Go Back  RCU Forums > RC Airplanes > RC Jets
Reload this Page >

Wing structure question.

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Wing structure question.

Old 05-09-2021, 08:21 AM
  #1  
Agrav8ed
Thread Starter
 
Join Date: Sep 2017
Posts: 315
Received 24 Likes on 20 Posts
Default Wing structure question.

I have a replacement composite wing for one of my jets. I happened to notice that there was a decent amount of movement along the whole top of the wing. When I borrowed a camera and scoped it, I can see about a 1/16 to a 1/8th inches gap between the lengthwise vertical wing structure and the skin. There is also asimilar gap between the wing ribs and the top skin. Even a couple in the front. Almost like the supports were a bit too short or not enough glue was used. This includes the landing gear area also and some point at the leading edge. This lack of attachment explains why the wing top skin is floating up and down so much.
Because this gap runs the length of the wing the majority of the supports I will not be able to reach to add additional glue. Is my understanding was that the top and bottom composite skin being attached to the vertical supports are what gave the wing its strength. Kind of like a engineered joist. So I am not sure how structurally sound this wing would be at 200mph or bank and yank turns. Nor do I want to unnecessariky risk my turbine and electronics. Therefore I am seeking the advise of some fellow builders. Do you guys think this wing will be safe?
Thanks
Agrav8ed.

This is the landing gear area. You can see a lack of glue and a large gap between the support and the wing skin.

This is near the wing tip, as you can see, the top skin is still not attached

Gap between the wing skin and the lengthwise support.

Gap between the vertical ribs, lengthwise support and the wing skin
Old 05-09-2021, 08:25 AM
  #2  
tp777fo
My Feedback: (28)
 
tp777fo's Avatar
 
Join Date: Feb 2002
Location: Greer, SC
Posts: 3,286
Received 28 Likes on 22 Posts
Default

What kit?
Old 05-09-2021, 09:33 AM
  #3  
Agrav8ed
Thread Starter
 
Join Date: Sep 2017
Posts: 315
Received 24 Likes on 20 Posts
Default

Originally Posted by tp777fo View Post
What kit?
I did not want to mention which kit it is until I heard back from the manufacturer.
Thanks,
Agrav8ed
Old 05-09-2021, 09:45 AM
  #4  
causeitflies
 
causeitflies's Avatar
 
Join Date: Jan 2003
Location: EASTERN OHIO
Posts: 2,327
Likes: 0
Received 13 Likes on 12 Posts
Default

I would not trust it. If you can see movement on the ground imagine what it would do in the air.
Old 05-09-2021, 11:32 AM
  #5  
jofunk
 
Join Date: Mar 2009
Location: willow springs , IL
Posts: 1,157
Likes: 0
Received 6 Likes on 5 Posts
Default

Contacting the manufacturer is the way to go. I think any reputable kit manufacturer would replace that in a heartbeat.
Old 05-09-2021, 01:08 PM
  #6  
cetigershark
 
Join Date: Mar 2009
Location: KlotenZurich, SWITZERLAND
Posts: 71
Received 5 Likes on 5 Posts
Default

Hi Agrav8ed

good thing not to fly this wing. Both wing skins must bond with the internal structure. When you build a wing mold, tuning up the perfect internal structure takes a lot of time - trial and check and again and again - so that the fit is perfect and the gaps between skins and the structure are minimal.
I wonder what the manufacturer will tell you.
I received a SkyEmaster F-15 EDF 3 weeks ago. First thing I did was to check the internal wing structure with an endosocopic camera. It was flawless, however some other spots could have become some more building time
The following users liked this post:
Ron S (05-09-2021)
Old 05-09-2021, 01:51 PM
  #7  
Agrav8ed
Thread Starter
 
Join Date: Sep 2017
Posts: 315
Received 24 Likes on 20 Posts
Default

Yeah, I was questioning the structural integrity of the wing myself, hence my post. Without the top skin being bonded to make a cohesive structure, there is not alot of support for the internal structures or the bond with the bottom wing skin. It's good to know I was not overreacting.
Agrav8ed
Old 05-09-2021, 03:45 PM
  #8  
crsetting
Junior Member
 
Join Date: May 2021
Posts: 2
Likes: 0
Received 1 Like on 1 Post
Default

That wing should have never left the factory. !!
The following users liked this post:
Lownverted (05-10-2021)
Old 05-10-2021, 02:59 AM
  #9  
Jetpilot24
My Feedback: (21)
 
Join Date: Jan 2003
Location: Niles, OH
Posts: 1,459
Likes: 0
Received 22 Likes on 14 Posts
Default

In the first picture it looks like it delaminated. In the next few looks like it was not a good fit. DON'T use that wing. It is not a matter of if it will come apart as apposed to it WILL come apart.
Hope the manufacturer steps up on the wing and sends you a properly built wing.
Just my 2 cents.

Joe
Old 05-10-2021, 03:44 AM
  #10  
scoeroo
My Feedback: (9)
 
scoeroo's Avatar
 
Join Date: Sep 2004
Location: Home PA
Posts: 627
Likes: 0
Received 4 Likes on 4 Posts
Default

Is there a QA sticker & number on the structure ?
Old 05-10-2021, 05:02 AM
  #11  
patf
My Feedback: (4)
 
patf's Avatar
 
Join Date: Jan 2002
Location: Dallas, TX
Posts: 1,843
Received 40 Likes on 34 Posts
Default

At first i thought delamination, but when you look at the 2nd photo you posted, one side of the rib has a good contoured joint, so it looks to me like the rib and wing skin never made contact. Tough one to fix yourself, hope the mfgr makes it right for you with minimal waiting
Old 05-10-2021, 05:16 AM
  #12  
Agrav8ed
Thread Starter
 
Join Date: Sep 2017
Posts: 315
Received 24 Likes on 20 Posts
Default

Originally Posted by scoeroo View Post
Is there a QA sticker & number on the structure ?
None that I noticed.

