Virtual 2 Reality

#1
Virtual 2 Reality

I use Cheetah for a little different purpose than most. I still do a little art here and there, but this hobby takes most of my free time. I added a few pics of the process below. This was my first prototype of a FH-1 Phantom fighter. I am now working on version 2.0 which is a little more complicated, but should look much nicer.

And here is a Video of the final prototype product...
https://www.youtube.com/watch?v=IgfUFVSFwho
My video editing skills still need some work. That and these where just test flights, not very exciting.:rolleyes:

Edit: I guess it did not like my attachments.Maybe it's firefox? Trying Safari...
 
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#3
I used Cheetah to design the plane.

There were some attachments that were supposed to be part of the post that would have explained things a little better, but I could not get them to upload from home. I do not have the best internet service at home unfortunately. :frown:

I will try again today from work.

Sorry about that.
 

Swizl

Well-known member
#5
Very cool! Thanks for sharing.

My dad was a fighter pilot in the USAF, so I grew up on air bases. I liked to go watch the planes take off and land.
 
#6
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My stepdad was a navigator on a B-17 Flying Fortress. The only tattoos I'd ever get would be of he and my grandpa who was a Seabee in the Philippines at that time. Keep up this cool stuff.
 
#7
I thank them for their service!

I love all things in flight, always have. I used to just buy the RC kits, but I have much more fun designing them myself. There is just something about taking an idea and turning it into a working/flying machine that is just so rewarding.

I have semi user friendly plans of the prop and slot F-18 available if anyone is interested in making one. I will also release the plans of the FH-1 once I am happy with the design. I am pretty much done with the design work and already started building version 2.
 
#9
Hi Since I am an RC flyer myself (Goblin 630, Piper Cub 2.30M Kit build, Sbach, custom build Quadcopters etc) I am interested in your workflow: how is your design process in C3D?
 
#11
Thank you gents!

As far as the design process goes, it’s really simple and complicated at the same time.

The overall design work is aircraft dependent. The F-18 prop and slot was fairly simple. The FH-1 prototype was pretty complicated. The new FH-1 V2 is way too complicated for what it is, but I am using all of this for testing and experimentation. The FH-1 is a special case where the engines are mounted in the wing root which causes all kinds of technical issues. I got around that with the prototype by mounting the engines aft of the wing spar and cutting holes in the bottom of the wing to let them breath better. Version 2 I figured out a way to mount the EDF’s in the wing spar but it complicated the build quite a bit. The wing spar / engine mount looks strong enough, but I will not really know if it will hold up until the maiden flight.

Exciting stuff!

Workflow starts with picking a subject, scale and electronics. In this case I wanted a Prop and Slot F-35. With this particular build the scale was set by the motor and prop I had available at the time. Most of my new builds are set to a scale of 1:12 or 1:10 and I buy the electronics for that size.

Next is a 3 view of the aircraft and then a low poly mock up. I model all of the electronics I plan to use as well. This adds quite a bit of time to the design process for the first few models, but once drawn you can use those for future designs where applicable.
See Fig A.

I use Dollar Tree foamboard for these builds which I can buy locally dirt cheap, but there are plenty of materials out there to use. Foamboard as a thickness of 0.1875” so I create a box 1x0.1875x1 to use for building each face of the structure.

The fun part begins with converting the low poly mock up to the actual design. There is no trick to this, you just have to know how the foam behaves. It’s just like paper. You can bend it, but only on one axis at a time. Rounded bends can be achieved by removing the paper from one side but it loses some strength and it’s a lot more work. It’s easier to score one side and bend along the crease. Once you wrap your head around that you can wrap your mock up with foam faces.
See Fig B.

