Random Question time!

Hi Guys and Girls,

I have recently ordered a 3d printer and I intend to build myself a RC plane, I'll 3d print the structural parts and the custom power circuit boards mysellf. I intend to use a small ducted fan and have other toys installed in the body.

So the question is what should I model? I'd like a military plane with a single engine, with a flat bottom to aid the design of the circuits and battery packs. Any thoughts?

The TSR2 would be cool but the thing is far to long.

This is just a evolving idea at the moment so nothings set in stone.

Kind regards,

RAB

a reply to: RAB

I build mostly balsa planes of my own design. How do the 3d printed plastic parts compare to balsa as far as weight goes?

a reply to: RAB

I own a 3D printer but I do not know how to use it (heritage). But I know a few things about them. One is that you can not just print circuits.

There are different materials, one shatters easy but can be made smooth and it stinks when it is printed. The other is not smooth, can not be made smooth with the fuming chamber but smells sort of like popcorn when it is printed.

I know there are many materials so maybe you just have to find the right one

A flat bottom? C-130.

a reply to: RAB

Get your model's weight in ounces. Then buy a ducted fan system that puts out more thrust than your model weighs. This way when you go vertical with your model it will have enough power to fly straight up.

Also, make sure you buy a speed controller that supports your amp draw. And a lipo battery capable of handling the load. If 15A draw then get a 1500mAh 20c+ type battery. At 15A a 1500mAh pack will give you 6 minutes of flying time which is plenty.

If you need to cut down on the weight of the battery pack you might be able to get away with a 750mAH 30C pack but your flight time will be around 3 minutes.

a reply to: RAB

One more thing. The physics of air does not translate well when scaling down models. Make your vertical and horizontal stabilizers 10% bigger than scale so you have enough control surfaces to compensate for the difference of air physics.

Cool, it's gotta be 54 inches or so wingspan, and a highwing type holds the batteries better

You can catch it by grabbing the wingtip......stalling out just right,

The wing is so fun to complete.....to see it fly

Horten HO-2 flying wing.

B-2 flying wing.

XB-70

Has it ever been done before?

How about a North American F-100 Super Saber? Single engine, large intake, and a relatively wide, flat bottom.

Well, my observation would be you don't have enough 'fan' for your load, unless you go to a (mini) turbine. You don't have the rpms with an electric motor to overcome the changes in airflow. Especially with a flat-body lifting design. 1-2 times the thrust to weight is good for prop planes, but lifting bodies are going to take 10-12 times the weight in thrust.

I assume when you are talking about "flat bottom", you are referring to a 'lifting body", correct?

BTW...they're not really "flat" (not as far as the airstream goes.)

ETA - A Hi-bypass fan works on a different principle. The turbine creates a lot of momentum which the fan eats up to bypass the turbojet and provide forward thrust. Ever heard that low 'groaning' noise when one of the Rolls Royce engines start up on an Airbus?? That's the transition between the jet and the fan taking over. That kind of power is reserved for some turbine type engines.

a reply to: RAB

Do something original.
You can either design in CAD or purchase Bi-plane plans.

Or if your feeling fired up build a F117 Stealth.

Spitfires are cool also.

SHARC