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Old Sep 24, 2012, 08:57 AM
Don't Move I've Dropped My Nut
bamaguy's Avatar
United States, AL, Huntsville
Joined Feb 2009
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Quote:
Originally Posted by pulsery2k1 View Post
not sure what happened , was very windy 20+ with gusts ......... the wing came off at the engine , it appears to have gone back
starting at the leading edge Carbon rod .
.
pulsery2k1; Very sad, indeed.

I know the NTSB investigation is still ongoing, but I noticed that in the 4th photo, that I could not see any evidence of adhesive on the plywood or the foam surface of the pylon that would contact the surface of the wing!.....just a thought. Also, it appears that the "factory supplied" carbon rod was not glued into the wing....wing halves were not glued together???
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Last edited by bamaguy; Sep 24, 2012 at 09:03 AM.
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Old Sep 24, 2012, 10:24 AM
Registered User
United States, TX, League City
Joined Jun 2008
368 Posts
I didnt glue in my engine pylons but i did use a flat spar on top and bottom across the wings and it stiffened it up, unfortunately my aileron tore off in midflight causing a crash not too long ago...

good news is I have fuse sections if anyone wants to do a 737-800+
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Old Sep 24, 2012, 10:27 AM
NiCd + Mabuchi 550 was da bomb
NY USA
Joined Apr 1999
610 Posts
Quote:
Originally Posted by hi2nr View Post
I didnt glue in my engine pylons but i did use a flat spar on top and bottom across the wings and it stiffened it up, unfortunately my aileron tore off in midflight causing a crash not too long ago...

good news is I have fuse sections if anyone wants to do a 737-800+
Did you rehinge the ailerons or was it the stock foam hinge??
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Old Sep 24, 2012, 10:54 AM
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United States, TX, League City
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Stock foam hinge lol...bad idea
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Old Sep 24, 2012, 11:16 AM
Registered User
United States, TX, League City
Joined Jun 2008
368 Posts
I am LOVING the slats right now..a few finishing touches and itll be bullet proof!
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Old Sep 24, 2012, 11:23 AM
NiCd + Mabuchi 550 was da bomb
NY USA
Joined Apr 1999
610 Posts
Quote:
Originally Posted by hi2nr View Post
Stock foam hinge lol...bad idea
I believe Doug runs stock foam hinges and so far he hasn't had any issues.
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Old Sep 24, 2012, 11:26 AM
Fly and let Fly!
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United States, CO, Grand Junction
Joined May 2010
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Quote:
Originally Posted by hi2nr View Post
I am LOVING the slats right now..a few finishing touches and itll be bullet proof!
Pictures of progress?
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Old Sep 24, 2012, 12:29 PM
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United States, TX, League City
Joined Jun 2008
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Originally Posted by Cocg View Post
Pictures of progress?
Just a hinge lol. No pictures yet until I actually finalize lol
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Old Sep 24, 2012, 12:43 PM
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jurgen01's Avatar
Mexico City
Joined Apr 2007
329 Posts
Quote:
Originally Posted by Pannoch RC View Post
... thinking of hooking it up to some fish scales and see what kind of numbers it shows.
Paul: Right fish scale or similar. I am using a baggage scale I have to fill suitcases to the last gram of the allowed 23 kgs. It's precise to 10 grams and has a 'hold' function.

Pulsery: Sorry for your loss. Seems to be the first wing to let go. I agree with Bamaguy that lack of glue might have to do with it. The openings for the pylons are weakening the wing which only recovers its integrity when the pylons are glued in.

I have rehinged only the rudder which showed evident lack of material, see post #3649. The other hinges looked fine, but I reenforced them with strips of Oracal in the recess of the moving parts at both sides of the wing. Will be carefully monitoring these parts before each flight.

Jurgen
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Old Sep 24, 2012, 12:49 PM
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Mexico City
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329 Posts
Question for the WBPU masters. When you talk about 'tissue' you mean disposable tissues like Kleenex or similar?
Isn't that a lot of patchwork? Don't the overlays of the tissue pieces show after the WBPU dries?

