Production rates?

U¿ytkownik "Mark James Boyd" napisa³ w wiadomo¶ci
news:41a255a1$1@darkstar...

One wonders what would happen if the Sparrowhawk construction concept
were adopted in a country with very low labor costs. Perhaps a
(strange) side benefit may be that US certification of a Polish
Sparrowhawk might be easier than doing the same thing inside the US.

Uniting low cost (overseas) labor with excellent innovation.
Van's does this for its quickbuild kits, apparently with good commercial
success. I'd love to see what SZD would do, in terms of price,
producing a Sparrowhawk... Maybe an idea for the next World Class?

Well... It's just a question of contacting certain person in the SZD, or
Papiorek works (the one who builds the Stemme S-10) ans asking them if they
would be interested in cooperation. If there will be an interest of both
of the parties... maybe using our affordable workforce, and Your
professional marketing skills, could make the Sparrowhawk sales to soar?
The contacts to the particular persons may be found without the problem, so
is there any problem?
A single email may begin a cooperation which would be profitable for both
sides, plus for the pilots, and our sport of course.

With kindest regards,


--
Janusz Kesik
Poland
to reply put my name.surname[at]gazeta.pl
-------------------------------------
See Wroclaw (Breslau) in photography,
The XIX Century, the Festung Breslau, and photos taken today.
http://www.wroclaw.dolny.slask.pl

Janusz,

Thanks for the information on build time hours. This is very useful
information. I think it illustrates that labour is where we need to work at
reducing the cost. One many year is approximately 2000 hrs .. actually more
like 1700-1800 when holidays etc are considered. So 1400 hrs is a lot.

What I am now wondering is what the difference is between the Jantar
Standard and the SZD-55 ... I need to do some research to answer this for
myself because I am not that familiar with the later. 760 to 1400 hrs is a
big difference. However perhaps you have some comments on this. Are the
materials and tooling similar ? Are the tolerances tighter on the later
model ? Perhaps it is a question of the volume being produced ?

Thanks again,

Steve


"Janusz Kesik" wrote in message
...
Hypothetically, if the very skilled workers require 1400 hours to
produce
a
SZD-55, then there must be opportunities for production engineers to
reduce
that time.

As we see, it depends a lot on the type of sailplane which is being build.
When we compare that to the 760 hours needed to complete the Jantar
Standard
3 this is the slashing of the half You're writing of. And... cosidering
that
these 760hrs has been counted in 1982yr., I believe without any problem it
could be reduced to let's say 600 hours. When we compare the cost of the
hour in Germany (~30Euro/h), and in Poland (~2.5-3.0Euro/h). That makes a
huge difference.

Then... add to this a low-cost workforce, and this may reduce the prices a
lot. The molds for th Jantars are still available, and I believe the
producer would be happy to respond an inquiry how much could cost a single
glider when let's say an order for a few pieces would be placed. I am sure
it would be veeeery attractive.

Regards,


--
Janusz Kesik
Poland
to reply put my name.surname[at]gazeta.pl
-------------------------------------
See Wroclaw (Breslau) in photography,
The XIX Century, the Festung Breslau, and photos taken today.
http://www.wroclaw.dolny.slask.pl

I think the biggest issue with the Sparrowhawk is the cost of materials.

As I have said before in another post I am not quite sure exactly what
materials are used but I think they are Toray Prepregs - which weave / style
I am not sure. However they are carbon. Assuming a woven cloth, say a Plain
Weave of approx 193 g/m2 (a very common carbon prepreg cloth made by a
number of prepreg companies - Fibercote, Cytec etc)) then the cost is likely
to be in the range of $60 USD / yd (based on a purchase of Fibercote T300
3KPW in the last month) ... perhaps reducing some with quantity (but then
the company needs capital which a producer of a dozen sailplanes a year is
unlikely to have). Compare this to a 92125 or 7781 glass cloth which is
probably in the $6 USD / yd price range (for the 7781 anyway) the difference
is HUGE. OK you might use a little less carbon and you need to add the cost
of resin to the glass. However for the prepreg you also need a lot of
consumables (Vac Bag, Release film, Breather, Bag Tape, Flash Tape etc) -
this can add another $10 USD / yd even with the cheapest products.

