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Radio problem, interference, or what?

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Old 07-13-2014, 01:33 AM
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aframe2
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Default Radio problem, interference, or what?

I was so excited yesterday when I fired up my new DLE-55 for the first time. I adjusted the high
speed needle valve a couple of clicks and its purring like a kitten. All systems seemed to be go, or
so I thought. I'm looking for screws to vibrate loose, which I had a couple; no big problem. I'm going
through the controls, elevator rudder, and then I get to the ailerons. They work fine, they just happen
to cut the engine out when I deflect them. I couldn't believe it at first. I thought my engine had finally
got the hiccups from running and being new. I stopped all control deflecting and the engine is
running once again like new money. I deflect the ailerons once again and the engine cuts out. I can stop
the engine if I hold the aileron stick one direction or the other. If I hit it and let it go the engine will hiccup
and come back strong. Has anyone experienced this problem with their radio or engine. I am using a
Spektrum DX-8 with a 8 channel receiver. Any constructed criticism will be greatly appreciated.
Thanks, Aframe2
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Old 07-13-2014, 02:10 AM
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Steve Percifield
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Are you running any type of engine kill device?

are you running the ignition from the receiver battery?

Try disconnecting the servos from the receiver and trying it. If this works, you have a servo/s binding, over amping and causing a voltage drop, that maybe causing a receiver failsafe which would shut off the engine.

make sure there are no mixing programs active.
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Old 07-13-2014, 02:20 AM
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aframe2
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Steve, Yes I am using just one battery, for the recover and the ignition. I also have a opto kill switch installed. Did I hook it up wrong? Aframe2
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Old 07-13-2014, 03:11 AM
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flyinwalenda
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Maybe you have a mix enabled in the transmitter, a bad servo, too small of a battery or regulator.?
First : remove the opto kill switch from between the mechanical switch and the ignition box and then try it again and see if it works OK. If so then something is activating the opto switch as you move the ailerons . You would need to look for a mix turned on in the transmitter.
If the problem is still there then
Second: disconnect the aileron servos , start the engine , move the aileron stick and see if the engine still quits. If it runs OK then either one of the servos is bad and pulling down the battery or regulator and/or the battery regulator is maxed out and can't provide the current to the ignition box. Check the servos ;if OK then plug in a separate battery to the ignition and try again.
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Old 07-13-2014, 03:16 AM
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Steve Percifield
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I am not a fan of using 1 battery. no matter what others argue, it provides a path for interference back to the receiver. I would try a couple of things. unplug the opto kill switch and try running it. If that doesn't do anything then try a different receiver. I would try running the engine with a dedicated battery. You're going to have to isolate things 1 at a time until you find the problem. I would start with the receiver first. It's hard to guess without being there.

I;ve been running these engines since the 80's and still retain a lot of the old habits. I know it's common today to run the ignition from the reciever battery, but old habits are hard to break, and I never will do that. 2.4 or not, I will keep the ignition parts as far away from the receiver parts as i can. Many things on the engine/ignition system can cause Rf and interference. A bad plug, a bad module, a bad plug cap, a loose wire..etc...The 2.4 stuff is resistant to most, but not 100% imune. I also know that a few years ago, opto cut off switches were creating a problem for early Hitec 2.4 systems. I don't know what that was and I know they corrected it with a programming change. That's why I suggested try running the engine with the switch disconnected. It's trial and error. Good Luck. steve
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Old 07-13-2014, 03:50 AM
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flyinwalenda
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I agree with the single battery comment. On a 50cc plane I can't think of any reason to not use a second battery for the ignition
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Old 07-13-2014, 04:10 AM
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aframe2
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Thanks guys for all of the advice, going to work on it today, will let you know the results. Aframe2
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Old 07-13-2014, 04:59 AM
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lopflyers
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Weird, never heard of that before, I vote for a weird mixing
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Old 07-13-2014, 05:17 AM
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CafeenMan
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Sounds like a weird mix or or you're battery can't handle the amperage draw. Or maybe the wiring from the battery can't handle the amperage draw.

