Why so many rivets?

[Brian Sponcil]

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???


-Brian
N33431

[Ron Wanttaja]

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. :-)

Ron Wanttaja

[Ric]

"Ron Wanttaja" > wrote in message
...
> 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.
> :-)
>
> Ron Wanttaja

I'm not sure where I read it, but I remember something about by using more
rivets the strength of the structure will not be compromised by the
occasional badly driven rivet.

Ric

[Ron Wanttaja]

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

>6. Eighth-inch rivets are supposed to be installed about 32 to a foot...

For those who are wondering, this isn't a "real" specification....

Ron Wanttaja

[Matt Whiting]

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

[[email protected]]

Matt Whiting wrote:
> 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


************************************************** **********************************

Whatever: The RV is sure a LOT more airplane than anything Piper
built !!!!

Bob Olds RV-4
Charleston,Arkansas


************************************************** **********************************

[Orval Fairbairn]

In article >,
"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???
>
>
> -Brian
> N33431


One of the things I have noticed on Comanches is that their rivet
spacing for #3 rivets is about twice that spelled out in the manuals.
The result is that a lot of Comanches show signs of distress along those
rivet lines with too much space between rivets.

I have not checked Warriors that closely but would expect to see the
same thing there, too.

[Dan Nafe]

In article . com>,
wrote:

> Whatever: The RV is sure a LOT more airplane than anything Piper
> built !!!!

You'd best smile when you say that, Pilgrim.

Dan
Vero Beach, Florida

(Yet when asked if I wanted to get checked out in the company Cheyenne,
I replied: "I don't really want to be going 400mph in something we
built")

[Michael Pilla]

"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???

SNIP

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
====================
Regardless of the number of rivets, the actual riveting process is not all
that time consuming. Yes, you do have to clean 10,000 holes (at least
double, for the mating parts) and debur them, and even countersink/dimple a
lot of those holes, but you develop a rhythm that goes by rather quickly. I
found that the actual setting of rivets, once the prep is finished, is so
quick that it is almost anti-climactic.

So, if the original poster was concerned about the sheer number of rivets;
i.e., the level of effort, then I recommend that he not be concerned about
that. The systems work will consume the most time as well as looking at the
plans, figuring out the steps, etc. The learning part is the most fun, for
me.

Michael Pilla

[MJC]

.... 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.
>
> So the question is, why so many???
>
>
> -Brian
> N33431
>
>

[John Kunkel]

"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!!!

[Matt Whiting]

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

[Brian Sponcil]

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 :-)

[Matt Whiting]

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

[Roger]

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
>>
>>
>

[Byron J. Covey]

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
>>>
>>>
>>
>

[UltraJohn]

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 Hammer]

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.

Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
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[Bob K.]

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

[Stealth Pilot]

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

[smjmitchell]

I agree with Bob ... the numbers seem very low. However I have little doubt
that a production airplane will have less rivets than most homebuilts.

In general homebuilt airplanes tend to be quite complex in their
construction ... there are more bits in the firewall of an RV-6 than an
entire C-150 fuselage (OK maybe a little exageration but not too far wrong).

There are several reasons for this:

(a) Designers of homebuilts don't have access to production tooling such as
guerin presses to make firewalls in a single piece. Consequently they use
more, simpler to make pieces, which need more rivets.

(b) In general designers of homebuilt airplanes are not as focused on
refining the product for production ... if you work for C, B or P etc then
you need to design lean for production. You also have the facilities, budget
and extensive test programs to help refine the design. The big companies in
some cases design unconservatively and then beaf up the structure where it
fails. Homebuilt designers in general design conservatively and cannot
afford for a part to fail during test.

(c) Few homebuilts are subject to extensive structural analysis and
consequently the designers has no idea what the margins are re rivet shear
and inter-rivet buckling etc so they have no choice but to stick to the
typical minimum rivet spacings.

I think it would be safe to say that you could not produce many homebuilts
economically .. they are simply over built and their crudeness, whilst good
for homebuilders is not suited for volume production .... the number of
rivets is a huge cost driver WRT to cost of production since the labour in
any airplane will be the most significant single cost in its production.
That is why stir friction welding is being used in the Eclipse business jet.

There are some exceptions to my generalisation re homebuilts being more
complex that factory produced airplanes. The MM-I for example is an
elegantly simple airplane with a minimum number of bits - but then Dave Long
was a Piper design engineer. The T-18 is also a very simple airplane ... of
course John Thorp also had a background in the design of airplanes for
production. I think it all comes down to the designers background.







"Bob K." > wrote in message
oups.com...
> 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
>

[Ron Wanttaja]

On Thu, 30 Dec 2004 16:57:26 +0800, Stealth Pilot > wrote:

>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.

