Flying wing designs and remove able wing question

[xMeox]

Hi there!

Im searching for a good way to build a flying wing with remove able wings.

During the last few months I have been experimenting with several flying wing designs, airfoils, materials and so on. Thought, new wing designs are build up pretty fast, the whole electronic part took ages compared to that. With a fuselage and a good remov eable wings, I could spend way more time on trying new wings, instead of redoing the whole electronic mount stuff all over again.
Also I found a very promising design and I want to build it with a larger wing span (>2m). But without remove able wings, Im simply not able to store it, nor to transport it, so a fixed wing is a total no go.

The road so far:


I build several flying wings from plans. Though all of them had good characteristics (eg: DizzyBird: very stable flight characteristics and a good glider but not very attractive for maneuvers as rolls; FT Versa: very crash resistant, fast maneuvers possible, bad glider) I wanted to create a plane which fits better to my flying style. In other words: the plane must be not very crash resistant, but must be able to land in pretty much every environment without (bigger) damage.
Though plane should be a decent sloper, it also should be able to do straight rolls and some faster maneuvers.


After several wing designs, I settled with this one:

With the nose attached, I only needed a 500mAh 1S battery to reach the wanted cg. The wingload of this one was about 6g/dm^2 (Note: I added winglets after I took the image, but before weighting it)


The next version I build with a 24g motor, which is quite over the top for this model. The weight of the choosen electronic nearly doubled the planes weight from 160g to 350g (I only had 1000mAh 3S batteries).

The performance of this model really impressed me. It was really agile with motor on, but still was able to 'glide' (I managed to stay up for more than half an hour without motor usage once, though with the right wind you can keep up pretty much anything I guess ). I changed the winglets to 90° ones later. The performance during powered flight was just better this way.





In the last design, I changed the specs of the wing again. Though the plane does not perform as good as the last one, Ill use the fotos of this one to explain my basic Idea for my swapable wings.

Because Foam Board is nearly twice as heavy as Adams Foam Board (and very expensive here in europa), I decided to use a different material: Selitron. It is way lighter than foam board, but there for not as robust. There for I used two layers of foam for the downer side of the wing. As you can see, it is very easy to get a nice airfoil with this material.



The fuselage was designed to accept a 500mAh in the nose (this determend the width) and a swapable motor mount in the back. For this model, I used a balsa spare and glue to keep the wings in place.


As you can see, there is quite more surface than on the last model.


I installed the motor, which is featured by FT with their mini series. It performed really good! I was able to climb height within a reasonable amount of time and the electronics weight are not that much difference in gliding performance.


With electronics, I reach 312g at the scale, which is (compared to the size of the surface) way less than with the last model and electronics.


Now:


Because the second last model (second picture) performed so good, I want to create a 2m version of it, but as explained before, I cant store a plane of this size so the wings have to be remove able. I also want to try to build a symmetrical and half symmetrical wing with the same specs. To save time, Id like to build one fuselage and be able to mound different wing designs.

So my question is: do you guys have any experience with remove able foam wings? I would really appreciate any input
best regards

xMeox

 

[Team_Monkey]

Very nice wings and great process. :applause:
I built a homemade wing tube for a large scale balsa plane similar to this procedure but the same process could be used on any scale. I used kraft paper instead of carbon fiber weave but we'll get to that.
- Find a light Aluminum or carbon fiber tube (even a wooden dowel would work) in a length approx 1/4 of your wingspan.
- Now wrap that in a layer of waxed paper. The kind used for cooking, in the US Reynolds is popular.
-Instead of the fiber weave in the directions, I used light weight brown kraft paper saturated with 20 minute epoxy thinned out with rubbing alcohol.
-Set that to dry for a looooong time as the inner layers are not exposed to air to dry quickly.

Once it is dry you can slide out your center support tube (or dowel) and cut your new wing tub in half. Glue the paper tubes into the wings and figure out a way to keep the two halves together. the joining force can be weak compared to the torsional loads of the spar.

Here are two shots I found of me gluing the created paper tube into the balsa wing.



Instead of ribs you can just glue it to the inside of the wing skin/foam.

 

[xMeox]

Thank you very much! This is exactly the thing I was looking for!
I dont have fiber weave so I will have to use other materials. I will give craft paper a shot, though I think it will be quite hard to use on <8mm tubes. Instead, I do have some different materials in mind. I think the first thing Im going to try is news paper and wood glue (papier mâché). This might not be stiff enough for big planes, but for planes (< 1.3m wing span, < 0.35kg) it should be more than enough, especially when I use a lot of hot glue to fix it.

To keep the wing halfes together, I will use tape.. at least at the beginning. Im thinking of installing a second (shorter) shaft in front of the wing spear (higher in one wing, lower in the other) which do overlap in the middle of the fuselage. One screw should be enough to hold the wings together.

Im not at home the next days, so Im not able to try this week. But Ill give updates after I managed to try this stuff at my next version of my flying wing.

Thanks again for your answer Team_Monkey, this really helped me a lot!

 

[RAM]

Very nice wings and great process. :applause:
I built a homemade wing tube for a large scale balsa plane similar to this procedure but the same process could be used on any scale. I used kraft paper instead of carbon fiber weave but we'll get to that.
- Find a light Aluminum or carbon fiber tube (even a wooden dowel would work) in a length approx 1/4 of your wingspan.
- Now wrap that in a layer of waxed paper. The kind used for cooking, in the US Reynolds is popular.
-Instead of the fiber weave in the directions, I used light weight brown kraft paper saturated with 20 minute epoxy thinned out with rubbing alcohol.
-Set that to dry for a looooong time as the inner layers are not exposed to air to dry quickly.

Once it is dry you can slide out your center support tube (or dowel) and cut your new wing tub in half. Glue the paper tubes into the wings and figure out a way to keep the two halves together. the joining force can be weak compared to the torsional loads of the spar.

Instead of ribs you can just glue it to the inside of the wing skin/foam.

I wonder if you could do the same thing using tyvek or a fedex envelope. It has longer fibers than craft paper.