How to program a throttle cut switch on the DX7?

[flymo]

Is it possible to program a throttle cut switch on the DX7. I could use the Idle2 position on the flight mode switch, but that would mean losing idle2. I already have throttle hold set to tick over. All thats left are the mixer switches, but I can only mange to get prortional responses on the throttle from these and end up overdriving the throttle servo.
I think using the throttle trim to kill the engine is unacceptable as it is not instantaneous (imagine the heli hurtling groundward in idle2....no time to wait for the trim to wind down the throttle).
Anyone got any ideas?

Thanks

[kgfly]

You have to use Pmixes. There are some examples here (search the thread for throttle cut) : http://www.rcgroups.com/forums/showthread.php?p=6765442
and a very clear example here: http://rc-soar.com/spektrum/

[flymo]

Kgfly,

Thanks for the response and links, but when the DX7 is setup in helimode and using idle1, idle2 and Hold, there are no pmixs left for a throttle kill function.....so back to square one I'm afraid!

[flymo]

Kgfly,

Appologies.......the Kill switch can be set up in helimode on pmix1. But in order for the throttle kill to work the heli needs to be in normal/hover mode at lowest stick...so really might as well use the trim as a throttle kill as stated in the manual!!

Cheers

[capebob]

I think using the throttle trim to kill the engine is unacceptable as it is not instantaneous (imagine the heli hurtling groundward in idle2...

That's what throttle hold is for. With throttle hold activated and used motor kill is instantaneous.

Bob

[kgfly]

Flymo - thanks for the clarification, I got that info from plank pilots and had not looked into the constraints in Heli mode.

Bob - It depends what the pilot is after, especially on a nitro where ThrottleHold simpy cuts the engine back to Idle, ThrottleCut is used to stop it altogther.

[flymo]

YES Throttle hold is a safety feature that "holds" the engine at idle whilst carrying the heli to the field or checking servo function. It is also used for practicing autos as it has an associated pitch curve. However when you are about to have a crash, you don't want the heli to hit the ground with the engine running at all! The reciever, throttle servo, throttle link could break and send the engine into screaming high revs.

[xStatiCa]

The DX7 has a neat feature called 'Throttle Recovery' for nitro helis that is disabled by default (Page 37). If enabled it will remember the trim setting on the throttle so that you can hold the throttle trim down to kill the engine and then just click once up on the throttle trim and it will return to where the previous trim setting before holding the trim down.

For electric helis the throttle hold feature works great except that fact that you can not start the tx up in throttle hold mode without it complaining :/. You have to turn the tx on and then flip throttle hold.

[flymo]

I think using the throttle trim to kill the engine is unacceptable as it is not instantaneous (imagine the heli hurtling groundward in idle2....no time to wait for the trim to wind down the throttle).

It's the "Throttle recovery" "throttle trim down to kill engine" i was refering to.

[xStatiCa]

I have not flown nitro in 16 years but I at first thought throttle hold would still work for that purpose(crash) because throttle hold puts the engine in an idle mode that does not engage the clutch and would minimize crash damage. My brain just started to work again and I see now where the flaw is in that... If the throttle lever gets bumped back up during the crash (doh!). I forgot all about that :/. Electric of course does not have that issue.

[helisforfun]

Is it possible to program a throttle cut switch on the DX7. I could use the Idle2 position on the flight mode switch, but that would mean losing idle2. I already have throttle hold set to tick over. All thats left are the mixer switches, but I can only mange to get prortional responses on the throttle from these and end up overdriving the throttle servo.
I think using the throttle trim to kill the engine is unacceptable as it is not instantaneous (imagine the heli hurtling groundward in idle2....no time to wait for the trim to wind down the throttle).
Anyone got any ideas?

Thanks

Im using AUX 2 switch set up in mix 1 here is a photo of my setup cuts the throtle on my Raptor 30 Hope this helps

http://www.helifreak.com/album_mod/upload/99f1f972448458fa9edf82faf234fccc.jpg

[capebob]

Bob - It depends what the pilot is after, especially on a nitro where ThrottleHold simpy cuts the engine back to Idle, ThrottleCut is used to stop it altogther.


I was addressing flymo's concern about his heli plowing into the earth at full power. Using throttle hold will eliminate that concern. Throttle hold has been the traditional switch of last resort for all of us who have found ourselves in the condition that flymo envisions. It's true that in some rare cases an idling engine has, because of impact forces, has gone back to full throttle, but that's extremely rare.

Bob

[helisforfun]

Thank you for your response Bob (capebob) I am using throtle hold to keep the engin at idle while practicing autos and to safly carry the heli form the table where I strated it to the spot I will fly from. And programed the aux switch to have an instant engin kill if and when needed. Now if only I could be lucky enough to remember to use it in an emregency. This assumes a nitro heli

JMHO

Bob

[capebob]

Now if only I could be lucky enough to remember to use it in an emregency.


That's the point. You will have practiced hundreds of autos, When you do have that emergency you will have a much better chance of hitting the hold switch, which you have hit many times without looking, than groping around for the aux switch which you probably have never hit without looking. JMHO It really doesn't matter too much, a smoking hole is a smoking hole. :)

Bob

[flymo]

smoking hole plus burnt out clutch liner, bent bellhousing brokenclutch, bent chipped main blade holders, all head links,arms ripped off and probably swash bust not tomentionallthe usual stuff like boom, blades, canopy etc......no not really worth programming a throttlecut is it.

[cdrking]

I'm with you there Bob. I've been flying for 11 years now and auto all the time but could I remember to hit hold or cut when I'm doing a 20 foot tail down tailslide before it smashes and takes a dirt nap. I doubt I could remember to do that. :glasses2:

Jeff

[xStatiCa]

I am have yet to hit throttle hold any quicker than 4 seconds after it hits the ground. I am busy trying to save it.

[flymo]

Maybe it's because I started with electrics that I feel I need a quick flip throttle cut.