Best homebuilt for ~700 nm commute

Re the Tango (composite) and RV (metal) an article in July Sport
Aviation (pg 54) addresses Drag Coefficient as a function of
construction process. The multiplier for the Drag Coefficient for
composite is 1.0-1.05 and for flush rivet metal is 1.10. Composite
can reduce drag then by 5 - 10% over a metal constructed aircraft.
Food for thought.

On 2008-07-07, wrote:
Re the Tango (composite) and RV (metal) an article in July Sport
Aviation (pg 54) addresses Drag Coefficient as a function of
construction process. The multiplier for the Drag Coefficient for
composite is 1.0-1.05 and for flush rivet metal is 1.10. Composite
can reduce drag then by 5 - 10% over a metal constructed aircraft.
Food for thought.

The flip side: what happens when it collects hangar rash? Repairing aluminum
is well known; repairing composites is not.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

Jay Maynard wrote:
On 2008-07-07, wrote:
Re the Tango (composite) and RV (metal) an article in July Sport
Aviation (pg 54) addresses Drag Coefficient as a function of
construction process. The multiplier for the Drag Coefficient for
composite is 1.0-1.05 and for flush rivet metal is 1.10. Composite
can reduce drag then by 5 - 10% over a metal constructed aircraft.
Food for thought.

The flip side: what happens when it collects hangar rash? Repairing aluminum
is well known; repairing composites is not.


Exactly, which along with the health related issues associated with
building a composite aircraft is why any of us still work with aluminum.

"Jay Maynard" wrote in message
...
On 2008-07-07, wrote:
Re the Tango (composite) and RV (metal) an article in July Sport
Aviation (pg 54) addresses Drag Coefficient as a function of
construction process. The multiplier for the Drag Coefficient for
composite is 1.0-1.05 and for flush rivet metal is 1.10. Composite
can reduce drag then by 5 - 10% over a metal constructed aircraft.
Food for thought.

The flip side: what happens when it collects hangar rash? Repairing aluminum
is well known; repairing composites is not.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

Could you clarify that Jay?

The way I read it your saying that composite repair is not possible or much
harder than aluminum repair.

There are well established methods for repairing composite damage, without any
annoying rivet bucking noise.

Paul

On 2008-07-07, Paul Hastings wrote:
The way I read it your saying that composite repair is not possible or much
harder than aluminum repair.

There are well established methods for repairing composite damage, without
any annoying rivet bucking noise.

Why, then, can't you get composite factory aircraft repaired short of
sending the broken part back to the factory?

Yes, I know the discussion is around homebuilts, but if composite repairs
are well understood, then there should be no reason to require all repairs
to be done at the factory.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

"Jay Maynard" wrote in message
...
On 2008-07-07, Paul Hastings wrote:
The way I read it your saying that composite repair is not possible or much
harder than aluminum repair.

There are well established methods for repairing composite damage, without
any annoying rivet bucking noise.

Why, then, can't you get composite factory aircraft repaired short of
sending the broken part back to the factory?

Yes, I know the discussion is around homebuilts, but if composite repairs
are well understood, then there should be no reason to require all repairs
to be done at the factory.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

Not knowing which factory you are speaking of, my guess is more of a company
policy issue for liability reasons. I know Northwest(I live in MN too) isn't
sending parts back to Airbus they are repairing them onsite.

So are many homebuilders with composite planes, imho composite repairs are
easier. Especially in your example of hangar rash, if you ding the leading edge
in aluminum How many rivets do you have to drill and rebuck if it is a single
piece leading edge. It gets even worse if you bend an aluminum spar.

Paul

On 2008-07-07, Paul Hastings wrote:
Not knowing which factory you are speaking of, my guess is more of a company
policy issue for liability reasons. I know Northwest(I live in MN too) isn't
sending parts back to Airbus they are repairing them onsite.

