Cyclic Hardover

My Feedback: (3)

Now although I am in the lower end of the giant scale, i have not done the gasser yet but I am putting together a plan. I have been around the big gassers here since i started this a few years back but never really paid much attention to certain items.]
Usually when they start these up ,they stick their finger in their and manually run the choke. Somebody here lately either had on or suggested a choke run by a servo and a switch on the TX. This sounds like a good idea which i am going to consider on my setup. Any comments on it? Thanks

mglavin

My Feedback: (31)

I install a servo activated choke on all my gasser's. It's easy and offers a secondary method of killing the engine if need be...

extragiles

I use a separate choke servo on all my gas A/C as well. There are many resons for having it the most important being a backup incase you can not kill the engine with the throttle. The rules for gas engines I believe require you have some sort of kill from your transmitter. I use the choke instead of any of these electrical devices on the market. But the best reason for the servo is the ease of starting. No more reaching under the plane to turn on the choke and getting gas all over your self.

Allen

Cyclic Hardover

My Feedback: (3)

This is good info and thanks, I use "throttle cut off" on all my planes right now instead of the trim swtich but thanks.

citation X

My Feedback: (6)

Cyclic Hardover-
Throttle cut off works great as long as your throttle servo is funtioning properly, But it is best to have an alternative source to kill the engine, so the choke servo double's as a kill switch in the event of a throttle servo failure plus the convenience of not using you fingers to push-pull the choke. Ricky

Stick Jammer

Another vote for the choke servo. It can be a good mini, a Hitec 225BB works for me.

Cyclic Hardover

My Feedback: (3)

You know its really amazing how much people are influenced by others. Now we have some real IMACC Giant scale pros here and I mean this. There is one particular man who is basically the humble pro and all go by his lead yet not one of them have this servo operating their chokes. Go figure!

ncsanik

My Feedback: (1)

I am pretty new to the giant scale scene but i was thinking on putting these three in my plane: servo choke, servo on/off for ignition battery, and throttle cut off. do you guys thing this is overkill or not [sm=thumbup.gif][sm=thumbdown.gif] (it is going in a 35% Extra 330, if that makes a diffrence). thanks guys.

Stick Jammer

Hey Cyclic,
Sounds like you could start a new trend in your neck of the woods!

Stick Jammer

fli4fun,
While you can never be too safety conscious, I think the servo operated on/off for the ignition battery is a little much. I personally like having the option of manually switching off the ignition when the plane is on the ground. If you set up the throttle servo so it will kill the engine when fully closed and you have a choke servo as well, chances are extremely rare indeed that you will ever need a third option. If both of these options were to fail in an emergency, you've most likely had a complete electrical system failure in which case a servo for on/off ignition would be useless anyway. Smart-Fly (and others I'm sure) makes an optical ignition cutoff that kills the engine if a complete loss of battery power or receiver failure occurs. I personally like to put things together with a reasonable safety cushion while at the same time keeping it simple.

R/C Foolish

My Feedback: (6)

I'm not new to gas but new to Zenoah. What do you guys do for them? No ignition battery or module. Do you just use a servo for the choke or is there any other way to kill a magneto other than a manual switch?

John

RickP

My Feedback: (2)

This is where me and Ricky see eye-to-eye. You have one mechanical method to kill the motor (throttle) a mechanical linkage to the choke is a good secondary but it is still mechanical and subject to the same mode of failure. Worst case being if your mount comes loose and the mechanical linkages are now ill-adjusted. You can still kill the motor with an electrical cut off.

I saw something slick where someone used a standard radio servo and ran a nyrod to the switch for isolation. Cheap, but you save weight by leaving out the choke servo.

Basically both work and it is a matter of preference. Servo isolation is important and it is only necessary to do one or the other. choke servo or kill switch.
RickP

sfaust

My Feedback: (11)

I've personally seen this happen on more than one occasion where the mechanical methods were rendered useless, and the electrical method did, or would have come in handy. I had a Cap231 that had the muffler loosen up which changed the engine dynamics such that I could not idle down or kill the engine with the mechanical method. I flew the airplane for almost 30 minutes trying to run it out of gas and perform a dead stick landing. Another friend of mine (sorry Mitch) had his engine mount break loose and jammed his throttle linkage such that he basically lost control over the throttle. If he had an alternate method to kill the ignition, he could have shut it down and landed dead stick. Unfortunately, he couldn't and was flying it around trying to come up with a solution to the problem when the engine finally vibrated loose and departed the airframe with the expected consequences. There are a few other instances very similar.

I use a throttle kill switch instead of the throttle trim for the mechanical shutdown via the throttle servo. I also use a ignition kill switch as backup to the mechanical setup. And I use a servo operated choke mainly for the convenience of starting, but it also provides another method of shutdown if ever required. When I hit the throttle kill switch it turns off the ignition via the ignition kill switch, offsets the throttle linkage to fully closed, and operates the choke servo to fully closed. All three methods assure the engine is stopped. The choke servo is also closed momentarily by pushing the snap roll button for starting. Once I hear the engine cough with the choke on, I just let go of the button and it continues to run.

RickP

My Feedback: (2)

Hey Allen,
What could be simpler then this? Plus I have no choke servo so my airplane is lighter then yours
RickP

Forgues Research

My Feedback: (7)

After 3 years of flying with the choke servo in there, I have yet to have a problem. But then I do regular maintenance in case something is coming loose, or bad wires etc.

Remote choke to keep the finger away, and a perfectly good kill switch. By the way, at the end of every flight, I shut the engine down with the choke servo.

choke servo


Roger

Stick Jammer

There you go, preventive maintenance. The single most effective way of minimizing ANY potential problems. I'm not by any means insinuating about anyone on RCU, but too many people treat their R/C planes like the car that they drive. Just put gas in it til it don't work no more.

mglavin

My Feedback: (31)

One could argue a case for the potential to create EMI with this setup...