riveted/bolted onto the clip angles.. Or
similiar to those wooden semi-circular gussets used to sandwich a wooden
fuselage member joint.

It appears to me that the linear inches of weld could be greater than
those
fishmouthed connections so tedious to make.

Thanks, Dick