Go Back  RCU Forums > RC Airplanes > Crash & Rebuild
Reload this Page >

GP Lancair wing failure

Notices
Crash & Rebuild Post your crash stories, pictures and if you want to document your rebuild you can do that here too!

GP Lancair wing failure

Old 08-15-2004, 01:16 PM
  #1  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default GP Lancair wing failure

I have just lost my GP Lancair on its 9th flight due to the wing joiner failing.
I was 3/4 of the way through a roll at about 1/2 throttle when the wing snapped in two.
I have heard that this has happened before - has anybody had a successful claim for a replacement or refund?
The model has never even been looped, and that was about its third roll!
It has damaged my brand new os91fs and I have yet to check my Rx, my scale strut from Sierrascale is also broken.
[&o]
Attached Thumbnails Click image for larger version

Name:	Db83895.jpg
Views:	265
Size:	110.8 KB
ID:	164147   Click image for larger version

Name:	Rm37884.jpg
Views:	262
Size:	128.6 KB
ID:	164148   Click image for larger version

Name:	Fl18738.jpg
Views:	273
Size:	119.3 KB
ID:	164149  
Old 08-15-2004, 01:59 PM
  #2  
8178
My Feedback: (17)
 
8178's Avatar
 
Join Date: May 2004
Location: Atlanta, GA
Posts: 4,348
Likes: 0
Received 7 Likes on 4 Posts
Default RE: GP Lancair wing failure

I sorry and sad mess! How could anyone expect a single ¼ plywood wing spar to hold a wing together on an aircraft of that size? The manual says “ 3. Apply 30-minute epoxy to both sides of the wing joiner, the joiner pocket in both wing panels and to the root rib of each wing panel. Push the wing panels together and hold them in place with masking tape. Before the glue cures, set the wing flat on your bench and measure the dihedral.” Your photos don’t show that but I doubt if that would have helped much. Expect the center section would need glass cloth and epoxy to make the wing strong enough.
Old 08-15-2004, 05:03 PM
  #3  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

Did you epoxy the root ribs? Looks awful dry...
Old 08-15-2004, 05:32 PM
  #4  
8178
My Feedback: (17)
 
8178's Avatar
 
Join Date: May 2004
Location: Atlanta, GA
Posts: 4,348
Likes: 0
Received 7 Likes on 4 Posts
Default RE: GP Lancair wing failure

ORIGINAL: warren

Did you epoxy the root ribs? Looks awful dry...

Doubt if that would have helped much!
Old 08-15-2004, 05:45 PM
  #5  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

ORIGINAL:

Doubt if that would have helped much!
Actually it helps immensely. The combination of the ply joiner, epoxy in pocket, and on the root ribs become a combined mechanical presence.

The way it is glued now, just the joiner, causes all the sheer exertion directly on the center of the joiner, whereas if it were glued according to the manual you have to fail the shear strength of the ribs and spars as well, which is actually many times stronger than the joiner itself.

There was a post about a month ago where another guy did the same thing you did on his Venus, which has a dual ply joiner, which also failed in flight.

Sorry for your loss, but you'll have to own this one. The other wing failures reported and dealt with were outboard of the center section and as far as I know was remedied late last year.
Old 08-15-2004, 06:31 PM
  #6  
8178
My Feedback: (17)
 
8178's Avatar
 
Join Date: May 2004
Location: Atlanta, GA
Posts: 4,348
Likes: 0
Received 7 Likes on 4 Posts
Default RE: GP Lancair wing failure

ORIGINAL: warren

ORIGINAL:

Doubt if that would have helped much!
Actually it helps immensely. The combination of the ply joiner, epoxy in pocket, and on the root ribs become a combined mechanical presence.

The way it is glued now, just the joiner, causes all the sheer exertion directly on the center of the joiner, whereas if it were glued according to the manual you have to fail the shear strength of the ribs and spars as well, which is actually many times stronger than the joiner itself.

There was a post about a month ago where another guy did the same thing you did on his Venus, which has a dual ply joiner, which also failed in flight.

Sorry for your loss, but you'll have to own this one. The other wing failures reported and dealt with were outboard of the center section and as far as I know was remedied late last year.

If that is the case GPs should add the information to the manual in big bold print so the friesianflyer’s of the world glue it correctly.

I would have added some more wing spars or glassed the center section on an aircraft of this size.
Old 08-15-2004, 07:06 PM
  #7  
Tired Old Man
Senior Member
My Feedback: (1)
 
Join Date: Feb 2002
Location: Valley Springs, CA
Posts: 18,602
Likes: 0
Received 3 Likes on 3 Posts
Default RE: GP Lancair wing failure

If you refer to the manual quote by 8178, you will note that the application of epoxy to the wing root rib is noted in the manual. That's the visible surface of both of the ribs that come together when the wing is joined.

