CRRC Pro GF26I

[ipsik]

Did you either replace your receiver on/off switch or just plug the radio battery in directly? a bad switch here will show up under vibration. It has happened to me

[Wingman26]

	Quote: Originally Posted by ipsik
	Did you either replace your receiver on/off switch or just plug the radio battery in directly? a bad switch here will show up under vibration. It has happened to me

I've replaced the ignition power switch, then I plugged the ignition battery directly into the ignition module. I haven't messed with the receiver switch up to now, I'm not getting a flashing light on the receiver which is supposed to happen with a power problem, I can bypass or replace that switch easy enough.

I'll try to get some stills on the radio and engine installation, I might be able to do that tomorrow, weather prediction for tomorrow calls for wind gusts to 40 mph, so I sure won't be flying!

[wilde1j]

Wingman26, just curious, are your long leads (elev, aileron) twisted? From my poking around on this topic, twisting the servo leads seems to be the single most effective solution (along with physical distance from RFI sources). I don't have much experience with gas yet, but have routinely always twisted any long servo leads (and never have had any problems), but not sure whether or not I would have otherwise. In the work environment I was in for many years, we had routine applications of very long (sometimes thousands of feet) leads for low level voltage and current signals and always used twisted leads, sometimes in grounded metal conduit or cable trays, other times in plastic conduit, etc. My understanding was twisted leads were imperative to avoid RFI pickup. BTW, we never used ferrite beads, etc. for dealing with interference. Just a thought.

[Wingman26]

Elevator extensions are the longest, and they are twisted, you will note that I am getting glitches on the elevators as well as ailerons.

On the ferrite ring, I also run electrics, as an example I have the 3D Hobby Shop Extra 300SHP 47" wingspan. I have had glitches on that size electric before, at least when I was on 72 mhz, I finally ran onto a post about reducing interference on electrics by using a ferrite ring or beads in the receiver power line to reduce glitches. I was having a heck of a time with glitches on that electric, after reading the post about ferrite rings I added one to the lead between the ESC and the receiver and it stopped the glitches completely. Since it was suggested that the throttle servo might be picking up interference from the ignition, I added a ferrite ring to hopefully filter that out, but it seems that the throttle servo probably isn't the guilty party in this case.

I'm going to try replacing the receiver power switch this afternoon and hopefully will be able to run it for a few minutes and check it out. That plane has been essentially ready to fly for a couple of months, but engine issues and bad weather have both been conspiring against me, Jody got me fixed up with a new ignition module which helped tremendously, but now I'm having the glitch issue to deal with, hope I can solve it soon cause this plane is begging to get airborne!

I'm also new at gas, but not RC, here's a photo of me in 1969 with my first RC plane, it had a Citizenship galloping ghost radio and was powered by an Enya 09 glow engine! That's 41 years ago!

[3Dguy]

Maybe you can try unplugging servos one by one? Perhaps the vibrations at that RPM cause something to jiggle loose... just a thought. Sorry in advance if you've already tried that.

[Wingman26]

OK, here's a test with a different radio power switch. With the eingine cutting out like it is, it seems like its ignition related, the plug that was in it was pretty new, but just to be sure I changed the spark plug for a brand new one, engine running was somewhat better but it was still glitching. This video is before I changed the plug.

YouTube- Engine test 4 28 2010

[ipsik]

It seems like you have a definite radio problem, what happens if you run the engine with the radio off and operate the throttle manually with a rod or even manually turning the servo arm if you can reach it. It seems like the engine burps ar coming from the throttle servo jumping along with the elevators and ailerons.

good luck

[Wingman26]

Photos as requested

[wilde1j]

I would consider putting any RX related wring, including power, in a braided shield(s), tied to RX ground or battery (-) and twisting all servo leads. Hard to tell what is in the forward area, where RFI will be strongest.

Make sure the braid is only grounded in ONE place, or ground loops will be introduced.

One other thing might help. If you could place a grounded piece of metallic screen aft of the ignition, but forward of the control system, that would serve to prevent RFI from propagating to the RX and servos. Where I worked, they had an RFI testing facility and it had all five wall surfaces covered with a grounded screen, to prevent testing from adversely affecting other areas of the facility, since very high levels of RFI were being introduced. Also, they didn't want any external RF sources affecting the test facility. A ground shield is a very effective method of controlling RFI. The screen should be tied to the same ground as the braid above.

[Wingman26]

I'm familiar with a Faraday cage. All the servos are Hitec's, and the leads come twisted from the factory, and I've introduced a mild twist in the long extensions for the elevators. I may have some solder wicks, so I might be able to use those as braided shield.

[Jedijody]

There should not be any need to apply any type of Faraday shielding. I don't want to sound critical but it's a little hard to tell what's going on in the fuse, for such a small plane there seems to be a lot of wires going all over the place. I only see 1 battery, it looks like a 2 cell Lipo I don't see a regulator or an ignition battery.

It looks like you have ignition system wires tied up or laying on top of radio wiring or servos, one of your satellite antennas is mounted less than an inch from a switch, if that's the ignition switch that's not good.

Sanitize the wiring, completely separate the radio wiring from the ignition wiring, I put them on opposite sides of the plane. I've had RFI from bundling ignition wires and radio wires together in the past, that's why I don't do it anymore.

[wilde1j]

Jody, I agree, and not being able to tell what was where, suggested the bigger wrench idea. You're certainly right about segregating all ignition stuff including power from all the RX related stuff. I have a plane which has the throttle servo mounted on the engine box and used some 3/8" metallic braid over the servo lead. Hopefully that will work, since I didn't have many other easy servo choices.

[Wingman26]

All ignition related wiring is forward of the wing tube, there are two wires from the opto kill switch that are behind that line, the wire connecting the opto kill to the receiver, and the wire for the LED indicating the opto kill switch is power on. The ignition battery is beside the fuel tank wrapped in foam, and the ignition switch is right behind the firewall.

Photos below show the location of the components.

[flymoor]

I would seriously consider at this point sending the radio to the maker to have it checked out for trouble, I run the same motor and am not any better with my set up on several planes with other gas and glow applications, and have never had a glitch. It could be the battery itself or connecting wire. It is true that I do not run ingnition wire and receiver servo wires together, but with my spektrum seven have never had even a hint of glitch. If separating the wires does not help and perhaps a change of battery, then I would send in the radio and see if there is something wrong there.

[Wingman26]

I have run several different batteries on both the receiver and the ignition during the various tests I have been running, none of the ignition wiring is within 4 inches of the receiver wiring with the exception of the throttle servo. The opto kill switch is connected in the photos since I was wanting to show the setup as I had originally intended it, the opto kill switch hasn't been hooked up in any of the recent tests, it was in place but nothing was plugged into it.

I have a (already flown) 6200 receiver that isn't in a plane right now, if there is some way to run 2 elevator servos on the 6200 I might be able to make that work since I can always put a Y connector on the ailerons. I can test it with only one elevator servo hooked up if I need to. This 7000 receiver is new and hasn't been in a plane before, so it hasn't been proven, I just got the DX7 and the 7000 receiver for this plane, I couldn't figure out an easy way to run the dual elevator servos on the DX6i and 6200 receivers I already had.