I started my building career covering with dope and 'Japan paper', then moved to silk, but that material is not available anymore.

Jurgen
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Last edited by jurgen01; Sep 24, 2012 at 02:22 PM. Reason: Wrote WAPU, meant WBPU.
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Old Sep 24, 2012, 12:59 PM
What tree??.......Doh!!
Smokin_Joes's Avatar
USA, WA, Seattle
Joined Aug 2007
757 Posts
J,

I've used the lightest silkspan on one of my models with WBPU. If you have done your own covering via epoxy/fiberglass, then this is a walk in the park and cleanup can be done in any sink. State side it's readily available from K&S which is a good thing because at $35US a pack, I'm glad a local hobby shop bought it, and sold by the sheets.. IIRC, you can also get the Japanese stuff on eBay.

See here for K&S sample.

Neil
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Old Sep 24, 2012, 02:26 PM
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jurgen01's Avatar
Mexico City
Joined Apr 2007
329 Posts
Thanks Neil,

I actually am intrigued by those tissues. If its' Kleenex I guess it probably comes out lighter than anything else.
Just found out that the local Home Depot carries Minwax Polycrilic. I will get a can and make some tests. Looks like an interesting product.

Jurgen
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Old Sep 24, 2012, 02:43 PM
What tree??.......Doh!!
Smokin_Joes's Avatar
USA, WA, Seattle
Joined Aug 2007
757 Posts
In it's virgin state, silkspan is closer to a fibrous piece of paper than to kleenex. Not sure how well you could apply the Minwax Polycrylic (MWPC) over kleenex since I figure like toilet paper, kleenex would just dissolve/rip apart, when brushing on the MWPC if that makes sense.

You may have already seen this 16 year old article, but it's good for the basics of silkspan. With the article or thread being that old, just replace "dope" with mwpc and "balsa" with foam.
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Old Sep 24, 2012, 03:32 PM
6 months to finish a rtf
pulsery2k1's Avatar
upstate ny
Joined Jun 2003
1,848 Posts
Wing issue

well with out seeing what happen it hard to tell what happened
but after seeing some like fotor's flex mine never flexed that much
the polyglass made the wing flex less, then just before the NEAT FAIR
I added flaps and a extra carbon reinforcement to the wing .

while checking the balance I noticed even less flex in the wing
now the model flew 3 times before the accident and its
possiable that by making the wing to stiff , it tranferred the
load more toward the inner part of the wing , add the high gusting
wind and it couldn't handle the load - also the wing from the damage
appears to come off down and back not up , as you might expect.

this model is under reconstruction and may fly again will mount
the little video camera's to check wing flex

I did this to get rid of excess flex in my cessna 421

wing flex cessna 421.wmv (6 min 43 sec)


then with the fix
Cessna 421 flat carbon reinforcement.wmv (6 min 11 sec)
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Old Sep 24, 2012, 06:25 PM
Don't Move I've Dropped My Nut
bamaguy's Avatar
United States, AL, Huntsville
Joined Feb 2009
1,737 Posts
737 Wing Issue

Quote:
Originally Posted by pulsery2k1 View Post
Wing issue

well with out seeing what happen it hard to tell what happened
l flew 3 times before the accident and it's possible that by making the wing to stiff, it tranferred the load more toward the inner part of the wing , add the high gusting wind and it couldn't handle the load.
this model is under reconstruction and may fly again
I agree, some of the load may have been transferred to the inner part. As I surmised earlier, if that entire pylon was not securely glued to the wing, that area of the wing would be the first to break. There is very little foam "meat" there. No, the pylon would not leave the wing, as the carbon rod keeps it there, unless the laminated ply breaks in that area, of course.

When you rebuild, just be sure and glue that baby into the wing (both of them). Just my $0.02

Looking forward to see that beautiful airliner fly again!
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