35 replies to this topic

[momentsky]

Is there any way to configure coaxial 3 motors heli?

The scheme is quite simple. Classic coaxial with two motors, no plates at all, and one more tail rotor for the pitch and thus for horizontal movement.

It's in 450-500 class.

[dankers]

Mix Master Mat would be the best guy to ask, I think there should be, I can't imagine anything that stops it but I can't say for sure.

[momentsky]

Ok, I should try to pm him if no responce here.

[dankers]

I think other people will have ideas also, but Mat is really active on the forum so will likely reply.

[kevo]

Am I understanding you correctly ? You want to duplicate the control system on a $20 syma s107 ( toy heli ).

Something like this ??

http://site.rctoyz.c...i-Yellow-02.jpg

Or am I not understanding your description correctly ?

[Mat Wellington]

no problem at all.
so what does the altitude correction, purely based on the self correcting flybar ?

will set up a mix for ya...but.... how is the tail motor for pitch done ? are you going to use a forward/reverse ESC and a Brushed motor ? if so, you could modify a servo to run the tail motor (basically disconnect the wires from the internal motor, run them to the tail motor, and then if we send a 1500 us signal the motor wont run, greater than 1500 it will spin one way , and less than 1500 will spin the other

[Mat Wellington]

kevo, on 30 January 2012 - 02:14 AM, said:

Am I understanding you correctly ? You want to duplicate the control system on a $20 syma s107 ( toy heli ).

Something like this ??

http://site.rctoyz.c...i-Yellow-02.jpg

Or am I not understanding your description correctly ?

yea, but 450 sized, no way a single board syma will controll 2 big brushless motors, and hey, having axis lock on the tail and variable forward/rear pitch has to be a bonus, as well as being RC controlled and not infrared-10ft range inside LED control

[Adverse Effects]

thinking out of the box

you could do the tail so its a little to heavy and it wants to go in reverse all the time it the tail motor is not running
then just make the tail motor run from no thrust tail falls down(fly backwards) to max thrust tail lifts up (fly forwards)

that way you would not need to reverse the motor

Edited by Adverse Effects, 30 January 2012 - 06:56 AM.

[Mat Wellington]

Great idea

[Adverse Effects]

thanks

i like thinking out side the box and fixing things in different ways

[momentsky]

kevo, on 30 January 2012 - 02:14 AM, said:

Am I understanding you correctly ? You want to duplicate the control system on a $20 syma s107 ( toy heli ).

Something like this ??

http://site.rctoyz.c...i-Yellow-02.jpg

Or am I not understanding your description correctly ?

That's right! You have got it.

[dankers]

Should be a cool little project

[D-OCHO]

Adverse Effects, on 30 January 2012 - 06:54 AM, said:

thinking out of the box

you could do the tail so its a little to heavy and it wants to go in reverse all the time it the tail motor is not running
then just make the tail motor run from no thrust tail falls down(fly backwards) to max thrust tail lifts up (fly forwards)

that way you would not need to reverse the motor

Even simpeler.
Take a 450 or a 250 tailrotor place it horizontal.
Add a gyro for the center position.

And use the main motor with a belt or a torque tube to drive it.

[momentsky]

dankers, on 30 January 2012 - 04:25 PM, said:

Should be a cool little project

In success we can add a new preset section in the aircraft setup. Is it usefull? This type of aircrafts is extremely widespreaded.

[momentsky]

Mat Wellington, on 30 January 2012 - 02:18 AM, said:

no problem at all.
so what does the altitude correction, purely based on the self correcting flybar ?

will set up a mix for ya...but.... how is the tail motor for pitch done ? are you going to use a forward/reverse ESC and a Brushed motor ? if so, you could modify a servo to run the tail motor (basically disconnect the wires from the internal motor, run them to the tail motor, and then if we send a 1500 us signal the motor wont run, greater than 1500 it will spin one way , and less than 1500 will spin the other

In the kit config it have 3 motors. 2 on the main rotor and one on the tail rotor. All motors are Brushed. Gyro, RX and ESC are designed in one small block, wich a still not examined.

So I want to replace 2 motors for the main rotor to brushless ones with correspondent ESCs.

Tail rotor... Hmm thats the great problem for now on. As for now i have only brushless motors and brushless ESCs. Wich as I am not mistaken can be reversed only in two ways 1. reprogram the esc 2. switch wires. Nothing of it can be used in the sky.

So the other way is to get the kit main rotor motor and put it to the tail rotor. In this way I should find the way to control it's ESC wich is integreted to the general board. I should check it. If it's possible.

Edited by momentsky, 31 January 2012 - 12:31 AM.

[momentsky]

Adverse Effects, on 30 January 2012 - 06:54 AM, said:

thinking out of the box

you could do the tail so its a little to heavy and it wants to go in reverse all the time it the tail motor is not running
then just make the tail motor run from no thrust tail falls down(fly backwards) to max thrust tail lifts up (fly forwards)

that way you would not need to reverse the motor

cool idea! if there should be no chance to reverse tail motor I should use it! many thanks!

We should also add pitch stabilization.

For example arm the CC in manual mode. The switch to leveling mode. The tail rotor have to accelerate to level up the aircraft. Then we can go on.

[momentsky]

Mat Wellington, on 30 January 2012 - 02:18 AM, said:

will set up a mix for ya...

this mix should get deal with the balane of two motors. Im I right? How it could be done?

[Mat Wellington]

momentsky, on 30 January 2012 - 11:35 PM, said:

Tail rotor... Hmm thats the great problem for now on. As for now i have only brushless motors and brushless ESCs. Wich as I am not mistaken can be reversed only in two ways 1. reprogram the esc 2. switch wires. Nothing of it can be used in the sky.

I think I alluded to the answer to this earlier in a post

Keep the STD tail rotor, get a standard sevo, pull out the control board, disconnect the wires to to servo motor, and solder them to the tail rotor motor. Disconnect the feedback pot on the servo and solder in two 2.2 k resistors, to simulater center position.

Now all we have to do is send a 1500 us signal to make the motor stop. Go above that and the motor will spin on way, below it will spin the other

Mix

Ch1
Type =motor
Throttle = 127
Yaw= 65

Ch2
Type = motor
Throttle  = 127
Yaw = -65


Set ch1-3 4000 Hz

Ch4
Type = servo
Pitch = 127

In the output screen, make ch4 minimum = 1000, midpoint about 1500( or wherever motor stops spinning) and Max 2000

[D-OCHO]

D-OCHO, on 30 January 2012 - 04:57 PM, said:

And use the main motor with a belt or a torque tube to drive it.

Or direct drive + a servo.
Then you don't have the problem of trying to reverse the motor for pitch. You can keep the motor running at a constand speed and use the tailrotor for pitch.

[D-Lite]

Adverse Effects, on 30 January 2012 - 06:54 AM, said:

you could do the tail so its a little to heavy and it wants to go in reverse all the time it the tail motor is not running
then just make the tail motor run from no thrust tail falls down(fly backwards) to max thrust tail lifts up (fly forwards)

That's exactly how it is done on those little toy helicopters and it works pretty well. I have one sitting around here that is broken and I always thought of attaching a CC to it but with an AUW of 40g this would be very challening :-)