AU flyer

My Feedback: (2)

Has anyone come up with a good way to operate the choke with a servo. The lever to operate the choke is at an awkward angle to operate with a servo. Any suggestions...and/or pictures?

Tired Old Man

My Feedback: (1)

The angle can be easily changed!!

Simply use a Dremel cut off wheel to gently grind the retaining flange off the end of the choke shaft. Dump the stock choke lever and replace it with a nose wheel steering arm and collar of the appropriate size. Set the angle to suit your needs.

Another thought... Do away with the choke servo altogether by adding a rod to the above that hangs out the bottom of the cowl. Push-pull. Really easy and save the weight of a servo while eliminating an accidental method of shutting off the engine in flight. That happens to people all the time. Use the throttle trim to shut down the engine. You will still have an ignition switch as another way to shut off the engine.

TLH101

My Feedback: (90)

Check the first pic in this thread:
http://www.rcuniverse.com/forum/m_3331039/tm.htm
has an added belcrank to operate the choke.

Wings-RCU

My Feedback: (2)

I would never go without a choke servo! Use a mini servo & link the control to a rotary knob. You can set the choke where ever you want during starting and you will never accidentally shut it off in flight. A mini servo with linkage is only 1oz so the weight penalty is minimal.

Geistware

My Feedback: (16)

Just use a bell crank to tun the motion 90 degrees
I have had 2 2.4 and one 3.2 brison.
It works great.

buchtes

My Feedback: (7)

no need for a servo, run a short piece of 4-40 all - threaded to a ball link- bolted to the choke lever- to the out side of the cowl, 4-6 flip's with the choke and it sputters, choke off, and she's ready to run. No hassle- no pain, KISS theory.
Works for me all the time

Geistware

My Feedback: (16)

I would recommend that if you don't want the added safety of killing the engine with the choke. I can kill my engine with a switch to cloes the throttle or one to close the choke.

Wings-RCU

My Feedback: (2)

Although a rod sticking out of the cowl is easy & simple, i'm not convinced it's a good idea. Moving the idle trim down is painfully slow if you have digital trims. The engine cut switch doesn't always work very well with a gas engine. (The throttle butterfly doesn't close completely like it does on a glow engine). That also means you may need to retrim your idle every flight. I think that is the reason it's required by the IMAA...so you can instantly kill the engine from the transmitter. I think it's fine if you have an opitical kill switch or some other transmitter controlled ignition kill switch. I found that a choke servo, besides controling the choke, is an instant kill and you don't need anything else.

buchtes

My Feedback: (7)

flipping the trainer switch twice quickly kills my Brison 3.2 every time.
6 EXA Futaba

Tired Old Man

My Feedback: (1)

Since when does the IMAA require a choke servo? Unless the rules changed, they only require a switch that will cut power to the ignition. Properly adjusting the trims on the transmitter and the length of the throttle push rod will eliminate any problems with a throttle trim lever.

Wings-RCU

My Feedback: (2)

You don't need a choke servo! According to the IMAA You only need a way of killing the engine from the transmitter in addition to a on-plane ignition switch. Cutting power to the ignition from the transmitter is the best way, but also not required. You can kill the engine with the throttle trim if you like. The reason for this, is to kill the engine in an emergency. The best way to kill the engine is to cut power to the ignition. Choking the engine also works well. For some people like buchtes a throttle cut will work like it does on a glow engine. It's your choice. I just think a choke servo accomplishes both of these task well with little cost or weight penalty. If you would rather have a rod sticking out of you cowl for the choke and using some other method to kill the engine from the transmitter that's fine.

Tired Old Man

My Feedback: (1)

Thanks for the clarification.

kolarshooter

My Feedback: (1)

I used a 4-40 ball link at thr choke arm, and a wheel collar to grip onto. Pull out - choke closed...push in - choke butterfly open. Weight penalty: a few grams.