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Old Jul 16, 2012, 10:57 AM
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Shadrack's Avatar
Winnipeg
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Ok, thanks Jurgen.
I still remember emailing with you in the late 90's about the twinjet when you had a brushless one and had an article in a magazine about it.
So then are you stating that my amp use will be less at cruise with the eprops vs the slow flyers?
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Old Jul 16, 2012, 12:37 PM
Registered User
Canada, BC, Vancouver
Joined Aug 2011
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How balance power output

I am stumpted. I have a TS2 and I cant figure out how to balance the motor outputs. The left motor has about 10% more thrust than the right one. At higher power settings, the plane wants to pull right. The more power I apply, the more it pulls to a point where it is uncontrollable. Is their a way to calibrate the motors/esc so the output is the simular or is this just a attribute to flying multiengines? Both motors are the same, I use one batery with a "T" conector, and both ESC are the same brand (I realize that it the ESC that is the problem).
I have searched the forums in vain but I don't even know what you call this problem. Both ESC's are calibrated to match the Tx throttle and I have cut one of the power cables (red) coming from the esc to Rx. I am hoping their is a way to solve this either by changing my wiring setup or by using a setting in the Tx (Turnigy 9X).

Thanks is advance
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Old Jul 16, 2012, 12:44 PM
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United Kingdom, London
Joined Jan 2005
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Quote:
Originally Posted by hotspur View Post
I am stumpted. I have a TS2 and I cant figure out how to balance the motor outputs. The left motor has about 10% more thrust than the right one. At higher power settings, the plane wants to pull right. The more power I apply, the more it pulls to a point where it is uncontrollable. Is their a way to calibrate the motors/esc so the output is the simular or is this just a attribute to flying multiengines? Both motors are the same, I use one batery with a "T" conector, and both ESC are the same brand (I realize that it the ESC that is the problem).
I have searched the forums in vain but I don't even know what you call this problem. Both ESC's are calibrated to match the Tx throttle and I have cut one of the power cables (red) coming from the esc to Rx. I am hoping their is a way to solve this either by changing my wiring setup or by using a setting in the Tx (Turnigy 9X).
Confirm the motors are spinning in the right direction and the props are on the right way round.
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Old Jul 16, 2012, 12:53 PM
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Winnipeg
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I suggest using a BEC as well instead of power off one of the ESC's.
Don't know if it is related but I have both the power and ground of both of the esc's removed when using a BEC and just have the signal wires present as the ESC has a ground usually right to the battery. Avoids a ground loop.
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Old Jul 16, 2012, 04:01 PM
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Denmark, kbh
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Quote:
Originally Posted by Gerry__ View Post
Confirm the motors are spinning in the right direction and the props are on the right way round.
+1 on prop check. MUST face the same way.

Double check ESC setting/calibration.

Don't try to fix the problem by programming the Tx. That would be symptom treatment - find the cause instead and fix that.

Did you try switching the motors to exclude a motor problem?
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Old Jul 16, 2012, 04:14 PM
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Even swap the motors from one esc to the other to see if the problem is the esc or the motor.
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Old Jul 17, 2012, 02:28 AM
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53859 Niederkassel, Germany
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Originally Posted by Shadrack View Post
Ok, thanks Jurgen.
I still remember emailing with you in the late 90's about the twinjet when you had a brushless one and had an article in a magazine about it.
So then are you stating that my amp use will be less at cruise with the eprops vs the slow flyers?
Must have been early 00's, because the Twin-Jet was introduced in 2001.

Optimizing drive systems is a fairly complex subject. Without knowing the cruise speed of your FPV equipped TwinStar 2, the required thrust, and the prop characteristics at this speed, we can only guess.

Unless you have a wind tunnel to test props, you need to get several suitable props from various manufacturers and test them in flight. Cruise at the desired speed and your FPV system should tell you, which ones have the lowest current consumption.

