Re: epoxy aircraft seats?

[Lpmcatee356]

>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

[Larry Smith]

"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
>

I used an ergonomically designed race-car seat as a mold and laid one up
using Rutan cloth and epoxy, then reinforced it with foam and a few more
layers of glass. The best way to learn about glass layups and molds is
reading Rutan's treatise on moldless foam construction and watching Mike
Arnold's AR-5 videotapes. Btw, the strength is not in the epoxy but in the
fiberglas. Or S-glass, or carbon fiber. However the resin matrix permits
the fibers to realize their strength.

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.

Plus, when is the last time you saw a laminar flow wing made of aluminum?

You have to be very careful not to get your glass layup overweight. You
have to be very careful not to let your glass ship get hot in the sun. You
have to be very careful not to let UV rays eat the resin. But then,
composite construction must be viable or you wouldn't see so many Lancairs,
Cirruses, White Lightnings, Pulsars, and Eezies boring holes through the
sky.

Composite construction is labor-intensive, and that's part of the reason why
Boeing and M-D haven't migrated to it completely. Give them time.

[Kevin Horton]

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

[Larry Smith]

"Kevin Horton" > wrote in message
...
> 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.

[Kevin Horton]

On Sat, 29 Nov 2003 18:20:53 -0500, Larry Smith wrote:

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

I certainly agree that if your design needs very smooth exterior surfaces
or compound curves that you need to use some sort of composite.

And yes, the Voyager was a very light design. But was it really
fibreglas as you were originally talking about? I thought it had
graphite skins.

http://www.compositesengineering.com/Pages/Links.html

Some aluminum aircraft manage a good speed. Kent Paser made a long series
of incremental mods to his Mustang II and eventually had it doing 239 mph
at 8,000 ft on a 160 hp O-320. I wonder what the fastest fixed gear
Glasair does at 8,000 ft with an O-320.

So, lets agree - if you want the fastest speed, composite is probably
better. If you want the lightest weight, a review of similar
designs shows that aluminum usually wins.

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

[Paul Hastings]

One has to also consider the quality of workmanship, composite designs are
generally overdesigned because the designer is trying to cover differances
in workmanship from builder to builder. With aluminum, the same thickness
aluminum will yield the same strength part, but with composites differences
in technique and preparation can yield widely different results with the
same materials and number of layups. Designers compensate for this in the
beginning, IMHO this is the main reason why a composite will weigh more than
an equivilant aluminum structure. This is just a generalization that applies
mainly to amatuer built wet layups, in more controlled conditions(prepreg
carbon, vacuum bagged parts) the composite part can be lighter and stronger
than a similar aluminum part. However most homebuilders do not have access
to low cost supplies, tooling, and an oven large enough to do a complete
fuse, wing, etc... YMMV

Paul Hastings
"Kevin Horton" > wrote in message
...
> On Sat, 29 Nov 2003 18:20:53 -0500, Larry Smith wrote:
>
> >
> > "Kevin Horton" > wrote in message
> > ...
> >> On Sat, 29 Nov 2003 14:17:48 -0500, Larry Smith wrote:
> >>
> >> >>
> >> > 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.
>
> I certainly agree that if your design needs very smooth exterior surfaces
> or compound curves that you need to use some sort of composite.
>
> And yes, the Voyager was a very light design. But was it really
> fibreglas as you were originally talking about? I thought it had
> graphite skins.
>
> http://www.compositesengineering.com/Pages/Links.html
>
> Some aluminum aircraft manage a good speed. Kent Paser made a long series
> of incremental mods to his Mustang II and eventually had it doing 239 mph
> at 8,000 ft on a 160 hp O-320. I wonder what the fastest fixed gear
> Glasair does at 8,000 ft with an O-320.
>
> So, lets agree - if you want the fastest speed, composite is probably
> better. If you want the lightest weight, a review of similar
> designs shows that aluminum usually wins.
>
> --
> Kevin Horton RV-8 (finishing kit)
> Ottawa, Canada
> http://go.phpwebhosting.com/~khorton/rv8/
> e-mail: khorton02(_at_)rogers(_dot_)com
>

[Morgans]

Larry Smith wrote:
>
Aluminum and compound curves don't mix.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Bull****.

