Aluminum differences

No I include structural parts in my discussion. There is no reason why
structural parts should not be made from the alloys under discussion. They
can be, have been and will be ... you just need two important ingredients:

1. Data on the strength and fatigue characteristics so you can do the
analysis and ensure that the sections are large enough.

2. A paper trail providing an acceptable level of quality assurance for the
material.

You can built an airplane out of any material you want if it satisfies these
two requirements - granted some materials are more efficient (better
"strength to weight" ratio than others).

I don't see the relevance to Zenair and blind (POP) fasteners.





"Orval Fairbairn" wrote in message
news ...
In article ,
Philippe wrote:

Orval Fairbairn wrote:



6063 is commercial cheese ... would be the lower strength of the
three
alloys mentioned. Don't have data handly but you can find it on the
web.

Nothing stopping you using it in an airplane if you select an
appropriate
size to account for its lower strength. I have used it in some
modifications to a restricted category aircraft. Just be aware that
you
cannot by 6063 to an accepted aeronautical spec such as QQ_A Fed Spec
etc
so you might want to allow an extra margin of safety to account for
the
commercial nature of the material.


Bottom line: DON'T do it! Real, aircraft grade aluminum is not all
that
expensive -- just check the Airparts catalog or their ad in Sport
Aviation. 2024-T3 is the standard aircraft structural aluminum, and
substituting a lesser grade only adds weight and can reduce safety in
structural applications.

Are you sure that all aircraft parts are designed for ultimate stress
ability. Sometime, it's for stability in compression and the best
ultimate
resistance is not needed.
For example, a 0.5mm skin on a MCR01 is oversized.
Another example: Zenith aircraft don't use 2024.


By

You should note that I specified STRUCTURAL aluminum. Yes, nonstructural
parts are made for other reasons and have a places for other grades of
aluminum.

BTW, Zenith also uses pop rivets rather than driven rivets, so they
should not be used as an example.

Orval Fairbairn wrote:

(snipped)
You should note that I specified STRUCTURAL aluminum. Yes, nonstructural
parts are made for other reasons and have a places for other grades of
aluminum.

BTW, Zenith also uses pop rivets rather than driven rivets, so they
should not be used as an example.

6061-T6 is so structural aluminum.
You _can_ even get it "clad" if you got the bucks.

And the Zenith rivet technique is quite fascinating.

They start off with countersunk head steel cored rivets and use a
modified nose piece in the rivet gun to form a domed head when the
rivet is pulled. The head gets work hardended furing forming.

It's a very sound rivet approaching driven rivets in strength.

In article
, Orval
Fairbairn says...

You should note that I specified STRUCTURAL aluminum. Yes, nonstructural
parts are made for other reasons and have a places for other grades of
aluminum.

BTW, Zenith also uses pop rivets rather than driven rivets, so they
should not be used as an example.

Thorp used pop rivets on the T-18 as well .Cherry Max's are pop rivets too and
are used all over the place. Zenith doesn't have parts coming apart because
of pop rivets. You just have to use the right ones and have them sized for the
loads.
See ya

Chuck S

There is nothing wrong with the Zenair approach ... it is used on the
CH-2000 and thus has been certificated by the FAA ... the method is however
a little unusual and can be a little confusing for some builders. I am not
quite sure why Heintz uses this method in lieu of a more standard
installation. Perhaps someone can enlighten us.

Whilst some blind rivets do have strengths that approach or in some cases
exceed the strength of standard MS20470/426AD solid rivets the main draw
backs a

1. They can leak and thus need to be sealed.

2. They are more prone to working and loosening. The extent of this problem
is a function of the type of blind rivet. The Avdel rivets used by Zenair
are the cheapest and simplest type of blind rivet and will be more prone to
working and loosening than a Cherry Max or Cherry Lock. Pop rivets are
generally best used in lowly stressed areas for this reason (which is really
most of the structure in a light aircraft). Note that Zenair and many other
designers don't use blind rivets in the main spar prefering standard AD
rivets. Even the more expensive and sophisticated Cherry rivets will
work/loosen and most manufacturers or real airplanes will place restrictions
on where they may be used to replace AD rivets for repair work.





"Richard Lamb" wrote in message
...
Orval Fairbairn wrote:

(snipped)
You should note that I specified STRUCTURAL aluminum. Yes, nonstructural
parts are made for other reasons and have a places for other grades of
aluminum.

BTW, Zenith also uses pop rivets rather than driven rivets, so they
should not be used as an example.

6061-T6 is so structural aluminum.
You _can_ even get it "clad" if you got the bucks.

And the Zenith rivet technique is quite fascinating.

They start off with countersunk head steel cored rivets and use a
modified nose piece in the rivet gun to form a domed head when the
rivet is pulled. The head gets work hardended furing forming.

It's a very sound rivet approaching driven rivets in strength.

Thorp used Monel pops .... a number of certificated aircraft also use Monel
pops.


"ChuckSlusarczyk" wrote in message
...
In article
,
Orval
Fairbairn says...

You should note that I specified STRUCTURAL aluminum. Yes, nonstructural
parts are made for other reasons and have a places for other grades of
aluminum.

BTW, Zenith also uses pop rivets rather than driven rivets, so they
should not be used as an example.

Thorp used pop rivets on the T-18 as well .Cherry Max's are pop rivets too
and
are used all over the place. Zenith doesn't have parts coming apart
because
of pop rivets. You just have to use the right ones and have them sized for
the
loads.
See ya

Chuck S

In article , Stephen Mitchell
says...

Thorp used Monel pops .... a number of certificated aircraft also use Monel
pops.

Correct, proving the point that all rivets don't have to be the solid bucked
style as someone wrote. There's pop rivets and there's pop rivets just like
there's alum and there's alum. So just because some designers use pop rivets
does'nt mean their design is inferior to one that's using buck rivets.That's all
:-)

See ya

Chuck S

"Stephen Mitchell" wrote
There is nothing wrong with the Zenair approach ... it is used on the
CH-2000 and thus has been certificated by the FAA ... the method is however
a little unusual and can be a little confusing for some builders. I am not
quite sure why Heintz uses this method in lieu of a more standard
installation. Perhaps someone can enlighten us.

Actually, he makes no secret of it and discussed it at a seminar at
Oshkosh. With any luck, I remember this correctly, so here goes:

He opted for mechanical rivets because they can be set by one person,
and without the noise of a rivet gun. Basically, this is so married
builders can keep peace in the household. Given the domestic
situation of most pilots/builders, I can see his point.

Given that he was going for mechanical rivets, the next question is
which ones. He did not opt for Cherry/CherryMax solely because of
cost; they are a good rivet and has structural properties such that
significantly fewer rivets could be used. However, the overall cost
would have been higher. He decided not to go with the commercial
(POP) rivet because the round head did not lead to a consistent
installation, so while the individual rivets are substantially
cheaper, he would have had to design in a lot more of them. He opted
for Avex rivets because the mushroom-shaped head yielded a reasonably
consistent installation and the cost was reasonable.

In fact, Avex rivets were originally designed for aircraft use and are
used in some certified aircraft. However, the approval process took
too long, and meanwhile they found a market in consumer goods. In the
end, that turned out to be the lucrative market, and aviation was
abandoned. Hooray for certification...

Michael