Wednesday, December 7, 2011

New Crazy Creation! The Dual Motor, Differential Steering RC Airboat Utilizing the Turnigy 9X User Mixes

Finally got around to throwing a video together of my latest creation, the dual motor, differential steering RC airboat!

The Video

Explanation of the Turnigy 9X Mixes to Accomplish Differential Steering

I had to use 3 mixes in order to accomplish the differential steering. First, I had to pick a channel for the other ESC. I used channel 7 and made sure none of the switches controlled channel 7.

User Programmed Mixes

  1. Throttle (Channel 3) -> Channel 7 (Aux)
  2. Rudder (Channel 4) -> Throttle (Channel 3)
  3. Rudder (Channel 4) -> Channel 7 (Aux)

Quick Video of the Mixes


Using differential steering can catch you off guard! Once you set the mixes, if you bump the rudder, one of the motors will turn on! Try not to lose a finger. Also, as the battery drains, you will lose the ability to steer. Don't get caught downriver without a paddle!

Wednesday, November 16, 2011

Complete Guide - Getting into RC Airboats for a complete Newbie

Every time I take 'Das Boot' out and put it in the water, I get people wondering how to get started in the exciting (and relatively cheap) way to get into the world of RC boats. This is a complete guide to acquiring all the components needed to build a cheap airboat.

The Parts of a Cheap Airboat


The first step to building a cheap airboat is picking a cheap motor. Once you have selected the motor, the rest of the boat will fall into place. This may seem like a long list, but most of the small parts come in multi-packs. Once you have a supply of the small parts, all you need are a few main parts and you can build numerous boats.


The motor and prop set up sets the size for the entire boat. To keep the boat small and manageable you want to select a fast spinning motor with a small prop. This generally also helps the boat be fast. A good start is the AX 2306N 2000kv brushless Micro Motor from HobbyKing. HobbyKing rates the motor up to 9A, but it handle more with ease. You always want extra motors. Grab a couple of these.


Next, lets just pick the cheapest ESC that we can find. the Hobbyking SS Series 25-30A ESC is a good choice if it is in stock. Otherwise, the Hobbyking SS Series 15-18A ESC will work. As with the motors, the more ESCs the merrier. These tend to get damaged by water, so grab at least 2 ESCs


Monday, October 17, 2011

The PinPiYak - Home Depot pink foam flying pizza -yak

The Picture

I had a bunch of these hexTronik DT750 Brushless Outrunners sitting around for use in a multi-rotor project I have yet to make a lot of headway on. I decided I wanted to make something that took advantage of the thrust of the motor, had 3D capabilities, and was dirt simple to make.

After searching through RCGroups, I found the PiYak. A circle with elevons and a rudder. Perfect! I grabbed my sheet of pink foam, and threw something together using the proportions given on the rcgroups thread.

The Parts

  1. hexTronik DT750 Brushless Outrunner 750kv
  2. TGY Slow Fly Prop 12*3.8SF w/ shaft adapters
  3. ZIPPY Flightmax 2200mAh 3S1P 20C
  4. HobbyKing 939MG Metal Gear Servo 2.5kg/ 12.5g/ 0.14sec
  5. FlyZone 25amp ESC
  6. Turnigy 9X 2.4GHz 8Ch Receiver (V2)
  7. Hex locknuts M4 10pc

The Results

The plane has plenty of power. I tried to balance the TGY SF 12x3.8 prop, but the thing is grossly out of balance. The motor doesn't seem to care, however, and the plane shoots vertical with ease. The 3S 2200mAh battery lasts too long considering that the recommended battery for the motor is a 1300mAh. However, the larger battery keeps the CG in the right ball park.

I can't wait to put these motors in some multi-rotor configuration!

Saturday, September 10, 2011

Turnigy 9X now sold from USA Warehouse!

Good news! The Turnigy 9X from is now available from the USA warehouse!

Link to Turnigy 9X (USA Warehouse)

This is great news for us United State-ians. Shipping the 9X overseas was costly and slow. Hopefully they keep the stock coming as well as include some of the receivers from the US warehouse.

Tuesday, August 16, 2011

Turnigy 9X Antenna Hack

I finally finished my Turnigy 9X Antenna Hack video! This moves the antenna to the wireless module, making it possible to completely remove the wireless module. The video is a little long, enjoy!


As requested, I'm posting some better closeup pictures of the coax soldering. Hopefully they help.

Yes, it is FREAKING small coax (about 1.2mm diameter). There is a small amount of insulator between the coax soldered down and the trace. The pad on the left of the signal trace is not connected. This is not for the faint of heart. A good soldering iron and a microscope can help.

