Ok, I have been flying for many years but just got into gas engines.
I am setting up a BME 50 up on a GP Patty Wagstaff but here is my question:

Do I have to set the choke up on a servo? And if so, How do I do it (see pics)?
The degree of the arm would not work with a servo.
The first pic is with it closed and the second is open. Look at the arm. How can I get that to work or do I need it hooked up to a servo?

Thanks for your help
David

I can not give you any SPECIFIC tips withthat combo, BUT

You do NOT have to use a servo, but it is a good idea....You can use a piece of control rod and put a "HOOK" on it to reach in and operate the choke through a small hole in the cowl....This can even be made a permanant fixture

OR

remove the arm on the CHOKE and solder it back on in a position that makes the geometry better.....It is nice to be able to use a servo on the choke...if you really get into it, you can take the choke completely out and remove the BALL that ratchets the choke. This would allow you to use the FLAP POT on your TX to adjust the choke to what ever you may need for the cold days....The choke also serves as an alternate method of killing the engine.

Can you kill these engines by pulling down to idle and putting the trim all the way down? I would like to have a way of killing the engine throught the radio.

Any others out there that have this engine/airframe combo?
Like to hear your thoughts


Thanks
David

Yes you can set the travel so that pulling the throttel trim and stick all the way back will kill it, the check will serve as an ALTERNATE method

Ounds good, would it start if you don't choke it?

I really doubt it......Typically the best starting procedure is......

1) Ignition on, CHOKE ON and flip till it farts
2) Ignition on, CHOKE OFF and about 3 or 4 flips till it is running

You will have a hard time getting that initial correct AIR/FUEL charge without choke on

Hey thanks, With the way the choke is, I don't think I can put a servo to it. I'll just put a small hole in the cowl to acsess is by hand since it is close to the cowl.


David

I have that combo exactly. The servo hook-up is easy. If you have a dremel tool with the composite cutoff wheel, use it as a grinder and remove that small brass lip from that arm. Once you have ground it down level, the arm will pop off. Buy a $2.00 dubro steering arm, some nyrod, a servo, set it at the angle you want, and you are good to go.

14th reaper, how did you get the steering arm to stay on?

I'm a little bit nervous to take a dremel to my new $550 engine.


Thanks
David

I have not seen anyone put the choke on a servo. On all of my gas engines, I simply reach in and close the choke by hand. If you can reach the lever, use that. If you can reach the butterfly itself, use it. As far as a positive way to shut the engine down other than the throttle, you can put an e-switch in your battery feed to the ignition and assign that to an unused channel of your Tx. I have several of both and don't really have an opinion. You can also use the throttle down switch on your Tx - if it has it - and use that to kill the engine using throttle only. I set that up last year and really like it.

Dan

Actually, no need for the dremmel. Just grab the end of it with a pliers and work it up and down till it comes loose. Quite simple. Then use the nylon steering arm (like the ones used on the front wheel of a trike setup) The whole process takes about 5 minutes.

On my GP Patty with a BME 50. I just attached a bit longer arm on the choke lever and positioned it so I could reach it from the normal opening in the cowl.

Jemo, Overall, how do you like this combo and what is your AUW?

Hey guys, I don't think I am giong to rig it up on a servo.


Thanks for all your help
David

No servo, wasted weight and complication in the aircraft.

Just put a screw in the choke arm with a nut above and below the arm to retain the screw. Now the screw will stick straight up and become a handle to operate the choke.

You stick your finger into the cowl from the front intake vent, and push the screw to the side closing the choke. Flip it until it runs and quits, and then push the choke with your finger back to open, flip it 5 times and it should pop on the 4th and run on the 5th flip.

To kill the engine in the air or away from you, just pull throttle to idle and trim full back. If you are next to the plane you can do the same or just turn the ignition switch off. Works fine and no need for extras (kill switch or servo on choke).

Nice engine, enjoy!

-=>Raja.

