Using rate switches to turn off electric motors.

[Richard Putnam 1]

After seeing several incidents caused by motors starting unexpectedly. I believe there is a method of using one of the rate switches to blank out the throttle until you are ready to take off. I appreciate that the simpler radios will not have this facility but I understand it is possible with the more sophisticated computer radios. I own a Futaba FF7 and a T6 EXA.

My transmitters don't have rates on the throttle, which is a shame.

 

 

Richard

[John Privett]

A rate switch on throttle would work IF there was one,  but I'm fairly sure none of the Futaba txs I have now, or have had in the past (old FF6,  FF8,  new FF7) have this.  The heli "throttle hold" switch may be an answer,  but I doubt it's available in "acro" (ie fixed-wing) mode on the tx,  just in "heli" mode.  May be worth a look though? 

 

(In heli mode, the throttle hold switch sets the throttle to a pre-determined setting - usually a fast-idle - regardless of the position of the "throttle" stick.  It's used on helis for autorotation landings.)

[Ultymate]

If you have the ability you can do it with a mix assigned to a switch, I think details are available on Futaba web page under FAQ  obviously dependant on what's available on specific T/X

Edited By Ultymate on 02/08/2010 11:05:13

[Reno Racer]

Spectrum DX7 has this facility; I used it to kill the motor on a TREX450 heli, so that it would start up in my face when plugging in the lipo, particularly after changing the programming for throttle pitch.

Details are in the DX7 manual.

[Martin Harris - Moderator]

I sent a step by step method I'd worked out to do this very thing to another magazine (sorry David) in response to one of their articles but as they published it on a letters page I don't know that I could reproduce it here without some sort of copyright breach.  However, in essence, it's a relatively simple matter of mixing an equal negative value of throttle to the throttle channel controlled by a switch.

 

If it's detailed on the Futaba site then that's the best way but perhaps someone from the magazine might care to comment on the copyright aspect and if it's OK I'll post details...

[Ultymate]

This is the wording from Futaba's web page it obviously depends on what T/X you have and it's functions 

 

 I want to have a "throttle lock" that will prevent the accidental bumping of the throttle stick causing my motor/engine to increase in speed. How can I do this?

To do so you need a free programming mix. Activate the mix and assign the MASTER and SLAVE as THROTTLE. Turn TRIM ON and LINK OFF. Choose a switch and position at which you want the throttle to hold. Then on the rates screen, you need to set the high and low throttle rates. The high rate will be a negative value, the low rate will be positive. So for example, if you desire the throttle to hold around the 5% range (low idle in most cases) then the high rate will be -95% and the low rate would be +95% with no offset. This will still allow you to trim the throttle but will hold it to a preset position with little or no effect if you move the throttle stick when the mix is active.

[Martin Harris - Moderator]

For an electric then, you'd need to set -100%

[Tim Mackey]

I activated this quite simply on my DX6i and DX7 for an electric spitfire which my wife also flies on the slope - I wanted a way of de-activating throttle when on the slope.

Select heli mode in the tx setup list, and use the throttle up ( 2 position switch on dx6 and 3 pos switch on dx7 )

In pos1 the throttle curve is set at  normal, and pos 0 ......throttle is 0% - 0%.

[Andy Butler]

I've been pondering this as I have just bought an E-Flite Beaver. I like the idea of a 0% throttle curve but being a bit of a belt and braces type, would it be possiible to design something that had a physical hold on arming the ESC? For example on full size, the ejector seat charges are pinned until flight ready, then pulling out the pin arms the seat. Something like that would be perfect - and to be really sad I could attach a "remove before flight" penant.

What do you think?

Andy.