Need Help matching servos with my project????
12-07-2009, 08:14 PM
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Need Help matching servos with my project????
Hello folks. i am a newbie so no long life stories before i get to the point so here it is. i have just gotten the urge to build a 1/5 th scale or larger weedwacker monster. i have started with the controller
and receiver that i hope will be fine. it is a JR max multi function am digital proportional radio control system. 4 channel abc & w system. 4 channelservo reverse switch for radio control airplane. it works but what i dont know about is what else i need. i have an old rc10 b4 that has a speed controller and receiver. what i need to know is if i need a speed controller to provide power to my receiver or not. i will also need to know what size or ounce servos i will need to provide fair turning power for the front wheels. i think that i will only need to use three servos rather than four as i will need throttle steering and brakes. please any help would be very useful. one last thing is what type of voltage do i need for the receiver. as previously stated the rc10 b4 works off a 7.2 volt battery and it ran the 4 channel receiver just fine. will 7.2 volts be enough or should i go bigger??.. please elaborate on your past experiences with what a newbie runs into.
and receiver that i hope will be fine. it is a JR max multi function am digital proportional radio control system. 4 channel abc & w system. 4 channelservo reverse switch for radio control airplane. it works but what i dont know about is what else i need. i have an old rc10 b4 that has a speed controller and receiver. what i need to know is if i need a speed controller to provide power to my receiver or not. i will also need to know what size or ounce servos i will need to provide fair turning power for the front wheels. i think that i will only need to use three servos rather than four as i will need throttle steering and brakes. please any help would be very useful. one last thing is what type of voltage do i need for the receiver. as previously stated the rc10 b4 works off a 7.2 volt battery and it ran the 4 channel receiver just fine. will 7.2 volts be enough or should i go bigger??.. please elaborate on your past experiences with what a newbie runs into.
12-07-2009, 10:00 PM
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RE: Need Help matching servos with my project????
I assume you are building a monster truck of some sort?
If the radio system you have ("for radio control plane") operates on the 72 MHz frequency band it is against FCC rules to use it for a surface vehicle. Surface vehicles can use 27 MHz, 49 MHz, 75 MHz, or 2.4 GHz.
I do not know the answer to the voltage questions.
If the radio system you have ("for radio control plane") operates on the 72 MHz frequency band it is against FCC rules to use it for a surface vehicle. Surface vehicles can use 27 MHz, 49 MHz, 75 MHz, or 2.4 GHz.
I do not know the answer to the voltage questions.
12-08-2009, 08:08 AM
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RE: Need Help matching servos with my project????
Great information i would like to vent about how people make rules for everything but i wont. i guess all i need to do is change the crystals????
12-08-2009, 08:45 AM
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RE: Need Help matching servos with my project????
Changing Crystals cannot change from AM to FM or from 72Mhz to 75Mhz. You have to use a different Tx and Rx.
When we fly aircraft on Non 2.4 radios, we have to obtain a Frequency Pin and be careful not to turn on our Tx's without it. Airplanes not only fall out of the sky when they are shot down, but they are a danger to people and property.
People operating RC cars, trucks, and boats can do so just about anywhere, not realizing that RC Aircraft are nearby.
RC Aircraft can be up as high as 1000ft, in the line of sight of Tx's for ground vehicles. RC cars, trucks, and boats are hardly ever in the line of sight of ground vehicle Tx's.
This is why the FCC has separate frequencies for Air and Ground vehicles.
When we all move to 2.4Ghz, it won't be a problem and for the most part, no one can shoot down anyone else. Until then, it is important to follow the FCC rules and use the correct frequencies for the type of vehicle you are operating.
I agree that there are many rules in this world that do not make sense and you wonder who thought them up and why. This frequency rule makes perfect sense.
When we fly aircraft on Non 2.4 radios, we have to obtain a Frequency Pin and be careful not to turn on our Tx's without it. Airplanes not only fall out of the sky when they are shot down, but they are a danger to people and property.
People operating RC cars, trucks, and boats can do so just about anywhere, not realizing that RC Aircraft are nearby.
RC Aircraft can be up as high as 1000ft, in the line of sight of Tx's for ground vehicles. RC cars, trucks, and boats are hardly ever in the line of sight of ground vehicle Tx's.
This is why the FCC has separate frequencies for Air and Ground vehicles.
When we all move to 2.4Ghz, it won't be a problem and for the most part, no one can shoot down anyone else. Until then, it is important to follow the FCC rules and use the correct frequencies for the type of vehicle you are operating.
I agree that there are many rules in this world that do not make sense and you wonder who thought them up and why. This frequency rule makes perfect sense.
12-08-2009, 12:27 PM
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RE: Need Help matching servos with my project????
I looked up the RC10B4 on the Associated web site http://67.199.85.166/ae/b4/b4_home.php and the RTR version shows an ESC as part of the package.
Usually the ESC will send power (at a regulated voltage) to the receiver; and the servos see the same voltage as the receiver.
The only thing that should see full battery voltage is the motor.
I do not know what qualifies as "giant" but RCU has a 'RC Giant Scale Cars' forum http://www.rcuniverse.com/forum/forumid_234/tt.htm
You might be able to get servo recommendations there from someone who has built a big vehicle.
Usually the ESC will send power (at a regulated voltage) to the receiver; and the servos see the same voltage as the receiver.
The only thing that should see full battery voltage is the motor.
I do not know what qualifies as "giant" but RCU has a 'RC Giant Scale Cars' forum http://www.rcuniverse.com/forum/forumid_234/tt.htm
You might be able to get servo recommendations there from someone who has built a big vehicle.