I too just ran a DLE 55 for the first time this week and I have (4) high voltage (HV) servos on the ailerons, (2) HV servos on the elevators, (1) HV servo on the rudder, (1) HV on the throttle and (1) HV on the choke. I have all the throws set up for max (about 45 degrees) and the whole time the engine was running I was deflecting all the controls as far as they would go. No problems or hiccups.

I have a 2500 A123 for the receiver with two leads going in and an 1100 A123 for the ignition going through a mechanical switch then an opto switch.
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Old 07-13-2014, 06:05 AM
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It seems tome that if moving the aileron servos causes the problem then the FIRST thing to do is diconnect the servos!
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Old 07-13-2014, 06:19 AM
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All Day Dan
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Here's a quote from the Futaba website that has merit. Send your RC manufacturer an email and see what they say. Dan.

Guidelines for setting up gasoline engine models. All ignition equipment, including an electronic kill switch, must be mounted at least 12", and preferably 14", away from all radio equipment, including throttle servos, etc. Ignition kill switch should always be on opposite side of fuselage from radio kill switch. All pushrods going to anything related to the engine must be non-conductive (just nonmetal clevises is not sufficient).
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Old 07-13-2014, 06:36 AM
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Does the throttle servo move when the aileron servo moves?
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Old 07-13-2014, 09:51 AM
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Airframe:
Do this to see if you have a mix issue in the programming. Take the wing off but have it still hooked up the the receiver. Turn everything on but do not start the engine. Make sure you can see your throttle servo. Now move the ailerons with your transmitter back to where the engine died. Look at your throttle servo when you are doing this. If it moves you have a mix set somewhere in the programming. All you need to do to get rid of that is either null it out or do a new setup for a new airplane. If the throttle does not move you got some EMF occuring and sometimes the optical kill switches on spektrum radios do not get along with each other. Also if you have a "Y" connector anywhere in the airplane this is another thing to try and get rid of especially in Spektrum setups. I did not have an issue with a "Y" connector when I was flying with JR but my Spektrum DX7 did not like the "Y" at all. Some may have no issues but just one thing to eliminate. Another thing is to ensure your spark plug boot is firmly seated on the plug. One more thing is to ensure the receiver and the ignition boxes are not close together.

You said you are running one battery. I would recommend you use 2 batteries. One for ignition and one for receiver.

Hope this helps.

Regards
Glenn
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Old 07-13-2014, 11:20 AM
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Granpooba
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Originally Posted by flyinwalenda View Post
I agree with the single battery comment. On a 50cc plane I can't think of any reason to not use a second battery for the ignition
Ditto ! But will add, I can't think of any reason not to use a second battery for ignition on any size gas model.
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Old 07-13-2014, 01:07 PM
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Len Todd
 
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I have several gas planes. Never built one that was based on a single battery. Using a single battery creates a direct hardware path for the RF interference generated by the CDI and Engine to the Receiver. Actually, I never built one that did not have two batteries on the Receiver. A second battery on the receiver is cheap insurance, and I have had one battery failure where the second battery has actually saved the $5K plane.

Also, the throttle linkage is the second direct hardware path for the RF Interference to the Receiver, unless you have a non-conductive linkage. However, I personally believe that one non-conductive connection is enough to brake any direct circuit (Basic Electricity 101). But, ... I personally like two and a carbon fiber rod. But, this is a path has to be addressed as it is a path for both engine and CDI generated RF.

My Spektrum gear has always worked great. Having three or four Rxers scattered all over the plane gives me more confidence. Reading the Flight log data and having alarms on it also adds to the trust factor. I trust Spektrum to my jet and giants, as many other pilots do. Don't want to start a gear war.

I do have Smart-Fly optical ignition kill-switches. They also work great, especially the ones that have the built-in voltage regulators. Using an optical kill-switch is the only way I know of eliminating that RF path back to the Rxer.

