Range Check Problem
 

I started up the engine on my just finished quarter scale Waco today for the initial check before flying it for the first time. The plane range checked just fine with the engine off, but when we started the range check with the engine running, all the servos started to jump when the receiver was in front of the plane at 10-15'. The G62 has RCIGN's ignition conversion which never gave an oz of problem on the plane it came off of. I found by touching the rigging wires for the top center wing, the interference stopped, and would restart as soon as I let go. Any suggestions as where to start with trying to solve this issue would be greatly appreciated.

Notes:
The rigging wires do cross and touch in the fuselage.
Hitec 5645 with Futaba S3004 on the throttle
Futaba PPM receiver
Ignition battery 8-10" from receiver

RE: Range Check Problem
 

[8D] exact same problem with the same engine and ignition. I moved the antenna out of the fuse and away from the the control rods going to the tail plane.. Range was then great and the Giant Aeromaster and Ralph g62 is a superb combo...

Don//

RE: Range Check Problem
 

Don,

I was just thinking the same thing regarding the antenna, and will try your suggestion tomorrow. The antenna runs right between the two elevator control rods and real close to their corresponding servos.

Thanks,

Chuck

RE: Range Check Problem
 

You have already solved the problem. If touching the rigging wires makes it go away, moving the antenna most likely will not fix it because the RF still exists. On pull pull systems for Giant scale rudders I always place one wire inside a section of push rod tubing, that way the wires cannot rub on each other.

So I would take a piece of tubing and cover one wire right where they touch inside the fuselage.

Plastic soda straws work well also

An easy way to install the tube is to slit it then "snap" it over the wire. It must be long enough so that if the tube slides on the wire it does not slide enough to allow the wire to rub again

RE: Range Check Problem
 

Spray the wires with WD-40.

RE: Range Check Problem
 

Chuck, which Waco is it?


Bob

RE: Range Check Problem
 

Well, antenna location is the problem, I moved it out of the fuselage and the problem still exists. I'll try putting some space between the rigging wires tomorrow and see what happens.

Bob,
The Waco is a Peter Barth kit. Proctor Enterprises sells it here in the US. If you are interested in the plane, PM me with your email address and I'll send you some construction pictures.

http://www.proctor-enterprises.com/p.../waco/waco.htm

RE: Range Check Problem
 

Looks like turn buckles on the rigging wires. Put lock tite on the threads.

RE: Range Check Problem
 

Well, I'm not having much success, just lots of frustration. I epoxied the rigging wires on the top center section so they wouldn't rub and the interference is still there. It was 20 degrees out yesterday and prop wash on the hands was a killer, so testing was short. Removing the antenna from the fuselage didn't help either. The interference does increase with engine speed. I've done a little searching and found several comments regarding the rigging acting as an antenna creating interference on a biplane, and that a PCM receiver should be used. The supplier of the plane also said to use PCM. I've always tried to eliminate interference and fly a plane with PPM before switching to PCM, but it's starting to sound like that might not be possible. Does any one know much about flying wires causing interference on biplanes?

I've got a few more things to try yet as the process of elimination continues.

Chuck

RE: Range Check Problem
 

" all the servos started to jump when the receiver was in front of the plane at 10-15'. " Did you mean to say, " when the transmitter was in front of the plane " ? How does it perform with the transmitter behind, or off to the side of the plane. The flying wires could be blocking the signal from the front. I had this same problem with some complex wire landing gear. I had to run the Rx antenna up to the fin. Try running it out to a wing tip.

> Jim

RE: Range Check Problem
 

Jim,

Yes you are correct about the transmitter, not the receiver. I really haven't noticed any interference from the side or back now that you mention it, but really haven't checked it enough. I'm going to check out it thoroughly tomorrow even if it is 20 degrees out.

Thanks for the suggestion.

Chuck

RE: Range Check Problem
 

Example of RFI vs Vibration
Antenna down, engine off range check 200 ft
Antenna down, engine running, range check 100 ft... classic case of RFI this is a 50% reduction in range. Max reduction is 15%
Antenna down, engine running, range check 10 ft..... classic case of vibration induced funnies. Problem areas, bad RX, bad switch, bad battery, bad servo(s), metal to metal contact

RE: Range Check Problem
 

Kevlar rigging?......lot of re-work but.............

RE: Range Check Problem
 

----------------


Switch out the conductive rigging wires for Kevlar rigging wires.

