ElectricFlight PHOTOGRAPHY: STEW MEYERS
The Dynamic Foamies like this Yak 55 (above) present a problem with the profile wheel pant skid. The glue joint to the carbon rod gear support is vulnerable to rough landings. Note the pant/skid has rotated 90 degrees. The solution is shown on Randy Kleinert’s Dynex 24 (at right). A music wire axle has been glued to the carbon rod to support a real wheel which takes landing loads better.
t our indoor flying sessions, I keep diagnostic equipment in my bat- tery box along with the chargers. Of course a digital volt meter is the prime tool. Mine has a couple of adapters. The one matching the batteries used on ultra micro models is most often used. I check the voltage on my batteries before and after every flight. If the voltage is below 3.7 volts I know I have been flying too long. If the time becomes short, it’s time to replace them. I have the cells numbered and I really ought to keep a log. Li-Pos don’t last forever. Remem- ber, if you leave them fully charged they will lose half their capacity in a year. The AR6400 receiver has a three-pin mo- tor port that can be configured to use the in- tegrated brushed motor ESC or to output a ppm signal to drive an external ESC. In ad- dition to sometimes losing bind, occasionally the receiver toggles the programing of this port. I don’t know why, but it happens. When the throttle channel of an AR6400 seems to malfunction—i.e., the motor doesn’t respond correctly—the first thing to do is check the output of this port. I have a couple of tools to do this.
A
One is a LED with a 330-ohm resistor in one lead. This is plugged into the brushed motor port. If it’s programed for a brushed
motor, the LED will glow proportionally to throttle position. If a pulse width meter is plugged into the port and it has been switched to an ESC output the meter will read the pulse width in milliseconds in re- sponse to the throttle.
The pulse meter also is useful to check on the status of the fifth and sixth channels as well as the reversed aileron channel, all of which are capable of being reprogrammed. This Milli-S-Meter – Digital Pulse Width Meter is available from
www.emsjomar.com. It comes with a standard Berg connector, so I have adapters to mate with the motor and servo ports. These are available from
www.rc-connectors.com.
I refer you to the AR6400 users guide for programing information to get these ports in the desired configuration:
1. Ensure a successful bind was complete. 2. Turn the transmitter on.
3. Move THRO stick to full throttle posi-
tion. 4. Move control sticks to the correspon- ding position to change between the avail- able options. Sticks must be held in this po- sition while the transmitter is on and the receiver is off. [Looping rubber bands around the sticks aids in this.–SM] 5. While holding this position, plug the
battery into the receiver; power on the re- ceiver. [This process is greatly aided if you have a switch between the battery and re- ceiver. It’s much easier to flip the switch than plug in a battery.–SM]
6. The LED on the receiver will go solid and within 5 seconds, the LED will flash 3 times quickly, indicating the option is now changed.
7. Disconnect the battery from receiver. 8. Turn the transmitter off.
Another problem that arises with an AR6400 or Vapor receiver or AS2000 servo is the loss of the retainer on the screw drive shaft of the servo resulting in the servo mal- functioning. This retainer is crimped in place and is not a replacement part. It can be replaced by a 3⁄16 inch length of insulation from #26 wire. After pushing this insulation on the shaft, a drop of medium (not thin) cyano is carefully placed on the end of the shaft. A drop of catalyst is then applied to the cyano to set it before it can migrate to a moving part and gum things up. Flying quadcopters doesn’t turn me on,
but the electronics involved intrigue me. A very inexpensive ($30) Multi-Rotor con- troller is available from HobbyKing. The ca- pabilities of this unit are truly impressive. Here’s something from the brochure: “The
by stew meyers You can reach Stew Meyers at 8304 Whitman Drive, Bethesda, Maryland 20817, or via e-mail at
stew.meyers@
verizon.net
HobbyKings’ KK2.0 Multi-Rotor controller (above left) weighs only 17 grams, but has amazing capabilities for $30. Don Srull’s quadcopter (above center) using the KK2.0 Multi-Rotor controller uses a tail flag to aid in orientation. A
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problem that crops up with ParkZone linear servos is loss of the screw shaft retaining collar. This can be replaced with a length of #26 wire insulation. This has been done on the left servo (above right) on the Vaporreceiver in the photo.
MAY 2013
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