01-28-2012, 01:48 AM
Join Date: Apr 2008
Location: Wisconsin, USA
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Club: www.racinercclub.com (I'm the newsletter editor)
DX7 gear/throttle interlock
Originally Posted by paxskipper
I did some searching and did not find anything that seems to help with my question.
I have had some people tell me that I should always turn on my TX (Spektrum DX6i) before I connect my battery to my receiver (AR600).
My DX6i manual says it does not matter which order I use.
The reason for my question is that I have heard about people who accidently advanced the throttle while getting their plane ready / positioned. If they had delayed turning on the TX they would not have had the resulting damage / injury because of the unexpected prop rotation.
Another option, don't know if the DX6i has this ability, but the DX7 has the ability to mix the throttle with the gear switch. With the gear switch "down", the throttle is dead. With the gear switch "up", the throttle is active. This is not original with kyleservicetech, I found it in the internet.
Electric Flight Safety
Ideally every electric aircraft you have should be equipped with an arming device on the craft itself
(either and ESC switch or power interrupter plug) as well as having a throttle cut switch on your
transmitter. Since electric motors can startup unexpectedly and inflict a lot of painful damage the
double precaution can avoid some nasty injuries. Although an arming switch/plug on the aircraft ought
to be sufficient on its own there are times when it is armed with the intention of flying but something
distracts you and the aircraft is now vulnerable to a careless jog of the throttle lever, the transmitter
becomes your last line of defense.
I have implemented a transmitter disable switch for all my aircraft (helis as well as conventional planes)
this way the process is second nature to me. The idea is that whenever the aircraft is not expected to fly
the transmitter switch is in the disable position. The moment before takeoff I switch it to enable, fly as
required then the moment the aircraft touches down and I have completed taxiing it I always click the
switch to disabled.
Some of the more advanced transmitters have the ability to set a throttle cut switch up within their
menus however others need a little work to make it happen. Below I give the process needed to set up a
Spektrum DX7, it is likely this technique can be used on other transmitters, it is well worth doing and if
you are still unsure how try looking online for your particular transmitter.
In my case I use the switch at the top right hand corner of the transmitter as the kill switch, this seems
to be a standard as far as I can tell, the DX7 does have a label saying HOLD for this switch (as well as
Setup Process For the Spektrum DX7 Transmitter:
From your selected plane setup menu (pressing scroll and select simultaneously) move to one of the
mixing channels (kyleservicetech used Mix 3, for mixing with the gear switch).
Select source and destination for the mix to be THRO (short for throttle), the display should show:
THRO -> THRO
Now move to the rate section and set both sections to -100% (you will be able to set one of them with
the throttle stick down and the other with it up).
Move to the SW: section and set it to MIX
Move to the OFFSET section and set it to -100%.
If you toggle the gear switch you should see the text to the right of the THRO -> THRO change from OFF
to ON, when this reads ON the throttle is disabled (this should be with the switch pulled toward you).
THRO->THRO ON RATE: -100%-100%
Carefully try this out with your model turned on, with the switch toward you it should not be possible to
start the motor at all (even helis should be disabled despite the position of the idle up switch). And, as
always, check all remaining transmitter functions for both direction and unexpected operations. In case
something else got changed by accident.
All that remains now is to cultivate the habit of ensuring the switch is in the disabled position whenever
you pick up the aircraft and whenever it is not on the flying field.
Last but not least, be sure to set the throttle trim to center, or zero off set. If this is not done with the DX7, throwing the gear switch can change the throttle setting at the idle speed of the ESC.
Retired and the days are just too short, busier than ever!