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Old 08-10-2010, 08:54 AM   #1
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Default Throttle return spring when using a torque servo on throttle?

I usually use a 9100s at throttle but they SUCK so i put an extra 9100T i had at throttle. Issue is it takes more spring tension to return the servo to neutral should the servo lose power. I usually run rubber bands so should i just put more rubber bands until the throttle will close? Will the extra load kill the servo? Thanks.
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Old 08-10-2010, 08:58 AM   #2
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I usually use a 9100s at throttle but they SUCK so i put an extra 9100T i had at throttle. Issue is it takes more spring tension to return the servo to neutral should the servo lose power. I usually run rubber bands so should i just put more rubber bands until the throttle will close? Will the extra load kill the servo? Thanks.
Set you trim correctly and you should not need extra spring tension. The servo should center it self. the rubber band should not be use to close the carb, its a fail safe in case the servo loses power. with out the rubber band the servo should be able to close all the way.
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Old 08-10-2010, 09:08 AM   #3
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Set you trim correctly and you should not need extra spring tension. The servo should center it self. the rubber band should not be use to close the carb, its a fail safe in case the servo loses power. with out the rubber band the servo should be able to close all the way.
Right if the servo loses power at WOT the rubber bands on the slide of the carb have to have enough tension to pull the carb closed right? I found that i need more rubber bands on the carb for the 9100T than i did with the 9100S so will the extra rubber bands kill the life of the servo because it has to pull against those.

I understand the spring should be set properly to close the carb with servo under power and no rubber bands. I'm talking only under loss of power situation.
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Old 08-10-2010, 11:14 AM   #4
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Set you trim correctly and you should not need extra spring tension. The servo should center it self. the rubber band should not be use to close the carb, its a fail safe in case the servo loses power. with out the rubber band the servo should be able to close all the way.
As bacchus explained, that is not correct. The return spring/band needs to be able to return the servo arm completely to neutral in the event of power loss.

bacchus, you should use as many bands as needed. The servo should handle it just fine, especially with more torque to begin with. You'll be fine with more bands.
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Old 08-10-2010, 11:21 AM   #5
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As bacchus explained, that is not correct. The return spring/band needs to be able to return the servo arm completely to neutral in the event of power loss.

bacchus, you should use as many bands as needed. The servo should handle it just fine, especially with more torque to begin with. You'll be fine with more bands.
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Set you trim correctly and you should not need extra spring tension. The servo should center it self. the rubber band should not be use to close the carb, its a fail safe in case the servo loses power. with out the rubber band the servo should be able to close all the way.
Maybe I should have wrote it differently.
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Old 08-10-2010, 11:24 AM   #6
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Maybe I should have wrote it differently.
Well you're right about that part. The servo/linkage should close the carb when operating properly, but bacchus was asking about return spring in a loss of power situation. In which case they need to be able to pull the servo closed all the way.
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Old 08-10-2010, 11:26 AM   #7
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Hey jammin what kind of luck are you having with the 7940? Is it lasting on the losi?
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Old 08-10-2010, 11:33 AM   #8
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Hey jammin what kind of luck are you having with the 7940? Is it lasting on the losi?
I'm in love with this servo on throttle. It is absolutely awesome! I've been running it since early November and it hasn't given me one little issue. Both the 40 and 50 have been issue free for me and they're very impressive on direct lipo. I wouldn't trust the 40 on steering though. That seems to be where guys are burning them up.
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Old 08-10-2010, 11:47 AM   #9
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My JR z9100hvs burned up on my throttle on my Losi 8T.Got like two months out of it. I replaced it with a Hitec 7940 thv. Do other people have problems with the JR 9100's. I knock the case out on my 9100t in my Revo steering.I blew a few 9100s over the past 3 years on Revo throttle.I am thinking of going Hitec 7940 hvt ,7950 hvs if JR does not want to cover these under Warranty.What do you guys think ?
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Old 08-10-2010, 11:53 AM   #10
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The idea of the bands on the carb, is so if the servo horn comes off the servo the carb will still close.
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Old 08-10-2010, 12:53 PM   #11
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The idea of the bands on the carb, is so if the servo horn comes off the servo the carb will still close.
Well yes, and if you lose power they will pull the servo/carb closed. They need to be able to do both. In other words, like I've been saying, the bands need to be able to pull the carb closed with the servo connected.
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Old 08-10-2010, 02:08 PM   #12
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My JR z9100hvs burned up on my throttle on my Losi 8T.Got like two months out of it. I replaced it with a Hitec 7940 thv. Do other people have problems with the JR 9100's. I knock the case out on my 9100t in my Revo steering.I blew a few 9100s over the past 3 years on Revo throttle.I am thinking of going Hitec 7940 hvt ,7950 hvs if JR does not want to cover these under Warranty.What do you guys think ?
Yeah i'm unimpressed with the 9100s regular or high voltage. I literally put a BRAND NEW 9100s at throttle and the second time i pulled full throttle it twitched from full to neutral back to full. It is ridiculous. I set my endpoints correctly everytime as well! I have heard people say for the losi to get 2 7955's and be done with servos. Well i'm assuming the torque servos last longer at throttle and i have 2 9100T's so we'll see. I'm gonna miss the extra speed on throttle tho.
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Old 08-10-2010, 02:43 PM   #13
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Yeah i'm unimpressed with the 9100s regular or high voltage. I literally put a BRAND NEW 9100s at throttle and the second time i pulled full throttle it twitched from full to neutral back to full. It is ridiculous. I set my endpoints correctly everytime as well! I have heard people say for the losi to get 2 7955's and be done with servos. Well i'm assuming the torque servos last longer at throttle and i have 2 9100T's so we'll see. I'm gonna miss the extra speed on throttle tho.
The new Hitec 7945 will probably be the bomb for throttle or steering in a buggy. Something like 320 oz/in torque and .10 sec. speed. You can have torque and still have your speed.
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Old 08-10-2010, 02:52 PM   #14
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The new Hitec 7945 will probably be the bomb for throttle or steering in a buggy. Something like 320 oz/in torque and .10 sec. speed. You can have torque and still have your speed.
Nice i'll take a look at that one next season maybe...hopefully the T will last awhile.
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Old 08-10-2010, 03:07 PM   #15
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I am running the Sanwa HVS-ZV servos on both the steering and throttle on my MBX-6 with great results, and with speed on .12 at 7.4 volts and torque of 333 in/oz thety are just what was needed to do the job. I am running the M11X also so it was a nice fit having Sanwa allround.

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