On Sat, 01 Jan 2005 17:36:39 +1100, jc wrote:

David Findlay wrote:

snip

Is there a reason why aircraft would be riveted rather than welded
together, particularly on the airframe, not the skin? I would have
imagined that welding would produce a stronger join, although it may be
harder or impossible to disassemble if needed. Thanks,

One key point is QC.

With the rivets a Al batch of a known alloy is turned into a bazillion
rivets by a machine. A small number of these rivets are tested to confirm
the batch of rivets is up to spec.

Using well understood and documented techniques a joint is designed for the
required stresses with x rows of rivets at y spacing etc. The joint is then
riveted.

QC on the joint itself merely requires visual examination, no fancy ND
techniques etc.

Routine inspection in service likewise is done by visual inspection.

and in service a stuffed rivet can be merely drilled out and replaced.
a cracked weld would probably result in expensive repair, or the
resorting to rivetted in place patches.

rivets may not be the best in an ideal world but they are practical
and result in almost infinitely repairable aircraft.

david something that bears consideration is that over the full life of
an aircraft every component will come to need repair as it wears out.
so every component needs to be got at, removed, replaced or repaired
and put back into service. rivets may be tedious but allow this to
occur. welded components may lead to an entire airframe sitting on the
tarmac or in a hangar while repairs to cracks are thought through and
attempted.

australia's macchi jet trainers have cast ring beams in the fuselage
to which the wings attach. cracks in these saw lots of downtime while
repairs were contemplated and eventually led to the scrapping of the
aircraft. ...which isnt good for repeat business.

Stealth Pilot
Australia.