Just because most who homebuild have no English wheel, or shrinking hammer
skills, or that kit makers have not invested in the molds and dies to stamp
parts, does not mean that they can not be done. Do you mean that the
Mustang and Spitfire have no compound curves? Every one I have seen are
loaded with them.

Also, your comment that aluminum and laminar flows don't mix is equally full
of ****. Mustang was laminar flow, right?

As usual, you are in left field.
--
Jim in NC

[Larry Smith]

"Morgans" > wrote in message
...
>
> Larry Smith wrote:
> >
> Aluminum and compound curves don't mix.
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
> Bull****.
>
> Just because most who homebuild have no English wheel, or shrinking hammer
> skills, or that kit makers have not invested in the molds and dies to
stamp
> parts, does not mean that they can not be done. Do you mean that the
> Mustang and Spitfire have no compound curves? Every one I have seen are
> loaded with them.
>
> Also, your comment that aluminum and laminar flows don't mix is equally
full
> of ****. Mustang was laminar flow, right?

No. It claimed to be but wasn't. When you sober up, read the research on
its failure to deliver true laminar flow. Rivet countersinking didn't do
the job and the skins were never true enough.
>
> As usual, you are in left field.
> --
> Jim in NC

What is this guy building, other than an image as a morphine-addled kook?

Morgie, compound curves and aluminum don't mix because you have to have an
expensive press and molds to get them to. Maybe you have those. At least
in your opium dreams.

[Kevin Horton]

On Sat, 29 Nov 2003 21:00:54 -0500, Morgans wrote:

>
> Larry Smith wrote:
>>
> Aluminum and compound curves don't mix.
> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Bull****.
>
> Just because most who homebuild have no English wheel, or shrinking hammer
> skills, or that kit makers have not invested in the molds and dies to
> stamp parts, does not mean that they can not be done. Do you mean that
> the Mustang and Spitfire have no compound curves? Every one I have seen
> are loaded with them.
>
> Also, your comment that aluminum and laminar flows don't mix is equally
> full of ****. Mustang was laminar flow, right?
>
> As usual, you are in left field.

Well, I hate to defend Larry, as I was on the other side of this arguement
from him, but I think you've gove a hit over the top here.

We were generally talking about homebuilt aircraft, and it is pretty rare
to find any aluminum ones with much in the way of compound curves. The
only kit that comes to mind was the Questair Venture - it performed well,
but didn't survive long in the market.

As far as the Mustang and laminar flow - yes it had a very early laminar
flow airfoil that worked well in the wind tunnel. But it was later
concluded that they didn't really get that much laminar flow in service
due to manufacturing imperfections, etc. See:

http://history.nasa.gov/SP-4305/ch4.htm

"...practical experience with this and other aircraft using advanced NACA
sections in the 1940s also showed that the airfoil did not perform quite
as spectacularly in flight as in the laboratory. Manufacturing tolerances
were off far enough, and maintenance of wing surfaces in the field
careless enough, that some significant points of aerodynamic similarity
between the operational airfoil and the accurate, highly polished, and
smooth model that had been tested in the controlled environment of the
wind tunnel were lost."

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

[Big John]

Jim

There was a group (don't remember who, could have been NASA????)
sometime after the War who ran tests on the mustang wing and concluded
it was not laminar. Not sure now if this was from wind tunnel tests or
computer simulation? Also not sure what their object was, maybe just
too much time on their hands?

Do know that it paid off rather rapidly in a stall. Much faster than a
Clark Y type of airfoil. Also in cruise you would climb several
hundred feet above your cruise altitude and in a shallow descent back
to that altitude pick up 10 mph + which the bird would hold if you
were careful and held a constant attitude. Was told (bar talk) that
was a characteristic of a laminar flow wing????

