Break away wing alternatives

[Inq]

I'm still in pilot learning phase. I'm currently using rubber-band tie downs so the wing can break away instead of damaging itself and/or the body. I want to do something more cosmetic where that capability still exists, but isn't front and center. I know for wings attached directly to the body people use nylon bolts. But I'm interested in doing a parasol type configuration (Fokker D-VIII) and wonder if there are any suggestions for something like that. The wing will be typical FT fold type and the body will be pretty similar to the FT DR-1 body.

Thanks.

 

[telnar1236]

I haven't heard of anything like that for a parasol wing. One possibility that comes to mind is to have some method of covering the rubber band on the wing -- maybe a slot partway through the wing and then some foam board to cover it. The concern for a parasol wing is getting enough rigidity for the struts that hold it, but for a large plane you might be able to join the struts to a sheet that only extends part of the wingspan and then mount the wing to that sheet using rubber bands or nylon or similar. In terms of nylon bolts, I haven't ever seen something like that which actually worked. Foam wings are just too weak and nylon too strong to prevent damage in crashes where the bolts break, and the wing spar, if it runs through the fuselage also causes problems. However, if others have seen working versions of this please correct me since I have not seen everything out there by any means.

Edit: I also just thought of another possibility: you could make the struts themselves weak/sacrificial when loaded in the wrong axes but you might end up with trouble transporting the plane if you did that.

 

[Foamforce]

How about white rubber bands so that they stand out less?

 

[Inq]

white rubber bands so that they stand out less?

... but the Acrylic paints can make this happen!

 

[Foamforce]

... but the Acrylic paints can make this happen!

View attachment 233422

That’s a beauty! Coincidentally, I built the Mini Scout using the “Lozenge” camo pattern seen on the tail in your picture. I used Rasterize’s skin. It’s pretty! Last week I was on vacation in London and we visited the RAF museum. On the ceiling in Hangar 2 was a WW1 German fighter wearing the same paint. Cool! The RAF Museum was a highlight of our trip.

 

[Inq]

That’s a beauty! Coincidentally, I built the Mini Scout using the “Lozenge” camo pattern seen on the tail in your picture. I used Rasterize’s skin. It’s pretty! Last week I was on vacation in London and we visited the RAF museum. On the ceiling in Hangar 2 was a WW1 German fighter wearing the same paint. Cool! The RAF Museum was a highlight of our trip.

Oh... No kidding! We went to London several times as children and the two things I remember the most was... that museum and Stonehenge when you could walk up and touch the stones. I hear now, you can't get near.

Anyway... I'm going to have to look into this rasterize skin thing. I was just trying to wrap my mind around how to airbush such a pattern... so you can just print it out on your printer and glue it on??? I can't imagine one continuous sheet that would cover all the curves and angles without being cut... and then the pattern wouldn't mesh up at the butt joints. How is something like that handled?

 

[Foamforce]

Oh... No kidding! We went to London several times as children and the two things I remember the most was... that museum and Stonehenge when you could walk up and touch the stones. I hear now, you can't get near.

Anyway... I'm going to have to look into this rasterize skin thing. I was just trying to wrap my mind around how to airbush such a pattern... so you can just print it out on your printer and glue it on??? I can't imagine one continuous sheet that would cover all the curves and angles without being cut... and then the pattern wouldn't mesh up at the butt joints. How is something like that handled?

Rasterize is a member of the forum who made several really nice skins.
https://forum.flitetest.com/index.php?resources/authors/rasterize.4420/

There’s a nice article on how to apply them too.
https://www.flitetest.com/articles/skins-make-your-planes-look-ridiculously-good

At least for the Mini Scout skin, all of the visible parts (which was most of them) from the original plans are duplicated on the skins, so I didn’t use most of the original plans. I roughly cut out each of the parts from the skins, lightly sprayed 3m 77 on the back of the paper, stuck the skin part onto pre-peeled foam, and then directly cut out the part from the skin. Assembly after that was normal. It was pretty easy and looked good!

 

[Inq]

Rasterize is a member of the forum who made several really nice skins.
https://forum.flitetest.com/index.php?resources/authors/rasterize.4420/

There’s a nice article on how to apply them too.
https://www.flitetest.com/articles/skins-make-your-planes-look-ridiculously-good

At least for the Mini Scout skin, all of the visible parts (which was most of them) from the original plans are duplicated on the skins, so I didn’t use most of the original plans. I roughly cut out each of the parts from the skins, lightly sprayed 3m 77 on the back of the paper, stuck the skin part onto pre-peeled foam, and then directly cut out the part from the skin. Assembly after that was normal. It was pretty easy and looked good!

