Why so many rivets?

"Matt Whiting" wrote in message
...
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???



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.


BINGO!!!

MJC wrote:
... or it that's a "problem" for you, do what I did.
RV7-A Quickbuild kit. Poof; lot's less rivets :-)

I thought the design was the same and hence the same number of rivets
.... just fewer for you to set! :-)


Matt

The numbers of rivets isn't a make or break detail in terms of whether I
build or not, it's just something that jumped out at me. An RV has FIVE
TIMES as many rivets as my Warrior and the guys I talked to are building
RV-9s! I suppose an RV-10 might have even more.

-Brian
N33431

"MJC" wrote in message
...
... or it that's a "problem" for you, do what I did.
RV7-A Quickbuild kit. Poof; lot's less rivets :-)

Brian Sponcil wrote:

The numbers of rivets isn't a make or break detail in terms of whether I
build or not, it's just something that jumped out at me. An RV has FIVE
TIMES as many rivets as my Warrior and the guys I talked to are building
RV-9s! I suppose an RV-10 might have even more.

Well, I'd rather have too many rivets than too few. :-)


Matt

On Wed, 29 Dec 2004 12:31:03 -0600, "MJC" wrote:

... or it that's a "problem" for you, do what I did.
RV7-A Quickbuild kit. Poof; lot's less rivets :-)

MJC

"Brian Sponcil" wrote in message
...
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.

You could go glass!
I'd guess on the G-III doing just the 96 individual lay-ups for the
engine mount attach point, reinforcements probably took as long as
setting those 10,000 rivets. (It seemed longer)


So the question is, why so many???

Strength.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


-Brian
N33431

Roger:

My Super II FT has over 200 individual pieces of cloth in the firewall
bulkhead for the bulkhead itself, the engine mount reinforcements,
reinforcing ribs, etc.


BJC

"Roger" wrote in message
...
On Wed, 29 Dec 2004 12:31:03 -0600, "MJC" wrote:

... or it that's a "problem" for you, do what I did.
RV7-A Quickbuild kit. Poof; lot's less rivets :-)

MJC

"Brian Sponcil" wrote in message
...
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.

You could go glass!
I'd guess on the G-III doing just the 96 individual lay-ups for the
engine mount attach point, reinforcements probably took as long as
setting those 10,000 rivets. (It seemed longer)


So the question is, why so many???

Strength.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


-Brian
N33431

Ron Wanttaja wrote:



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

Ron Wanttaja


Which the saying goes this is why women can't tell distance, because they've
been always told "this is six inches ----- -----

LOL
I'm ducking!

Don't know about Piper et al but some aircraft structures are bonded
on the same lines of the rivets with them spaced far apart. The
rivets are there to essentially hold the parts in place until the bond
is cured. Faster to manufacture, stronger, and less likely to corrode.
That process wouldn't suit itself to a home builder.

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Earlier, Brian Sponcil wrote:

...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.

I've seen various RVs, Cherokees, and Comanches. I've kitted rivets for
HP-series sailplane kits. And I just plain do not belive those numbers
for the Warrior and Comanche. Not for relatively conventional riveted
aluminum airplanes with few composite components and no metal-to-metal
bonding. Until it's demonstrated otherwise, I propose that someone has
cooked the books on this one to make for a good story.

Consider the Warrior wing: Let's guess that the rib spacing is a
relatively lean 12" OC. Let's guess that the rivet spacing is an
equally lean 2". The span of the metal stuff (minus fiberglass tips) is
probably about 32". Taking the fuselage out probably leaves room for at
least 14 ribs on a side. The wing area of 170 ft^2 over the span of 35'
yields an average chord of about 58". Since the skins are riveted top
and bottom, I think that there are going to be about 58 rivets per wing
rib. So that yields at least 58*30 skin-to-rib rivets, and that's 1740.

Admittedly, that's a pretty rough estimate, and disregards the
(probably negative) contribution of the flaps and ailerons to the rivet
count. But it's a start. When you factor in the rivets between the spar
and the skin, between the ribs and the spars, and for the many
inspection panel rings, stringers, and other local additions, you see
you can easily exceed the stated rivet count for the wings alone. And
you've still got an entire fuselage and set of tail surfaces to go. And
also the extremely close-pitched rivets around the baseball-stitched
fuel tanks, and other miscellanea.

I'll change my mind if, when I next see a warrior, I see fewer than 28
wing ribs or greater rivet spacing than 2". But until then, I'm not
convinced.
Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com

On Wed, 29 Dec 2004 04:39:06 GMT, Ron Wanttaja
wrote:



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

a piper cherokee has literally a plastic bucket full of bolts in it.

....as we found out during a restoration.
Stealth Pilot