Just more trivia for the grist mill.

Big John

On Sat, 29 Nov 2003 21:00:54 -0500, "Morgans"
> wrote:

>
> Larry Smith wrote:
>>
> Aluminum and compound curves don't mix.
>!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
>Bull****.
>
>Just because most who homebuild have no English wheel, or shrinking hammer
>skills, or that kit makers have not invested in the molds and dies to stamp
>parts, does not mean that they can not be done. Do you mean that the
>Mustang and Spitfire have no compound curves? Every one I have seen are
>loaded with them.
>
>Also, your comment that aluminum and laminar flows don't mix is equally full
>of ****. Mustang was laminar flow, right?
>
>As usual, you are in left field.

[Ron Wanttaja]

On Sat, 29 Nov 2003 21:27:21 -0600, Big John > wrote:

>There was a group (don't remember who, could have been NASA????)
>sometime after the War who ran tests on the mustang wing and concluded
>it was not laminar. Not sure now if this was from wind tunnel tests or
>computer simulation? Also not sure what their object was, maybe just
>too much time on their hands?

Then again, I've heard that it's very difficult to get true laminar flow
for *any* type of construction...at least in the real world. A bit of
dirt, a fuel cap, a small dent from a dropped tool, a few bugs splattered
on the leading edge....

On the opposite side of the spectrum, I'm considering goofing around with
some homemade VGs on my Fly Baby next year. Figured I buy a batch of 1/4 -
1/2" aluminum angle and cut up a batch. Anybody have any rules of thumb
regarding size, placement, stupidity of the idea, etc.?

Ron Wanttaja

[Larry Smith]

"Ron Wanttaja" > wrote in message
...
> On Sat, 29 Nov 2003 21:27:21 -0600, Big John > wrote:
>
> >There was a group (don't remember who, could have been NASA????)
> >sometime after the War who ran tests on the mustang wing and concluded
> >it was not laminar. Not sure now if this was from wind tunnel tests or
> >computer simulation? Also not sure what their object was, maybe just
> >too much time on their hands?
>
> Then again, I've heard that it's very difficult to get true laminar flow
> for *any* type of construction...at least in the real world. A bit of
> dirt, a fuel cap, a small dent from a dropped tool, a few bugs splattered
> on the leading edge....

True. Arnold did his world-record run purposely in the early morning
before the bugs were out, and on a Sunday since most of them are
protestants.

I'm trying to remember which lam flow airfoil it was in one of the mags.
The Stallion, maybe? The pilot/designer wrote that he had a jolting hard
landing at Oshkosh because he had descended and flown into bug territory
altitude for the last several hundred miles and picked up a layer of them on
his leading edge, causing his stall speed to increase about 10 knots.

>
> On the opposite side of the spectrum, I'm considering goofing around with
> some homemade VGs on my Fly Baby next year. Figured I buy a batch of
1/4 -
> 1/2" aluminum angle and cut up a batch. Anybody have any rules of thumb
> regarding size, placement, stupidity of the idea, etc.?
>
> Ron Wanttaja

[Philippe Vessaire]

Larry Smith a écrit:


> 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.

I don't realy agree.... We kwon two airframe from same design:
The "Banbi" MC100, homebuilt from plans and the MCR01 kit (known as
Lafayette in USA).
The aluminium alloy homebuilt weight is 202kg, the carbon/epoxy kit
wieght is 232 all with Rotax 912 engine.
This plane is design by Michel Colomban, desinger of little twin
Cricri or Criquet. He designed bonded aluminium skin, realy good for
laminar flow and light weight and true homebuilt too.