Friday, July 8, 2011

Turnigy 9X Wireless Module Resistor Fix

I recently posted how to do the Turnigy 9X resistor fix on rcgroups. Somebody pointed out that you could do the fix without opening the radio itself. You could apply the fix to the wireless module on the back of the 9X itself. I felt a little 'hackish' tonight, so I thought I'd give it a try and post a video HowTo.

Friday, June 24, 2011

HobbyKing AX-2306N-2000 motor review

Recently I've been using HobbyKing's AX-2306N-2000 motor in a couple of my projects, so I thought I'd throw together my thoughts about the motor.

Why did I buy the motor in the first place? My friends and I got into scratch foam boats. We discovered that smaller props made life easier. I found the cheapest high Kv motor I could find, which happened to be the AX-2306N-2000. I, then, bought a couple of them. Now, if you haven't seen 'Das Boot vs the world', I suggest you look it up. I've flipped the boat, submerging the motor in water, and the motor shows no sign of damage.

Moving on, I threw the motor in a failed delta wing, and then my scratch built dollar store foam F-22. Now that I have used the motor in 3 different applications, I present my video review.

In the video I flew the motor with the H-KING 10A Fixed Wing Brushless Speed Controller, GWS DD-5043 Prop, and a 20C 800mAh 3S LiPo.

Thoughts about the AX-2306N-2000

The good:

  • Incredible deal. For being the cheapest motor from HobbyKing, it is surprisingly good. The motor is a perfect match for a cheap ESC, cheap-ish batteries, and small .5lb to 1lb planes
  • Medium Small motor, works great with cheap GWS 5043 propellor
  • I think they underestimated the power rating of the motor. I have yet to get the thing warm.
  • Comes with mount, lock nuts, and washers
  • Smooth part of shaft could be used with propsaver or other prop adapter if shaft were cut

The not as good:

  • Motor shaft is long. Really long.
  • Kinda ugly (no sexy blue/red/gold trim)
  • No included connectors
  • Axial play in shaft

The verdict:

Buy a couple! I've gotten a ton of use out of mine. The have survived several wrecks and being submerged in pond water. The AX-2306N-2000 hits a perfect price point for a cheap RC setup.

Thursday, June 9, 2011

Turnigy 9XResistor Fix

**Update Jul 2011** Created a new post and an instructional video on how to do this fix on the wireless module, which is much easier and does not require cracking open the main radio body

A couple months ago I received my Turnigy 9X radio. For the price, I couldn't be happier. When I purchased the transmitter, I expected to be taking it apart and tinkering with it. I happened to drop the radio, almost brand new, breaking off a switch and forcing me to crack it open. While open, I figured I could take care of the resistor fix while the thing was open.

The Resistor Fix

What people refer to as the 'resistor fix' solves the fairly annoying problem that in order to use the training port on the Turnigy 9X, you must unplug the 2.4GHz module. Not usually a problem to unplug a wireless module, but someone decided it would be nice to hardwire the antenna to radio on the 9X. Unplugging the 9X wireless module leaves the wireless module dangling on thin fragile coax.

A Little Theory

The trainer port on the Turnigy 9X contains a switch (that triggers when a plug is inserted into the trainer jack) that powers off the wireless module to ensure the 9X no longer transmits its signal. Normally, when wireless module is powered on, the radio sends a data signal to the wireless module that is between 0V and +3.3V.

Unfortunately, when the 2.4GHz wireless module loses power, the data signal coming from the radio processor is essentially shorted to ground through a high voltage protection diode on the signal pin of the wireless module. The data signal that goes to the wireless module happens to be the same signal routed to the trainer port. Adding a resistor in series with the signal going to the wireless module breaks the short to ground and allows the full voltage signal to reach the trainer port.

Notice, the short to ground only occurs when the 2.4GHz module loses power. When the wireless module receiver power, the data signal behaves like a proper input and maintains high impedance, probably in the 10kOhm and above range. By selecting a resistor much lower in resistance than the input impedance of the wireless module, say 1k, the resistance added by the fix is negligible and does not affect normal operation of the radio.

The Actual Fix

I followed the PDF document found here. I recommend checking out the PDF as well

The 'resistor fix' involves cutting a trace on a PCB inside the transmitter, and soldering a resistor (usually a 1kOhm resistor) in series by bridging the cut trace.

Items needed
  • Philips Screw Driver
  • Xact-O Knife or sharp blade
  • Resistor with value around 1k Ohm
  • Soldering iron

  1. Start by taking off the back of the 9X by removing the 6 screws on the back
  2. Carefully open radio. Manipulating the sides should allow you to be able to lay both sides flat without disconnecting any cables.
  3. Locate the trace for the data signal.
  4. Using the Xact-O knife, cut a small notch in trace and scrape the solder mask (green enamel) off of the trace far enough apart so the resistor bridges the notch and both leads lay on bare copper.