The oversight in the application of adhesive was very probably the cause of the failure.
Old 08-16-2004, 03:24 AM
  #8  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

I can see what you guys are saying, but surely the only rib that I can, or should have to apply epoxy to is the final rib on each wing? As an ARTF, the parts that have already been constructed should be adequately glued already. At the very least this is a fault in the actual wing design with the ribs the way they are. As you can see in the photos, the ribs that I had epoxied are still together. Anyway, if the wing joiner had been up to the job in the first place, then this probably wouldnt have happened.

I will be taking the remains into my LHS where the kit was purchased and requesting a replacement model - and it wont be a Great Planes kit!
Old 08-16-2004, 05:15 AM
  #9  
frank99
My Feedback: (29)
 
Join Date: Jun 2002
Location: Sheridan, AR
Posts: 810
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

where can i get the scale strut thanks frank sorry about it going in[:'(]
Old 08-16-2004, 11:24 AM
  #10  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

ORIGINAL: friesianflyer

I can see what you guys are saying, but surely the only rib that I can, or should have to apply epoxy to is the final rib on each wing? As an ARTF, the parts that have already been constructed should be adequately glued already. At the very least this is a fault in the actual wing design with the ribs the way they are. As you can see in the photos, the ribs that I had epoxied are still together. Anyway, if the wing joiner had been up to the job in the first place, then this probably wouldnt have happened.

I will be taking the remains into my LHS where the kit was purchased and requesting a replacement model - and it wont be a Great Planes kit!
It looks from the picture that there isn't any epoxy at all covering the root ribs (the ribs with the inspection stamp on them), the entire root ribs should be coated, not just the edges??
Old 08-16-2004, 11:59 AM
  #11  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

The rib with the stamp on already has another rib glued to it which becomes the root rib - it is impossible to glue directly to the rib with the stamp on. I did apply epoxy all over the root ribs, which is why these are still stuck together and on the other wing!. It is the manufacturers glue joint that has failed, not mine, and short of undoing the manufacturers glue joint and re-glueing it, I cant see this as a building fault on my behalf.
Old 08-16-2004, 12:33 PM
  #12  
FOD MAN
Senior Member
 
FOD MAN's Avatar
 
Join Date: Oct 2002
Location: gurdon, AR
Posts: 345
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

I may be wrong but it looks like the balsa skin extends over the rib with the stamp,if this is the case we are looking at the inboard side of one root rib.on page 12 of construction manual paragraph 3 it clearly covers the joining of the wings. wing is not joined with enough epoxy as stated before. also in photo you can see the covering on the inboard ribs on both wings. we are looking at the joint of the root ribs.
Old 08-16-2004, 12:50 PM
  #13  
frank99
My Feedback: (29)
 
Join Date: Jun 2002
Location: Sheridan, AR
Posts: 810
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

i not sure iam ever going to put mine up in the air[&:] do you where sierra struts are need the nose gear???
Old 08-16-2004, 01:39 PM
  #14  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

ORIGINAL: FOD MAN

I may be wrong but it looks like the balsa skin extends over the rib with the stamp,if this is the case we are looking at the inboard side of one root rib.on page 12 of construction manual paragraph 3 it clearly covers the joining of the wings. wing is not joined with enough epoxy as stated before. also in photo you can see the covering on the inboard ribs on both wings. we are looking at the joint of the root ribs.
That's what I am thinking...
Old 10-09-2004, 04:35 AM
  #15  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

Just as an update, it has taken about 7 weeks, but I have now received a full refund on the model.

Its such a beautiful model, and really drew a lot of attention, but I just can't feel confident in flying another one.

Sort out that wing joiner Great Planes!
Old 10-09-2004, 09:55 PM
  #16  
nicadflyer
Member
 
nicadflyer's Avatar
 
Join Date: Aug 2002
Location: Cushing, OK
Posts: 39
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

Glad to hear that you got your money back.
On your next airplane join the wing halves with 30 minute epoxy and also use 3" or wider Fiberglas tape and 30 minute epoxy around the wing at that joint. If it is an ARF remove the covering to do this and then recover.
Old 10-10-2004, 05:28 PM
  #17  
jw637362
Senior Member
My Feedback: (1)
 
jw637362's Avatar
 
Join Date: Jan 2004
Location: Golden, CO
Posts: 610
Likes: 0
Received 1 Like on 1 Post
Default RE: GP Lancair wing failure

I am a firm beliver in fiberglassing all center sections upon completion of gluing the wing ribs together, good complete coat over the entire root area / Let cure over night then peal back monokote from center section 2 inches then add the fiberglass - top and bottom. 24 hour procedure to save a lifetime of heartache. Had a 60 size Stick ARF fold the wings on me, and the manufacturer had a warning about the center sections design not strong enough- I heard about a later date. That set me in motion!
Old 10-12-2004, 06:04 AM
  #18  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

