FTFC ’25 MONSTER SCALE CHALLENGE - FoamyDM

[FoamyDM]

While i have a Giant scale project in the works ATM. I started reviewing a project Recently that i finished and succeeded with, but i can find one of the finishing parts. Either a the flight video or a ‘final’ set of plans posted) it was turning a balsa flying wing kit called “PURI”, from BavarianRC, into an FT style DTFB solid-skinned kit. I don’t own one, but i love the shape and love the conversion challenge.

The original is park-scale. ~1m (30-40”). Mine was two FB sheets wide around 50” (1.25m?).

I want to make a balsa style replica, sized to be about 14’ WS. That will make the wing chord around 48”. The original relies in Carbon Fiber tubes to joint the wings halves together.

Once you start scaling anything to this size, the weights scale exponentially, and you have to consider native material sheet sizes. And it closes on the material strength limits.

So, now to scale-up the CAD sections, lay it out and start cutting. 1/4” fanfold or DTFB.

 

[FoamyDM]

Building Log

 

[Houndpup Rc]

While i have a Giant scale project in the works ATM. I started reviewing a project Recently that i finished and succeeded with, but i can find one of the finishing parts. Either a the flight video or a ‘final’ set of plans posted) it was turning a balsa flying wing kit called “PURI”, from BavarianRC, into an FT style DTFB solid-skinned kit. I don’t own one, but i love the shape and love the conversion challenge.

The original is park-scale. ~1m (30-40”). Mine was two FB sheets wide around 50” (1.25m?).

I want to make a balsa style replica, sized to be about 14’ WS. That will make the wing chord around 48”. The original relies in Carbon Fiber tubes to joint the wings halves together.

Once you start scaling anything to this size, the weights scale exponentially, and you have to consider native material sheet sizes. And it closes on the material strength limits.

So, now to scale-up the CAD sections, lay it out and start cutting. 1/4” fanfold or DTFB.

Cool! Glad you can join!

 

[Houndpup Rc]

While i have a Giant scale project in the works ATM. I started reviewing a project Recently that i finished and succeeded with, but i can find one of the finishing parts. Either a the flight video or a ‘final’ set of plans posted) it was turning a balsa flying wing kit called “PURI”, from BavarianRC, into an FT style DTFB solid-skinned kit. I don’t own one, but i love the shape and love the conversion challenge.

The original is park-scale. ~1m (30-40”). Mine was two FB sheets wide around 50” (1.25m?).

I want to make a balsa style replica, sized to be about 14’ WS. That will make the wing chord around 48”. The original relies in Carbon Fiber tubes to joint the wings halves together.

Once you start scaling anything to this size, the weights scale exponentially, and you have to consider native material sheet sizes. And it closes on the material strength limits.

So, now to scale-up the CAD sections, lay it out and start cutting. 1/4” fanfold or DTFB.

Image not showing up.

 

[Mr Man]

Awesome! Glad to have you on board!

 

[Flying Monkey fab]

Following.

 

[FoamyDM]

Here is the PDF of the plans to go over the 1/4" fan-fold XPS 2'x4' panels. The spacing on the Section is 8-9". The top three are on a 1/2 sheet. The Small holes are the for the support CF spars in the original. for this one, this should help set the dihedral. The larger circles are the control surface, hinge center.

I have printed the sheets (22?) an when I clear off my build surface(s), I will get to cutting.
What I haven't done is set the motor and prop.

 

[FoamyDM]

I am thinking a 5010 with a 16-18” folding prop

 

[Mr Man]

Nice!

 

[ithink2020]

WOW, I can't wait to see how this turns out. It is going to be massive!

 

[Tench745]

While i have a Giant scale project in the works ATM. I started reviewing a project Recently that i finished and succeeded with, but i can find one of the finishing parts. Either a the flight video or a ‘final’ set of plans posted) it was turning a balsa flying wing kit called “PURI”, from BavarianRC, into an FT style DTFB solid-skinned kit. I don’t own one, but i love the shape and love the conversion challenge.

The original is park-scale. ~1m (30-40”). Mine was two FB sheets wide around 50” (1.25m?).
View attachment 253261

I want to make a balsa style replica, sized to be about 14’ WS. That will make the wing chord around 48”. The original relies in Carbon Fiber tubes to joint the wings halves together.

Once you start scaling anything to this size, the weights scale exponentially, and you have to consider native material sheet sizes. And it closes on the material strength limits.

So, now to scale-up the CAD sections, lay it out and start cutting. 1/4” fanfold or DTFB.

That's nearly the size of one of the wing panels for my Jr Ace. (13' x 54")

 

[Piotrsko]

You're talking a person carrying Junior ace, right? 13 foot sounnds about right

 

[FoamyDM]

Finally got a moment to cut the sections out.
View attachment IMG_6615.jpeg

 

[FoamyDM]

I forgot to number them… and the digital files are inaccessible, so i had to lay them out again. View attachment IMG_6618.jpeg
If I’m smart, i will write down the order on the parts. Before i mix it up and start fitting spars and such.

 

[Mr Man]

I forgot to number them… and the digital files are inaccessible, so i had to lay them out again. View attachment 254023
If I’m smart, i will write down the order on the parts. Before i mix it up and start fitting spars and such.

😂. Nice big airfoil

 

[FoamyDM]

So i got to thinking on spars for this plane. It’s not as simple as I was originally thinking.

The wings around 8’ each (i think i measured 7.5’ from tip to perpendicular of center. But that is near 9’ along the spar line (tip to center at ~30deg). These are the CF rods in the original. In front and back of it are shorter spars joining the two halves, reinforced by thin balsa strip on top and bottom. They would be ~4.5’ each at this scale.
I’m thinking of rip cutting 4- 3/8” thin strip off a 2 x 4. Then cutting them a few times to bend it and laminate glue it in place, To follow the spar line. Infill vertically with foam or some 1/4 ply squares for the first few bays.
Cut a 10’ 2x3 gutter in half for the joiner spars.
Time to get cutting , I guess

 

[Piotrsko]

Looks like it could be line drilled using at least a 12" long bit. Have lusted after gun drills 36" long........

How about main spar conveniently located and sub spars?