Glider Waxing
HOWARD PETRI
I would like to wax my Pegasus, but as most of us know, the
people who do glass repairs beseech us not to use a silicone based
wax. So does anyone know of a good non-silicone based wax that
can be used? I know the pure carnubas are OK , but I haven't found any
around here and I suspect they are hard to use. I have heard that
there are some teflon based waxes. Anybody know something about them?
Finally last year I read an article in a car magazine that evaluated
auto waxes. There are some auto waxes out there that claim not to have
any silicone in them, but when analyzed were found to contain silicone
after all. So reading wax labels won't help. Anybody know for sure
what is OK to use?
Howard Petri
Pegasus (EJ)
Tom Serkowski
I usually buy a day's shop time & use his heavy-duty buffer & wax the whole
plane annually.
They also make a cleaner that I guess is a mild rubbing compound that works great to remove minor blemishes by hand - if you dont have a power buffer.
Tom Serkowski
ASW20B (5Z)
Paul Raveling
In article <BvpFw...@avalon.nwc.navy.mil>, t...@kestrel.nwc.navy.mil (Tom Serkowski) writes:
> I use Meguiars (sp?) Classic car cleaner/wax with the blessing of my sailplane repairman. ...
Does anyone know of comparative performance tests for
different techniques of wing preparation?
I'm curious because similar questions apply to racing sailboats
that are stored out of the water -- i.e., those with gelcoat
rather than bottom paint below the waterline. The majority
opinion among those racing such boats was clearly to avoid
waxing below the waterline, but to keep the gelcoat in shape
by wet sanding with 600-grit paper, then buffing.
When I was into racing sailboats, virtually all racers had
concluded that waxing hurt performance. It's possible that
wax could countribute to boundary layer disturbances or
increased skin friction.
So if anyone knows of comparative performance tests, I'd
be interested in the results. I'd appreciate copies of
followups by email -- it looks like our news server is retaining
articles on this group for less than a day right now.
------------------
Paul Raveling
Rave...@Unify.com
Rich Carr
that the factories supposedly approve of. Try emailing al...@fc.hp.com
(Aland Adams), who has used it on his LS6, or call up Pik Pacific for
more leads.
I haven't had much trouble finding carnauba paste wax around here to use on
our club gliders. I agree that it's wise to avoid any high-tech
polishes, no matter what they say on the label. I wouldn't use a
teflon-based product for fear of it having the same effect as silicone
if repairs are needed.
Rich Carr
Richard J. Miller
> Does anyone know of comparative performance tests for
> different techniques of wing preparation?
>
> I'm curious because similar questions apply to racing sailboats
> that are stored out of the water -- i.e., those with gelcoat
> rather than bottom paint below the waterline. The majority
> opinion among those racing such boats was clearly to avoid
> waxing below the waterline, but to keep the gelcoat in shape
> by wet sanding with 600-grit paper, then buffing.
i don't have any data, but there is some out there. for the record,
waxing contest sailplanes in the US went out of vogue in the mid-70's
and is only starting to come back now because the current mania seems
to be gelcoat and glass degradation which waxing can reduce.
Mark Maughmer, who did some of the wing design for Cygnet (and is at
Penn State and available on e-mail if he could be coerced to read it,
hint hint to you Happy Valley folk! (tell him i sent you :-))) )), has
told me that it's just not possible to make the wax surface smooth enough,
especially compared to the glass surface. wax doesn't follow the surface
form perfectly, but rather clumps up creating bumps that cause the flow
to detach. but he also said that air flow seems to like a smooth surface
(the glass) that has then been roughened slightly with 400 or finer
sandpaper. that seems to keep the flow attached better, even if it is
slightly turbulent (or because it is!).
Rich Miller
ex-Schempp-Hirth Discus JBX and
ex-Rolladen-Schneider LS-4 TQ
rmi...@i88.isc.com
Rich Carr
of rain in my PIK 20D. From 10 miles out, I needed only a 14:1 glide
ratio to make the field at 500 feet. I finished at 200 feet and 60
knots.
If I get time this winter, I'll sand the wings out to 600-grit.