The advantage to the choke servo is that it offers a "backup" kill system in the event of an emergency. Let's say for whatever reason, your throttle is stuck wide open while in the air[X(] An extra 2-3 oz is nothing to be concerned about. Not at all complicated. You do, of corse have the option of a fiber optic kill switch.
Really, I can't think of any reason NOT to use a servo.
1 Simple to set up
2 Convenient
3 Minimal weight
4 SAFETY, SAFETY, SAFETY.

Just my opinion. Merry Christmas.

I have the BME 44 and it is exactly the same setup as the 50, the 50 just has more power. You dont have to use a servo in which matter of fact im not. Its much easier to just drill a hole in the cowl, then stick your finger into the cowl and push the screw to the side which closes the choke. Flip it until the motor farts then turn the ignition off and stick your finger back into the cowl and push the screw the opposite way you pushed it to close the choke which reopens it. It should pop on the third or fourth flip and should run on the fifth. By the way yes you can shut the motor off by radio if you do this. The servo will just add weight to the aircraft and will be much more complicated.

Later!

Thanks for all your replies, I think I am not going to put a servo on it.

Hoping to test fly the plane on Satarday.


Thanks again
David

Geneh_RCU

I am curious to know how you can shut the engine off with the radio without a choke servo if the throttle servo should malfunction???
Hop on a flying broom ??
Poor advise IMHO.
Once again. These things are not toys and safety should be priority 1.

Much more complicated? Please explain. 1 servo, 1 pushrod.

Here's the senario.
You are on your last flight for the day. You fuel up and take off. Your throttle for a number of possible reasons sticks at 1/2 throttle. What runs out first your gas or your batteries. Cross your fingers.

"You dont have to use a servo in which matter of fact im not"
2 wrongs don't make a right.
You probably took alot of time building this plane. Trying to make it perfect. Don't get lazy now. Take 5 minutes and install that servo.

Good luck with your maiden flight.

Crash, you are so right. The first flight on my patty the throttle did stick open... wide open. I don't remember the exact reason why now, but it taught me a valuable lesson. A simple servo on the choke is cheap and easy to do, repairing or replacing a plane as beautiful as the patty isn't. Fortunately, my Patty flew nice easy circles until it ran out of fuel and landed safely. I won't have another gasser without a choke servo.

No choke servo on my BME 50 setup. I used a short piece of wire thru the cowl with a ball link on the choke arm.
Normal engine kill is low throttle and low trim (just like a glow engine).
Emergency kill is with an electronic switch in the ignition line (as mentioned in post 10), I'm using the rc-100 switch from RCAT Systems. Around $20 and weighs almost nothing. Plugged into the retract switch channel.
Works well with no problems.
I did however install a choke servo on my ZDZ 80 in another plane before I found out about these e-switches. That works well also.

Hmmm... Now second thoughts


Another question for the BME; Where are you guys putting that wire that comes off the spark cap? They tell you to DO NOT SOLDER but I did heat shrink it.


And one More question? I have head not to have any eletronics within 12" of a running gasoline engine and that is O.K with my setup BUT the ignition box is not. The receiver is about 11.5" from the ignition box. Do I need to change this? There is A LOT of wood between the two but does it still matter? I'm probably going to run the motor tomorrow so we will see. What oil do you reccomend for break in on this BME 50?


Thanks for all your help guys
David

You will hear different opinions on this matter. Some say 8" and others will say 12". At 11.5" you are fine. Just make sure you do a ground check with your radio with the engine running. Perform your check at idle and at full throttle.

I think that most people are clamping the ground wire right to the base of the spark plug with a hose clamp.

As stated in an earlier post. An electronic kill switch is a good alternative to a choke servo.

I am using lawnboy ashless for the first 5 gallons then switching to amsoil 2000. I also used a hose clamp to secure the ground wire to the plug. This is a very nice engine with lots of power in the extra. THe ignition module can be closer than the rest. Good luck with yours and I hope everyone has a great Holiday Season!

Thanks again,
and hope all you guys have a very, merry, Christmas (or Chawanika)



David

Guys I don't have a dog in this hunt, but I do have a question. What would keep the choke from opening or closing in flight if there nothing attached to it to keep it from moving around?