But then there are other issues with the Sparrowhawk ... the tooling is more
expensive because it needs to be made from high temperature tooling resins
and presumably carbon so it can be put in an oven. There is the cost of
renting (I think they use the Lancair oven) and running the oven. The
materials needs to be stored at 0 deg F and all prepreg materials are life
limited which implies a certain amount of wastage. The core material will be
more expensive because it must sustain the high cure temperatures (I am
assuming Sparrowhawk uses a 120 deg C cure system). I assume the core is
either nomex homeycomb or a high temperature PVC foam. You will need
surfacing films and film adhesives which are I think in the $30-$50 USD / yd
range (my memory is hazzy but I have bought Cytec FM-300 film adhesive
recently and can check). Probably one surfacing film against the mould and
then one ply of film adhesive on each side of the core .... that is another
$130 USD / sq metre of airplane surface - a lot more than gelcoat and micro
to seal foam !

So .. the material costs for the Sparrow hawk could be easily an order of
magnitude higher than for a simple glass, wet layup glider.

Please don't get me wrong here ... I am not trying to discredit the
Sparrowhawk. There are of course a lot of advantages to prepreg materials
.... I am just making the point that you don't get something for nothing. The
question is are the advantages worth the extra money ???

I have looked at the concept of a sailplane made from prepreg materials in
the past and have always concluded that it is not viable .... unless you
could use carbon uni-tape which currently sells for approx $2.something USD
/ sq ft or approx $20 USD / sq yd (i.e. Hexcel AS4/3501 or similar).
Newport, YLA, Fibercote + others all make products.

Finally ... I cannot see how prepreg materials can save any labour unless
you are using ply cutting machines or a computer controlled tape layer etc.
For an operation like the Sparrowhawk I assume they still need to cut the
plies manually, they still have to be laided up one by one manually. In some
cases (more than say 4-6 plies) you will have to bag and debulk in the
middle of the layup, then you need to do the final bagging and curing ...
there is really no less work but potentially some more work here than for a
simple wet layup.

There is also a lot more to go wrong in a prepreg process and so the
production process needs to be more closely monitored. You need
thermocouples on the parts with data loggers to verify the cure cycle, you
need processes to make sure that backing films are not left inside laminates
etc.

BTW ..... I have plucked all these numbers from memory so please don't hold
me to them that closely ... if anyone wants more precise costs etc just yell
out and I will get them. I have them all available.


"Mark James Boyd" wrote in message
news:41a255a1$1@darkstar...
One of the hopes of the Sparrowhawk was presumably to significantly reduce
the amount of labor involved. Of the 10 production run modern gliders
I'm aware of, the Sparrowhawk seems to most significantly contrast
the time-honored build process of other gliders, like the SZD 55-1 .

Which is why I'm surprised that the Sparrowhawk price
has increased (not decreased) so much since Serial # 1.
Eric Greenwell's article seemed to indicate
production on the order of weeks, certainly not the 1400 man-hours
described here. Do the materials really cost 40% more than they did
several years ago or is this a labor cost increase, or is it
payments on sunk engineering costs?

One wonders what would happen if the Sparrowhawk construction concept
were adopted in a country with very low labor costs. Perhaps a
(strange) side benefit may be that US certification of a Polish
Sparrowhawk might be easier than doing the same thing inside the US.

Uniting low cost (overseas) labor with excellent innovation.
Van's does this for its quickbuild kits, apparently with good commercial
success. I'd love to see what SZD would do, in terms of price,
producing a Sparrowhawk... Maybe an idea for the next World Class?