The UV unwrapper in Cheetah like most other programs does not care about scale or face geometry so you are going to have to unwrap this thing yourself. In order for this to work you have to model each face as it’s own object. This is a very time intensive process that you can not get around unfortunately. When you are placing the faces together, picture each 3D face as a piece of foam. Treat the outside top and bottom faces as a paper skin and the ring faces that make it’s depth as foam. It’s important to move and rotate the “foam face” as an object to get it into location. On folds, treat the outside paper face as the skin, the interior face will compress when bent. (The outside face will make your template, the inside fades will over lap and look messy but are not important) Once in place you can move each vertex around any way you like, but only using “object” coordinates and in two dimensions . Do not move the points on the Y axis at any time. Using these rules, place and tweak each piece until you get the desired result.
See Fig C.

Once you have all of your 3d faces placed and aligned, you now have to pull them all back apart again. At this point you never want to touch a vertex. Each face will be reoriented and laid flat next to its neighbor matching the faces by “object” rotation and position. Each stitched back together laying flat.
See Fig D.

Once you have manually unwrapped your foam skin you now have you basic template for your foam. To keep everything scale you will need to create a face to an exact known dimension. Im my case my foam board is 20”x30” I create a face 20 x 30 in Cheetah and place all of my templates in this square and combine them. With my new 20 x 30 template I take it into the UV mapper and do a Cubic mapping of the template with a scale set to 1” larger than the template which is 31 x 1 x 31. Once I write the UV’s I export to PDF.
See Fig E.

And finally, import the PDF in photoshop with the dimensions of 31 x 31 @ 300 DPI. Next using the magic wand tool I do an area selection inside of the square template. @ 300 DPI the UV lines are about 4 pixels wide so I expand my selection by 2 pixels. Once expanded, crop the image by selection and you are good to go. You now have a 100% accurate template to cut out your foamboard.

This long post is just scratching the surface. If you are really interested in building your own RC aircraft, I would suggest checking out the “FliteTest” YouTube channel. Those guys do all sorts of crazy things with RC and are foamboard aircraft pioneers. I have done some cool stuff, but there are plenty of more talented people than I out there that do this sort of thing. I am just the only insane one manually unwrapping models in Cheetah 3D which allows me to get more intricate than most, but still using cheap and sometimes easy foamboard builds.
 

Attachments

#13
Thank you! ^^

After the design and prints are made, I print the templates out on standard printer paper and tape the templates to foamboard.
See Fig F.

Ahh, the joys of cutting foam…
See Fig G.

Once everything is cut out, I assemble the pieces using mostly hot glue. A good industrial hot glue gun is not required, but highly recommended. I use a 200 Watt AdTech Pro. The glue literally boils out of the nozzle. This gives you more time to work before the glue cures. Some of the larger pieces are hard to glue with a smaller glue gun.
See Fig H.

Many hours later…
See Fig I.

Note that this is the F-35C version with larger wings and control surfaces. I never did build the A version. I am going to redesign the entire air frame using an EDF rather than a prop and slot. It will have a more scale appearance as well as a higher cool factor.
 

Attachments

#14
Newest Project.

I am making custom skins we are going to use for a Veterans airshow during an RC event.

This is the Marine Corps version, just trying out the new Falcon renderer. I did not spend much time on it, but it gets the idea across.
 

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Swizl

Well-known member
#16
Cool stuff! :cool:

I remember making Balsa wood plane models when I was in Boy Scouts. The propellers were powered by rubber bands.

Thanks for sharing. :D
 
#17
Thanks bud!
I did the same thing when I was a kid. I used to drool over the massive gas/nitro powered planes back then. That was something I never could really afford.


Once nice thing about foamboard aircraft, you don't have to worry about crashing them. They only cost you time to rebuild or repair.


I did a quick vid on the texture process...
https://www.youtube.com/watch?v=eY8_JRPpC8M


Next I will be building the actual aircraft. I will post pictures when I am finished.
 

uncle808us

Well-known member
#20
Flew my elevons only test air frame today and it flew great.:icon_thumbup:
https://youtu.be/8QDLu-WfODU


I am going to have Staples print my full sized color skins for the actual build this week. I am eager to get it built and in the air.
Wow How do you control it so it doesn't just fly away forever? That is so cool I want one. Two many trees at my park though but there is a close by baseball field. Very nice job! Love the video.
 
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