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.