I'm astonished that the 55-1 takes 1400 man-hours to built.
I had absolutely no idea it was that consumptive...

In article ,
Janusz Kesik wrote:
I don't care such comments, and well, the most funny is that I wouldn't
have
noticed that post, if someone hasn't commented that. It looks like this
guy
has withdrawn his 'not so nice' posting from the server sooner than I did
retrieved fresh postings from my news server. Anyway, thanks for the
support
for all of You my gliding friends.

Finally, as asked I feel obliged to deliver the final reply that the
total
working hours involved in complete (from the first minute of work, to
the
very end of finish) in case of production of the SZD-55, total at 1400
hours. So, well... it's a huge amount, and the lower cost of labour helps
so
much indeed to keep it's price still 4500Euros lower than the *predicted*
price of the LS-4 which is going to re-enter production according to the
news I have red on the R.A.S.

With kindest regards,


--
Janusz Kesik
Poland
to reply put my name.surname[at]gazeta.pl
-------------------------------------
See Wroclaw (Breslau) in photography,
The XIX Century, the Festung Breslau, and photos taken today.
http://www.wroclaw.dolny.slask.pl



U¿ytkownik "Ed Byars" napisa³ w
wiadomo¶ci
...
Janusz:
Thank you for your continued input. Your contributions to this thread
are
appreciated. Please ignore the "Ugly American" comment (if it was an
American). I guess all countries have a few rude and inconsiderate
types,
even in the soaring fraternity.
Ed Byars





--

------------+
Mark J. Boyd

U¿ytkownik "smjmitchell" napisa³ w
wiadomo¶ci u...
Janusz,

Thanks for the information on build time hours. This is very useful
information. I think it illustrates that labour is where we need to work
at
reducing the cost. One many year is approximately 2000 hrs .. actually
more
like 1700-1800 when holidays etc are considered. So 1400 hrs is a lot.

That is more interesting, is that the old wooden gliders were even more time
consuming. When You look insede let's say the Bocian's wing, You'll see
thousands of "matches" inside which had to be glued prior to covering the
wings' surfaces. Glass is a much step forward in reducing the cost.

What I am now wondering is what the difference is between the Jantar
Standard and the SZD-55 ... I need to do some research to answer this for
myself because I am not that familiar with the later. 760 to 1400 hrs is a
big difference. However perhaps you have some comments on this.

I shink that Jantar has much less complicated design than the SZD-55.
Consider only the wingtip. Jantar's one is straight and there seems to be
much less work required. In case of the '55', it is tapering and, moreover
it doesn't do this in a Schempp-Hirth way (just like the Discus') where it
is divided into three or four legs, but it tapers continously. It is surely
the most perfect option when looking at it from the aerodynamics point of
view, but it also requires way more work than in Discus, not to mention the
Jantar. Also the interior of the Jantar wing seems to have a simplier
design.

Note also what I was writing of earlier, that the SZD was able to shorten
the production of the Junior to just two days when using the two shift per
day system. It has also some 20% less elements than Jantar. Maybe there's a
way out - simple designs which won't be too sophisticated, but still will
give a chance to fly for as wide spectrum of people at it is possible. [And
the PW-5 fits this definition quite well]. For me I don't want a racer, I
just want to fly for fun. A few hours of wandering around 10-20 miles away
from the airport, or some ridge would be enough for me, still being heaps of
fun. Flying for fun, not racing.

Are the
materials and tooling similar ?

Materials then were mostly locally produced, like the Epidian resins. Glass
cloth too I believe. (Jantar)

Are the tolerances tighter on the later
model ?

I don't think so. More probably it was simplier design.

Perhaps it is a question of the volume being produced ?

Possibly yes, however that wouldn't influence the number of workhours (with
exception of the prototypes where the hours are circa doubled). The savings
may come from sharing the fixed costs (like the production site rental or
the monthly social security fees) by a larger number of products (in whose
price these costs had to be included).

