"Kevin Horton" wrote in message
news
On Sat, 29 Nov 2003 14:17:48 -0500, Larry Smith wrote:


"Lpmcatee356" wrote in message
...
where can I find construction details - howto files?

Try downloading the Quicke construction manual. It's not much more
than
a
seat
with wings.

www.finleynet.com


At its website Cessna explains why it uses exclusively aluminum
construction. Cessna says there are too many unknowns regarding glass
and that aluminum is better. Well, aluminum IS better in some
respects,
but glass is also better in many respects too. Fiberglas is easy to
repair, it lends itself nicely to compound curves, it does not corrode
or
fatigue like aluminum, it is capable of absorbing more shock than
aluminum, and its strength-to-weight ratio cannot be beat.


There is no doubt fibreglas construction has its advantages, but I'm not
so sure that light weight is one of them. My impression from comparing
specs of similar aircraft is that aluminum construction is usually
lighter. For example, if we look at two seat, side-by-side fixed gear
aircraft, the RV-6 seems to come out at least 100 lb lighter than a
Glasair II TD if we have similar engines and props. And the RV-6 has a
lot more wing (110 sq. ft. vs 81 sq. ft).

http://www.airsport.com/kits/ksuper2.htm
http://www.vansaircraft.com/public/rv-6spe.htm

The Zenair CH2000 and the Diamond DA-20 were both designed to meet the
same requirements (JAR-VLA). The aluminum CH2000 is about 100 lb lighter
than the composite DA-20:

http://www.newplane.com/amd/spec.html
http://www.diamondair.com/contentc/c1spec.htm

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com


I don't disagree with you here at all. It is true that most composite
kitplanes and most composite factory-built aircraft are a little heavier
than similar aluminum aircraft. However, you will find that careful layups
like those in the lighter Longezes and Variezes, and indeed in Rutan's
Voyager, will produce an aircraft lighter and stronger than aluminum.
Matter of fact you can't really make a comparison because of the variations
and the dissimilar advantages and disadvantages in each method of
construction.

Let me ask you something. Do you believe an aircraft like the
around-the-world Voyager could have been constructed of aluminum? Has
anyone ever built an aluminum Quickie or Cozy or Velocity?

I'll give you another example --- Mike Arnold's 213 mph world champion
speedster, the AR-5. Do you believe that same airframe, which is very
light, btw, because of judicious (but not vacuum-bagged) layups, could have
been made of aluminum? I don't. The AR-5 defeated the previous world
record-holder, which was an aluminum BD-5. Aluminum and compound curves
don't mix. Aluminum and laminar flow airfoils don't mix either. So I'd
say that the composite aircraft 100 pounds heavier than the RV-6 is faster
on the same engine and prop combination. I may be wrong. At least you can
hide antennas inside the airframe.

Not taking anything away from 2024-T3, of course. Duralumin is still a
miracle material for aircraft construction. And, having recorded the "From
the Ground Up" series with Joe Schumacher and Mark Annick, I'm envious of
your RV-8 project.