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

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