A Remote Controlled Air-Plane

December 11, 2017 by Brian Benchoff 37 Comments

The Air Hogs Sky Shark was a free-flying model airplane powered by compressed air. When it was released in the late ’90s, it was a fairly innovative toy featuring a strikingly novel compressed air engine made entirely out of injection molded plastic. Sales of these model planes took off, and landed on the neighbor’s roof, never to be seen again.

A few weeks ago, [Tom Stanton] revisited this novel little air-powered motor by creating his own 3D printed copy. Yes, it worked, and yes, it’s a very impressive 3D print. That build was just on a workbench, though, and to really test this air motor out, [Tom] used it to propel a remote-controlled plane through the air.

The motor used for this experiment is slightly modified from [Tom]’s original air-powered motor. The original motor used a standard 3-blade quadcopter prop, but the flightworthy build is using a much larger prop that swings a lot more air. This, with the addition of a new spring in the motor and a much larger air tank constructed out of plastic bottles results in a motor that’s not very heavy but can still swing a prop for tens of seconds. It’s not much, but it’s something.

The airframe for this experiment was constructed using [Tom]’s 3D printed wing ribs, a carbon fiber boom for the tail, and only rudder and elevator controls. After figuring out some CG issues — the motor doesn’t weigh much, and planes usually have big batteries in the nose — the plane flew remarkably well, albeit for a short amount of time.

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3D Printed Ribs For Not 3D Printed Planes

September 8, 2017 by Brian Benchoff 14 Comments

A few months ago, [Tom] built a few RC planes. The first was completely 3D printed, but the resulting print — and plane — came in a bit overweight, making it a terrible plane. The second plane was a VTOL tilt rotor, using aluminum box section for the wing spar. This plane was a lot of fun to fly, but again, a bit overweight and the airfoil was never quite right.

Obviously, there are improvements to be made in the field of 3D printed aeronautics, and [Tom]’s recent experiments with 3D printed ribs hit it out of the park.

If you’re unfamiliar, a wing spar is a very long member that goes from wingtip to wingtip, or from the fuselage to each wingtip, and effectively supports the entire weight of the plane. The ribs run perpendicular to the spar and provide support for the wing covering, whether it’s aluminum, foam board, or monokote.

For this build, [Tom] is relying on the old standby, a square piece of balsa. The ribs, though, are 3D printed. They’re basically a single-wall vase in the shape of a wing rib, and are attached to the covering (foam board) with Gorilla glue.

Did the 3D printed ribs work? Yes, of course, you can strap a motor to a toaster and get it to fly. What’s interesting here is how good the resulting wing looked. It’s not quite up to the quality of fancy fiberglass wings, but it’s on par with any other foam board construction.

The takeaway, though, is how much lighter this construction was when compared to the completely 3D printed plane. With similar electronics, the plane with the 3D printed ribs weighed in at 312 grams. The completely 3D printed plane was a hefty 468 grams. That’s a lot of weight saved, and that translates into more flying time.

You can check out the build video below.

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KFC Winged Aircraft Actually Flies

April 14, 2017 by Jack Laidlaw 41 Comments

[PeterSripol] has made an RC model airplane but instead of using normal wings he decided to try getting it to fly using some KFC chicken buckets instead. Two KFC buckets in the place of wings were attached to a motor which spins the buckets up to speed. With a little help from the Magnus effect this creates lift.

Many different configurations were tried to get this contraption off the ground. They eventually settled on a dual prop setup, each spinning counter to each other for forward momentum. This helped to negate the gyroscopic effect of the spinning buckets producing the lift. After many failed build-then-fly attempts they finally got it in the air. It works, albeit not to well, but it did fly and was controllable. Perhaps with a few more adjustments and a bit of trial and error someone could build a really unique RC plane using this concept.

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Flying Planes With Squirrel Cages

December 29, 2015 by Brian Benchoff 42 Comments

Fixed wing remote control planes are ridiculously overpowered. Whereas normal, manned fixed wing aircraft need to take into account things like density altitude, angle of attack, and weight limits, most RC aircraft can hover. This insane amount of power means there’s a lot of room for experimentation, especially in new and novel power plants. [Samm Sheperd] had an old squirrel cage fan taken from an electric wall heater and figured one man’s trash was an integral part of another man’s hobby and built a plane around this very unusual fan.