Jürgen
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Old Jul 17, 2012, 10:19 AM
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That is what I have been doing.
Trying a different prop set each time.
I have video of some cruise speeds so I will check what was a comfortable speed if that helps with this heavy fpv tank. Have had it down to around 12 amps so far.
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Old Jul 17, 2012, 10:37 AM
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Quote:
Originally Posted by Shadrack View Post
That is what I have been doing.
Trying a different prop set each time.
I have video of some cruise speeds so I will check what was a comfortable speed if that helps with this heavy fpv tank. Have had it down to around 12 amps so far.
Most likely your motors are running noticeably below max. efficiency at 6A (each). It may be necessary to use smaller, lighter motors in order to optimize your setup.

Jürgen
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Old Jul 18, 2012, 11:07 AM
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Thanks for all the ideas on why one motor has more thrust. I know its the ESC for I have tried both motors on both ESC's and the thrust is still 10% more on one ESC than the other. Both motor have the same props in size, orientation and direction. I don't know I am expecting too much from a HK ESC in terms of tolerances, but I just wanted to know how others overcome this issue.
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Old Jul 18, 2012, 04:24 PM
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Winnipeg
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I always buy castle esc's.
Have never had an issue.
Don't know if there is a fix.
Can you calibrate the ESC's?
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Old Jul 18, 2012, 04:37 PM
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Denmark, kbh
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Quote:
Originally Posted by hotspur View Post
Thanks for all the ideas on why one motor has more thrust. I know its the ESC for I have tried both motors on both ESC's and the thrust is still 10% more on one ESC than the other. Both motor have the same props in size, orientation and direction. I don't know I am expecting too much from a HK ESC in terms of tolerances, but I just wanted to know how others overcome this issue.
I have at least 12 of HK's ESCs, and I have not experienced a 10% power deviation in any of them. I does sound as if something is wrong with one of yours. Does one of them get warm? (note : if only one is supplying 5V, this will get warmer)

Why not purchase one more of the same, and see if you get at least one balanced pair?
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Old Jul 19, 2012, 01:19 PM
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I just bought a used twinstar II, and it is 100% in stock form, and I just have some minor assembly to do to it to get it back up and flying. It came with one 2200 2-cell battery.....which is the ONLY 2 cell battery I now own.

I also own 2 e-flite 370 brushless outrunner motors (I think 1080kv), and I have a pair of matched 18A esc's as well. I have an assortment of various sized 3 cells I could use with this setup too.

My question is will these brushless 370 motors be a good upgrade from the stock brushed 400 motors? I beleive the 370's can handle a 8 or 9 inch prop, so I'm thinking that would be a good thing I'm thinking if I can use these 370's, then I would not have to invest in 2 cell batterys for my only plane that currently uses 2 cells
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Old Jul 19, 2012, 03:13 PM
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53859 Niederkassel, Germany
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A 2s/2200 mAh battery is way too light to ballance a TwinStar. It would be much better to use a bigger size (3200 to 4000mAh).

Your brushless motors would be a suitable upgrade, but you would need to do some re-wiring. Also ensure, that your 18A ESC can support 4 servos on 3s.

Jürgen

Quote:
Originally Posted by Air Cooled View Post
I just bought a used twinstar II, and it is 100% in stock form, and I just have some minor assembly to do to it to get it back up and flying. It came with one 2200 2-cell battery.....which is the ONLY 2 cell battery I now own.

I also own 2 e-flite 370 brushless outrunner motors (I think 1080kv), and I have a pair of matched 18A esc's as well. I have an assortment of various sized 3 cells I could use with this setup too.

My question is will these brushless 370 motors be a good upgrade from the stock brushed 400 motors? I beleive the 370's can handle a 8 or 9 inch prop, so I'm thinking that would be a good thing I'm thinking if I can use these 370's, then I would not have to invest in 2 cell batterys for my only plane that currently uses 2 cells
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Old Jul 21, 2012, 07:12 PM
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on page one there is a post with all the weights of the foam parts , i am asking myself how light can it become ? i fly my twinstar with fpv equipment with about 1.4kg but if you would use 1300kv blue wonder ( 24g ) and 10A escs with 2200mAh 3s lipo one should be able to get a flying weight of under 900g .... has anyone ever tried to build that model really light ??? are there any flight videos ?



cheers
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