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mixing servos help

Old 11-28-2007, 03:45 PM
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rccrasher9
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Default mixing servos help

Hi, I have trex se v2 and LHS is limited on supply.... ds3400g for the tail, 1 hs-65 mg for pitch, 2 jr 285's for swash,

questions

1. how would you use the options above?

2. not much into 3d, just hovering around..... maybe later just flips or rolls....

3. these would be my setup, Id have to wait 7 days to get all hs65-mg..... should I wait or will this work?

1- hs-65 mg has .14 sec 4.8v with 24.99oz of torque

2- jr ds285 has .18 sec 4.8v with 18oz of torque

is the diff really noticable beween both?

4. I am using a 240 gyro with g3400 jr servo and a jr8103 tx ..... I've read this setup will and wont work. Is anyone using this setup?

thanks,

joe
Old 11-28-2007, 03:59 PM
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hennesseylord
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Default RE: mixing servos help

i would wait and get all the servos the same for the cyclic controls...having different servos will make the swash not move all together. your heli is ccpm so all the servos work together to make the swash move left/right/forward/backward/up/down.
Old 11-28-2007, 04:10 PM
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USHobbySupply
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Default RE: mixing servos help

Agreed. Its best to have all three cyclic servos the same. They really should have the same response time, or your cyclic response will be off.

I dont see why the GY240 and tail servo would not work, but am open to others opinions.
Old 11-28-2007, 04:12 PM
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Default RE: mixing servos help

With a ccpm setup you want 3 identical servos.
Old 11-28-2007, 06:47 PM
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brcottam
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Default RE: mixing servos help

Hello, I was wondering if someone could help me with a 450 Class Hello (Electric). I am new to heli's but not RC. My helio is a 6Ch ROBO 450 CCPM 3D RC EP almost the same as the t-rex. I’m having problems with the controls. The blade pitch is reversed, I cant figure out how to track my blades, one turns a 1/4 in higher than the other, and today while trying to work through the problem I disabled the motor somehow? I'm stuck and getting frustrated, any ideas?
Old 11-28-2007, 06:59 PM
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RussWisc
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Default RE: mixing servos help

I was told too .... not just the same 3 servos on the Cyclic ,,,but 3 from the same batch so they run the same ... not 1 new 2 used ... ECT

all of the servos you have listed look good ,,, personaly I like Digitals ds285 ... the ds3400g/GY401 is what i have its a great servo
Old 11-28-2007, 08:38 PM
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rccrasher9
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Default RE: mixing servos help

????confused.... I was told on the pitch you can have a hs-65 mg and on rock n roll you can have ds285's. as the pitch is controlling the angle of blades and the rock n roll are moved together. these are digital...... Why do you need pitch to move the same as rock n roll?


Please guys, help me sort this out as my LHS recommended this as they did not have all three hs-65mg in stock....


I will take them back 2-ds285's and wait for the hs-65 mg.

***they have 3 hs-56..... do you think these will work?

Thanks,

Joe
Old 11-28-2007, 09:04 PM
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RBCCONT
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Default RE: mixing servos help

I think you would be better off with the 3 56s.when you increses or decrese pitch all 3 servos move at the same time,I am prety sure they are a little quicker than the 65s just not as much torque.but if you are not doing 3d there wont be alot of stress on them.
Old 11-28-2007, 09:26 PM
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tippy
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Default RE: mixing servos help


ORIGINAL: rccrasher9

????confused.... Why do you need pitch to move the same as rock n roll?
Read the previous posts ... if your heli is CCPM then ALL THREE OF your servos perform the Pitch FUNCTION ... not just the one plugged into the Pitch CHANNEL.
Don't confuse the Pitch CHANNEL/SERVO with the Pitch FUNCTION (what makes the blade pitch change).

For a 120° swash config (eCCPM) ... ALL THREE swash servo/channels (Pitch, Aileron, & Elevator) perform the Pitch Function and ALL THREE swash servo/channels perform the Elevator function.
This is why you need all your servos to perform the same.

If you had a non-CCPM heli (ala TT Raptor), then the Pitch channel/servo can be different because only the Pitch channel/servo performs the Pitch Function.
Old 11-28-2007, 11:06 PM
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RussWisc
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Default RE: mixing servos help

the pitch servos as you call it are 3 of the same brand and model the 3 going to the swatchplate have to be the same, you can have a Gryo servo like the DS3400g with your GY240Gyro .. save the 2 ds285s and get 1 more ... or get 3 HiTecs both 65MGs or 56HB will do fine
Old 11-28-2007, 11:12 PM
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hennesseylord
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Default RE: mixing servos help

i like the hs-65mgs, thats what i use on my trex and they are amazing, i cant do hard 3d but i can jump the heli around and the servos respond and center very nicely.
Old 11-29-2007, 01:26 AM
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rccrasher9
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Default RE: mixing servos help

I already have the gyro 240, and 3 hs-55. and can get a 50.00 anolog servo for tail tl $50.00.... is $225.00 for a 401 and a ds 3400g worth the diff in quality for normal flying and a few flips and rolls, or will I see a big diff as to where I wont regret spending 225.00?


