whats a throttle return spring

[spyderpact]

I have a diff servo head it dosent look like that, but i managed to install it i put it on the servo to the back where u put the clips it seems to work fine any thing wonrg with this?

 

[mattyk6]

If you connect the TRS to the servo arm, then you negate one of the reasons to have a TRS. What if the servo arm breaks or the thottle linkage comes off? You should attach it to the carb.

This is all IMHO!:cheerful:

Matt

 

[SkyMaxx]

Matt has the right of it. TRS are called throttle return springs, not throttle servo return springs. If you want to get the true protection offered by a TRS, connect it to the throttle arm and then to some fixed point on your RC. You want to afix it to the ride in such a fashion that it pulls counter to the throttle and will over power the servo if necessary to close the carb.

 

[spyderpact]

gotcha guess i gotta take it off ... man where to put it now ok well ill tell u later :beer:

 

[grantt]

I agree it really should be connected right to the carb.

man where to put it now

Thats where the creative juices come into play. If you see other cars like yours, see how they did it.

 

[spyderpact]

ya but I see them mostly on trucks on with those wierd servo arms mines different

 

[grantt]

If you have a picture of the setup, perhaps we can help you figure out a way to mount it.

Is it a slide carb or rotary carb? The one in the picture is a rotary carb. If its a slide carb, I've heard of people just using a thick rubber band and simply wrapping it around the arm and engine. The tension of the rubberband pushes the arm back in when the servo loses power.

 

[Waste Land]

Originally posted by mattyk6


Why do you need a strong throttle return spring? The only time the TRS is used would be if the throttle linkage came off or the battery had problems, thus the servo wouldn't even be a factor. A failsafe would be used if the servo still had power.

And remember, do not connect the TRS to the servo horn or servo linkage. Connect it to the carb itself, in case the linkage comes unhooked from the carb.

Matt

You do understand that if your car gets out of range, your batteries get to low in either reciever or remote your throttle servos goes to WOT and your car goes wild while you have NO control over it.

 

[SkyMaxx]

Waste Land, his question was of the rhetorical variety. He answers it with the very next sentence. He does understand why you need a TRS and recommends using one.

As for servos going anywhere when out of receiver range, most of the time they hold whatever setting they had when the transmitter's signal is lost.

 

[grantt]

most of the time they hold whatever setting they had when the transmitter's signal is lost.

In my setup and I thought most radio setups, the servos don't hold their current position once the signal is lost. If I turn on my receiver without my transmitter, I can turn the front wheels and turn the throttle servo with my hand. Once I turn on my transmitter, only then does car seem to come alive and the servos jump into position. And then if I go to full throttle and then shut off the transmitter, the servos go limp again and the TRS pulls the sevos back to idle.

If you have a failsafe, then it does hold in its preset position when it loses a signal (transmitter gets shut off). This is why a failsafe that is not set properly is not just bad, its even worse than not having one at all. A failsafe could for instance be incorrectly set to full throttle upon loss of signal instead of idle. Even a TRS can't save a runaway if an improperly set failsafe is also in the vehicle. I'm sure most that invest in a failsafe also invest the time to not only set the preset failsafe position, but also test it and get comfortable with how it works before starting the engine and taking it on the road.

 

[SkyMaxx]

The servo would stay at WOT or whatever setting it was at without the TRS. That is the whole purpose for having a TRS in the first place.

 

[grantt]

The servo would stay at WOT or whatever setting it was at without the TRS. That is the whole purpose for having a TRS in the first place.

Right. Thats exactly what a TRS does. But what I mean is that if a failsafe is ALSO in the vehicle, and kicks in to an incorrect position of full throttle, the failsafe will hold that position even with the TRS trying to pull it back. Its the same thing as when your vehicle is under your control and at full throttle. The TRS won't pull it back because your servo is actively holding its position at full throttle.

Maybe I am misunderstanding what you are trying to say. Sounds like you are saying that a TRS has to be strong enough to pull an active servo trying to hold its position. A TRS will not have the power to overcome a servo actively trying to hold a position.

 

[spyderpact]

um ill get a pic soon so far i left it on the servo yaya i know pps: but its the only way i can't seem some way to make it work if i put it on the throttle arm I can't find a way to find it so ya ill post a pic asap

 

[SkyMaxx]

Originally posted by grantt

Maybe I am misunderstanding what you are trying to say. Sounds like you are saying that a TRS has to be strong enough to pull an active servo trying to hold its position. A TRS will not have the power to overcome a servo actively trying to hold a position.

You are misunderstanding what I am saying. I'll try and be clear here. Remove any thoughts of a fail safe from your mind. Now remove any thoughts of a TRS from your mind. When your transmitter gets shut off, a linkage breaks, or your receiver loses power and thus your servos do also, what happens to the servo? The servo remains where its last input had it. So, if the last input was WOT, it will remain at WOT. If the last input was half throttle, it remains at half throttle.

Now introduce a properly installed TRS. What should occur when any of the above events occurs is that the TRS returns the throttle to the closed position (idle position). Now, if you have a weak-assed spring and the TRS is trying to return the throttle back to closed against a servo (inactive to use your terminology) and linkage, the TRS will probably not work so well. So, yes. You do need a TRS with a spring that is strong enough to overcome your servo when it is in an unpowered mode.

Hopefully, this clears things up, grantt.

 

[grantt]

Skymaxx,
Gotcha. I think we are both on the same page now.

yaya i know but its the only way i can't seem some way to make it work if i put it on the throttle arm I can't find a way to find it so ya ill post a pic asap

You're not running it in the ideal location, but I'd say with your setup, you are now at least safe from many runaways. Next time your battery gets disconnected or falls off the truck and your truck slows to an easy idle, give yourself an attaboy.

 

[spyderpact]

is it safe to use 2 springs?

 

[mattyk6]

You can use as many springs as you would like. Just make sure that the servo still has enough power to pull it to full throttle!

Matt

 

[spyderpact]

ok cool also just to make shure the trs should be able to pull the servo back when the battery dies or if it gets out of range right? because yesterday forsome reason my radio wasn't getting any communitation , I was in a big parking lot and it lost connection, I wasn't far either and then it kept on going not that fast though just slow enough for me to run lol, does this mean weak trs or is it something with the reciever, i would also want to know why this happened possibly low battries?