Regards,


--
Janusz Kesik
Poland
to reply put my name.surname[at]gazeta.pl
-------------------------------------
See Wroclaw (Breslau) in photography,
The XIX Century, the Festung Breslau, and photos taken today.
http://www.wroclaw.dolny.slask.pl

"smjmitchell" wrote in message
u...
Janusz,

Thanks for the information on build time hours. This is very useful
information. I think it illustrates that labour is where we need to work
at
reducing the cost. One many year is approximately 2000 hrs .. actually
more
like 1700-1800 when holidays etc are considered. So 1400 hrs is a lot.

What I am now wondering is what the difference is between the Jantar
Standard and the SZD-55 ... I need to do some research to answer this for
myself because I am not that familiar with the later. 760 to 1400 hrs is a
big difference. However perhaps you have some comments on this. Are the
materials and tooling similar ? Are the tolerances tighter on the later
model ? Perhaps it is a question of the volume being produced ?

Thanks again,

Steve

Carbon layup, complex curves, flaperons, sparless construction(?), and
finishing work on the SZD-55 and certainly the Diana will take longer than
Standard Jantar glass fiber construction. There's still cure time. If the
molds are heated, then there's the cost of doing that involved. Otherwise,
the parts spend more time in the molds. Earlier mold design was subject to
distortion with time, so only so many accurate pulls could be made before
the planform of the wings changed. These things have been overcome, but
there are incremental price increases as a result. The 1000 hours I
originally mentioned was the early Ventus (15m) line from a visit to
Schempp-Hirth in 1981. I'm sure the number was only approximate, or perhaps
the ideal, but it was quoted to me. Gel-coats may be a bit quicker than
polyurethane during the original build. At one time SH delivered gliders
withn minimal finishing since they knew competition pilots would tune the
wings anyway.

Pre-preg can reduce layup time, but it's nearly 2x the cost of wet layup
(even in filament winding processes) according to some sources I've glanced
at. As far as building a Junior in two days, maybe, but I'd still think in
terms of 680 man hours as the substantial difference is fixed gear vs
retract. Two days is a meaningless concept without knowing whether 30-40
people were involved for 8 or 12 hour shifts.

Filament winding is one method that's been shown to work, at least by Rutan.
However, there are limitations to the process that might make it impractical
for most glider production. Even then, the pod took something like 7 hours
to wind and the fuselage was 24 hours of continuous processing. I'm sure if
any of the factories could conceivably create a paradigm shift in glider
production that would create a price advantage, it's would already be in
use. All that's actually happened is to re-locate to cheaper labor markets,
which is not always the best solution.

Frank Whiteley

"F.L. Whiteley" wrote in message
...

"smjmitchell" wrote in message
u...
Janusz,

Thanks for the information on build time hours. This is very useful
information. I think it illustrates that labour is where we need to work
at
reducing the cost. One many year is approximately 2000 hrs .. actually
more
like 1700-1800 when holidays etc are considered. So 1400 hrs is a lot.
snip


Steve

Carbon layup, complex curves, flaperons, sparless construction(?), and
finishing work on the SZD-55 and certainly the Diana will take longer than

The SZD-55 has no carbon; it is all fiberglass. It has conventional wing
spars. It does not have flaperons or even flaps.

As far as building a Junior in two days, maybe, but I'd still think in
terms of 680 man hours as the substantial difference is fixed gear vs
retract. Two days is a meaningless concept without knowing whether 30-40
people were involved for 8 or 12 hour shifts.


I suspect that one Junior emerged from the factory every 2 days but surely
they must have spent longer on the line than 2 days. If for instance you
have 5 stations on the line and each airframe spent 2 days at each station
that is a total of 10 days on the line. Now if 3 guys worked in each station
with two shifts that is a total of 5 (stations) x 2 (days) x 3 (# guys) x 8
(shift hours) x 2 (# shifts) = 480 hours. This seems achievable for a simple
glider. I just cannot see how a sailplane of conventional construction could
be made in an elapsed time of only 2 days when cure time etc is allowed for.

