Interference, engine on - orientation dependent.
 

So, I've got my new gasser out for it's second day of flying, and get hit after about 5 minutes up. Land right away, take it back to the pits. I watch it for a half hour with the engine and xmitter off and there are no glitches to be had.

Run the engine - at first, no glitches, then start seeing the problem as I walk around the plane (with an assistant holding of course). The glitches only occur with the engine running and with the transmitter (8U with 1 segment up) pointing directly parallel to the fuselage. I'm thinking this is either because the antenna runs from the wing TE to the fin (also parallel to the fuse) or because of the aileron extensions which would be perpendicular to the antenna during the glitching.

I have all the standard remedies in hand, twisting wires, ferrite beads, separation of ignition system. What I'm looking for is if anyone has ever had similar TX position/orientation dependent interference and what was most effective in curing it?

BTW - engine is Brisson 3.2 with CH ignition.

Thanks

Interference, engine on - orientation dependent.
 

I don't know if this helps but it worked for me. I was having the same kinda problems with a brison 2.4 on my sig cap. Intermitent radio hits. I tried everything. It turned out to be the manual ign. switch i had bought. I bought a toggle switch from radio shack. It is the kind that you solder the wires onto the poles. I went with a cermark hd rx switch and it cured the problem.

I had used shrink wrap to cover any exposed wiring but i guess it wasn't good enough.

Interference, engine on - orientation dependent.
 

Sounds kinda silly asking, but are you running a resistor spark plug with a grounded plug wire? Is there any metal to metal contact on your aircraft?

Vince

no problem
 

With a newbie, no question is too simple. Even though I was quite sure of the answers to your question, I still got up and rechecked. The plug is a Bosch R10 371. I'm assuming the R10 means resistor. However, maybe I go see if Bosch has an on-line guide to be sure. The braided ground shield is tight to the barrel of the plug with a hose clamp that is completely immobile. The plug wire type is the regular rubber cap, not Bosch, not McDaniel.

AS far as metal on metal, I even cut the pull-pull cables off of the aluminum tiller and removed them from the airplane to be sure that wasn't the problem. Even my lead ballast pieces are wrapped in tape to prevent them from rubbing.

I have not yet twisted wires - but I'll be doing that first. ANybody know a good placxe to get the right kind of ferrite beads? Local radio shacks are out of stock - don't look like the right size beads anyway. Right now I have some long leads going to 4 wing surfaces that really aren't very well protected.

Interference, engine on - orientation dependent.
 

Call CH and they will tell you to get the BOSCH plug cap.. It will help trust me. It is like $ 10.00.

Last season a buddy at the field bought a Brison 2.4 and I Got a Fox 2.4. Mine came with Bosch cap and his came with rubber cap. I never had a problem. He got all kinds of radio glitches and finally sent his in and got the bosch cap. Problem solved.

When you talk to CH they will tell you why some companies don't run the bosch cap.

Good luck

Bosch cap
 

Thanks for the advice. I believe I will send the ignition in soon to have it checked over - and have the plug cap replaced. I still need to find a good source for the right kind of ferrite beads to get on these long wires.

Beads?
 

I have two Brison 3.2's with the rubber caps & have never had any glitches.I've seen other Brison 3.2's with the rubber caps - no glitches.If these caps cause rf, Brison wouldn't use them & neither would anybody else.Could be the rx ....I'd try another one & then do a proper range check(engine running-at all throttle settings,antenna down,walk away) before taking off.
Any way, what the heck are ferrite beads???? I have seen ALOT of gassers & have not heard anybody using ferrite beads.

This worked for me.
 

I had a similar problem. I found that when I moved the receiver antenna away from the long servo leads that ran to the tail group that my problem was solved. Try moving the antenna to different locations before you rip up too much stuff. Test this like crazy from as many perspectives around the plane as are possible on the ground. Worked for me.

Interference, engine on - orientation dependent.
 

I too had an identical problem. Only difference is I was on glow. I changed the battery and switch just to be sure. I also rerouted my antenae. This is what fixed it. I think the push rods were doing something weird. Try just running your ant. out towards a wing and taping it there for trials and see if that helps. remember that metal will shield the ant. behind it. I spoke to a EE about installing ferrite beads (metal cores like on your monitor) and he couldnt see that it would help too much due to freq at which the servos run. He suggested a grounded sheild around the wires instead.

Some cardinal rules for gas...
 

:p Thou shalt obey these "Cardinal Rules" when "Gassing"

1. Thou shalt use a plastic pushrod for thy throttle linkage.

2. Thou shalt keep all thine radio gear at least a foot away from thy engine.

3. Thou shalt use a high quality kill switch which doth not vibrate in its parts

Observe these rules, lest the ground come upeth and smote your airplane mightily due to interference.

Interference, engine on - orientation dependent.
 

Although Glowplugboy came down from the mountain with the
"3 gas radio installation comandments" ,what do you do if these
suggestions do not help??? The bosch cap fixed 90% of my glitches,making a plane that would glitch on the ground at 50ft.
to one that was flown over 50 times sucessfully.Now the bad
news, ALOT has been writtien about Futaba radios having less
than stellar output and are much more likely to have glitches
in certain installations.Some are blaming receiver filters,others
say it is poor T.X. output.I fly only Futaba,and still my gassers
glitch once in a while,while other flyers at the same field with
the same engine-plane combo,but different radio brands have
no problems at all...Any help or suggestions on this radio
problem would be nice. P.S I have tried 5 different Futaba
receivers with the same results...

Interference, engine on - orientation dependent.
 

Hay Knife-Edge Buy a Hitec tx and all your problems will go away. I've tried to tell you newbies these little secrets but you just don't listen. Some day you may though. Good luck.

new plug cap myself?
 

Hey Finnz - is that bosch plug cap the kind of thing I can do myself, or is it something I need to send the ignition to CH for service on?

Bosch
 

I would send it to CH because then you know it is right.

Interference, engine on - orientation dependent.
 

The Bosch cap just screws onto the end of the wire..Can't be too hard...Some of the C&H ignitions have a shielded wire to the plug..The shield is soldered to the bosch cap....

replaced whole wire
 

Got on the phone with Bill at C&H. Gave some good advice. He sold me the bosch cap already attached to the wire. I just had to open the box, unwrap the heat shrink from the coil, and replace the whole wire and cap. Had to find electrical grade RTV to secure the wire, and some new 1" heat shrink to re-cover the coil. No big deal though.

Now that I've got the new wire on, I'm working on the timing. I'm a bit confused, because in order to get a good setting for the low end, it's too retarded at the high end - and there's no good way to adjust the amount of travel the pushrod provides on this Brisson. Already posted on another thread anyway............