I am a firm believer that an ARTF model should not need me to cut away covering and apply extra strengthening!
The strength should be an integral part of the design.
None of my other ARTF's have needed this, and they havn't had any problems.
Old 10-12-2004, 06:06 PM
  #19  
MHall
Senior Member
My Feedback: (7)
 
MHall's Avatar
 
Join Date: Nov 2002
Location: Auburn, CA
Posts: 439
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

I own an Lancair and was told to never exceed "scale" maneuvers. I have pushed it a little more than that with NO wing issues, until I ground looped it in a bad cross wind. It has seen loops, snaps, spins, stalls, inverted flight, and almost anything else I could throw at it, but did most of it all as scale as possible. I agree that the picture makes it look like the root ribs were not glued just the joiner, but pictures can be deceiving. I plan on rebuilding mine and flying it till it comes apart then getting something else. I would only want to suffer with one of these, they should redesign the wing. [8D]
Old 10-13-2004, 03:51 PM
  #20  
edh13
My Feedback: (9)
 
edh13's Avatar
 
Join Date: Mar 2002
Location: Mesa, AZ
Posts: 427
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

I am sad to see he got anything back from the vendor. Mistakes like his blamed on the manufacturer only drive prices up for us. Sorry I'm not as politically correct as most, he clearly didn't follow instructions. That IS the wing root that we are looking at and it's looking back at us with little or NO epoxy on it. It is NOT the inside of the opposite rib. The balsa sheet and ply doublers would not be sanded flush! And an inspector couldn't stamp the inside of the root rib for a quality check. Yea, the wing joiner looks a little spindly but not much could survive without the wings being completely bonded together. Imagine the twisting forces on that joiner! It failed while rolling…Duh!

EDH13
Old 10-13-2004, 03:58 PM
  #21  
Warren
My Feedback: (72)
 
Warren's Avatar
 
Join Date: Oct 2002
Location: Alpine, CA
Posts: 473
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

ORIGINAL: edh13

I am sad to see he got anything back from the vendor. Mistakes like his blamed on the manufacturer only drive prices up for us. Sorry I'm not as politically correct as most, he clearly didn't follow instructions. That IS the wing root that we are looking at and it's looking back at us with little or NO epoxy on it. It is NOT the inside of the opposite rib. The balsa sheet and ply doublers would not be sanded flush! And an inspector couldn't stamp the inside of the root rib for a quality check. Yea, the wing joiner looks a little spindly but not much could survive without the wings being completely bonded together. Imagine the twisting forces on that joiner! It failed while rolling…Duh!

EDH13

Yup... Bingo...
Old 10-13-2004, 04:11 PM
  #22  
Balsa Master
Senior Member
 
Balsa Master's Avatar
 
Join Date: Oct 2003
Location: _,
Posts: 999
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

ORIGINAL: Warren

Did you epoxy the root ribs? Looks awful dry...

all it woulda done is snap the ribs out of position at the spars w/o glass over the cventer sheeting to reinforce it. i always glass my wing joints even if they say u dont have to. just makes me feel safer.

sorry to hear about what happened though :-( was a nice looking plane from what i can c.
Old 10-13-2004, 04:42 PM
  #23  
DBCherry
My Feedback: (4)
 
Join Date: Jan 2002
Location: Hubbardston, MA
Posts: 5,550
Likes: 0
Received 1 Like on 1 Post
Default RE: GP Lancair wing failure

I do have to agree, that sure looks like the root rib in the photo. If it is, bite the bullet and learn from a mistake.

If it isn't, call Great Planes and send them the damaged wing. If it was a manufacturing defect, they'll most likely make good on it.
Dennis-
Old 10-14-2004, 03:19 AM
  #24  
friesianflyer
Member
Thread Starter
 
friesianflyer's Avatar
 
Join Date: Jun 2003
Location: London, UNITED KINGDOM
Posts: 67
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

edh13 - I'm sorry, but I dont remember yourself and your sidekick Warren being present when I was joining the wing?
Obviously you must have been to make such a sweeping statement.
I have other photos which show even more clearly that the two root ribs are still epoxied together where I joined them with plenty of one hour epoxy. I know in my own mind that the instuctions were followed to the letter so this is why comments like yours are un-necessary. I have club members who actually pay me to construct their kits for them as in over 30 ARTF's built, I have never had a problem with any of them, and had nothing but praise for my work

If you had been anywhere near the model in question, you would also notice that it claims to be capable of snap rolls etc. so it should be able to cope with a slow roll.

Why not stick to the facts in future before wading in.

I look forward to you having a problem, so that I can repay the favour with a damning post that I cannot possibly back up.
Old 10-14-2004, 07:02 AM
  #25  
rc-sport
My Feedback: (12)
 
rc-sport's Avatar
 
Join Date: Apr 2002
Location: Round Lake, IL
Posts: 3,180
Likes: 0
Received 0 Likes on 0 Posts
Default RE: GP Lancair wing failure

Ummm, if the root ribs are still glued together why do I see monokote wrapping the edges?

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.