By
--
MinCab F-PRAZ
Philippe Vessaire Ò¿Ó¬

[Bsg]

"Larry Smith" > wrote in message >...
> "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
> >
>
> I used an ergonomically designed race-car seat as a mold and laid one up
> using Rutan cloth and epoxy, then reinforced it with foam and a few more
> layers of glass. The best way to learn about glass layups and molds is
> reading Rutan's treatise on moldless foam construction and watching Mike
> Arnold's AR-5 videotapes. Btw, the strength is not in the epoxy but in the
> fiberglas. Or S-glass, or carbon fiber. However the resin matrix permits
> the fibers to realize their strength.
>
> 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.
>
> Plus, when is the last time you saw a laminar flow wing made of aluminum?
>
> You have to be very careful not to get your glass layup overweight. You
> have to be very careful not to let your glass ship get hot in the sun. You
> have to be very careful not to let UV rays eat the resin. But then,
> composite construction must be viable or you wouldn't see so many Lancairs,
> Cirruses, White Lightnings, Pulsars, and Eezies boring holes through the
> sky.
>
> Composite construction is labor-intensive, and that's part of the reason why
> Boeing and M-D haven't migrated to it completely. Give them time.


Boeing are rapidly moving over to composite manufacturing if you look
at the press releases on the new Boeing 7E7 dreamliner project the use
of composite parts in the aircraft has risen dramatically and now it
is not just non-structural items composites are now being used to
manufacture major structural items such as tailplanes fins bulkheads
etc. The Airbus A380 is also making extensive use of composites to
minimise weight.

I believe that Boeing and Airbus both realise that the time of
composites has come they are just being cautious and implementing a
bit more with each new model.

[George A. Graham]

On Sun, 30 Nov 2003, Ron Wanttaja wrote:

> On the opposite side of the spectrum, I'm considering goofing around with
> some homemade VGs on my Fly Baby next year. Figured I buy a batch of 1/4 -
> 1/2" aluminum angle and cut up a batch. Anybody have any rules of thumb
> regarding size, placement, stupidity of the idea, etc.?

Better Yet, Jim Price (altitude record holding Long EZ) shows how
to make VG's from a strip of plastic panel edge moulding. It cost
about $1 at Home Depot for an eight foot length. He offers instructions
on placement, IIRC we put two on 20 degree offset, at about 20 percent
chord, every ten inches or so. Better check with Jim.
You stick them on with silicone caulking. Work great at increasing lift.

I could fly so slow that my ailerons felt too mushy, took mine off.
He can fly at 50 mph.

George Graham
RX-7 Powered Graham-EZ, N4449E
Homepage <http://bfn.org/~ca266>

[Big John]

Ron

Some ramblings.

Tuft the section(s) and see what is happening. You can probably just
duct tape short lengths of knitting yarn to show air flow (smooth or
turbulent, etc.).

As I recall, you can then 'glue' VG's on temporarily and see the
difference in orientation of the yarn tufts.

There is probably some info that can be found on the Internet about
how the VG's work and where they should be placed to smooth out the
flow.

Might have to go to some NASA papers to get the info (your government
dollars at wok :o)

You might also design and make a smoke generator and blow smoke over
the section you are working with (instead of flying) to find the best
locations of VG's on your bird (and if they do you any good).

Interesting project. Lots of luck.

Big John


On Sun, 30 Nov 2003 03:37:20 GMT, Ron Wanttaja >
wrote:

>On Sat, 29 Nov 2003 21:27:21 -0600, Big John > wrote:
>
>>There was a group (don't remember who, could have been NASA????)
>>sometime after the War who ran tests on the mustang wing and concluded
>>it was not laminar. Not sure now if this was from wind tunnel tests or
>>computer simulation? Also not sure what their object was, maybe just
>>too much time on their hands?
>
>Then again, I've heard that it's very difficult to get true laminar flow
>for *any* type of construction...at least in the real world. A bit of
>dirt, a fuel cap, a small dent from a dropped tool, a few bugs splattered
>on the leading edge....
>
>On the opposite side of the spectrum, I'm considering goofing around with
>some homemade VGs on my Fly Baby next year. Figured I buy a batch of 1/4 -
>1/2" aluminum angle and cut up a batch. Anybody have any rules of thumb
>regarding size, placement, stupidity of the idea, etc.?
>
>Ron Wanttaja

[David O]

Big John > wrote:

>Also in cruise you would climb several
>hundred feet above your cruise altitude and in a shallow descent back
>to that altitude pick up 10 mph + which the bird would hold if you
>were careful and held a constant attitude. Was told (bar talk) that
>was a characteristic of a laminar flow wing????

