FTFC20 Dunne type Tailless Flyer by FoamyDM

[FoamyDM]

So I had an unfortunate day at the field. Specifically with this plane... It started with three nose-ins.
Then a fourth poor launch... The fifth got up ( got on the controls fast enough )

This flew for about 100' and during a short unexpected turn. It twirled to the ground with collapsed wings.

I learned a few things about the build.

• The nose needs to be reinforced.
• The servos extension holes should be installed flat. And clipped
• The skids should be anchored more solidly
• next build I need to mark the cg on the upper wing.
• I should add wing dihedral should be braced to promote it

It was time to build another, now I have a good reason. This time I will film it

I may have some on-board of the crashed.

 

[Michael9865]

You shouldn’t need much dihedral with the sweep in the wings. Learning to make it better is progress. She definitely looks good in the air.

 

[JennyC6]

I say leave the dihedral out. Most flying wings have minimal, if any, and tend to have little trouble with stability in the roll axis. That's their most stable axis anyway!

 

[FoamyDM]

The reinforcement is probably more to ensure the wings stay together in a crash.

The landing skids, and crumpling fuse may have allowed for intact wings after five crashed. V2 needs to have slots and tabs. It will help mechanically lock the pieces, In the event the glue fails.

 

[FoamyDM]

I just took a few minutes with the hopeless plane, and I think I can repair and improve.

 

[FoamyDM]

After the 5failed launched and wing folding "success" of Saturday, I re-constructed the leftovers. Surprisingly it wasn't as far gone as it looked. I did NOT rebuild the boat. Didn't need it. The battery sits right at the front of the wing 1500 3S or 2200. I continued to try a rolling takeoff, but they are eluding me still.
The launch has been tricky I started with a few clicks of up trim to ensure a slight upward take on release.:

Here is the rest of the flight... I had a couple tumbles that took a small toll and decided to cut it, rather then push it

 

[JennyC6]

steerable nose gear would go wonders towards ground handling.

 

[FoamyDM]

Here is a Printable Pipe for you to make your own pipe as you like.

 

[jpot1]

@FoamyDM - thinking of giving this a go. Confused by one thing. If these are flat plate wings how are you getting any curve to the lower wing to match the purple line on you vertical pieces? Removing paper?

 

[FoamyDM]

Sorry for the confusion. I'm not matching the curve, it's straight flat plate construction.

The curve was for a V2, or for anyone that wanted to slow it down, and add more lift - for surveillance. However to curve the wing would be easy, remove the front 2/3 of the wing paper, and curve to match. cut on the purple line and glue. I would then glue the removed piece to the underside of the curve at the verticals. This would benefit from some truss wiring. but I don't have a great method for grommets so the string doesn't cut the foam. Ideas, but no tests as of yet.

 

[DokCosmac]

Hello and happy holidays. I built your BD wing. It went together very easily. It's a great plane! Here's some info on my build and thoughts, as requested.

I did not make control surfaces on the upper wing. Instead I have 4cm wide elevons on the lower wing only.

I have added bamboo skewers to the leading edges of all wing surfaces and a pair of heavy foam skids. My main flying location is a rough mown field with many thorny stalks, so this helps protect the plane on landing.

The skids and their supports also form a bay for my drop mechanism.

The nose has been almost filled with vertical strips of foam for more strength, leaving room to wedge the battery on top. This was an attempt to reinforce the nose for landings, before I added the skids, so it may not be as necessary now. This area has been reinforced with gorilla tape and has velcro for my FPV pod. The receiver is mounted to the upper wing.

The plane flies very well. Electronics are from the FT B pack. Prop is a 9x5 folding prop and hub combo. Power wise I only needed to use a little under half throttle to maintain level flight. A 1300mAh 3S battery yielded about 15 minutes of pattern flying. My CG is approximately 10cm back from the leading edge of the top wing, measured at the root of the wing. It is more stable than the other bank and yank wing I have flown (my Mowe design). However, the BD wing is less controllable in windy conditions. Basically, the wing becomes a box kite. I expect it would not be as much of an issue if I had put control surfaces on both wings. In calmer conditions it is an extremely fun slow flyer. I am sure I will be flying this plane for a while.

With the above mentioned reinforcements and gear, it is remarkably durable. It has sustained a dozen fairly hard landings (before I added the skids) and one hard crash and tumble into a 20 meter tall tree. The simplicity of design works to its advantage in ease of repair. Plus you can build a whole new one with just a couple sheets of foam.