If indead it is true that the Junior was made in 2 days with two shifts then
this deserves careful study. Does anyone have a PDF copy of the Junior
maintenance manual ????

Janusz ... do you have any more info on this ????


Frank,

Filament winding is one method that's been shown to work, at least by
Rutan.

There is a lot of conflicting information around on exactly how Rutan builds
his airframes. Some people say thay he uses a tape layer and others filament
winding. How confident are you in your information that he filament winds ?
If filament winding is used (and I believe this is probably the case) then I
am assuming he uses prepreg tow ???? Or is he using a wet layup with one of
the resins that has an extraordinarly long pot life (1-2 days) (there are
some excellent wet layup resins available now that are meant for this sort
of application).


However, there are limitations to the process that might make it
impractical
for most glider production.

Such as ????


Even then, the pod took something like 7 hours
to wind and the fuselage was 24 hours of continuous processing.

Are you refering to the Boomerang ????

It sounds like you have some knowledge of the Rutan processes ... can you
outline the process. What does he use for the plug to wind around ??? What
sort of winding machine - a simple two axis thing or something more complex
?? What sort of tow (12k ... 24k etc) ??? Does he wind a grid arrangement
of stiffeners on the inside of the fuselage ??? (it appears so from some
photo's you see) And the really big question .... how does he get the
outside smooth (perhaps this is one of the limitations you mention ??? -
perhaps this involved a lot of hand filling and sanding ?). What is the cure
.... oven ??? room temperature ??? What are the thickesses of the skins ?
What is the typical winding angle ?

You have two moulds for each wing, and two moulds for the fuselage (plus two
for the stabilizers). All can be layed up in parallel (you need three men
less than 8 hours on one mould), that takes one day. Spraying of the gel
coat is done the night before. Glueing them together and hot-curing them
takes another day.

However, cost is counted in manhours, not in days. The time needed for layup
is about the same for carbon and for glass (some experience needed, though)
and the planiform of the wing has no influence whatsoever.

Improvements for this? The capital expenditure for any of it never pays off,
so just forget about it.

The main amount of manpower is needed AFTER the thing is demoulded -
finishing is quite a job, even for professionals. And that has been the
reason why Grob gliders were very reasonably priced at their time - they
just had less finish.

--
Bert Willing

ASW20 "TW"


"smjmitchell" a écrit dans le message de
news: ...
As far as building a Junior in two days, maybe, but I'd still think in
terms of 680 man hours as the substantial difference is fixed gear vs
retract. Two days is a meaningless concept without knowing whether 30-40
people were involved for 8 or 12 hour shifts.


I suspect that one Junior emerged from the factory every 2 days but surely
they must have spent longer on the line than 2 days. If for instance you
have 5 stations on the line and each airframe spent 2 days at each station
that is a total of 10 days on the line. Now if 3 guys worked in each
station
with two shifts that is a total of 5 (stations) x 2 (days) x 3 (# guys) x
8
(shift hours) x 2 (# shifts) = 480 hours. This seems achievable for a
simple
glider. I just cannot see how a sailplane of conventional construction
could
be made in an elapsed time of only 2 days when cure time etc is allowed
for.

If indead it is true that the Junior was made in 2 days with two shifts
then
this deserves careful study. Does anyone have a PDF copy of the Junior
maintenance manual ????

Janusz ... do you have any more info on this ????


Frank,

Filament winding is one method that's been shown to work, at least by
Rutan.

There is a lot of conflicting information around on exactly how Rutan
builds
his airframes. Some people say thay he uses a tape layer and others
filament
winding. How confident are you in your information that he filament winds
?
If filament winding is used (and I believe this is probably the case) then
I
am assuming he uses prepreg tow ???? Or is he using a wet layup with one
of
the resins that has an extraordinarly long pot life (1-2 days) (there are
some excellent wet layup resins available now that are meant for this sort
of application).


