Sunday, August 29, 2010

Connector Mania: JST-XH

The small connector on most batteries is called  a JST-XH and is used for balancing.  A 2S pack will have a 3-wire connector, a 3S pack will have a 4-wire connector, etc.

Two adjacent wires will connect to one cell.  The first and last wires will be connected through all the cells.

Batteries can be charged through this connector up to a current of 3A.

The crimper seems to be $480 (!!?!?!??)  Some possible replacements are mentioned here.  Magic search keyword seems to be "D-SUB/DOUBLE-D SERVICE TOOL".

Connector Mania: T Connectors, aka Deans Ultra

T Plugs: generic Deans Ultra Connectors
  • popular 'Battery to ESC' connector
  • male plug is soldered to the ESC
  • get the polarity right
  • sometimes tight fit, lube with graphite
  • put shrink tube on before soldering
  • plug M/F together before soldering
  • polarity: while flat on table: vertical bar is positive, horizontal bar is negative

Connector-related youtubage: 

Wednesday, August 25, 2010

Things I'd like to try: Parrot AR.Drone

"The Flying Video Game"  Intuitive Piloting.

Flying Hobby has it here.
Imagine you are the pilot of an aircraft that flies like a dragonfly, and with an on-board video camera, you see exactly what the pilot sees. By tilting your iPhone you control the AR.Drone, and by releasing it, the Drone is instantly stabilized.

The AR.Drone is the result of a high tech development: the quadricopter, a helicopter that is extremely easy to fly. It is controlled by means of micromechanical accelerometers, gyros, ultrasonic sensor, two video cameras, combined with a powerful embedded Linux platform. All of these
technologies have been combined for the first time by Parrot’s engineers to create the first fully-integrated Augmented Reality device: the Parrot AR.Drone.
Controlled by iPhone.  There's a development SDK and related web site.

Arducopter project on google code
We're pleased to announce that we've joined forces with the other Arduino-based powerhouse in the aerial robotics world, the AeroQuad quadcopter team, to extend the ArduPilot platform to whirlybirds of all kinds. The project will use the ArduPilotMega and IMU shield hardware along with a low-cost custom platform that will be available commercially to provide a full quad UAV with both stabilization and GPS waypoint navigation. It builds on the awesome work of Jose Julio in ArduPilot quad development, with the excellent full-systems integration of the AeroQuad team. We expect that first code and hardware will be available this summer.

Arducopter dev team member kinderkram's RCGroups blog.

Monday, August 23, 2010

Vendor: RCTiger Motor

RCTiger has a really small motor and some other interesting products.
US Vendor here, $84, eta mid-september.

Vendor video here. Customer video here. RCGroups thread.

ESC with data recording capability

Phoenix Ice from Castle Creations.

Data Logging
Ice brings another incredibly useful feature, extensive data logging capabilities. The controllers are able to measure and record many parameters at sample rates that you choose between 10 samples per second and 1 sample per second. Data points include:
  • Battery Voltage
  • Battery Ripple
  • Battery Current
  • Controller Temperature
  • Controller Input Throttle
  • Controller Motor Power Output
  • Motor RPM
This data is stored directly in the controller and may be accessed once the run is over using the Castle Link USB adapter (sold separately) and Castle Link software (available free at The Max Log Size is 21,504 bytes, everything takes one byte except for motor rpm which takes two.
  • Logging 'Battery Current' at only a 1 sample / second - 358 minutes of logging time (almost 6 hrs)
  • Logging 'Motor RPM' at only 1 sample / second - 179 minutes of logging time
  • Logging everything at only 1 sample / second - 44 minutes of logging time
  • Logging everything at 10 samples / second - 4 minutes and 28 seconds

Porco Rosso was a manga!

And in other Porco Rosso news, Miyazaki originally drew Porco Rosso as The Age of the Flying Boat.
"Hayao Miyazaki wrote and painted The Age of the Flying Boat in 1989 for Model Grafx Magazine in Japan.  This story was later evolved and expanded into Studio Ghibli's 1992 movie, Porco Rosso.  In 1993, Animerica Magazine scored an impressive scoop: an English translation, released in three monthly installments, as part of their extensive coverage of Porco Rosso and all things Miyazaki".

Story here, and all parts posted online here.  Beautiful!

Porco Rosso to fly again!

Possibly. Story here.  Quoting Miyazaki:
"So I want to escape to "Porco Rosso: The Last Sortie". I have all its materials." "It should be interesting." "It is set for Spanish Civil War."
"If next two films succeed and Suzuki-san lets me make it (Porco) while saying, 'It cannot be helped because it's a hobby of the old man', I'm happy. It's my hobby."
If you have any interest in planes at all, you owe it to yourself to see this heart-breakingly great movie.

All about wattmeters

By all reports, the HobbyKing X1 Wattmeter is a nice box.  It looks to be a rebranded AEO-RC P1, which has a really nice in-depth review and writeup on RCGroups, including a lot of detail on the actual electronics.

