Jump to content

DB Mighty Barnstormer


EarlyBird
 Share

Recommended Posts

I suggest starting a new thread asking about modifying to a two piece wing might produce some good ideas.  No point in 'reinventing the wheel' when you could benefit from other people's experience!  

  • Like 1
Link to comment
Share on other sites

Advert


After a couple of days off from the build here we are back again. I have turned the board around and finished all of the internal bits. 

IMG_20241126_093044.thumb.jpg.5d35e908a7a4315cde3fb675601ed049.jpg

I have decided to glue the top sheet before the the leading edge. The straight edge has now been positioned and the top sheet will be dampened on the top only this will help the bend form and reduce the stresses.

IMG_20241126_093205.thumb.jpg.332515a2e43fb93793b6a97ebeb73482.jpg

 

The decision has been made to make this a two-part wing on the basis that if I leave it together then I will have a single piece Wing with the option of taking it apart when I feel it is necessary, best of both worlds, I think. 

 

Steve

  • Like 2
Link to comment
Share on other sites

After damping the sheet the glue was applied and then the sheet placed and weighted down and left overnight. Here we are ready to reveal the results. 

1171764663_IMG_20241127_0851542.thumb.jpg.c5f8be167228e2bfb6abcd069ad49df0.jpg

 

Incidentally I do find my new steel straight edges excellent for the job of just adding weight. 

 

Steve 

 

 

 

 

Link to comment
Share on other sites

Hi Ron, 

I am looking at the options now and wondering if I can use the braces I have already glued in place on the first part of the wing. 

In the meantime the leading edge has been plained and sanded down to the ribs ready for glue. 

IMG_20241127_102546.thumb.jpg.73a08730d6902395e94d8d3afd593622.jpg

 

IMG_20241127_102615.thumb.jpg.5a9bf345d7dd80dcf1b188613516bff2.jpg

 

Steve

Link to comment
Share on other sites

Look at types of joining glider wings

 

Various ways.

 

Vertical steel plate in boxes.

Bent steel rod...

Carbon rod/tube

 

Etc.

 

2 parallel large dia carbon tubes would be my choice. With smaller ones that slide inside.

 

Set the wing dihedral. The outers set through the ribs straight and parallel.

 

Near to top sheet at root. And end of tube near bottom sheet outboard.

 

Then cut the tube in half at root ribs

 

You then have straight joiner(s)

 

A bit late as you've built most of the wing surgery will be required.

 

  • Like 1
Link to comment
Share on other sites

Thanks Nigel and Ron, I was trying to keep the wing as original as possible however a two part Wing is the way to go. Leaves the issue of how to achieve the join. Surgery was my first problem that made me think of boxing in the existing braces. 

Meanwhile the leading edge has been completed.

1109606240_IMG_20241127_1443522.thumb.jpg.24a5e6b4138ff4603589232ec86a23a5.jpg

 

The plane is keen to get workingIMG_20241128_081257.thumb.jpg.5324e6c85a07a4f15331b6ff86691299.jpg

The top looked good but I can feel that the bottom is not right at the tip. This has been caused by mixing methods and not being able to see what is happening to the bottom. 

 

Steve

Link to comment
Share on other sites

With the leading edge planned down to the top sheeting. 

IMG_20241128_092759.thumb.jpg.1b15d152ec04626c542d71c70286c225.jpg

It's now time to unpin from the board and have a look at the bottom. 

1435372314_IMG_20241128_0940192.thumb.jpg.661fc41135a22054f4390b240c777a07.jpg

As I suspected🙄 a bit of glue a couple of clamps and a piece of wood should sort that out.

IMG_20241128_095448.thumb.jpg.0b6cda52ddf30babe9e2cceea557268e.jpg

 

Once dried I can plane the leading edge down to the bottom sheet and then glue on the leading edge cap strip. 

 

Steve

Link to comment
Share on other sites

Steve, if you are going to make the wing two piece, then I’d advise not getting too far ahead with the sheeting until you’ve decided how you’re going to do it.

I think the easiest way would be two phenolic and aluminium, or carbon fibre tubes. As the model is already advanced it would be difficult to get two tubes the same size to line up precisely and be parallel – if they are not then then binding will occur. You could fit one main tube either against, or very close to, the main spar and a smaller, much shorter one as a keeper toward the rear.

One method of aligning the main tube is to cut oversize holes in the ribs so that the tubes easily go through each hole in the ribs, then have rings of ply, 1/8” liteply would be fine, which will just slide along the tubes and are glued to the ribs to take up the gaps and spread the load into the ribs.

Choose a tube which will take all the anticipated loads (around ¾” – 1” I’d suggest) and a smaller tube at the rear end which only fits into the end ribs. That way any slight parallel misalignment won’t be a problem.

You could talk to Graham Buckingham at Bucks Composites about telescopic carbon tubes, or SLEC for phenolic and aluminium, both will work though phenolic and aluminium may be cheaper, but perhaps a bit heavier.  

  • Thanks 1
Link to comment
Share on other sites

Thanks John for the excellent explanation, as usual, you have made it sound easy for the tubes. As it happened I have the phenolic tubes scaled from the plan I just thought that using the ply braces would be easier. I am now beginning to think that the phenolic tubes will be easier due to your explanation. As to the sheeting I will only complete the tips.

The leading edge has now been finished until I do the final sanding.

1039010744_IMG_20241129_0740162.thumb.jpg.a9921c8a42624ed62b2e952261e810f6.jpg

 

Next is the tip sheeting. 

 

 

Steve

 

Link to comment
Share on other sites

The bottom of the tip have now been finished and the cap strips done.

 

IMG_20241201_182955.thumb.jpg.e9e31b42e1e25394cb3571e82c7bc793.jpg

 

Just to repeat on the top, incidentally the sheeting of the tips is not an easy option. I am now wondering if it was all worth it but that's me liking a challenge. 

 

Steve

  • Like 1
Link to comment
Share on other sites

I shouldn't have posted those last two photographs, they were too good to be true, because when I checked the wing alignment they were out and I had to fit a wedge to make good. 

 

1170348251_IMG_20241207_1029102.thumb.jpg.6b6d5626c74abac153c4eade34d4274d.jpg

And the bottom was even worse so I have not taken any photographs of the mess. While I am in a confessing mood I also made a mess of the first Wing which needs a bit of sorting out beyond that it all looks good and probably would fly anyway as it is. 

 

Steve

  • Like 1
Link to comment
Share on other sites

Yes kc, I hate undoing what I already have done and it was so tempting just to glue it together as it is that that's what I did also it fits in the room and will stand on its wing tip for storage. I also realised for me it is more important to minimise the work at the field and the consequences of a single Wing will simply be put up with.

 

IMG_20241207_124509.thumb.jpg.fb02c6f241922b7bd03e2136ac97fcd4.jpg

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...