With all due respect, John, I rather think it is a characteristic of
people's ability to fool themselves. For my part, I'll believe that
Mustangs and/or Mooneys have a cruise "step" when an organization such
as NASA or CAFE documents the phenomena.

The following post by Dr. Philip Bridges of the Aerospace Engineering
Department at Mississippi State University echoes my sentiments on the
subject,

http://tinyurl.com/x48p

For the record, Dr. Bridges has recently retired from the ASE
department at Mississippi State.

Regards,

David O -- http://www.AirplaneZone.com

[Jerry Springer]

David O wrote:
> Big John > wrote:
>
>
>>Also in cruise you would climb several
>>hundred feet above your cruise altitude and in a shallow descent back
>>to that altitude pick up 10 mph + which the bird would hold if you
>>were careful and held a constant attitude. Was told (bar talk) that
>>was a characteristic of a laminar flow wing????
>
>
> With all due respect, John, I rather think it is a characteristic of
> people's ability to fool themselves. For my part, I'll believe that
> Mustangs and/or Mooneys have a cruise "step" when an organization such
> as NASA or CAFE documents the phenomena.
>
> The following post by Dr. Philip Bridges of the Aerospace Engineering
> Department at Mississippi State University echoes my sentiments on the
> subject,
>
> http://tinyurl.com/x48p
>

Correct David, there is no such thing as a step. I had not read Dr Bridges
before but fully agree with his statements.

Jerry

[Tim Ward]

"David O" > wrote in message
...
> Big John > wrote:
>
> >Also in cruise you would climb several
> >hundred feet above your cruise altitude and in a shallow descent back
> >to that altitude pick up 10 mph + which the bird would hold if you
> >were careful and held a constant attitude. Was told (bar talk) that
> >was a characteristic of a laminar flow wing????
>
> With all due respect, John, I rather think it is a characteristic of
> people's ability to fool themselves. For my part, I'll believe that
> Mustangs and/or Mooneys have a cruise "step" when an organization such
> as NASA or CAFE documents the phenomena.
>
> The following post by Dr. Philip Bridges of the Aerospace Engineering
> Department at Mississippi State University echoes my sentiments on the
> subject,
>
> http://tinyurl.com/x48p
>
> For the record, Dr. Bridges has recently retired from the ASE
> department at Mississippi State.
>
> Regards,
>
> David O -- http://www.AirplaneZone.com

WRT the "step" on powered airplanes, I wouldn't dast say. But Richard
Johnson, in his testing of sailplanes, has documented "bi-stable" polars --
measurably different drag at the same constant airspeed, depending on
whether the airspeed was approached from above or below. IIRC, he attributed
the difference to the formation (or not) of a laminar bubble at the
transition from laminar to turbulent flow. Gliders typically have lower
Reynolds numbers than power planes, so this probably doesn't apply to the
P51 and the Mooney.

Tim Ward

[cddb]

In properly done flight test work, the altitude is held very constant (10 ft)
for at least 5 or 10 minutes, no power changes, after you think you are
already stable. It takes this long for the speed to stabilize that last
5 kts or so. The data is taken after it is truly stable. Dead smooth air
is required. When done this way, it becomes obvious that there is
no such thing as a "step".

What we percieve as a step is a climb above the desired altitude and
then descend to the altitude before reducing power. After 5 or 10
minutes, we "fall off the step" and have to climb and descend again.
We conveniently don't count the extra climb or extra power time.