A better manual for another product, that has some nice electrical theory: fillin...

Two Chinese Manufacturers

Aero Electronics. Lots of nifty electronics, including fpv.  It looks like a lot of vendors source their things through here.  Their programming card is awesome, just a PCB waiting for a cover.

Maytech.  Check out the ESC programming tools.

Note on reprogramming ESC's for tricopter

Msg 4 by Les Newell in this aeroquad thread:

These were HobbyKing Super Simple card programmable ESCs, not Turnigy Plush. They are virtually identical to the Towerpro 18A.
I don't think I2C is really needed. PWM can easily go up to 400Hz which is plenty fast enough.
This thread has a vast amount of Tricopter info. Tricopters use three motors for roll/pitch and rotate one motor for yaw. Stabilization can be done with one standard heli gyro per motor plus one for yaw. You use helicopter CCPM mixing to generate the correct throttle signals. This approach has a few drawbacks so I would like to have a go at doing all of the signal processing on-board.

And some notes on RCGroups.

Sunday, August 22, 2010

Improving connectivty of T Connectors (Deans clones)

From a DX discussion group:

If you push hard enough on the soldering side of the tabs, they should pop right out!   I did that on mine, and the contact resistance is indeed lower. 
If you look at the original (compatible) plugs, you'll see that they mate using the flat part of the metal. (One side is flatter than the other).

These mate with the almost-flat, slightly round side of the metal parts. We modified the DX connectors by reversing the metal parts so that mating happens with the flattest possible part of the metal.

I measured the contact resistance:

Original expensive: 0.4 mOhm.
DX replacements: 5.2 mOhm.
DX replacements, modified: 0.5 mOhm.

With these values, I would recommend: Max 50A for original, Max 15A for unmodified DX connectors, and Max 45A for modified DX version.

Saturday, August 21, 2010

Ingenious Landing Gear

A brilliant solution by Leadfeather at WM Park Fliers.  Follow the link for full directions.

Reselling Hobby King Assan Micro Linear Servos

RC Connectors resells Assan:
Assan Micro Linear Servo 2.1g (Left) from HobbyKing
Completely stock/NIB servo as sold here:
HobbyKing Product Here
All I've done is taken it out of the package and fully tested it for you!
This servo has no service/warranty at all

Vendor: RC Connectors

Specializing in small connectors and accessories, as for a Vapor and 1S batteries.

Wednesday, August 18, 2010

Power Guidelines

Courtesy of PhilipA on RCGroups:
  • 50 watts/lb: Minimum required for flight.
  • 70-90 watts/lb: Trainer and slow flying aerobatic models.
  • 90-110 watts/lb: Sport aerobatic and fast flying scale models.
  •  110-130 watts/lb: advanced aerobatic and high speed models
He notes:
  • 80-100w/lb nice target for many planes.
  • The Blue Wonder maxes out around 85 watts on a 3S lipo and GWS 9x5HD (straight blade) prop. 
  • Sufficient for up to a 16oz AUW plane with decent performance including a 4ch aileron version.

Things I'd like to try: The Tuffy

Tony's version of a nearly indestructable trainer.

Power is a TP 2408-21 which is a BP-21 clone with a 1060 prop and 1100 mah 2s lipo.

Variable Pitch prop system

The V-Pitch:
Revolutionary variable pitch prop system allows for midair reverse-thrust -- making "stop-and-start" direction-changing maneuvers an exciting reality for experienced flat foam pilots!

Sunday, August 15, 2010

Changing an Outrunner Motor Shaft

Abridged from HeadsUp RC:
  1. Remove firewall mount. Requires 1.5mm allen wrench (12 cents at Ace Hardware!). Sometimes can be quite difficult to remove.
  2. Remove C-clip and washer at rear of the motor that retains the shaft. Removing washer can be most difficult part, as it tends to hang in C-clip groove.
  3. Pull motor bell off of stator. (motor bell = outer part with the magnets, stator = inner part with windings). Do this by grasping motor tube with a pliers where the firewall mount was located, and pull on the motor bell with your fingers. There will be resistance from the magnets.
  4. Remove flange from the motor bell by removing 10mm retaining nut on inside of motor bell. (May be asier to remove nut if shaft removed from the flange first. Loosen two set screws on front of motor bell, then drive shaft out of flange with hammer and small punch.)
  5. Insert the new shaft with flange, and secure with nut on inside of motor.
  6. Reinstall stator, washer and C-clip.

Saturday, August 14, 2010

Things I'd like to try: The NutBall

The famous NutBall, from the RCGroups page:
It's what you get when you combine a Pizza Box Flyer with a Smart Dart, the best of both. It's round and it flies like crazy, hence the name.