Bottom Line: With a CDI, in most cases, you have to isolate it electrically from the Receiver, and there are two paths to consider.Anything less is a crap-shoot!
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Old 07-13-2014, 05:15 PM
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Check that the ignition cap is pushed solidly onto the plug.
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Old 07-13-2014, 05:52 PM
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Len, the only optical kill switch that I know of that provides both RF and conductive isolation is the Smart-Fly version. All the others use the term “optical” in a reckless manner as they only provide conductive isolation. You mention that you use carbon fiber pushrods to you engine. Carbon is a poor conductor not near as well as metal, but still a conductor. Is it sufficient to avoid RFI or is plastic the only way to go? Dan.
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Old 07-13-2014, 06:05 PM
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You're begging for trouble by not using a BEC for the ignition if you truly feel you must run the whole plane on one battery. I think a better route is redundant receiver batteries that go to both the receiver and the BEC. That way you have redundancy to both systems with no weight penalty compared to the separate battery setup.

So what battery and servos are you running? Have you checked your amp draw?
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Old 07-14-2014, 03:46 AM
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I believe it is a programing or setup issue, I say this because in 2006 I built a 40% Carden 260, and flew it over 500 flights with a Spectrum DX-7 with two batteries plugged into a single Fromco switch that powered the ignition and receivers on the same circuit without a single hickup. I did this as a test bed after speaking with the boys at Desert Aircraft about their ignition modules and Fromco that set me up with a switch the had a two battery input and a 3 power supply output. Anyway I am happy to say the 260 is still alive and well today.



Bob
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Old 07-14-2014, 09:39 AM
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Originally Posted by sensei View Post
I believe it is a programing or setup issue, I say this because in 2006 I built a 40% Carden 260, and flew it over 500 flights with a Spectrum DX-7 with two batteries plugged into a single Fromco switch that powered the ignition and receivers on the same circuit without a single hickup. I did this as a test bed after speaking with the boys at Desert Aircraft about their ignition modules and Fromco that set me up with a switch the had a two battery input and a 3 power supply output. Anyway I am happy to say the 260 is still alive and well today.



Bob
Its very hard for fliers to believe that it is virtually impossible to interfer with 2.4. They keep dredging up that obsolete Futaba warning. Why does Futaba keep it on their website? They still sell 72mhz equipment.
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Old 07-14-2014, 10:21 AM
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The truth is; 2.4 is just too far away to be of any concern, just like the old rule of placing the throttle servo a minimum of 12" away from anything to do with the ignition module, those are old school issues that I just don't worry about any more.

Bob
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Old 07-14-2014, 01:09 PM
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aframe2
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I didn't worry about that either Bob, until my aileron control started controlling my engine. Now I'm worried. Aframe2
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Old 07-14-2014, 04:42 PM
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Like I stated in my first post, you most likely have a programing or set up problem, maybe even a chaffing problem of sorts or something along those lines. Best of luck finding your issue.

Bob
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Old 07-14-2014, 06:09 PM
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Originally Posted by dirtybird View Post
Its very hard for fliers to believe that it is virtually impossible to interfer with 2.4. They keep dredging up that obsolete Futaba warning. Why does Futaba keep it on their website? They still sell 72mhz equipment.

Virtually impossible Yes, but not Impossible. I have seen First hand two Different DA85 ignitions on a twin engine airplane go bad and cause serious RF intereference with a 2,4ghz radio system (JR), and this was with the receiver 6 feet away from the nearest ignition and 14-16+" away from the nearest servo.
The only difference between the one flight where it worked w/o interference and the next day we went to fly it and it caused interference was the date. Had i not of seen it first hand i would of had a hard time believing it, and the guy who owned, built and flew the model has been involved in the hobby for a long time, so it wasnt a newbie mistake that was done.

Last edited by invertmast; 07-14-2014 at 06:11 PM.
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Old 07-14-2014, 06:49 PM
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As soon as you hooked the ignition to the receiver circuit you introduced all the old 72 MHz bug-a-boos into your system plus a few extra. Isolate the ignition battery and power the receiver with a seperate source.

I still like my old magneto gas engines. No ignition battery to fret over.
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