Guys, I am helping a buddy get his 110 rascal going and when we do a range check it goes nuts. First time out, Futaba 7cap 7 channel Futaba receiver, go about 60 feet with antenna collapsed and the surfaces go crazy. Antenna up, everything works fine. We drive to the end of our flying field with antenna up and have absolutly no control with surfaces going crazy (according to the people looking at the plane). We go buy a new receiver (thinking this was the cause) and same thing. My buddy decided the tx and receiver were out of tune so he sent the new futaba 7Cap back and got a Hitec Spectra 11-60 Tx. We dialed in 45 (his channel) on the tx walked 60 feet and same thing, surfaces go crazy. So we started trying to locate something in the airframe causing it, funny thing is you put your hand in the plane the jittering stops. We disconnected servos one at a time thinking a servo was bad causing it but still did same thing. We then removed the receiver from the airplane and moved over on a work bench and range tested it hooked up to one aileron and we had no problems. With the receiver still on and connected to the aileron we walk over and dropped the receiver back in the airframe and the jittering started. My buddy held the receiver in his hand covering it and the jittering stopped. At this point I have never seen anything with this much Rf interference. Help!!

Forgot to mention this but he does have a 26cc evolution engine. We even tried range test with no igniton anything connected, ign battery, module or switch and it still went crazy from about 60 feet antenna collapsed. We even tried another switch and same thing. He is using pull pull on the rudder. Do you think we should slide a nyrod over one of the rudder cables and test again? One other thing we tried was holding the antenna straight up in the air out of the plane and it was a little better but still had surfaces twitching to extreme throws just not as violent. I'm telling you this thing is nuts.

A couple of probably silly questions.

Can you put the plane up on the bench or at the very least off the ground when you do your long distance range check antenna up. Often the close proximity of the ground will cause you some greif.

What servo extensions are you using. Twisted or flat cables. Are they knotted or tied up in a bunch at all. Or are they nicely layed out and tied so as not to be too close to rudder cables, rods etc.

What voltage battery pack(s) are you using.

Just a few questions to start with.

A photo of the installation would also be great if you can.

Kiwi

We did think about putting it up on a table for the far away antenna up test but didn't really try it. As for the servo extensions they are not twisted but the only long one in the airframe is the tail mount elevator servo which is strapped nicely on the bottom of the fuse (it is under the pull pull) but we disconnnected that servo to take it out of the loop and we still received the interference. The only place the servo wires are kind of together is right at the receiver which we have them nylon tie strapped as they go into the receiver. He is using 6 volt nimh pack, we tried a 4.8 as well and samething. I can try and get a picture of the inside tonight from him. I told him to go to radio shack and get the rf rings (ferrite)and slide over every extension to see if this eliminates the problem. Has anyone else had to use these?

Accaptain,

Did you try changing out the power switch to your reciever. I had the same problem one time and sure enough I made a switch with it and it solved the problem.

Originally Posted by iflyrc3Dstyle

Accaptain,

Did you try changing out the power switch to your reciever. I had the same problem one time and sure enough I made a switch with it and it solved the problem.

Yes we tried another switch as well, still same thing. Any other ideas?

are u using a metal pushrod on throttle?

Is there any metal near the reciever?
How's the antenna run?
Are there any 90 degree bends in the antenna?
Is it run outside of the fuse?
Is the antenna run together with servo wires that might cause interference?
The pull pull cables might be Causing interference when run in parallel with the antenna also.
Did you try testing the plane at another location?(i.e. at your house?)


50%

quick question - was the plane near a chain link fence or trailer - ive gotten the same thing when i was near a trailer one time and a chain link fence another

seth

The throttle pushrod is nyrod and no I have not tried it anywhere except at the field. Like I said it worked fine at the field outside the airframe on our work bench. We tried it with the antenna in several locations including holding it up and out of the fuselage which helped some just not sure if the hand on the antenna did anything. The antenna is not bent nor running close to servo's or extensions. The only thing metal in the plane is the rudder pull pull cables.

Yes there is chainlink at our field but it was at least 30 foot away from the receiver (also it worked fine outside the airframe. The one and only thing left I can think of is the rudder pull pull cables.

We will try some nyrod over one of them this week.

30 ft away shouldnt have bothered it . . . hmmmmmmmm . . .

are all of the servos and everything in the plane new or have they been used on another airplane?

There all new, Hitec 475HB servos. There is a Jr on the throttle. Really strange, I have not seen anything like this before.

What frequency is he on?
Was anyone else flying at the time?
Are ya'll near an interstate or trucking lanes?
Is there any construction going on nearby?

Originally Posted by 50%plane

What frequency is he on?
Was anyone else flying at the time?
Are ya'll near an interstate or trucking lanes?
Is there any construction going on nearby?

He is on 45 and no there was only one other person at the field and he was not flying. There is no interstate within many miles of our field. I have range tested other things here before without incident. The only thing I can think of is those darn pull pull cables. We pretty much eliminated the receiver or transmitter because it worked fine away from the airframe. Also eliminated the servos, switch and battery as we tested each one individualy.

How far on the ground with the antenna up should you be able to control the model? Is the range more once it's in the air above the ground? Like I said in an earlier post we did not try raising the airframe from the ground when we did the antenna out test from the back of our airfield. There was nothing blocking us from the airplane when we did this but the plane was on the ground and not up on a table.