Originally Posted by patf View Post
At first i thought delamination, but when you look at the 2nd photo you posted, one side of the rib has a good contoured joint, so it looks to me like the rib and wing skin never made contact. Tough one to fix yourself, hope the mfgr makes it right for you with minimal waiting
So do I. Due to Covid it took me around 10 months and a ton of shipping to get these. Now that the flying season is finally opening I can't use them. It's a bit frustrating.

I appreciate everyone replying and weing in with their opinions. I was not comfortable with the wing integrity and wanted to make sure I was not overreacting.

Agrav8ed
Old 05-10-2021, 09:02 AM
  #13  
Dave Wilshere
 
Join Date: Jun 2002
Location: Watford, UNITED KINGDOM
Posts: 12,181
Likes: 0
Received 334 Likes on 258 Posts
Default

I saw the same thing on a Krill 3m aerobatic model someone in my local club bought. They had skipped putting adhesive on all but the leading and trailing edge joint. It’s impossible to fix. They gave him new wings.
Old 05-10-2021, 09:57 AM
  #14  
Agrav8ed
Thread Starter
 
Join Date: Sep 2017
Posts: 315
Received 24 Likes on 20 Posts
Default

Just spoke to the manufacturer. They were very receptive to the issue and we are working on replacement options so it looks like things will be handled. I appreciate everyone's feed back.
Agrav8ed.
The following users liked this post:
cetigershark (05-11-2021)
Old 05-10-2021, 11:42 AM
  #15  
scoeroo
My Feedback: (9)
 
scoeroo's Avatar
 
Join Date: Sep 2004
Location: Home PA
Posts: 627
Likes: 0
Received 4 Likes on 4 Posts
Default

That wing is an accident waitin to happen -
Old 05-10-2021, 12:18 PM
  #16  
T_CAT
 
T_CAT's Avatar
 
Join Date: Dec 2018
Posts: 140
Likes: 0
Received 10 Likes on 8 Posts
Default

I’d be curious to know the aircraft manufacturer also (not to bad mouth them), only to be informed to look out for issues if I either have or order the same aircraft. Mistakes happen, and all we can do is keep an eye out for any issues and notify the manufacturer for a resolution. I’m glad it sounds like this is working out for you and good for the company for stepping up to the plate when it matters.
Old 05-11-2021, 12:11 AM
  #17  
Joseph Frost
 
Join Date: Nov 2010
Location: Coffs Harbour NSW, AUSTRALIA
Posts: 786
Likes: 0
Received 31 Likes on 29 Posts
Default

Easy fix, rather than waiting for the replacement. Just fill it up with some ply bits and with the long brush fill in with epoxy or any bond agent, like gorilla glue, etc. Don't blame manufacturers, it is pilots responsibility to make sure the ARF models don't fall apart.
I have found similar problems with numerous ARF models over the years, I have covered few cavities and poured in pint of PVA , gave it a good gargel and shake, drained it out and let it dry, good as new, LOL.
Old 05-11-2021, 03:43 AM
  #18  
cetigershark
 
Join Date: Mar 2009
Location: KlotenZurich, SWITZERLAND
Posts: 71
Received 5 Likes on 5 Posts
Default

Originally Posted by Joseph Frost View Post
Don't blame manufacturers, it is pilots responsibility to make sure the ARF models don't fall apart.
Hi Joseph
Well, If I buy an ARF turbine jet ((kit) what it still is somehow) with composite wings, I expect the internal structure of the wing to be built correctly.
The following users liked this post:
Skunkwrks (05-11-2021)
Old 05-11-2021, 04:32 AM
  #19  
speedracerntrixie
My Feedback: (29)
 
speedracerntrixie's Avatar
 
Join Date: Jun 2010
Location: Happy Valley, Oregon
Posts: 8,265
Received 92 Likes on 85 Posts
Default

To me it looks like the mold halves weren't fully closed. The lack of prep on the bond line is an issue as well.
Old 05-11-2021, 06:34 AM
  #20  
Auburn02
My Feedback: (1)
 
Auburn02's Avatar
 
Join Date: May 2005
Posts: 1,017
Received 19 Likes on 15 Posts
Default

Originally Posted by cetigershark View Post
Hi Joseph
Well, If I buy an ARF turbine jet ((kit) what it still is somehow) with composite wings, I expect the internal structure of the wing to be built correctly.
Agreed - good on the owner to inspect the wings when he felt something was amiss, but that doesn't change the fact that the blame is 150% on the manufacturer here.

I just hope for his sake it doesn't take another 10 months to get the next replacement parts.
The following users liked this post:
Skunkwrks (05-11-2021)
Old 05-11-2021, 10:39 AM
  #21  
Skunkwrks
Senior Member
 
Skunkwrks's Avatar
 
Join Date: Sep 2020
Location: Calgary Canada
Posts: 114
Received 9 Likes on 9 Posts
Default

Like what happened to the Carf Extra 330XL when it had a flutter issue and it took quite a while for the replacement wings to arrive.

But Carf did fix the issue, the company does stand behind their product.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.