Hopefully, you didn't have half a bucket left when you were done. :-)

Ron Wanttaja

[Stealth Pilot]

On Thu, 30 Dec 2004 15:01:52 GMT, Ron Wanttaja >
wrote:

>On Thu, 30 Dec 2004 16:57:26 +0800, Stealth Pilot > wrote:
>
>>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.
>
>Hopefully, you didn't have half a bucket left when you were done. :-)
>
>Ron Wanttaja

no, :-) but there are two unique washers. hemispherical that sit in a
hemispherical socket down in the stabilizer attach area.
I think a fundamental law of physics exists that one will remain
faithfully in the bucket during all cleaning, drying and sorting
activities while the other must hide itself in the crack between two
sections of concrete just under the stabilizer.

the jones theory of special aviation fittings :-)

Stealth (dont design special one-off fittings into aeroplanes!) Pilot

[MJC]

Well yea, but that's what I thought Brian had a problem with, i.e., not
how many rivets are in the aircraft, but how many he personally had to set.
With the QB kit, the number of rivets the builder has to set is
inconsequential.

MJC

"Matt Whiting" > wrote in message
...
> 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
>

[Cy Galley]

Flush rivets are weaker so it takes more. smaller spacing between rivets,
means fewer wrinkles or puckers.


"smjmitchell" > wrote in message
...
> I agree with Bob ... the numbers seem very low. However I have little
doubt
> that a production airplane will have less rivets than most homebuilts.
>
> In general homebuilt airplanes tend to be quite complex in their
> construction ... there are more bits in the firewall of an RV-6 than an
> entire C-150 fuselage (OK maybe a little exageration but not too far
wrong).
>
> There are several reasons for this:
>
> (a) Designers of homebuilts don't have access to production tooling such
as
> guerin presses to make firewalls in a single piece. Consequently they use
> more, simpler to make pieces, which need more rivets.
>
> (b) In general designers of homebuilt airplanes are not as focused on
> refining the product for production ... if you work for C, B or P etc then
> you need to design lean for production. You also have the facilities,
budget
> and extensive test programs to help refine the design. The big companies
in
> some cases design unconservatively and then beaf up the structure where it
> fails. Homebuilt designers in general design conservatively and cannot
> afford for a part to fail during test.
>
> (c) Few homebuilts are subject to extensive structural analysis and
> consequently the designers has no idea what the margins are re rivet shear
> and inter-rivet buckling etc so they have no choice but to stick to the
> typical minimum rivet spacings.
>
> I think it would be safe to say that you could not produce many homebuilts
> economically .. they are simply over built and their crudeness, whilst
good
> for homebuilders is not suited for volume production .... the number of
> rivets is a huge cost driver WRT to cost of production since the labour in
> any airplane will be the most significant single cost in its production.
> That is why stir friction welding is being used in the Eclipse business
jet.
>
> There are some exceptions to my generalisation re homebuilts being more
> complex that factory produced airplanes. The MM-I for example is an
> elegantly simple airplane with a minimum number of bits - but then Dave
Long
> was a Piper design engineer. The T-18 is also a very simple airplane ...
of
> course John Thorp also had a background in the design of airplanes for
> production. I think it all comes down to the designers background.
>
>
>
>
>
>
>
> "Bob K." > wrote in message
> oups.com...
> > 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
> >
>
>

[Don Hammer]

On Mon, 03 Jan 2005 02:41:38 GMT, "Cy Galley" >
wrotD:

>Flush rivets are weaker so it takes more.
>

A&P school was 35 years ago, but if memory serves it's the diameter
and material of a rivet that sets the strength and not the head type
as they are basically a shear loaded device. Spacing is set based on
rivet diameter irrespective of head type.

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[B2431]

>Date: 12/30/2004 09:01 Central Standard Time
>Message-id: >
>
>On Thu, 30 Dec 2004 16:57:26 +0800, Stealth Pilot >
>wrote:
>
>>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.
>
>Hopefully, you didn't have half a bucket left when you were done. :-)
>
>Ron Wanttaja

They use buckets in their construction?

Dan, U.S. Air Force, retired

[Ron Wanttaja]

On 05 Jan 2005 23:16:52 GMT, (B2431) wrote:

>>>a piper cherokee has literally a plastic bucket full of bolts in it.
>>>
>>>...as we found out during a restoration.
>>
>>Hopefully, you didn't have half a bucket left when you were done. :-)
>>
>>Ron Wanttaja
>
>They use buckets in their construction?

Sorry, my mistake. I saw a guy working on a Cherokee, and thought he'd suddenly
exclaimed, "Oh, bucket!" Turns out he'd said something else. :-)

Ron Wanttaja