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Old Dec 18, 2005, 09:15 PM
Registered User
Rowlett, TX
Joined Apr 2003
123 Posts
Cox "Sky Cruiser" FF Conversion

I'm currently working on converting a cox sky cruiser free flight model to RC. I bought this model a while back from wal-mart, and it sat around forever. I just recently started working on it again. I did find a couple pictures in the gallery of one thats been converted, but it looks like he used standard radio gear with micro servos. I was hoping to be able to use a bitcharger radio. I originally wanted to have elevator and rudder control, and use a separate battery for the motor. But recently I have considered using the up/down channel to control motor speed (full throttle, cruise, and low).

Here are the current radio specs:
MotorWorks RX, lengthened antenna, added wires for channels and battery.
Using 2 bitcharger cells (NiCD i think), wired in parallel for 1.5V.

The problem I am currently having is that my actuators have no power. I'm using 36# magnet wire, which i think is too big. The large coil in the photo only yields about 7ohms resistance. Neither coils, or even the pager motor will move the elevator more than a millimeter or so. I figure there are 2 solutions. One, I can give the coil more voltage, and two, i can find smaller magnet wire. I see many people running LiPolys, which are around 3.7V if i'm not mistaken. Can the RX handle 3.7V, or is some kind of voltage regulator needed?
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Old Dec 18, 2005, 09:41 PM
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mharms's Avatar
San Jose, California
Joined Oct 2004
870 Posts
Plane is looking good!

The actuators and the bit motor used as a actuator are way too low in ohms. I'm not sure what your RX can drive, but you probably need around 50 ohms or more. Thinner wire is needed for sure (like below 40 AWG). Check the sticky threads for details.

I don't know what your RX can handle as far as suppy voltage goes. Was it powered by 2 cells (in series) originally or just one? Maybe someone is familiar with your particular bitcar RX and can chime in. Again, there are posts and stickies on bitcar conversions you can search through.

Mark
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Old Dec 18, 2005, 09:59 PM
Registered User
Rowlett, TX
Joined Apr 2003
123 Posts
The RX was originally powered by 1 cell. I am using 2 just to boost the flight time. I thought about wiring in series, but I was afraid of burning up the RX with 3V.
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Old Dec 19, 2005, 01:00 AM
Registered User
California
Joined Dec 2004
162 Posts
You should be able to use 3v on a bitcar rx. I ve done it with a couple of brands of bitcars. How are you hinging the elevator? How do you control direction?
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Old Dec 19, 2005, 10:31 AM
Registered User
Rowlett, TX
Joined Apr 2003
123 Posts
For right now I'm going to use rudder and elevator, but I might switch to rudder/motor control. The rudder is not installed yet, I've been working on the elevator. For testing, I'm just using 2 small pieces of scotch tape as a hinge, but I will probably use cellophane, or something similar.
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Old Dec 20, 2005, 08:20 PM
Registered User
Lake Orion, MI
Joined Jul 2004
91 Posts
GWS Implementation

I did this one using a GWS Pico flight pack, with a GWS 50CX direct drive motor
with a 3 x 3 orange prop. Rudder and Elevator. 250ma 2 cell LIPO. Full
length wire antenna.

A few club members helped me to reinforce the dihedral with carbon fiber top
and bottom.

Flown without landing gear outdoors. Pretty quick. Was fairly controlable
when kept to a pretty slow pace. Too fast and it would snap roll in to the
ground. Theory is that the wing may have had a bit of a twist issue at higher
speeds. Too fast and it tucks under at the front, twisting it right in.

Robyn
SE Michigan
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Old Dec 20, 2005, 10:24 PM
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shschon's Avatar
United States, CA, SF
Joined Aug 2004
2,364 Posts
Quote:
Originally Posted by Robyn_r
I did this one using a GWS Pico flight pack, with a GWS 50CX direct drive motor
with a 3 x 3 orange prop. Rudder and Elevator. 250ma 2 cell LIPO. Full
length wire antenna.

A few club members helped me to reinforce the dihedral with carbon fiber top
and bottom.

Flown without landing gear outdoors. Pretty quick. Was fairly controlable
when kept to a pretty slow pace. Too fast and it would snap roll in to the
ground. Theory is that the wing may have had a bit of a twist issue at higher
speeds. Too fast and it tucks under at the front, twisting it right in.

Robyn
SE Michigan
I did a similar plane, hobbico sky daemon using a J250 and I do not have the wing twist problem. I simply glued bamboo skewer to the wing leading edge and then "glass"ed the wing using packing tape. The wing is rock solid and I can fly it in more than 10 mph gusty wind
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