Rich Carr
Heiner Biesel
While the performance of your wings was certainly affected by drops of
water, it is also likely that you were flying through sinking air, since
you say you were flying through rain for 10 miles. That alone could
account for the poor L/D. If we assume an average sink of 1m/sec, that
would reduce your best L/D by more than 50%. I doubt that the performance
degradation of your airfoil due to bugs and/or rain drops is anywhere near
that great.
Regards,
H. Biesel
HOWARD PETRI
Rich;
Are you telling us that you had your wings waxed for this contest?
The PIK 20 is notorious for poor L/D in the rain; perhaps the rain and
not the wax was the cause. Perhaps rain and wax is worse than just rain.
I originally posted the question about waxing. I was more worried about
protecting the surface than about improving the L/D. Do my wings really
need any protection? Is just keeping them clean enough. Why wax at all?
Howard Petri
Pegasus (EJ)
Eric Niedrauer
performance of your wings was certainly affected by drops of
|> ... I doubt that the performance
|> degradation of your airfoil due to bugs and/or rain drops is anywhere
|> near
|> that great.
|>
|> Regards,
|> H. Biesel
Since I also own a PIK20, I can assure you most of the glide ratio
degradation is caused by wet wings. It is rather alarming to look
out at the horizon after flying through rain, since the ground appears
to rise MUCH faster than usual. There is also a noticeable increase
in wind noise (more of a roar instead of a whoosh).
My answer to flying through rain is: Don't. If I do happen to get the
plane wet, I get the airspeed up to about 80 knots to blow the water off.
I figure since I'm dropping so fast anyway, the extra altitude lost by
flying fast will be offset by reducing the amount of time flying a rock.
Eric Niedrauer
PIK20D N6VS
Truckee/Byron
er...@sgi.com
Rich Carr
> you say you were flying through rain for 10 miles. That alone could
> account for the poor L/D. If we assume an average sink of 1m/sec, that
> degradation of your airfoil due to bugs and/or rain drops is anywhere near
> that great.
Of course the achieved glide ratio was due to both airfoil degradation
and airmass motion, and I don't have any way to determine how much each
factor was responsible. On the other hand, a Finnish pilot once
posted here that the best L/D of the PIK20 in rain was generally
assumed to be as low as 7:1. This does seem hard to believe.
>
> Regards,
> H. Biesel
Rich Carr
Rich Carr
> Since I also own a PIK20, I can assure you most of the glide ratio
> degradation is caused by wet wings. It is rather alarming to look
> out at the horizon after flying through rain, since the ground appears
> to rise MUCH faster than usual. There is also a noticeable increase
> in wind noise (more of a roar instead of a whoosh).
I haven't flown any other gliders in rain (except a 2-33 :-)) so I
don't know how others feel, but the effect of rain on the PIK is
dramatic. I can tell by sound and feel if there are just ten
raindrops on the wing -- the whole airframe starts rumbling and
feeling draggy just like the spoilers were deployed.
> My answer to flying through rain is: Don't. If I do happen to get the
> plane wet, I get the airspeed up to about 80 knots to blow the water off.
Yes, I tend to take long detours around showers...
Rich Carr
Martin Gasthuber
In article <1992Oct20.1...@javelin.sim.es.com>, > While the
performance of your wings was certainly affected by drops of
|> water...
|> ... I doubt that the performance
|> degradation of your airfoil due to bugs and/or rain drops is anywhere
|> near
|> that great.
|>
|> Regards,
|> H. Biesel
Since I also own a PIK20, I can assure you most of the glide ratio
degradation is caused by wet wings. It is rather alarming to look
out at the horizon after flying through rain, since the ground appears
to rise MUCH faster than usual. There is also a noticeable increase
in wind noise (more of a roar instead of a whoosh).
This is a problem of all flap equiped Wortmann wings (LS3, PIK, Nimbus2 etc)
My answer to flying through rain is: Don't. If I do happen to get the
plane wet, I get the airspeed up to about 80 knots to blow the water off.
I figure since I'm dropping so fast anyway, the extra altitude lost by
flying fast will be offset by reducing the amount of time flying a rock.
