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9C gasser kill sw from dual rate on Throttle

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Old 05-16-2003, 05:51 PM
  #1  
mikenlapaz
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Default 9C gasser kill sw from dual rate on Throttle

Just exploring an idea to eliminate using a Chan and seperate servo for a remote kill switch on a gasser. New to RC and appreciate hearing the pros and cons.

Conditions:
1) Total linear control rod travel at the butterfly lever is about .50". This arm will travel past full open position about .1875" or more;
2) Servo with .62" length arm provides about 1.0" travel;
3) Remote gas kill switch lever arm requires a maximum travel of .09" to activate (close the N.O. switch)

Physical Setup:
1) Near the fire cut a lengthwise slit in the pushrod guide tube for a "T" control lever to contact the kill switch arm or cut guide and pushred at desired spot and secure both ends to fuse;
2) Cut a piece of bike spoke and fashion into the "T " shape;
anneal and thread as needed, retemper if desired;
3) Cut inner pushrod thread on "T", feed thru one side of guide tube, insert balance of pushrod from other end of guide tube, attach the other part of the non-metallic pushrod from far end.

Linkage: setup for full range (butterfly) of in mid travel range of servo (set as ? lower rate ? ; mount kill switch to be activated in some manner ............
This is where my knowledge of radio programming is insufficient .
Possibly:
1) when a switch is flipped from low to high rate,
2) use of throttle trim
OR ....... (share your thoughts)
Activation: Either flip the switch rotate the knob and push the throttle to full. The RPM and thrust increase in a fraction of a second should be minimal.

Advantages (preceived): Eliminate 1 servo cost and weight, opens up one channel on the Rx ....

Disadvantages: You furnish ..........

Any specific instructions on how to program this on a 9C would be appreciated .
Checked the manuf. site, found the thread aerobatic 8 chan. which included request for gasser kill switch, which manuf. did not address. No answer to a seperate request for elaboration.
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Old 05-16-2003, 05:59 PM
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R/C Foolish
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Default 9c set up

I have a 9C setup for my Patty Wagstaff with DA-50. I use top right triple rate switch as my idle down (center) and kill (down),
I am using upper left switch as fiber optic kill. And using left hand side slide as choke (up-off, down-on). Even though I am using servo for choke this gives me redundancy for engine kill. Throttle linkages can get messed up so I still have a way to kill engine electronically. I wouldn't want to wait until fuel runs out.

Hope this helps,

John
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Old 05-16-2003, 08:21 PM
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Default 9C gasser kill sw from dual rate on Throttle

RCFoolish:
use top right triple rate switch as my idle down (center) and kill (down),
idle down per man.P.33 kill = THR-CUT per man.P.34 (Both function off Chan 3) Ryobi would not die with butterfly closed; sodered small hole in butterfly closed, awaiting test stand run.

upper left switch as fiber optic kill. And using left hand side slide as choke (up-off, down-on).
I do not visualize/ understand how signal is sent to the FO kill unit? Does it take a dedicated chan on RX?
I visualize the choke on a dedicated chan. with its own servo. Correct?
Is it correct that you are using 3 Rx chans in your set-up for enginge management? 2 for fuel and 1 for elec. ignition

Rx 148DF (8 Chan) Presently got all assigned except Chan 5 Plane US 120 Quad
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Old 05-16-2003, 09:15 PM
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Default 9C gasser kill sw from dual rate on Throttle

Thats right, using 9 ch. PCM reciever.
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Old 05-19-2003, 10:01 AM
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amcross
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Default 9C gasser kill sw from dual rate on Throttle

Mike,
Your approach doesn't take into account that the most common need for a kill switch is loss of contact with the throttle servo due to pushrod failure, vibrating off the throttle arm, throttle servo failure, throttle servo mounting failure etc. Many of these happen frequently flying gas models due to the vibration from the engine, etc.

Otherwise, yes your approach COULD be used. You would need to do several things....

1. do a mix of throttle to throttle, active only above half stick, which limits how far the throttle servo moves in response to the throttle stick.

2. do an offset mix, OFFSET to throttle, +100% (for starters, play iwth it later) to offset the throttle servo in the clockwise direction to complete the process of shutting off your engine. it would also require you to be above half throttle for the shutoff to work.

(You can't do a "position" mix where you say, "hey throttle, no matter where you are, go here".)

3. you have channel 5 free. why not simply use it for your separate electronic kill?
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Old 05-20-2003, 05:54 AM
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Default 9C gasser kill sw from dual rate on Throttle

AMCross: Not trying to 2nd guess or be smart, just trying learn from those with experience.

most common need for a kill switch is loss of contact with the throttle servo due to pushrod failure, vibrating off the throttle arm, throttle servo failure, throttle servo mounting failure etc. Many of these happen frequently flying gas models due to the vibration from the engine, etc.
1) Is it a standard practice to use lock nuts and Locktite on the carb lever connector (ball swivel in this case)?;
2) same procedure for connection metal to inner Gold n Rod?
3) same as above for connect at servo arm?

(You can't do a "position" mix where you say, "hey throttle, no matter where you are, go here".)
I was visualizing, Whoa! This engine (Throttle) is out of control .., then flipping a switch and advancing the stick to get the extra movement to activate the remote kill.
[SIZE=3]DAAAA! I see the point. Dumb to put the safety directly on the link your trying to have a back-up for![/SIZE] I now know where I'll drill and mount the kill switch. Ch 5 and a seperate servo it is.
These posts serve multi-purposes 1) to get the person think out options to a problem, then put it in writing and 2) the chance to hear back from a forum.

Still curious about ?'s 1-3 above just from a safety and good construction point of view.
Thanks
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Old 05-20-2003, 03:51 PM
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Default 9C gasser kill sw from dual rate on Throttle

Mike,
Happy to share/help out! You're doin it exactly right....always best to ask first rather than try to undo something that it turns out a dozen other people have already figured out is a problem....

this is especially true with gas engines...ignition noise is an issue lots of modelers have beaten their head on the ground over before...

your pushrod setup for throttle and kill alike MUST BE (repeat that MUST BE) non-metallic in nature. non-metallic clevises are not enough to shield you from noise. don't try to use a cable in tube or pushrod in tube.

Yes it is common to do everything you can think of to secure the throttle linkage in place.

Be sure you have at least 12" between ANYTHING IGNITION (including a manual kill switch) and ANYTHING RADIO. mount your manual kill switch on the opposite side as your radio switch. Mount your kill switch and throttle servos at least 12" back with nylon or other non-conductive pushrod materials.
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