However, there are limitations to the process that might make it
impractical
for most glider production.

Such as ????


Even then, the pod took something like 7 hours
to wind and the fuselage was 24 hours of continuous processing.

Are you refering to the Boomerang ????

It sounds like you have some knowledge of the Rutan processes ... can you
outline the process. What does he use for the plug to wind around ???
What
sort of winding machine - a simple two axis thing or something more
complex
?? What sort of tow (12k ... 24k etc) ??? Does he wind a grid
arrangement
of stiffeners on the inside of the fuselage ??? (it appears so from some
photo's you see) And the really big question .... how does he get the
outside smooth (perhaps this is one of the limitations you mention ??? -
perhaps this involved a lot of hand filling and sanding ?). What is the
cure
... oven ??? room temperature ??? What are the thickesses of the skins ?
What is the typical winding angle ?

U¿ytkownik "smjmitchell" napisa³ w
wiadomo¶ci u...
As far as building a Junior in two days, maybe, but I'd still think in
terms of 680 man hours as the substantial difference is fixed gear vs
retract. Two days is a meaningless concept without knowing whether
30-40
people were involved for 8 or 12 hour shifts.


I suspect that one Junior emerged from the factory every 2 days but surely
they must have spent longer on the line than 2 days. If for instance you
have 5 stations on the line and each airframe spent 2 days at each station
that is a total of 10 days on the line. Now if 3 guys worked in each
station
with two shifts that is a total of 5 (stations) x 2 (days) x 3 (# guys) x
8
(shift hours) x 2 (# shifts) = 480 hours. This seems achievable for a
simple
glider. I just cannot see how a sailplane of conventional construction
could
be made in an elapsed time of only 2 days when cure time etc is allowed
for.

If indead it is true that the Junior was made in 2 days with two shifts
then
this deserves careful study. Does anyone have a PDF copy of the Junior
maintenance manual ????

Janusz ... do you have any more info on this ????

I ve got only the user's manual, more it's in Polish only:

http://www.szybowce.enter.net.pl/ins...ior/junior.pdf

What exact info on maitenance You need? A total life of Junior is now 9000
or 12000hrs if I remember correctly, the mid-inspection interval is 1000hrs.

However, the shorp production process has been achieved so far only by the
SZD and the Grob factories.
The production process of Junior comprised od TWO DAYS in a SINGLE SHIFT
system, so one day in a two shifts, I have checked this. This was achieved
due to e.g far going integration of the elements of glider just like the
main spar which is simply a Z shaped layer of the glassfibre (if I remember
correctly) and using the molds which didn't need the pressure forced forming
of the fuselage in the molds (well I am not sure if I had translated it
properly into English). Simply the stucture could form itself when just put
into molds (less workhours needed). This technologo also allowed to use
locally produced the "STR" (it's a brand I believe) glass cloth instead of
the Interglass cloth, and also it was possible to employ low skilled
employees (which are also a lot more affordable) at the production line if
needed.
It simply looks that simple technology could reduce lots of costs. Junior is
a good example of the way we should follow. Apart from this, it makes an
excellent sailplane for these who just want to fly for fun.

I have no specific knowledge of the technology, so I can't say how it was
achieved, and for me personally... I think there should be some time for
finish too! I know that factory won't say a word on this (I suppose so)
as it is their technology which they use, but if properly marketed the
Junior could make this what the World Class supposed to be - a glider for a
masses, safe, easy to fly, and affordable - all in one. By the way, I have
heard that Junior is produced under licence n Brasil, can anyone confirm
this information?

