this build log is a description of my project trying to use a 3d printer to print me a plane that will actually fly.
3d printers are printers that print solid bodies layer by layer from a computer file. they are usually used by mechanical engineers and art designers to create rapid prototypes of their designs. it's easy to find on the internet a model of cute little toy planes, but for a long time i wanted to design a plane that will fly.
3d printing gives you amazing freedom- almost anything you can think of and design, you can create. you can create complex wing profiles and profile changes along the wing, internal reinforcements and integral axes- to name just a few ideas. and the part i like best- you're not limited by your (mine) limited building ability and patience.
the problem, however, is what you print is plastic. it's not very light and not very strong, and worse, it's usually quite brittle- so the design has to take this into account.
of course, there's the price issue, but I'm lucky to have quite free access to a printer, so for me, that's not a consideration.

i started small and first designed a small free-flight glider and then a rubber powered one. they seemed to almost work (a little on the heavy side) but they always crashed beyond repair before i could trim them properly. the conclusion was that it's probably safer to build a radio controlled plane- it's a more complicated build, but much easier to trim before it crashes (for me at least) and if it's powered, weight is less of an issue.
i usually fly F3A and 3D, and that's what i really wanted to build, but thanks to some good advice, i thought building a flying wing will present less design and strength issues.
so for practice, i built a small Mugi style glider. it flew OK, but mostly it was easy to design, and relatively crash proof.

very interesting

so now for the real build:
i'm not a mechanical engineer, so i don't now solid really well- i learned as i went along. i also don't have experience designing airplanes and no experience flying flying wings. all this means that it could have probably been done a lot better.

i used the general dimensions from the FFF simple wing and the MH45 profile and completed the design with what looked right. i designed a 2deg wingtip washout- after reading some more, it should probably should have been over 5deg, but it seemed strange to me to warp the wing's shape so much, so i left it as it is.
to fit into the printing tray of the printer and to save printing time, i designed the wing in several parts- left and right halves, each of them in two parts.

i used the abilities of the software to calculate the expected weight of the design, which after some calibration came out as about 300gr empty weight, and added the motor and battery to the model in order to verify that the CoG will be in the expected place.

i want the wing to be relatively slow so i ordered a 1400kv, 30g motor. i intend to use a 8X4 or 7X5 prop and a 1000mAh battery.

i hope to print it over the weekend, and the parts are expected to arrive next week, so i hope to be able to get it in the air pretty soon.

what do you think- do i have a chance to get it in the air and land in one piece?

wow that pretty awesome, keep us updated, would love to see how it turns out.

Looks SWeet your plastic should be your templets to hotwire cut your very own EPP foam wingcores. Or have them cut 4 u. Very Strong stuff hope this helps.


Dave

get on a simulator if you have one. if you have never flown a wing before, they are a bit different. I would hate to see this end in disaster...

the simulator is a great idea. i have "Reflex" and i used it when moving from trainer to aerobatic and when learning 3D maneuvers, i just didn't think of it in this context.

I've had some other ideas to use the printer- such as for templates for cutting foam or for covering with composites, but i think printing something that will fly without much modification is cooler- so that's what I'm going for here.

Shai

Originally Posted by sqrt18

I've had some other ideas to use the printer- such as for templates for cutting foam or for covering with composites, but i think printing something that will fly without much modification is cooler- so that's what I'm going for here.

It's a more pure use of the new technology and more interesting because of it.

I do think using the 3d printer to cut templates to cut foam would result in a better performing (at least when it hits the ground) model but i can see why you don't want to go down that route.

3D printing is an exciting new technology - the limits on the materials that can be printed aren't going to remain for long. At the moment the choice is pretty much plastic or icing sugar though isn't it?

Originally Posted by teslahed

3D printing is an exciting new technology - the limits on the materials that can be printed aren't going to remain for long. At the moment the choice is pretty much plastic or icing sugar though isn't it?

that's exactly that- it's new and exciting. and the current limits on materials only make the challenge more interesting. just 2 years ago, i would not have tried it, but today i have access to materials that start to feel a little more like real plastic and don't break with every little knock.

most of the 3D printing market today is indeed fragile plastics and condiments, but there are even today printers that can print fiber reinforced plastics and even (with laser sintering) metals. I'm also quite sure there's someone out there printing ceramics.

the parts should be printing as I write, so I'm crossing my fingers everything comes out as i planned.

shai

well, i got all the parts printed.
it wasn't easy- over the weekend, one printer didn't print at all and another stopped in the middle of printing. after handling the smaller parts that were printed properly, i felt the material i chose was too flexible and the structure would flex too much. so i left some parts like this, but i printed the components of the main wing from a stiffer, but more brittle, material.

it looks OK to me now, almost everything fits (just a little sanding here and there), it feels strong enough, and the weight is about as planned- 240g for the frame.

after some tests on leftover parts, i found i may have another problem- the material is not very temperature resistant, so when i try to shrink the covering film, the heat deform the part. i can get a loose covering, or a crooked part, but not a properly covered, straight part.
i don't know where i can get reasonably quickly low temperature covering film, so i'm considering using a shrink wrap (like i did on my printed small gliders) or maybe an adhesive tape. we'll see.

for now i'll start assembling and gluing everything

glued everything together. it feels strong enough, but not straight enough. after joining the center and edge of the wing you can see the curve of the leading and trailing edges to not run smoothly form one part to the other. this is probably due to some deformation of the parts during the printing process. it's hard to show this in a photograph, and i hope it won't effect the flight characteristics too much.

finally, i covered it with clear adhesive tape which i shrunk just a little bit by heat from a cosmetic hot air blower. the colored trim is partly self adhesive and partly shrink-covering i ironed on at a low heat setting. the doubly curved surface of the canopy is to complex for covering with adhesive tape so here i used food shrink wrap.

getting all the equipment in took a little more sanding and fitting, but now it's all done and everything is working as planned.

well, the big day finally arrived. packed my wife and my camera and went to the flying field.

i planned on using a 1000mAh battery, but according to my markings, it did not bring the CG forward enough, so i decided to use a 1600mAh battery to bring the CG forward enough and hope it will not be too heavy.

i had quite a bit of trouble with the launch, i couldn't get it to power up and gain some speed before it reached the ground. i also noticed it had a hard time keeping the nose up, so i switched back to the smaller battery and it seemed to improve the diving tendencies, but i still did not manage a good launch. all this crashing caused a little damage to the front of the battery compartment from the battery sliding forward, but otherwise everything seemed to stay structurally sound. the color trimming, however, was starting to peel- apparently i used too low a temperature when ironing.

in the end my wife left the camera and launched the plane for me. after 2 tries we finally got it and the wing was truly airborne. then she had to rush back and pick up the camera, and this explains the rather shaky video.

i had to trim the controls quite a bit to get it to fly level, but then it was just great. it could putter along on a few clicks of throttle, and power up and go nearly vertical. i manged to do a roll and a loop and a little inverted flight, but then, maybe a little because a piece of the trimming started coming loose and adding drag, and maybe because i was being too cocky and flying inverted, i crashed.

3d printed flying wing- maiden and crash (1 min 41 sec)

when flying, the wing felt light and powerful, so that makes it harder for me to understand why it was so hard to launch.
any tips about launching technique would be appreciated.

Pretty cool! I would think that launching it with a small bungee would be much safer.

Brian

i see i'm not the only one testing this technique for producing RC planes:
sintered_aircraft

they have a better launcher, that's for sure.