I just got away to start digging into this... perfect timing. There are some really nice combinations and your plane looks great! Thanks for the links.

 

[Inq]

Just finished the video... I wish I had the artistic talent to the subtle shadowing, making it look like curved surfaces on the Red Baron or "wear", gun powder burns and such. Seen any videos that teach those skills?

 

[Foamforce]

Just finished the video... I wish I had the artistic talent to the subtle shadowing, making it look like curved surfaces on the Red Baron or "wear", gun powder burns and such. Seen any videos that teach those skills?

I know, those skins are beautiful! The Cub skins are my favorites. I built two Cubs before I found those skins and I’m tempted to build another just so I can use the skin.

I’d love to make my own skins some day, but I’m trying (not succeeding) to limit the number of projects I’m actively working on. 😂

 

[Merv]

... I know for wings attached directly to the body people use nylon bolts....are any suggestions for something like that....

Nylon bolts & rubber bands are what most people use.
Depending on the application, Velcro might work, maybe zip ties.

 

[Tench745]

The really light UMX planes and rubber-powered planes can use magnets to hold the wing on. If you have large enough magnets with the right mount, it might be doable on larger planes.

 

[Inq]

Velcro might work, maybe zip ties.

use magnets to hold the wing on.

Velcro or magnets... I don't think I'd ever thing of. Great idea. And just happened to burn up a motor full of rare-earth magnets. I'll have to check those out.

 

[Tench745]

Something to think about: In flight, the wing to fuselage joint almost exclusively sees compressive or tensile loads. In crashes you almost always hit one wing tip first, so crash loads often are sheer loads.
Most planes I have seen using nylon bolts to hold the wing on have dowels to pin the front of the wing and two, 1/4-20 nylon bolts to hold the rear. These bolts are monstrously strong for the loads they'll see and very often won't break in a crash. I have read recommendations for using a single, smaller, nylon bolt, something like a #10 or less depending on the model size. The bolt mounts through some plywood plates to spread the flight loads to the structure and close enough together to localize any sheer load so that a small enough bolt will actually shear in a crash. If there is a lot of space between the wing and the block the bolt screws into, chances are the bolt will just bend, which does dissipate some energy, but not as much as a break will.
Similarly, you could use some sort of mechanical fuse ie. an easily replaceable material that will shear when subjected to crash load. For small planes this could be something like a balsa dowel.

 

[Foamforce]

I’m inspired to over-engineer this. A spring arm over the top of the wing to hold the wing down, with a couple of ball detents on the bottom for alignment might just do it. The spring arm would go over the front of the wing and would hold the wing firmly against the top of the fuselage. The ball detents would align the wing and prevent it from sliding around under normal loads. In the event of a crash, the wing would be pushed back and up, which would push over the detents and backward out of the spring arm. Disassembly would be easy, just slide the wing backward.

 

[RossFPV]

I’m inspired to over-engineer this. A spring arm over the top of the wing to hold the wing down, with a couple of ball detents on the bottom for alignment might just do it. The spring arm would go over the front of the wing and would hold the wing firmly against the top of the fuselage. The ball detents would align the wing and prevent it from sliding around under normal loads. In the event of a crash, the wing would be pushed back and up, which would push over the detents and backward out of the spring arm. Disassembly would be easy, just slide the wing backward.

The clip would need to be strong for loops and other aerobatics. Maybe it could be made from landing gear wire with one clip on each side of the fuselage.

 

[Tench745]

I have seen parasol wing arrangements where the cabane struts are soldered together with a platform of some sort on top that the wing can rubber-band onto. The models I saw it on were probably larger, 50-60" winspans. I tried it once at a smaller scale and had a hard time getting enough strength in the structure without being really heavy for the size.

 

[Inq]

I have seen parasol wing arrangements where the cabane struts are soldered together with a platform of some sort on top that the wing can rubber-band onto. The models I saw it on were probably larger, 50-60" winspans. I tried it once at a smaller scale and had a hard time getting enough strength in the structure without being really heavy for the size.

That's kind of where I am. I shooting for a 30" wingspan... similar to the FT DR-1. Maybe I'm over thinking this and just do it permanent like the FT DR-1. It's not like I need to take it apart for travel and at some point... I got to quick crashing!