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FTFC20 Dunne type Tailless Flyer by FoamyDM

FoamyDM

Building Fool-Flying Noob
#61
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.
Thank you sir. Your feedback is a gift.
 
#66
New stress testing report. I managed to fly the second wing in 12mph winds (gusting to 20+) for a while, until they ripped the top wing in half leading to loss of control and crash! I am going to try building a third one with a stepped airfoil instead of flat sheets, for the extra strength.
 

FoamyDM

Building Fool-Flying Noob
#67
I urge you to use coat thread and do x bracing. Your repeat build are a testament to two things. 1. This is quick to build. 2. It is a true joy to fly. 3. You are a glutton for punishment.
 
#68
I urge you to use coat thread and do x bracing. Your repeat build are a testament to two things. 1. This is quick to build. 2. It is a true joy to fly. 3. You are a glutton for punishment.
I will try your cross bracing idea. Just an X on the front and back of each wing segment, I guess? I don't have any coat thread, might try fishing line instead if it sticks well enough to hot glue.
This design sure does go together fast and is a great flyer. When I printed your plans I made foam templates out of them, so I can trace as many as I need very quickly.
 

FoamyDM

Building Fool-Flying Noob
#69
Honestly most any thread should work fine. Push a round toothpick 1/2, sharp end in, at the top and bottom ends of the vertical supports, both front and back, for thread mooring pegs. Then run thread of any sort, pulled taught and wrapped around the pegs to diagonal brace the and keep them from flexing or sagging over time
 
#70
OK, after a break from flying wings to build a Mini Mustang, I'm back with "Get 'er Dunne" III. This one has the control surfaces moved to the top wing, for no particular reason other than they might be less damage prone. For the cross bracing you suggested, I used fishing line and BBQ skewers. The skewers are glued in place in the leading edge of wing. One at a time, each skewer has more hot glue applied, then the fishing line is wrapped around several times and held taut until the glue dries.
I got to maiden this today with some drone pals in 8-12mph winds. The cross bracing definitely reduces the amount of wing flutter. It still is a box kite in the wind, but the flex within the structure is noticeably less than on the previous model. After maybe half an hour of flying (which was very enjoyable in FPV), the cross bracing seemed to retain most if not all of its tension. We'll see if it lasts.
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Edit: did not try a step airfoil, maybe after I inevitably destroy this one.
 
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FoamyDM

Building Fool-Flying Noob
#71
OK, after a break from flying wings to build a Mini Mustang, I'm back with "Get 'er Dunne" III. This one has the control surfaces moved to the top wing, for no particular reason other than they might be less damage prone. For the cross bracing you suggested, I used fishing line and BBQ skewers. The skewers are glued in place in the leading edge of wing. One at a time, each skewer has more hot glue applied, then the fishing line is wrapped around several times and held taut until the glue dries.
I got to maiden this today with some drone pals in 8-12mph winds. The cross bracing definitely reduces the amount of wing flutter. It still is a box kite in the wind, but the flex within the structure is noticeably less than on the previous model. After maybe half an hour of flying (which was very enjoyable in FPV), the cross bracing seemed to retain most if not all of its tension. We'll see if it lasts.
View attachment 155925 View attachment 155924
Edit: did not try a step airfoil, maybe after I inevitably destroy this one.
Amazing! I'm glad to hear about the successful proof tested improvement of the rigging to the overall stability of the wing. I will be updating the plan in Feb. and making a build vid.
can you post some of the FPV footage here? (so perspective builders can see how enjoyable it is.
Was the 1/2 hour of flight on one Battery? (if so which what size) It does have a long flight life.

Have you considered having linked control surfaces on both top and bottom wings?
 
#72
can you post some of the FPV footage here? (so perspective builders can see how enjoyable it is.
Was the 1/2 hour of flight on one Battery? (if so which what size) It does have a long flight life.

Have you considered having linked control surfaces on both top and bottom wings?
I'll put up some footage as soon as I have something shot and edited. Next time I need to double up the cameras and put my HD action cam onboard as well as the (low res) FPV gear. I flew for about 10 minutes each on three 1800mAh 3S batteries. Haven't tried linked surfaces yet. It is fairly controllable as is, but maybe I'll give it a shot on the next one.
 

FoamyDM

Building Fool-Flying Noob
#75
Nice work... I finished my build-ruary re-build up of the plane
with rigging in both front and back. The wing assembly rigidity increased greatly. The corrugations along the fuse length worked perfectly, there was no damage. and an couple near
I only put in the control surfaces on the bottom wing. it was REALLY difficult to turn right... I need to add the upper surfaces as per the plans. the FB skids lined with craft sticks held up well buy needed to go further back and have a LITTLE more height.
 

jpot1

Well-known member
#76
Finally getting back to building this design. Of course I can’t leave anything alone so I’m going with a kfm2 step on the top wing and probably a kfm 1 on the bottom. That way I get some more rigidity without affecting the verticals. Added notches to align the verticals. I may double those up too.

Kfm step is just a leading edge double bevel with two creases a little further out so the leading edge rounds nicely.

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