RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

I am confused...


Old 07-23-2003, 03:45 AM
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Default I am confused...

After my first plane, T-hawk, not working anymore (bad crystal after crashing), I am going to build my first RC plane kit.

I ordered
Hitec Laser 4 4ch FM 2/55/Feather
(Feather 4 channel micro receiver, Two (2) HS-55 Micro Servos)


GWS Pico F

both items from greathobbies.com

and planning to use T-hawk ESC, and indoor cordless phone battery for now.

1. I have soldering skill, connecting should be no problem for now, but all those parts work with each others, right?
(can someone post a link for those JST, etc connectors pictures, so I know the right male w/ the right female ;-) for later upgrade.)

2. Pico need 7.2 V, and max voltage for HS-55 is 6.0V, so what should be the voltage for the battery??

3. I think I will go with Lithium Polymer later, 3.7 x 2 is 7.4v, it should be okay for the IPS (7.2v), but how about the Servos (again 6.0v max)??

4. I am planning to buy Li and charger from zebrahobby.ca, to save some s+h, I may get an extra Rx and ESC, will one should I get? (IFO 3, GWS e-starter/beaver, A-10)
Plantraco DSP4-SC 4-Channel 72 MHz FM Receiver w/ Built-in ESC including Crystal, any good?
Do I need a special ESC for Li-ion to aviod below 2.0v/cell??

5. Never change the length of the Rx antenna, right?? But why is so many aftermarket Rx antenna??

6. Which parts are okay for mix-and-match brand name? Tx, Rx, ESC, Servos. Futaba and Hitec are both negative, so they are ok?? How about the connector, J type ?? I am a bit confused.

I am using this Hitec Laser 4 for now, and plan to upgrade to Futaba 9Cap in a year or two, when I am buying new Rx, ESC, servos for both Tx, what should I looking for?


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Old 07-23-2003, 10:24 PM
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Default I am confused...

1. all those components should be happy together. Just check the amp rating on the T-Hawk's ESC against what the Pico Stick recommends.

2. Use a 7.2v pack then. ECS have what's called Battery Eliminator Circuitry (BEC). It sends a constant 5 volts to your reciever reguardless of your pack's voltage.

3. Li-Polys should do great on that. A 2 cell (7.2v and it will peak at 8.4), should do nicely.

4. A good 15-20A ESC should do for all those diffrent applications.
Also, check out GWS's recievers.I have one in my Edge 540, it weighs 8 grams and I'm completely satisfied with it. YOu shouldn't need a special ESC just because you're running Li-Polys. Your ESC should cut power before you get to even 5 volts (5/2=2.5 per cell).

5. The aftermarket ones are specially designed to be used with a shortened antenna and you do lose a little bit of range (usually under 15%). They're mostly to lighten the aircraft and/or hide an ungly antenna.

6. All servo will work with any radio system. Servo connectors differ slightly but you can easilly modify them with a #11 X-Acto. HOWEVER, a Tx of JR or Airtronics won't work with a Rx of HiTec of Futaba (or vise versa). JR And Airtronics are Positive Shift. HiTEc and Futaba are negative (except for the HiTEc Eclipse which is selectable). HiTec also makes shift-selectable recievers hat can be used with any make of transmitter.

The 9C is a good radio. When buying recievers, make sure that they're the rigth shift for your 9C (negative).
Always make sure that your ESC's CONTINUOUS CURRENT rating is eaqual to or greater then what your motor requires.
Always make sure your servos have enough torque for the application you're using them for. For park flyers, the HS-55 should be all you ever need.

Hope my long-windedness has been at least partially useful.
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Old 07-24-2003, 05:23 AM
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Default I am confused...

The BEC in an ESC only works if the voltage is above 5volts (Usually at least 1-2 volts OVER the regulated value is required to maintain proper voltage regulation, any less than that and the output becomes Dependant on battery voltage) Don't forget to have a voltage cutoff device if you're going to use li-poly's on an electric. If li-poly's are deep-discharged it will ruin the pack. Li-poly's will also not hold up to their rated capacity value's if they're discharged too fast (Anything over 2C and you start losing charge efficiency so it wastes a lot of energy as heat) Heat also destroy's them fast. Most lipoly's now days have built in thermistors in series with their anode/cathode that prevents the packs from overheating to the point of melting, burning, or otherwise toasting the cell, by causing the voltage to drop when the pack gets warm, so a heat sink is suggested on the pack. All that said, if you use em right they'll increase your flight time because of capacity, and increase performance because they're so much lighter.
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