I already bought a 401 and ds3400g with 2-ds285's and 1 hs-85mg TL $336.39.... but I can still return, have not opened package yet

I understand the hs-56 will work fine, but will the hs-55 work fine as will compared to hs 56?
Thanks,

Joe
Old 11-29-2007, 05:41 AM
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Default RE: mixing servos help

I understand the hs-56 will work fine, but will the hs-55 work fine as will compared to hs 56?
Nope. The HS55 is not up to the job. The centering is too poor on the HS55, and the cyclic control is one place where slop is not acceptable.
See if you can exchange the 3 cyclic servos they sold you for 3 matched ones. HS56 will work well. HS65 will work well.
Vince
Old 11-29-2007, 07:11 AM
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rccrasher9
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Default RE: mixing servos help

Thanks to everyone for pitching in your knowledge....


Thanks,

Joe
Old 11-29-2007, 09:43 AM
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RussWisc
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Default RE: mixing servos help

do not get a great machine and discount the electronics ... a heli flys great only with good electronics even for just hover ,,, do the good electronics ,, you can always reuse them on a diferent machine in the future
Old 11-29-2007, 02:14 PM
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Tolla
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Default RE: mixing servos help

get hs65's / 401 / 2100T/ 9650. Buy cheap, buy twice. Been there. take the advice given here...get decent electronics first time round.
Old 11-30-2007, 09:35 PM
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rccrasher9
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Default RE: mixing servos help

Ok,

I am 98% finished with my TREX SE new V2. I dicided with the help of a lot.... to go with the jr3400g servo on the tail, hs-65mg on the swash and a Futaba 401 gyro..... I played around with the tail that thing compensates for movement faaasst... as soon as I think it it is already there. Not that sensitive with the 240 gyro... anyways here are some pics of my almost finished trex...

I think I ll sell it for $1000.00 just add tx and rx.... any takers


Thank you,

Joe





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Old 12-01-2007, 02:23 AM
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Default RE: mixing servos help

RC Crasher, check your tail rotor. From the pic it looks like it's rotating the wrong way. As you look at the heli from the right side, the tail rotor should spin counter-clockwise. It should still fly either way. Anyone else drop in on why the tail rotor has to spin that way. Torque?
Old 12-01-2007, 04:05 AM
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rccrasher9
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Default RE: mixing servos help

Thanks cleared2engage, I missed that and I wonder what else?, I placed them blades without reading.... I was waiting for the servo from ups and have not put in on yet... I'm sooooo glad you cought that.... the book is kinda lame written in oriental and english... kinda hard to read that way...

Thanks,

Joe
Old 12-01-2007, 03:22 PM
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Default RE: mixing servos help

We've all done it. Like when I wrecked my Hurricane by not lock tite'ing the swash plate cause I was in too much of a hurry to get back in the air.
Old 12-01-2007, 07:00 PM
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RussWisc
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Default RE: mixing servos help


ORIGINAL: rccrasher

I think I ll sell it for $1000.00 just add tx and rx.... any takers
I hope your Jokeing
Old 12-02-2007, 02:07 PM
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tippy
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Default RE: mixing servos help

Cleared2Engage:: ...
Anyone else drop in on why the tail rotor has to spin that way. Torque?
One minor reason:
Some might say that the reverse rotating blades will move upward into the main blade downwash making the upward turning blade more efficient. This maybe true but it's minor because guess what the wash does when you fly inverted ...

The biggest reason is the design of the tail rotor (mainly the blade grips). If it is designed to rotate in the reverse direction ... you will have less, little, or no control in any other configuration.

The blade grips are designed with an offset so that when the slider is centered ... the blades will have the necessary NOSE RIGHT pitch to counteract the NOSE LEFT torque generated between the main rotor and fuse. The PROPER offset only exists if the rotor rotates in the right direction, the blades are installed in the right direction, and the blade grip links are in the right orientation to rotation (leading or lagging).

If you simply reverse the direction of the rotor (reverse the belt and tail rotor blades), the new leading edge is in the opposite direction as the proper leading. IOW ... with the control/slider centered, the leading edge of the (properly installed) blade will be angled toward the left side of the heli (providing a NOSE RIGHT command). This also means the trailing edge will be angled to the Right of the heli.

If you simple reverse the blades in the grips and reverse the belt to cause a forward rotating rotor (forward blade moves downward), then what was the trailing edge now becomes the leading edge ... and which way is the leading edge angled now??? To the right (just like the trailing edge was). This will give LOTS of NOSE LEFT command while the control is centered.
See any problem with that???
You'd be lucking to get the heli to stop YAWing left. It would even appear to some that your gyro was reversed (almost identical symptoms).

OK ... what if you reversed the blade grips while you reversed everything else. This will change the off-set amount but your blade leading edge will still be commanding nose left.

As you can see ... the rotor needs to rotate as designed, the grips need to lead or lag as designed, and the blades need to be installed as designed or you will have anything from odd handling problems all the way to uncontrollable handling problems.

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