I was thinking of the LSA market, as well as being told of one DA20 that
took out a landing light and was down for six months while waiting on
Diamond to fix it.

So are many homebuilders with composite planes, imho composite repairs are
easier. Especially in your example of hangar rash, if you ding the leading edge
in aluminum How many rivets do you have to drill and rebuck if it is a single
piece leading edge. It gets even worse if you bend an aluminum spar.

OTOH, damage that would bend an aluminum spar would break a composite wing
in half.

I don't mean to minimize the repairs required with aluminum, certainly...but
any A&P can deal with an aluminum repair. That's a major reason I ruled out
composite aircraft when I was looking. I would expect the same would go for
composite homebuilts. Sure, the builder might well be able to fix it - but
how well would the fix work, especially in the long run? How well would it
stand up to sun and weather?
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

"Jay Maynard" wrote in message
...
The flip side: what happens when it collects hangar rash?

So who has a hanger? Perhaps it is because I started out in sailplanes, but
I would not be comfortable parking a glass bird out in the sun for years at a
time, especially one finished in jellcoat.

Repairing aluminum is well known; repairing composites is not.

Sorry, I can't agree. I have seen some torn up sailplanes repaired so well
you can't see where anything ever happened. It all a matter of finding the
right repair station.

"Paul Hastings" wrote in message
.. .

"Jay Maynard" wrote in message
...
On 2008-07-07, Paul Hastings wrote:
The way I read it your saying that composite repair is not possible or
much
harder than aluminum repair.

There are well established methods for repairing composite damage,
without
any annoying rivet bucking noise.

Why, then, can't you get composite factory aircraft repaired short of
sending the broken part back to the factory?

Yes, I know the discussion is around homebuilts, but if composite repairs
are well understood, then there should be no reason to require all
repairs
to be done at the factory.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

Not knowing which factory you are speaking of, my guess is more of a
company policy issue for liability reasons. I know Northwest(I live in MN
too) isn't sending parts back to Airbus they are repairing them onsite.

So are many homebuilders with composite planes, imho composite repairs are
easier. Especially in your example of hangar rash, if you ding the leading
edge in aluminum How many rivets do you have to drill and rebuck if it is
a single piece leading edge. It gets even worse if you bend an aluminum
spar.

Paul

From what I've heard around my local chapter, composite repairs are not much
of a problem--at least as long as the spars and fuel tanks are still OK.

OTOH, you really can't beat the pre-punched aluminum from VanGrunsven for
assembly time. If you already have some wiring and systems knowledge from
your work experience, you could almost make an argrument to build an RV to
fly while you are building something that fit your "ultimate" solution. If
you don't have that experience, you will have to deal with the "90% done and
90% remaining" problem, but the same will sitll be true of the composites.

Peter

"Jay Maynard" wrote in message
...
On 2008-07-07, Paul Hastings wrote:
Not knowing which factory you are speaking of, my guess is more of a company
policy issue for liability reasons. I know Northwest(I live in MN too) isn't
sending parts back to Airbus they are repairing them onsite.

I was thinking of the LSA market, as well as being told of one DA20 that
took out a landing light and was down for six months while waiting on
Diamond to fix it.

So are many homebuilders with composite planes, imho composite repairs are
easier. Especially in your example of hangar rash, if you ding the leading
edge
in aluminum How many rivets do you have to drill and rebuck if it is a single
piece leading edge. It gets even worse if you bend an aluminum spar.

OTOH, damage that would bend an aluminum spar would break a composite wing
in half.

I don't mean to minimize the repairs required with aluminum, certainly...but
any A&P can deal with an aluminum repair. That's a major reason I ruled out
composite aircraft when I was looking. I would expect the same would go for
composite homebuilts. Sure, the builder might well be able to fix it - but
how well would the fix work, especially in the long run? How well would it
stand up to sun and weather?
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (got it!)

So, it is a personal issue that you have with composites. I'm glad we cleared
that up :^)