Then the real trick is to determine how much power is being produced.





In article .net>, Jerry
Springer > wrote:
>
>
>David O wrote:
>> Big John > wrote:
>>
>>
>>>Also in cruise you would climb several
>>>hundred feet above your cruise altitude and in a shallow descent back
>>>to that altitude pick up 10 mph + which the bird would hold if you
>>>were careful and held a constant attitude. Was told (bar talk) that
>>>was a characteristic of a laminar flow wing????
>>
>>
>> With all due respect, John, I rather think it is a characteristic of
>> people's ability to fool themselves. For my part, I'll believe that
>> Mustangs and/or Mooneys have a cruise "step" when an organization such
>> as NASA or CAFE documents the phenomena.
>>
>> The following post by Dr. Philip Bridges of the Aerospace Engineering
>> Department at Mississippi State University echoes my sentiments on the
>> subject,
>>
>> http://tinyurl.com/x48p
>>
>
>Correct David, there is no such thing as a step. I had not read Dr Bridges
>before but fully agree with his statements.
>
>Jerry
>

[Stealth Pilot]

On Mon, 1 Dec 2003 07:46:45 -0000, "karel adams"
> wrote:

>all this makes for an instructive and interesting discussion, dear
>gentlemen
>but to my regret it doesn't get me an inch closer to the subject...
>BTW I think seats are curvy enough to justify epoxy construction
>TIA,
>KA
>

Karel
there are no instructions or plans for aircraft seats as such. each
aircraft plan carries general instructions which most people adapt to
what they think will fit them best.

the corby starlet for instance uses a three and a quarter inch
polystyrene block with a thin temperfoam cushion. seat back is some
temperfoam on the plywood former.
the vans aircraft use aluminium to achieve something similar.
without knowing the position of formers that the seat attaches to you
are not going to produce anything useful.

if you are busting for a demo project to practise the skills can I
suggest making a battery box (these are epoxy/glass on many/most
designs)- you can always give it away to someone building,
or a flight toolbox - you know the sort of thing that you pack your
fly away tools, spare nuts and bolts, lockwire and a spark plug in.
use a piano hinge on the lid one side with the wire permanently in
place and a piano hinge with removable wire on the other side for
opening. with a little care you could make something just about
indestructable.
another project involves getting a worn out 5.00x5 tyre (you'll get
these given to you) and making a set of cool wheel fairings.
make two and sit one either side of the telly.
when the movies get boring you'll soon be thinking of building the
aircraft that sits between the fairings and you'll be off into the
workshop which is where you should be :-)

seats? bleagh, wheel fairings are way cooler to look at.
.....or maybe a set of wing tips.
Stealth Pilot

[Wallace Berry]

In article >,
"Larry Smith" > wrote:

Aluminum and laminar flow airfoils don't mix either.

Gotta say that I like composites best of all for aircraft. BUT, there
are some very successful laminar flow wing aircraft with aluminum wing
skins. Schreder HP series gliders, most of them anyway, use aluminum
skins bonded to wide foam ribs. This construction method can, and often
does, result in excellent laminar flow wings that hold their profile.

Still, composite is the way to go (unless rags and sticks, or rags and
tubes, or sheet aluminum fits the mission better)

Wallace Berry
N301BW (Glasflugel H301 Libelle, all composite glider)
N5423M (rags and sticks and tubes Stits SA6b)

[Wallace Berry]

In article <17byb.356395$HS4.2988006@attbi_s01>,
"Paul Hastings" > wrote:

