ฺBasic knowledge and common problems of micro heli
09-27-2003 | 10:51 PM
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From: TakTak, THAILAND
ฺBasic knowledge and common problems of micro heli
There are 2 kinds of E micro heli
1) Using mechanical tail rotor(like big glow and E heli) eg. MS Hornet
this type is look more alike the real heli but the weak point is you have to have more skill in construction from the kit and when repairing and the for the one who could not master well in flying heli the mechanical tail rotor easier broke when compare with the second type(not suitable for beginner),
2) Using motor for tail rotor eg. Hummingbird(the same as Dragonfly sold in Asia), Skylark(Aerohawk is a derivative of it), Piccolo
both 1) and 2) have the fix pitch version and collective pitch version(can do the aerobatic) and they both need gyro(the piezo small one)
this type is the innovation in our hobby the principle is it use main motor(280 type use 2-3 Amps)and the small tail rotor motor for torque compensation. So it need 2 ESC(electronic speed control) one for main motor and the other for tail rotor which have to use 2 ch of radio control(throttle and rudder). Because when the main rotor increase speed it cause more torque so it needs mixing system to make the ESC of tail rotor speed up. Most model in the market built the 2 ESC and mixer in the same board some add the receiver in one single board.
the important characteristics you have to consider
1. the motor power(280 type) is marginal for lifting. It means if anything doesn't go well it can not fly. and the Amps needed to fly is more than the maximum efficiency of the motor so after a period of time(some very short)the brush will burn out also occur to the tail rotor. Can you simply change to the more power motor and the problem gone. No. not easy like that
2. the control board has limitation of capacity. The bad behavior might occur quite frequently is "the great Amps always kill the less Amps" we all know that if there is any unbalance between the main rotor speed and tail rotor speed yaw control will not be done. From the problem in 1. if you change the main motor to the more power(speed 300 or 370 type) the more Amps feed to main motor compare with tail rotor and it will kill Amps feed to tail rotor especially when the throttle is up or the battery is almost run-out. On the way round if you change the tail rotor motor to get much more Amps so the main motor can not maintain it speed the result is no fly. The higher power motor(if it is brush type should be something higher than 280 but less than 300 or use the brushless one which you have to modify to have the separated ESC and mix system because no E board for it now)
3. As the power is marginal so the battery used to feed enough Amps for both main and tail motor is important. If it is not suitable there is no fly. (it really Amp-H can release, it weight, type of batt, cherger and charging process etc.)
4. Because it is micro heli so weight is very critical. Try to save weigth as much as you can
5. Balance for 1)the spinning rotor and fly bar( if you do it carefully it will be OK. I didn't find much problem in this point) 2)the CG.because it long tail but short nose so the weight of the tail motor will effect the CG., weight and position of the battery also
6. I try cutting the main balde and tail rotor blade to fly the best one after spend some the best one is not to cut it( changin the gear ratio instead)
7. If you prepare all things properly this micro heli would fly easily. it is stable in hovering(so you can fly in a very small room) and flying around in easily controlled.
1) Using mechanical tail rotor(like big glow and E heli) eg. MS Hornet
this type is look more alike the real heli but the weak point is you have to have more skill in construction from the kit and when repairing and the for the one who could not master well in flying heli the mechanical tail rotor easier broke when compare with the second type(not suitable for beginner),
2) Using motor for tail rotor eg. Hummingbird(the same as Dragonfly sold in Asia), Skylark(Aerohawk is a derivative of it), Piccolo
both 1) and 2) have the fix pitch version and collective pitch version(can do the aerobatic) and they both need gyro(the piezo small one)
this type is the innovation in our hobby the principle is it use main motor(280 type use 2-3 Amps)and the small tail rotor motor for torque compensation. So it need 2 ESC(electronic speed control) one for main motor and the other for tail rotor which have to use 2 ch of radio control(throttle and rudder). Because when the main rotor increase speed it cause more torque so it needs mixing system to make the ESC of tail rotor speed up. Most model in the market built the 2 ESC and mixer in the same board some add the receiver in one single board.
the important characteristics you have to consider
1. the motor power(280 type) is marginal for lifting. It means if anything doesn't go well it can not fly. and the Amps needed to fly is more than the maximum efficiency of the motor so after a period of time(some very short)the brush will burn out also occur to the tail rotor. Can you simply change to the more power motor and the problem gone. No. not easy like that
2. the control board has limitation of capacity. The bad behavior might occur quite frequently is "the great Amps always kill the less Amps" we all know that if there is any unbalance between the main rotor speed and tail rotor speed yaw control will not be done. From the problem in 1. if you change the main motor to the more power(speed 300 or 370 type) the more Amps feed to main motor compare with tail rotor and it will kill Amps feed to tail rotor especially when the throttle is up or the battery is almost run-out. On the way round if you change the tail rotor motor to get much more Amps so the main motor can not maintain it speed the result is no fly. The higher power motor(if it is brush type should be something higher than 280 but less than 300 or use the brushless one which you have to modify to have the separated ESC and mix system because no E board for it now)
3. As the power is marginal so the battery used to feed enough Amps for both main and tail motor is important. If it is not suitable there is no fly. (it really Amp-H can release, it weight, type of batt, cherger and charging process etc.)
4. Because it is micro heli so weight is very critical. Try to save weigth as much as you can
5. Balance for 1)the spinning rotor and fly bar( if you do it carefully it will be OK. I didn't find much problem in this point) 2)the CG.because it long tail but short nose so the weight of the tail motor will effect the CG., weight and position of the battery also
6. I try cutting the main balde and tail rotor blade to fly the best one after spend some the best one is not to cut it( changin the gear ratio instead)
7. If you prepare all things properly this micro heli would fly easily. it is stable in hovering(so you can fly in a very small room) and flying around in easily controlled.
