Flying Planes With Squirrel Cages

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.

squirrel-cage-fan-wideThe 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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RC Mini Flame Thrower Brings the Burn

It goes without saying that a radio controlled mini flame thrower can be nothing but a bad idea and you should never, ever build one. But once you watch the video below, you’ll be tempted to try. But don’t do it – you’ve been warned.

That said, the video below shows that [Make-log]’s remarkably compact build is chock full of safety interlocks and sports a thoughtful and informative user interface. It’s fueled by a small can of spray deodorant whose valve is actuated by a servo and ignited by a spark-gap igniter. Alas, this final critical component is no longer available from SparkFun, so if you choose to roll your own – which you shouldn’t – you’ll need to find a substitute.

We’ve featured an unreasonable number of flame thrower projects before, including a ton of wristmounted units. Of course if you’re a musically inclined pyromaniac, you’ll also want to check out this mini Doof Warrior setup too.

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3D Printed Turbofan Features Reverse Thrust

[Harcoreta] has created a 3D printed model of the GE GEnx-1B Turbofan. This is the engine that powers Boeing’s 787 dreamliner. What sets this model apart is that it has a complete working reverse thrust system. A real jet engine would be asking a bit much of 3D printed ABS plastic. This model is more of an Electric Ducted Fan (EDF). An NTM 1400kv 35mm brushless motor hides in the core, cooled by a small impeller.

jet-nakedWhat sets this apart from other jet models is the working reverse thrust system. [Harcoreta] painstakingly modeled the cascade reverse thrust setup on the 787/GEnx-1B combo. He then engineered a way to make it actually work using radio controlled plane components. Two servos drive threaded rods. The rods move the rear engine cowling, exposing the reverse thrust ducts. The servos also drive a complex series of linkages. These linkages actuate cascade vanes which close off the fan exhaust. The air driven by the fan has nowhere to go but out the reverse thrust ducts. [Harcoreta’s] videos do a much better job of explaining how all the parts work together.

The model was printed on an Reprap Prusa I3 at 0.1mm layer height. [Harcoreta] smoothed his prints using acrylic thinner, similar to the acetone vapor method. Unfortunately, [Harcoreta] has only released a few of the design files on rcgroups, but we’re hoping he will drop the whole model. We can’t wait to see a model dreamliner landing just like the big boys!

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Itsy Bitsy Teenie Weenie 3D Printed RC Truck

I think it’s safe to say that almost all of us grew up playing with toy cars. They were cheap, and darn near  indestructible. Some went by the brand name of “Hot Wheels”, and others “Matchbox”. As a kid, you most likely spent many an hour on the floor imagining your “toy” to be a real car – and of course, adding the all important sound effects. Vroom-vroommmmm!

Flash forward to 2015, and see how things have changed. There are several “micro” RC cars and trucks on the market you can buy for about $10, but this is the first micro-sized, DIY, 3D printed, 4×4 truck we’ve seen. And to add to that, it even has a working articulated front end loader.

Coming in at a minute 1/87th scale, this tiny truck and matching controller boasts 6 channels, 4-wheel drive, and a working trailer hitch. In the video after the break, you can see the amazing amount of work that [Mortimer] had to put into this build to get everything to fit in such a small space. Although the video is German, we think it’s fairly easy to see what’s going on. [Mortimer] is sharing the 3D printed files on his Shapeways page if you would like to give this build a go.

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Building A Dead-On-Accurate Model Ford Pickup From Scratch

In a world filled with 3D printed this and CNC machined that, it’s always nice to see someone who still does things the old-fashioned way. [Headquake137] built a radio controlled truck body (YouTube link) from wood and polystyrene using just a saw, a Dremel, a hobby knife, and a lot of patience. This is one of those builds that blurs the lines between scale model and sculpture. There aren’t too many pickup trucks one might call “iconic” but if we were to compile a list, the 6th generation Ford F-series would be on it. [Headquake137’s] model is based on a 1977 F100.

ford-thumb2The build starts with the slab sides of the truck. The basic outline is cut into a piece of lumber which is then split with a handsaw to create a left and a right side. From there, [Headquake137’s] uses a Dremel to carve away anything that doesn’t look like a 1977 F100. He adds pieces of wood for the roof, hood, tailgate, and the rest of the major body panels. Small details like the grille and instrument panel are created with white polystyrene sheet, an easy to cut material often used by train and car modelers.

When the paint starts going on, the model really comes to life. [Headquake137] weathers the model to look like it’s seen a long life on the farm. The final part of the video covers the test drive of the truck, now mounted to a custom chassis. The chassis is designed for trails and rock crawling, so it’s no speed demon, but it sure does look the part riding trails out in the woods!

[Headquake137] managed to condense what must have been a 60 or 70 hour build down to a 14 minute video found below.

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Send In The Drones: Putting Wheels And Wings On The Internet Of Things

Imagine you’re a farmer trying to grow a crop under drought conditions. Up-to-the-minute data on soil moisture can help you to decide where and when to irrigate, which directly affects your crop yield and your bottom line. More sensors would mean more data and a better spatial picture of conditions, but the cost of wired soil sensors would be crippling. Wireless sensors that tap into GSM or some sort of mesh network would be better, but each sensor would still need power, and maintenance costs would quickly mount. But what if you could deploy a vast number of cheap RFID-linked sensors in your fields? And what if an autonomous vehicle could be tasked with the job of polling the sensors and reporting the data? That’s one scenario imagined in a recent scholarly paper about a mobile Internet of Things (PDF link).

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In the paper, authors [Jennifer Wang], [Erik Schluntz], [Brian Otis], and [Travis Deyle] put a commercially available quadcopter and RC car to the hack. Both platforms were fitted with telemetry radios, GPS, and an off-the-shelf RFID tag reader and antenna. For their sensor array, they selected passive UHF RFID tags coupled to a number of different sensors, including a resistance sensor used to measure soil moisture. A ground-control system was developed that allowed both the quad and the car to maneuver to waypoints under GPS guidance to poll sensors and report back.

Beyond agriculture, the possibilities for an IoT based on cheap sensors and autonomous vehicles to poll them are limitless. The authors rightly point out the challenges of building out a commercial system based on these principles, but by starting with COTS components and striving to keep installed costs to a minimum, we think they’ve done a great proof of concept here.

Logging Engine Temperature For RC Models

[Rui] enjoys his remote-controlled helicopter hobby and he was looking for a way to better track the temperature of the helicopter’s engine. According to [Rui], engine temperature can affect the performance of the craft, as well as the longevity and durability of the engine. He ended up building his own temperature logger from scratch.

The data logger runs from a PIC 16F88 microcontroller mounted to a circuit board. The PIC reads temperature data from a LM35 temperature sensor. This device can detect temperatures up to 140 degrees Celsius. The temperature sensor is mounted to the engine using Arctic Alumina Silver paste. The paste acts as a glue, holding the sensor in place. The circuit also contains a Microchip 24LC512 EEPROM separated into four blocks. This allows [Rui] to easily make four separate data recordings. His data logger can record up to 15 minutes of data per memory block at two samples per second.

Three buttons on the circuit allow for control over the memory. One button selects which of the four memory banks are being accessed. A second button changes modes between reading, writing, and erasing. The third button actually starts or stops the reading or writing action. The board contains an RS232 port to read the data onto a computer. The circuit is powered via two AA batteries. Combined, these batteries don’t put out the full 5V required for the circuit. [Rui] included a DC-DC converter in order to boost the voltage up high enough.