rickshupe

I wanted to get some information on fail safes. What is a good brand? How do they work ? Any input would be helpful. Thanks.

racemaxx24

A duratrax would be a good brand. A failsafe hooks between your wire from the reciever to the throttle servo and it pulls the servo back to idle if the batterys run to low so your car or truck won't "run-away" like u sometimes hear on RCU
'

rickshupe

Is it just for low batteries or will it stop it from taking off when it gets out of range?

ajb1205

It'll protect against both your rx battery getting too low and then, of course, signal loss. These are another 2 that are quite popular (I am running the Venom in my NTC3 since I have upgraded to Spektrum in my Revo)...

http://www3.towerhobbies.com/cgi-bin...&I=LXEYG2&P=ML

http://www3.towerhobbies.com/cgi-bin...&I=LXHUH6&P=ML

nothinbetr2do

they work as said above, and i run the venom ones with no problems. you can actually set it so the brakes come on, it has a little turn adjustment on it to set it where ever you want. i'm not sure how the other are set-up. as i said i used the venom ones with no problems, so i never had to look at any more

racemaxx24

Ya they do protect against signal lose. My bad

rickshupe

Are there any that will shut the fuel off when the signal is lost.

racemaxx24

IDK but I don't think so.

envisa

The majority of the RC servos receive one pulse every 20ms from the receiver. Such pulses have a duration between approx. 1ms and 2ms.
1.5ms would typically be neutral position (idle in the case of the throttle servo). One of the extremes would be full throttle and the other would be full break.

The failsafe (which as explained before is placed between the receiver and the throttle servo) monitors the presence of such pulses. Under normal circumstances the failsafe is "transparent" and just lets the pulses pass by directly from the reciever to the servo. However if your receiver looses the connection no pulse is sent to the servo. The failsafe may wait for 1-2 seconds to see whether the pulses appear again (connection reestablished). If the pulses do not appear then the failsafe will automatically generate the pulses such that your servo automatically (if programmed correctly) applies the breaks or just orders to idle.

As said before, the failsafe monitors also the voltage to the throttle servo. If it goes below a specified threshold the failsafe handles it as if the connection is lost.

You should be aware that the failsafe may also fail... One friend was bashing in the beach with his MGT 8.0 and the M-troniks Micro Failsafe for unknown reasons went WOT and guess where it went.... yes....directly into the salty water... Miraculously only the receiver got damaged. He bought now a Spektrum DX3 which has a failsafe integrated in the receiver.

I've tested my Revo 3.3 at home and it worked approx. 9 out of 10 times. Every now and then it just would do anything. Once I was bashing and in one ocassion it went WOT instead of breaking! I got tired of it and removed the Optidrive. If I loose the connection the Revo will automatically go idle because the spring in the throttle arm will push the throttle back.

racemaxx24

Well put envisa. Couldn't of said it better myself.

utpimp

I have a MT2 and the On/Off switch is on the side of the truck. Yesterday I wrecked at WOT and the switch got turned off during the wreck, causing the vehicle to rev to max RPM (it was on its back). Would a failsafe have prevented this given that the truck was turned off? I guess my question is, would the lack of power impair the failsafes functionality?

rickshupe

So are you saying not to use the fail safe? Isn’t the optidrive what controls the shifting of the trans? Sorry if I am a little confused but I am still pretty new at this.

racemaxx24

ALWAYS USE A FAILSAFE!! U won't be sorry.[ i'm not mad, just trying to get my point across lol]

rickshupe

So what did that mean about removing the Optidrive?

envisa

I am not saying not to use the failsafe but I just don't use it...
The optidrive has a sensor in the transmission. If it detects movement then the optidrive won't let you shift gear (preventing ripping the gears). The optidrive will only let you shift gear if the truck is not moving. Because I removed the optidrive I just need to be carefull not to shift gear when the truck is in motion. Shifting gear with the optidrive was just a pain. Sometimes it wouldn't let me shift gear even though my Revo wasn't moving.

matts6887

It should stop it from taking off when it gets out of range; so long as ur batteries or receiver pack still has "juice" left in them. But as on small sidenote here; some additional insurance to help make sure the throttle returns back to idle is to put a throttle return spring on it if it does not already have one; as putting one on will help "spring" the throttle back to the idle position even if ur batteries or receiver pack go completely dead.

RenegadeRevo

My Feedback: (1)

Just FYI - the Optidrive is -NOT- a failsafe. It has been known to somewhat perform the same function, but it is NOT intended as a failsafe.

I've used the Venom failsafe for years now and have not had any problems or runaways. I also have 2 forms of failsafes. I have the Throttle Return Spring and a failsafe. If my Rx battery dies, the TRS takes over and will return the Revo to idle.... if I lose radio communication (out of range, low battery, accidentally flip the on/off switch) I'm generally OK.

rickshupe

Thanks for all the help. I am a little curious about the pros and cons with removing the optidrive.

matts6887

Not only this; but the optidrive has a tendency to "conflict" with some "aftermarket" radio system that work on the fm band, or even ones like the spektrum system. I have the spektrum system and thats the reason I removed the optidrive from my Revo; is because it can glitch with systems such as the spektrum and others as well....

RenegadeRevo

My Feedback: (1)

Well, in the Revo, the reverse gear is the "Weak link" of the transmission... it's otherwise BULLETPROOF (although it is plastic)... If I were to keep reverse in my Revo, I would have kept the optidrive... however, I didn't... (my reverse gear blew out... so, I did the FOC)... my LST2 has no reverse failsafe mechanism, and I have accidentally tapped the reverse button while on the throttle. I didn't destroy it, but... it scared me a bit. LOL That's the benefit of the optidrive...so... i would say... if you have reverse... keep the optidrive... if you don't... you actually HAVE to take it out, because if you do a FOC, it removes the sensor... which the optidrive won't work without it.