It can be setup for flying from mild to wild. It's an easy quick build, so any repairs are a breeze. There's no nose or tail to break off and the wing can't fold. As a trainer it can fly slower than slow, super stable and no bad habits. Turn up the volumn for advanced flying or silly fun. It flies almost as if has ailerons......rolls, loops, snaps and spins both way, flies inverted (but, not it's forte unless you drop the dihedral), prop hanges like a full blown 3D machine and has no pitch problems at high speed.

Heads Up RC Brushless Motor Guide

Heads Up RC has a great guide to brushless motors.

Adding a 1S lipo to a KeyCam

Quick YouTube video showing how to replace a KeyCam battery with the small E-Flight style battery.

Friday, August 13, 2010

Things I'd like to try: The Cheap and Easy

Most succinct intro ever, for the Cheap and Easy:
  • one piece dollar store foam board.
  • RET
  • Blue Wonder equivalant motor
  • 3cell 500 mah

Thursday, August 12, 2010

The legendary Blue Wonder motor

New, improved, and red:
Turnigy 2730 Brushless Motor 1300kv

  • Dimension: 32mm x 27mm, 43mm(with shaft)
  • Weight: 28g (not including connectors)
    Diameter of shaft: 3.1mm 
  • Voltage: 2~3S
  • Max current: 3.5~7.5A/20S
  • Propeller: 7x3.5~9x4.7
  • Pull: 250~470g
  • For small parkflyer and gliders.

Monday, August 9, 2010

Kline-Fogelman airfoil thread

Here's the official RCGroups discussion thread for the Kline-Fogelman airfoil.  With contributions by Dick Kline!

Things I'd like to try: Polaris Seaplane Parkflyer

A beautiful plane that takes off from water or grass.
[...]top speed is in excess of 70 mph, yet the model slows down well and can plop down into the water at high alpha under full control at less than 10 mph. This allows the model to be flown in very tight spaces if desired, or if you have a bigger flying site you can open it up and enjoy the speed. It handles wind and waves remarkably well, too. This model also flies very well off of grass—takeoffs require only 10-20 feet and it can even do easy touch and goes off grass.

Detailed review here.

Things I'd like to try: Gym-Blu

A simple indoor stick plane by Gene Bond.  And Dome-Blu, a blown-up version.

Vendor: Radical RC
  • $3 shipping
  • lots of cables, tons of great construction pieces.
  • awesome attitude - read the FAQ

TxDuino -- controlling a Futaba transmitter via PC

Controlling a transmitter via PC.

PC -> USB -> Arduino -> PPM -> Futaba module -> receiver.
The TxDuino project aims to create a single device that allows a PC to control an RC vehicle. At the time of starting this project, the only option for doing this was a device from here that could be plugged into the trainer port of a transmitter. An arduino has been used to achieve this same setup as described here. Going through the handheld transmitter, however, is a huge hassle for a number of reasons so I set out to create a simple single device that could accomplish this. As it turns out, so did the guys at Tom’s RC, their solution being this guy here. Anyway, since the work is done, I’ll share the results.

Stick movement and Control Surfaces

Because I seem to live in backwards-universe, here's what the sticks do.  Thanks to the NASA Aeronautics guide for the images.

  • stick back, elevator up
  • stick forward, elevator down
  • stick left, rudder to left
  • stick right, rudder to port
  • stick left: left aileron up, right aileron down
  • stick right; left aileron down, right aileron up

Saturday, August 7, 2010

Wednesday, August 4, 2010

Atrium Measurements

width: 63'
height to top of horiz beams: 32'
south bridge: 20' 8" to walkway, 24' 2" to railing
north bridge: 16' 9" to walkway, 20' 3" to railing
length, bridge to bridge: 143'

Monday, August 2, 2010

Things I'd like to try: Polaris Seaplane Parkflyer

This is a really sweet plane... check out the video taking off on snow.  I'll have something to do when shuttling everybody up to Tahoe, and I can fly it over at the little lake near our house!

There's a review thread show it taking off from grass, gravel, and water.

Here's a laser-cut kit.

Things I'd like to try: The Twins

A pair of Cargo Planes over on RCGroups.  Looks like a lot of fun to fly together!

Things I'd like to try: 3.9m Composite UAV

The ideal plane for my UAV HiDef Photo System.  I will tow it around in my Bugatti Veryon:
  • 3.9 meter wingspan
  • composite construction
  • 7kg empty weigh, 40kg AUW, including payload
  • 100cc engine.
  • 7-19 servos (min 10kg torque)
  • $2,999, shipping not included

Leading UAV, and RC model imitations.

AeroVironment are the world-certified Rock Stars of UAV.  Remember the Gossamer Albatross? that's them, and they've been going strong the past 30 years.  Here's a page describing their UAV solutions... this is the real deal, used by the Marines in Afghanistan and by NASA.  More on these later.

Unfortunately, you can't buy them... but there are clones available at reasonable prices (body only, no UAV). Check it out: