dan1220

My Feedback: (2)

what is a fail safe? what does it connect to? PLEASE help me

KyleSch

In case of a loss of signal, it will set the servo's to a pre-defined setting. This is if it runs out of range, your transmitter hiccup's it won't just run at WOT till it hits something, you can make it automatically put the brakes on

dg2b

It goes between your receiver and the servo.

dan1220

My Feedback: (2)

dumb question -- which servo

dg2b

Not a dumb question as I would ask the same.

To answer, any servo you want to failsafe.

If you want the throttle to failsafe, then it is goes between the throttle servo and the receiver. You attach the failsafe unit to the receiver and the throttle servo to the failsafe.

shoehead

what about loss of battery? does the failsafe hold a charge
to return the throttle to brake if the battery fails?

Thmaxxer

If you have loss of power, say a battery falls out or is jarred loose, then you will need a throttle return spring.

packfan88

My Feedback: (2)

i got a question
could you rig up a seperate battery (1 aa?) to power a fail safe?

mglavin

My Feedback: (31)

Fail-safes or the fail-safe concept is generally used on the throttle. For obvious reasons. I set my boats and cars to make a small radius turn and go to idle.

There are several methods of obtaining a fail-safe feature.

Probably the most common in aircraft is the a PCM radio system... You have the ability to set multiple fail-safe parameters. Most manufactures of top end car radio offer PCM 3-channel radio systems.

Hitec servos have a programmable fail-safe feature with there Digital servos.

Many companies offer an in-line fail-safe circuit that is installed between the servo and the RX.

NO power, nothing functions... Fail-safe listen the control signal from the RX, when there is no signal for less than second the fail-safe initiates a hold or movement to pre-defined parameter. Once a signal is again recognized the fail-safe or hold is released and your driving again. This all can occur in less than a second...

You could power the servos independently of the RX power and have a redundant power source, but I thinks its over kill. You'd have to use a 4.8V battery pack.

packfan88

My Feedback: (2)

ah so the failsafe by itself still needs 4.8 volts to work properly?

and
"NO power, nothing functions... Fail-safe listen the control signal from the RX, when there is no signal for less than second the fail-safe initiates a hold or movement to pre-defined parameter. Once a signal is again recognized the fail-safe or hold is released and your driving again. This all can occur in less than a second... "


is this with an "inline" failsafe?
like if the power goes out in your car it sends the servo to a spot like full brake?

WhiskyVR-4

Basically, yeah.

You wire it inline with your throttle servo between the Rx and the servo, and then the Rx loses contact with the Tx, the failsafe causes the servo to go to a pre-set position (you can set it for whatever you want, its like setting up an electronic speed control). I run mine at half-brake so it slows the car without locking the wheels.

if you lose reciever power (on-board power) you are in a bad spot. No failsafe is going to help you with that. Often a throttle-return spring can help pull the servo back to a closed-throttle position, bu there are some problems there too. Often, you need a pretty hefty spring to overpower the servo with no juice. Thats fine, but a hefty spring on the throttle arm is a lot of resistance for the servo to pull against all the time, so its going to increase wear on the servo gears and motor, and its going to draw a lot more power, so you are going to go through batteries (on-board) much more often.

Your best defense against losing power on the car is to run a good 6V rechargable pack (so the batteries cannot pop lose) and make sure they are always well-charged. That way there are no AA batteries to pop out and send your car careening into a curb, or worse.

grampi

If you lose your on-board power, you're screwed no matter what. In this case, your fail safe isn't going to do anything, and the throttle return spring is not going to override the servo. This discussion has been had in here many times about the throttle return spring. It's only function is to return the throttle to idle in the event the carb's throttle arm becomes mechanically disconnected from the servo. This spring cannot override the servo. The servo will remain in the last position it was at when it was receiving a signal.

jswinkos

i beg to differ, if you lose power the spring will work. It may not pull it all the way back but it is better than nothing. If your servo doesn't move without power on then there is a problem. I use a spring and it slows the car down good enough to recover.

grampi

I just turned my radio on, pulled the trigger to full throttle, then turned my radio off. The throttle remained at full throttle. The spring does not override the servo.

jswinkos

either your spring is too weak to be any good or your gears in your servo are too tight. can you move it by hand? if yes, you need a new spring. if no, somethings wrong with your servo.

grampi

It's working just fine. The spring isn't supposed to overcome the servo. If the spring was strong enough to overcome your servo, you'd wear out a servo after every hour of operation. That spring's only function is to return the throttle to idle in the event of a mechanical disconnect.

Akina'sMtx-2

My Feedback: (4)

I would disagree with you. 1. Your doing the wrong thing, if you turn off your TX, then thats when the fail safe come in use(Interference or radio lose). We are talking about LOSING power on the RX. Thats why if you lose radio signal, your car will be blasting down the road at full speed, no matter what, thats what theres a Fail safe. 2. When you turn off your RX when your full throttling, the spring should be able to return the servo back to Idling position. If it can't then it's too weak. If your servo can't open it fully, then it's too strong. Try to fine out what is right for your car. I have both on my car, I would NEVER run any car of mine with out the both. They have saved me many time before.

In order to test how both work, you should do the following:

Fail Safe: Turn on both RX and TX, turn off TX and see if the servo move to safe position with the warning light on(You can set the position you want it to be during interference or radio signal lost, I set it at full brake)

TRS: Turn on both RX and TX, full throttle, turn off RX switch, see if the spring pulls the servo back to idle. If not then it's too weak.

jswinkos

if the spring is only for mechanical linkage disconnect then why are all of them attached to the servo horn?

grampi

They aren't attached to the servo horn, they should be attached the ball joint attached to your carb arm. I don't have my fail safes yet. The reason I tested it the way I did by turning off my transmitter is because this will simulate exactly what will happen if you're driving your vehicle the the Rx looses it's signal. The throttle servo doesn't become any easir to turn just because the Rx lost it's signal. So think about it. If the spring were to be strong enough to move the servo when the Rx lost it's signal, then it would also be strong enough to prevent the servo from opening the throttle at all when the Rx is receiving a signal.

jswinkos

well, all the cars I've seen have them on the servo horn. even if it is on the carb linkage then the servo is still pulling on it, right? either way, the servo has to move the spring. do you have a pic of your setup?

Akina'sMtx-2

My Feedback: (4)

Its not design for for signal lost, it is incase the rx lose POWER(wire cut, battery fall out during a accident, etc). If you ask most people, they know it's not for signal lost, if it was then most people will not buy a fail safe. If there is power going to the servos, then the trs will no do the job that it's suppose to.

Akina'sMtx-2

My Feedback: (4)

Its better to be directly on the carb or engine. If a servo horn break off where you attach the spring, then it's going to cause a problem.

Here is a pic of my car with the TRS around the carb. I use a O ring, it work best for slide carb.

nitroman88

My Feedback: (5)

????????? I dont see a throttle return spring anywhere in that pic. can you circle where the TRS using a paint program and then repost it???

eltorito

Look at the base of his air filter. It looks like a black rubber band. See it now?

nitroman88

My Feedback: (5)

O ok i see it now, kinda hard to see when its black