> One has to also consider the quality of workmanship, composite designs are
> generally overdesigned because the designer is trying to cover differances
> in workmanship from builder to builder. With aluminum, the same thickness
> aluminum will yield the same strength part, but with composites differences
> in technique and preparation can yield widely different results with the
> same materials and number of layups. Designers compensate for this in the
> beginning, IMHO this is the main reason why a composite will weigh more than
> an equivilant aluminum structure. This is just a generalization that applies
> mainly to amatuer built wet layups, in more controlled conditions(prepreg
> carbon, vacuum bagged parts) the composite part can be lighter and stronger
> than a similar aluminum part. However most homebuilders do not have access
> to low cost supplies, tooling, and an oven large enough to do a complete
> fuse, wing, etc... YMMV
>


It will depend too on the configuration of the aircraft. Fer instance,
modern open class sailplanes that have wingspans in the 24 to 30 meter
(or more) range just could not be built out of aluminum. These things
have fantastically narrow wing chords with wing thicknesses less than
15% of chord. I'm not sure an aluminum wing like that could be made at
all at any weight. You should see the flexing of those big glider's
wings!

[Stealth Pilot]

On Mon, 1 Dec 2003 17:41:55 -0000, "karel adams"
> wrote:


>BTW what's temperfoam?
>
it is a blue foam that is quite tough but pliable. if you press into
it it will gradually yield. when you hop out of the seat it will grow
back to original shape in half an hour or so.

after market shoe inserts are made from it.

I dont know whether you see this stuff in the states but camping
stores here sell a half inch thick rolled up mat which you roll out
under a sleeping bag. it is quite comfortable to sleep on and is
similar in texture to temperfoam.

[Stealth Pilot]

On Tue, 2 Dec 2003 17:44:14 -0000, "karel adams"
> wrote:

>
>"Stealth Pilot" > schreef in bericht
...
>> On Mon, 1 Dec 2003 17:41:55 -0000, "karel adams"
>> > wrote:
>>

>Well if you think I'm in the US you're quite mistaken
>I'm in tiny Belgium, Western Europe.
>And where's YOUR 'here'?

perth
western australia

>The camping matresses you mention are known to me,
>are you suggesting I buy one & cut it up to suit my seats?
>
why not. you wouldnt be the first to do this.

>KA (demanding on the point of comfort)
>

[Ed Sullivan]

Stealth Pilot > wrote in message >...
> On Mon, 1 Dec 2003 17:41:55 -0000, "karel adams"
> > wrote:
>
>
> >BTW what's temperfoam?
> >
> it is a blue foam that is quite tough but pliable. if you press into
> it it will gradually yield. when you hop out of the seat it will grow
> back to original shape in half an hour or so.
>
> after market shoe inserts are made from it.
>
> I dont know whether you see this stuff in the states but camping
> stores here sell a half inch thick rolled up mat which you roll out
> under a sleeping bag. it is quite comfortable to sleep on and is
> similar in texture to temperfoam.

Actually Temperfoam comes in several colors depending on its density.
It was originally designed for astronaut couches where one would spend
a long time on it. It conforms to your contours providing even
support. It is great stuff and I have been using it for nearly 20
years. You might look up Oregon Aero.com. They sell it. It aint cheap,
but it's worth it.

Ed Sullivan

[RobertR237]

In article >, (Ed
Sullivan) writes:

>
>Actually Temperfoam comes in several colors depending on its density.
>It was originally designed for astronaut couches where one would spend
>a long time on it. It conforms to your contours providing even
>support. It is great stuff and I have been using it for nearly 20
>years. You might look up Oregon Aero.com. They sell it. It aint cheap,
>but it's worth it.
>
>Ed Sullivan
>
>

Bought mine from McMaster Carr and save a few dollars. They carry the Yellow,
Pink, Blue and Green which go from soft to fairly dense. It is great stuff and
is easy to work with and shape. I did my seats using the Pink, Blue and Green
with beautiful results.

Bob Reed
www.kisbuild.r-a-reed-assoc.com (KIS Builders Site)
KIS Cruiser in progress...Slow but steady progress....

"Ladies and Gentlemen, take my advice,
pull down your pants and Slide on the Ice!"
(M.A.S.H. Sidney Freedman)