    (Sorry for no action shots!)
  5. Solder both sides of the resistor down to either side of the trace where the solder mask has been scraped off.
  6. Carefully close the radio, redoing the screws in the back
  7. Enjoy not having to unplug the wireless module to use your radio with a sim or trainer!

Wednesday, June 1, 2011

Profile F-22 Obsession

I recently came across a thread on RCGroups for a profile F-22 with a wingspan of 18.8in. Ever since , I knew I had to build one. So I did!

The Video

Attempt #1

Originally I only had Home Depot pink foam to work with, so I threw one together out of pink foam.

The CG ended up being pretty far back due to the weight of the foam. Fortunately I found some foam core poster board at the local dollar store, Dollar Tree. The dollar store foam was much easier to work with, so I threw another one together.

Attempt #2

Here are the two planes side by side

The CG with the dollar store foam came out better this time and the whole plane weighs under 220g or less than .5lbs. Awesome, considering the motor is pumping out just over 100W!

The Guts

Notes on the build

  1. You can probably tell that I used gorilla glue. I live somewhere where summer highs reach 115+. My friend had some hot glue melt in his car in May. My planes often end up sitting in my car for hours, so hot glue was out. The gorilla glue is light and relatively easy to work with.
  2. For the stick mount motor, I had to cut out extra foam where the motor mounts. I attached the stick to the side to allow easy access to the screw that holds the motor on.
  3. My goal for Attempt #2 was speed. Not my finest work, but the plane came out ok. Won't win any style or perfectly straight awards, but the thing still flies.
  4. I will probably add some skids, just in case I want to land on a rough surface.

Parts List

I was unsatisfied with my pink foam delta, so I gutted it and threw the guts into this plane. The parts list is nearly identical.

Friday, May 20, 2011

The Pink Delta

The mission: Create a dirt cheap, uber simple, easy to make airframe that works with cheapo components.

I call it the Pink Delta. The Pink Delta came from a variation of the Mugi Evo.

List of parts


The dimensions of the Pink Delta match the Mugi Evo, except instead of hard to find 2mm coroplast, I used readily abundant 1/2" pink foam insulation from Home Depot.

  1. Cut a corner off of the 4x8' sheet of foam, by measuring 800mm/sqrt(2) = 565mm on both sides from the corner, and cutting across the two marks.
  2. Draw out and cut out the elevons and verticle stabs
  3. Glue on verticle stabs. I tried to angle them out, but they are quite uneven. I think next time they will be 90deg straight up
  4. Bevel elevons with razor and back of main delta section to allow full movement of the elevons once installed
  5. Using packing tape, or 3m tape with nylon fibers, install the elevons
  6. Glue reinforcement onto nose. I used some thin plywood I got from the Home Depot scrap bin
  7. Glue motor mount on. The selected motor is a stick mount, so I used a 3/8" dowel from Home Depot and glued it right down the centerline. I plan on switching the motor around to keep the thrust line at the same level as the airframe to hopefully improve handling
  8. Cut holes for servos, battery, receiver, and whatever else you need.
  9. Mount servos, control horns, and electronics. I had some 2-56 pushrods with ball ends for the elevons. The ball joints work fairly well. Most of the electronics are held down with sticky strips of hook and loop material.
  10. Charge battery and fly!

The Result


I chose not to round the leading edge of the wing to save time due to fear the thing would fly like a rock. It does fly kind of like a rock.  Maybe a light one like pumice.

Flies quite interestingly. The Pink Delta, despite no dihedral, will not flip or roll. The think does not want to go upside down. The controls are overly sensitive, when I get around to it I will add a little expo to th controls.

Some more pictures

Wednesday, May 4, 2011

Some Quadrotor Videos

I came across some videos from my quadrotor senior design class from college. Figured I'd throw them up!

Successful Demonstration Flight

Video one of my teammates took

Some 'Outtakes'

Tuesday, May 3, 2011

Kick off with a 'Boot' (That means 'Boat' in German)

List of parts

Some lessons that I've learned

  1. Keep weight low. The closer to water the less likely your precious creation will end upside-down
  2. A smaller prop keeps the motor lower, and easier to keep the weight low. Select a motor with a higher KV to allow for a smaller prop.
  3. Keep the boat nice and long. This keeps you from creating a water plow.
  4. Waterproof your parts. A little water in the motor won't kill anything, but ESCs are particularly sensitive to moisture. Receivers will tend to rust pretty quickly when wet. A cheap disposable tupperware or even dipping the ESC and receiver in epoxy seem to work.
  5. Components get hot when there is no ventilation and when they are surrounded in foam. Let me know if you figure out a cheap solution to this...
  6. Fasten the battery down. Failure to do so could lead to the boat flipping over in the middle of the pond at the local golf course.

One of my friends built one, too. Hopefully we'll get a video of them racing