Why so many rivets?

Ron Wanttaja wrote:
On Tue, 28 Dec 2004 20:26:00 -0600, "Brian Sponcil"
wrote:


I'm currently considering embarking on an RV project and after checking out
a few in our local EAA chapter I ran across a seemingly curious fact. I
recall the builders telling me that their RV kits have around 10,000 rivets.
Compared to a Piper Comanche at 3,714 and a Warrior at 1,785 that's a heck
of a lot of rivets.

So the question is, why so many???


Don't know for sure, but here are my guesses:

1. It's possible the RV uses smaller rivets. Smaller rivets are easier for
amateur installers, while a manufacturer with trained riveters might use larger
rivets to cut down the man-hours needed for construction.

2. Most of the RV series are aerobatic, while the Pipers are not. More rivets
needed due to higher load factors

3. The designers add a bit of extra margin due to mistakes the amateur might
make.

4. The "N" number of rivets listed for Pipers may not include rivets used by
any companies that subcontract parts, while the builder does all the RV rivets.

5. RVs seem to use rivets *everywhere*...perhaps the Pipers use more bolts,
molded sections, etc.

6. Eighth-inch rivets are supposed to be installed about 32 to a foot, and most
RV builders think this --- --- is six inches. :-)

I agree with Ron's guesses (not sure about #6 though), and will add a
7th possibility. It may be that the larger companies use more machine
formed sections (stamped, hydroformed, etc.) that can be larger and thus
have fewer seams to be riveted.

Matt