Or fly for example ASW-20, no problems with water.
Eric Niedrauer
PIK20D N6VS
Truckee/Byron
er...@sgi.com
--
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| Martin Gasthuber I. Institut f. Experimentalphysik, Luruper Chaussee 149 |
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Bruce Blackshaw
and glide ratio seems dramatic. I've heard it said that the water beads
up on the leading edge and disrupts the smooth air flow. The handling
of the glider also becomes shocking ...
--
****************************************************
Bruce Blackshaw bru...@ctpm.uq.oz.au
"... I'd rather be hang gliding ..."
****************************************************
Aland Adams
gelcoat. Polyester resins are porous and readily absorb
moisture (gelcoat is polyester resin based). I presum
the moisture eventually weakens the gelcoat and, when combined
with the repetitive flex loading of the wing, causes the
cracks. If you live in a cold climate, the effects of freezing
really make this worse. The other factor in gel-coat degredation
is UV exposure. My prescription for minimizing gel-coat degredation
is:
1. Wax your ship twice a year.
2. Keep/store your ship out of the sun. If it is in a trailer
make sure the top is metal or has aluminized paint.
3. Keep your trailer ventilated. I suggest installing a solar
powered fan. Maybe two if you are in a particualrly humid
place.
The concern about silicone is that it can make repair work difficult.
It can be hard to get new gel-coat to stick. I've talked to some
repair folks who think that this is not as big a problem as folks
fear. As pointed out in this notes string, most waxes have silicone,
even if they don't say so. Since sailplanes aren't falling apart,
and finishes aren't flaking off everywhere, I figure it probably
is not a horrible problem. But then again, I spend a lot of bucks
using a factory supplied wax.... I presume the concerns about
silicone apply to Teflon since it is an anti-stick substance as well.
Now folks with PIK's have an interesting dilema. Their finish is paint.
So do they wax to keep it from oxidizing and sufer in the rain or
go without?
Some of my experience with wax and sanding...
When I still lived at home my Dad owned 5 PIKs. I owned one later.
And yes rain is a PIKs worst enemy. I have several off-filed
landings due to getting wet.... Anyway on the D he had, we carefully
sanded it out with 600 grit. While it flew better in the rain, we
noticed a degredation in climb (with a noticeable control impact).
After a few months we polished it back out, but never waxed it
as this really hurt. The best thing to do is to get a pure soap
(with no detergents) and rinse the wing before flight. The Fin's
liked a soap called "Fairy."
I never waxed the ASW-20 I had. But then again I didn't have it
more than 4 months after I had it refinished. But that's another story.
Now my LS-6 is wonderful, especially when waxed. During a contest
I pay special attention to the leading edge as keeping it waxed seems
to keep the bug density down. I noticed this one day in particular
when I only had time to re-wax one leading eadge. The last day of
the 15M Nats this year I had the opportunity to take off and climb
out in the rain. This experience did two things. First it re-assured
me that waxing the ship didn't hurt. Second I was _real_ glad I had
the 6 and not a Ventus. Those guys thought I was dry as fast as I
climb through them. It was impressive.....
Aland "AA"
Paul Raveling
> The main reason to wax a fiberglas ship is to preserve the
> gelcoat. Polyester resins are porous and readily absorb
> moisture (gelcoat is polyester resin based). I presum
> the moisture eventually weakens the gelcoat and, when combined
> with the repetitive flex loading of the wing, causes the
> cracks. If you live in a cold climate, the effects of freezing
> really make this worse. The other factor in gel-coat degredation
> is UV exposure.
From my experience as a fiberglass sailboat owner I'd rate
UV as the #1 culprit. By the time I sold the boat it was
about 14 years old and the hull's gelcoat was still in
excellent condition. Most of its age showed on the deck.
The main problem with water, at least for boats, was that
marine borers would attack gelcoat if the boat stayed in
the ocean for more than a few days. Boats that are kept
in slips need bottom paint to protect against that sort
of biota. Fortunately sailplanes are rarely tied down under
water, except sometimes at Lake Elsinore :-).
------------------
Paul Raveling
Rave...@Unify.com