Failsafe or return spring??

[JYD]

I am currently putting together a NMTR and was wondering about using a failsafe vs return spring on the motor. Pros and cons?

Thanks

[NitroRacer10]

I only use a return spring as do most others..I personnaly see NO need for both and like the spring better out of both. You can get the return springs from Losi part #A-9409

[ 08-15-2001: Message edited by: NitroRacer10 ]

[InspGadgt]

I strongly reccomend both. The reasoning is this. If you get a glitch from a near by RF source this can (and does) cause the reciever to think it's getting the signal for full throttle. In this case the return spring is not going to make one bit of difference whereas a failsafe will. However if you have a failsafe and no return spring and your reciever pack gets disconnected, turned off, unplugged, or knocked off then there will be no power in the fail safe to tell the reciever to return the throttle servo to the neutral position. That is when the throttle return spring becomes necessary.

[JYD]

InspGadt, I tend to agree. I heard the Futaba fail safe only works with the Nicad RX batteries and not NimH. Is this accurate? Anyone?

[superpitstain]

the throttle return spring is better in any way if you hook it your your enginethrottle arm and than hook it to a part of hte upper deck

[T3_Racer]

BOTH! :D

[raffaelli]

I used the fail safe in my MRX-2. It lasted about 2 minutes...I could not get it out of my car fast enough. I thought it was too sensitive. With every single little glitch, it would kick in. Annoying.

[krayzie]

I use both for the exact reason Insp. said!

Krayzie http://www.plauder-smilies.de/tales/grim.gif

[bullfrog]

what is a failsafe what does it do and where can i get one????

[TC3Racer]

Dynamite makes a failsafe but it is called a Race Guard. i'm not sure where you can get them but they are both great and the failsafe prevents runaways.

[superpitstain]

but it's only for nitro, not for electric i donlt think, unless you plug it in to the esc...

[gubbs3]

Failsafe = $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

Return Spring = $.01

You do the math.

[JP]

try $3 gubbs...

[superpitstain]

he's close enough

[Grant Tokumi]

The ol saying, "You get what you pay for" does not apply here.

I recommend return spring. Most failures I've seen had more to do with things like dead batteries, batteries disconnecting, wires ripping apart or just coming apart under normal wear and tear, or linkages popping off or coming off (like if you forget to screw the servo arm back in). All things that would be saved by a return spring. A failsafe will only save the dead battery scenario. All other scenarios listed above will still result in a runaway even with failsafe.

The Sept edition of RCCA introduces OFNA;s failsafe adaptor. Page 130. Misleading in my opinion.

Quote:
OFNA's Fail Safe Adaptor protects your investment from radio interference and failure. Set the unit to apply brakes when the signal is lost or the receiver pack voltage is too low, and you'll never have to worry about a full throttle runaway, especially if you also use a throttle-return spring.
End Quote

That makes me think a failsafe will save majority of runaways, and that added return spring will pick up the rest. Don't be milsead by things like this. Its not incorrect information, but misleading. In my opinion, a return spring saves 95% of runaways. A failsafe, maybe 10%. A cheap return spring (one installed properly) is by far, a better runaway security than a failsafe device.

[gubbs3]

You brought up a good point to say that failsafes only protect against dead batteries and glitching. The last runnaway I saw happened because the guys receiver fell out. Don't ask how but it was just the receiver with all the wires disconnected. In this case the failsafe wouldn't do squat.

If you're really wondering how his receiver fell out, it was after a mid-air including myself. :rolleyes:

[superpitstain]

Yes, overall, return spring is the most effective against many cases, someone tried to argue that with me in the hpi forum, and after i proved him wrong, he stopped posting in that psot...

[JYD]

Great input from everone. Thanks for sharing you experiences and opinions....

[MtnKodiak]

So since we're on the subject, let me ask a question or two.

A friend and I picked up throttle return springs for our rigs after he had a nasty runaway w/ his Nitro Rush-- across a road & parking lot, under a truck, and into the side of a motel at about 35mph. Only melted his clutch and stripped the spur gear, lucky eh.

The thing is, the servos have so much torque on our trucks (I have a futaba), that it doesn't seem like the spring has enough pull to return the throttle arm if the receiver loses its signal.

On my truck, when it wasn't running, I tried giving it full throttle, switched off the truck's power switch, and the throttle arm just stays there. It takes some effort to push it back. Am I safe to assume that when the engine is running & vibrating, that the spring would have enough strength to (eventually at least) return the throttle to idle?

I haven't had enough guts to try this test when the truck's running!

Thanks, --mK

[superpitstain]

what springs to using? i have the losi springs, and it's very strong, make sure you get strong springs

[Spinner]

if the spring isnt torquey enough, just trim off a few mm off of it and erattach it,,, it will apply more pressure, just trim it as needed

[Railman]

Next time you get a chance, gheck out the resistance on a JR 4735 or 4750 (both coreless, 90, 96 oz). They have very little resistance to them when turned off. The differance is in the motor to final output reduction. These servos' motors devolope so much torque that they don't need a lot of reduction to have a high output shaft torque. Probably the best throttle servo's out there. It's also why I don't feel their conservative speed numbers do them justice. Which motor do do think could change directions (forward->reverse) faster for steering...a high rpm motor or aa low rpm motor? Just my $.02 ;)

[MtnKodiak]

Ya, I got the Losi return spring "kit" (two springs, and two "attach mounts"). I guess it's just not strong enough to return my arm with the servos I have. If I shorten it, I'll probably take a huge hit on battery (and servo?) life, since it will be harder for the servo to pull on the spring.

But, I think it's strong enough that when the engine is providing vibration, it will 'eventually' pull it back to idle. I guess I'll find out if it works eventually, huh?

--mK

[FTGT Racer]

are you only using one of the springs? I had to use both for an old standard servo, try that it might work.

[superpitstain]

i only used one my my sotck xr3 servo, but i streched mien out 3 inches to fit it safely into ym super nitro

[InspGadgt]

I'm not sure about aftermarket failsafe devices. I've never used them. When I talk about failsafes I'm talking about the ones built into a PCM radio which WILL help in a number of circumstances especially with radio hits. Most people I know are very careful with their battery mounting and charging so I see very few run aways due to a battery coming plugged or falling out. That's not to say it doesn't happen. It happens a lot. Especially with newer drivers who have not learned how to properly secure a battery into place. I also see a large number of run aways due to radio frequency interferrence. In this case a throttle return spring will not make one bit of difference. Your car will still run away. However with the failsafe feature built into a PCM radio many times this will save your car from a run away due to radio frequency interferrence.

[InspGadgt]

Additionally, Fail safe devices do not protect against battery failures. They need power in order for them to work. Their sole purpose is for RF interferrence. In the case of a battery failure the only thing that is going to save your car is a throttle return spring or a lot of luck.

[rims']

how much does a failsafe cost??????????

[Coconut]

both

[superpitstain]

the dynamite made failsafe cost 30, alot of them cost 30 bucks

[lilslyk]

i can get anyone that needs/wants a dynamite race guard one for $25 shipped...that's cheaper than you'll get one for at a hobby shop probably and i can do paypal and send it the next day or same day.

email me, mslykhuis@cfu.net, i can get them cheap.

slyk

[JYD]

Hey Slyk,

Do they work with nimh RX batteries...?
Ko Propo and Futaba do not. They only work properly with Nicads batteries.

JYD