The only part of the squirrel cage fan [Samm] reused was the impeller. Every other part of this power plant was either constructed out of foam board, plywood, or in the case of the brushless motor turning the fan, stolen from the ubiquitous box of junk on every modeller’s workbench.

The design of the plane puts the blower fan directly under the wings, blasting the air backwards underneath the empennage. During testing, [Samm] found this blower pulled around 350W from the battery – exactly what it should draw if a properly sized propeller were attached to the motor. The thrust produced isn’t that great — only about 400g of thrust from an airframe that weights 863g. That’s very underpowered for an RC aircraft, but absurdly powerful for any manned flying machine.

Does the plane work? Of course it does. [Samm] took his plane for a few laps around the neighborhood and found the plane flies excellently. It is horrifically loud, but it is a great example of how much anyone can do with cheap RC planes constructed out of foam.

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3D Printed Plane Flies High

October 6, 2015 by James Hobson 12 Comments

One of our avid readers, [Niklas Melton] loves RC planes. After getting into 3D printing, the next logical step was to start building is own planes… And now he’s done it!

He calls it the Air-Form 1 Micro RC plane, paying homage to the FormLabs resin printer he used. All of the parts except for the electronics were printed using a tough resin. It’s designed to take balsa wood wings into clips he designed into the parts. A 150mAh battery provides the power with a motor that exerts about 54g of thrust — not bad considering the entire thing only weighs 60g! Unfortunately he doesn’t have any video clips of it flying, though he assures us it does indeed fly — if you’re interested in building your own, he’s uploaded all the files to a page on Thingiverse.

As more advanced 3D printers come down in price, like the SLA technology, it becomes possible to design and 3D print even more complex parts. Some of the resins available have now some pretty amazing properties. One of our readers replaced a servo spline gear with one he printed — which works even better than the original!

Move Over Red Bull, Hot Wire Foam Cutter Now Gives You Wings

May 14, 2015 by Rich Bremer 13 Comments

Not many people will argue with flying RC airplanes is super fun. One big bummer is when a crash damages a part beyond repair. Sure, the RC pilot could keep buying replacement parts but doing so will add up after a while. RC plane builder and general guy with a cool name, [HuckinChikn], decided to build a hot wire foam cutter so making replacement wings would be quick and cheap.

The actual hot wire part is nothing special, just some wire pulled taut across a frame and a 24 vdc power supply pumping out current and heating the wire so it melts any foam in its path. The unique part of the build is that one side of the hot wire frame is secured in place and only allowed to pivot about that point. The other side of the frame traces an airfoil-shaped pattern. This setup allows [HuckinChikn] to make tapered wings. The difference between a straight wing and a tapered wing is similar to that of a cylinder and cone.

Check out the video after the break for a quick demonstration how easy it is to make a wing when you have the right tool!

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RC Plane Converted To Autogyro

April 21, 2015 by Rich Bremer 19 Comments

Out in the RC Airplane world, there is a great airframe called the Slow Stick. There is not much going on with this plane as it only has the bare necessities, a motor, wing, tail and a fiberglass tube (hence the ‘stick’ part of Slow Stick) as the fuselage. Yes, and as the name suggests it is slow. Although it’s intent is to be a starter plane for beginners, even experienced pilots like it because it is cheap, easy to repair and fun to modify. [StephanB] is the type of guy who likes to modify things so he set out to convert his Slow Stick to an Autogyro.

An Autogyro can be described as a cross between a plane and a helicopter. Like a plane it has a propeller that provides forward thrust. Unlike a plane, it does not have a wing. To provide lift, there is a large helicopter-like rotor on top of the craft but this rotor is not powered. It only spins when the craft is moving forward. Lift is created when the rotor is spinning, allowing the Autogyro to take off.

[StephanB] started by removing his Slow Stick’s wing. This takes all of 2 seconds and consists of only removing 2 rubber bands. Next he built a frame for the rotor. It was made to fit the wing mounts of the Slow Stick so that it could be quickly converted back to a plane. With a spinning Autogyro rotor, the side that the rotor is traveling in the forward direction creates more lift than the side of the rotor traveling rearward. To compensate for this unequal lift, [StephanB] added a sideways tilting rotor mount. An RC servo is connected to the mount and allows remote control of the rotor to balance out the lift.