This plane was used to strand this action figure paratrooper in a tree, using the drop mechanism. Rescue efforts were successful!

 

[FoamyDM]

All I can do here is urge more people to try this simple build.

I really like the foamboard skids. If you don't mind, I will add them to the plans. I imagine if you glue a skewer on the bottom, they would be incredibly durable.

I'm So pleased you had as much fun and success as I did.

 

[DokCosmac]

I really like the foamboard skids. If you don't mind, I will add them to the plans. I imagine if you glue a skewer on the bottom, they would be incredibly durable.

Glad you like my landing gear! I was trying to keep in the spirit of the 1914 model, but I was too lazy to make floats, and wheels would not help at all where I fly.

Sorry I have no plans or dimensions for the skids. I just threw them together from scraps. Please do go ahead and share something similar if you like. They are made from two layers of foam with hot glue smeared along the bottom edge to prevent delamination. Skewers or popsicle sticks would certainly make them tougher. There's also three simple cross braces, two underneath and one in front of the "boat," also made from two layers of foam. If I were to make any changes to the skid design, I would make them extend a little further back, just a tiny bit past the CG.

(You'll note that they seem to only be glued to the "boat" right at the front on my model. This is because I glued a sheet of reinforcing foam on either side to reattach the crashed nose after I cut it off and stuffed it with foam. To fit on an un-repaired, new wing like your plans, the skids really ought to be made so that the skid is glued along the entire side of the "boat," and the upper aft cutout part of the skid can sit up against the front edge of the bottom wing and innermost pair of vertical stabilizers. Hope that made any sense.)

Thanks again for a great design. I never thought wings made from flat foam could fly so well! But it really is a very easy, stable flyer. I hope others build this plane and that you keep improving the plans.

 

[DokCosmac]

P.S. Is it just me or does this guy

look a lot like J.R. "Bob" Dobbs of the Church of the SubGenius?

Hmmmmm

 

[FoamyDM]

Glad you like my landing gear! I was trying to keep in the spirit of the 1914 model, but I was too lazy to make floats, and wheels would not help at all where I fly.

Sorry I have no plans or dimensions for the skids. I just threw them together from scraps. Please do go ahead and share something similar if you like. They are made from two layers of foam with hot glue smeared along the bottom edge to prevent delamination. Skewers or popsicle sticks would certainly make them tougher. There's also three simple cross braces, two underneath and one in front of the "boat," also made from two layers of foam. If I were to make any changes to the skid design, I would make them extend a little further back, just a tiny bit past the CG.

(You'll note that they seem to only be glued to the "boat" right at the front on my model. This is because I glued a sheet of reinforcing foam on either side to reattach the crashed nose after I cut it off and stuffed it with foam. To fit on an un-repaired, new wing like your plans, the skids really ought to be made so that the skid is glued along the entire side of the "boat," and the upper aft cutout part of the skid can sit up against the front edge of the bottom wing and innermost pair of vertical stabilizers. Hope that made any sense.)

Thanks again for a great design. I never thought wings made from flat foam could fly so well! But it really is a very easy, stable flyer. I hope others build this plane and that you keep improving the plans.

Too easy to add the skids. And I agree past CG. Update posted on Monday

 

[FoamyDM]

@FoamyDM - thinking of giving this a go. Confused by one thing. If these are flat plate wings how are you getting any curve to the lower wing to match the purple line on you vertical pieces? Removing paper?

@jpot1 - did you ever give this model a try? I can't remember?

 

[DokCosmac]

One wing goes down... another takes its place! Much cleaner build on this one, and I made the control surfaces 25% larger. Reused all the electronics, motor pod, and even the stickers. Pleased to report the maiden flight went great.

 

[FoamyDM]

@DokCosmac - did you have any orientation issues? I'm not sure why I was so worried, as it's an arrow, pointing the direction it flies but I was worried if it was turned away or towards, it would be hard to tell.

 

[FoamyDM]

View attachment 152750 View attachment 152751
One wing goes down... another takes its place! Much cleaner build on this one, and I made the control surfaces 25% larger. Reused all the electronics, motor pod, and even the stickers. Pleased to report the maiden flight went great.

I love the Name of your Craft
Are you using a B or C pack?

 

[DokCosmac]

I love the Name of your Craft
Are you using a B or C pack?

I used a B pack. Cruises under 50%. As to orientation I find it not too difficult to tell which way it is pointing as it is a fairly large flying arrow. It could be more of an issue if you are doing a lot of stunts. I mostly just fly flat ovals and figure 8 patterns.