Returning to the previous post by mr Whiteley, the '55' is all glass, no
carbon inside, just the well designed glass design. No flapperons or flaps,
as it's a standard class glider, BUT Diana... it's carbon, and it's designer
mr Beres is one of the best specialists in using carbon materials here in
Poland. He runs his own business since he left SZD after it has gone bust
for a while: http://www.beres.com.pl/

With kindest regards,


--
Janusz Kesik
Poland
to reply put my name.surname[at]gazeta.pl
-------------------------------------
See Wroclaw (Breslau) in photography,
The XIX Century, the Festung Breslau, and photos taken today.
http://www.wroclaw.dolny.slask.pl

Is hot curing common in glider factories ? Are these using ovens, heater
blankets or perhaps heated moulds ?



"Bert Willing" wrote in
message ...
You have two moulds for each wing, and two moulds for the fuselage (plus
two
for the stabilizers). All can be layed up in parallel (you need three men
less than 8 hours on one mould), that takes one day. Spraying of the gel
coat is done the night before. Glueing them together and hot-curing them
takes another day.

However, cost is counted in manhours, not in days. The time needed for
layup
is about the same for carbon and for glass (some experience needed,
though)
and the planiform of the wing has no influence whatsoever.

Improvements for this? The capital expenditure for any of it never pays
off,
so just forget about it.

The main amount of manpower is needed AFTER the thing is demoulded -
finishing is quite a job, even for professionals. And that has been the
reason why Grob gliders were very reasonably priced at their time - they
just had less finish.

--
Bert Willing

ASW20 "TW"


"smjmitchell" a écrit dans le message de
news: ...
As far as building a Junior in two days, maybe, but I'd still think in
terms of 680 man hours as the substantial difference is fixed gear vs
retract. Two days is a meaningless concept without knowing whether
30-40
people were involved for 8 or 12 hour shifts.


I suspect that one Junior emerged from the factory every 2 days but
surely
they must have spent longer on the line than 2 days. If for instance you
have 5 stations on the line and each airframe spent 2 days at each
station
that is a total of 10 days on the line. Now if 3 guys worked in each
station
with two shifts that is a total of 5 (stations) x 2 (days) x 3 (# guys)
x
8
(shift hours) x 2 (# shifts) = 480 hours. This seems achievable for a
simple
glider. I just cannot see how a sailplane of conventional construction
could
be made in an elapsed time of only 2 days when cure time etc is allowed
for.

If indead it is true that the Junior was made in 2 days with two shifts
then
this deserves careful study. Does anyone have a PDF copy of the Junior
maintenance manual ????

Janusz ... do you have any more info on this ????


Frank,

Filament winding is one method that's been shown to work, at least by
Rutan.

There is a lot of conflicting information around on exactly how Rutan
builds
his airframes. Some people say thay he uses a tape layer and others
filament
winding. How confident are you in your information that he filament
winds
?
If filament winding is used (and I believe this is probably the case)
then
I
am assuming he uses prepreg tow ???? Or is he using a wet layup with
one
of
the resins that has an extraordinarly long pot life (1-2 days) (there
are
some excellent wet layup resins available now that are meant for this
sort
of application).


However, there are limitations to the process that might make it
impractical
for most glider production.

Such as ????


Even then, the pod took something like 7 hours
to wind and the fuselage was 24 hours of continuous processing.

Are you refering to the Boomerang ????

It sounds like you have some knowledge of the Rutan processes ... can
you
outline the process. What does he use for the plug to wind around ???
What
sort of winding machine - a simple two axis thing or something more
complex
?? What sort of tow (12k ... 24k etc) ??? Does he wind a grid
arrangement
of stiffeners on the inside of the fuselage ??? (it appears so from
some
photo's you see) And the really big question .... how does he get the
outside smooth (perhaps this is one of the limitations you mention ??? -
perhaps this involved a lot of hand filling and sanding ?). What is the
cure
... oven ??? room temperature ??? What are the thickesses of the skins
?
What is the typical winding angle ?