Running metal, or other conductive material, rigging wires is asking for trouble. The radio waves and the RFI from the engine will be reradiated by the wires.

Also, the original signal from your Tx will be reflected multiple times (multipath in radio jargon) and will confuse the decoder in your receiver.


Ed Cregger

RE: Range Check Problem
 

Chuck, tkg may have diagnosed the problem as vibration induced funnies. When you say that you can touch the rigging wires and the noise stops, are you using your bare hand. If so, try using a non conducting object such as a towel or stick. Can you remove the rigging wires?

With my G-62 on a Giant Aeromaster I have a lot of interference from the engine unless I do a little bit of shielding. Here is a photo of the shielding and it would be real easy for you to try in the event that the noise is coming from the ignition and not from vibration. I used aluminum foil. I got this shielding hint from Terry or Bill at CH Electronics.

I've been flying a 1/3 scale Bucker Jungmeister for several years with a full set of functional flying and brace wires and have never had a bit of RF interference from these. All joints must be kept tight. I also am running a PPM receiver. I think it would be a big mistake for you to mask the problem with a PCM receiver. Receiver lock up and crash is not a pretty picture.

RE: Range Check Problem
 

I was at an IMAA fly in where a modeler had the same trouble with a 1/3 scale Sopwith Pup. He had changed to a PCM receiver and claimed he solved the problem.
On his first flight the receiver went into PCM hold and he lost the airplane.
If you want to fix the problem change to non conductive wires.

RE: Range Check Problem
 

Chuck, if you have solid contact with the aircraft from the rear or sides, then it's not RFI or vibration related. Your flying wires are simply shielding the incoming signal when you stand in front. You have got to get your Rx antenna reoriented. Try it out to a wing tip, or go to non conductive wires.

> Jim

RE: Range Check Problem
 

Well, I'm frozen, 20 degrees out and prop wash on the hands is a bear. Anyway, I get interference from all side of the plane, front, rear, and sides with the antenna inside the fuselage and outside attached to the fin. However, I did notice something, the interference is affected by the location of the radio. Standing in a given spot where the interference is real active, moving the radio a couple of feet up, down, sideways will stop the interference. From the side of the fuselage, the radio has a clear view of the antenna without the flying wires blocking the signal. Any comments on this?

Chuck

RE: Range Check Problem
 

Well, I'm frozen, 20 degrees out and prop wash on the hands is a bear. Anyway, I get interference from all side of the plane, front, rear, and sides with the antenna inside the fuselage and outside attached to the fin. However, I did notice something, the interference is affected by the location of the radio. Standing in a given spot where the interference is real active, moving the radio a couple of feet up, down, sideways will stop the interference.
That is pretty normal with an interference problem. However, you need to be interference free at least 150' in any direction from the plane with a collapsed transmitter antenna.

From the side of the fuselage, the radio has a clear view of the antenna without the flying wires blocking the signal. Any comments on this?
The flying wires don't in any way shield the antenna at the frequencies (72 or 50 mhz) that we use for our planes. If you were using 2.4 Ghz this might be a different answer. My Jungmeister has flying wires, landing wires, and brace wires all over it and there is no sign of interference. Not to mention a big landing gear wire set.

You need to, once in for all, determine if the interference is ignition related or vibration related or........

You can temporarily shield the complete ignition wire with a piece of aluminum foil wadded around the wire and cap. Ground the foil to the plug with a clamp or tie wrap. Are you using a resistor plug such as a Champion RCJ-7Y?

RE: Range Check Problem
 

Bill,

I don't believe it is the engine causing the interference because I have quite a few hours on it, and has never been a problem. However, as you say, the ignition has to be eliminated so I will try your aluminum foil suggestion. The conversion is a RCIGN which are a better on interference. The plug is a resistor type, most definitely.

I got thinking over lunch and realized I used a metal clevis to connect to the tailwheel metal control arm on the pull-pull steering system. Could this be a contribrutor? I don't know why I did that, and it's buried inside tail.

Chuck

RE: Range Check Problem
 

I don't believe it is the engine causing the interference because I have quite a few hours on it, and has never been a problem. However, as you say, the ignition has to be eliminated so I will try your aluminum foil suggestion. The conversion is a RCIGN which are a better on interference. The plug is a resistor type, most definitely.
You are correct, it may not be the ignition. Where is the ignition battery located? Is the receiver, servos, switches and battery at least 10" back from the ignition and it's battery? Is the ignition switch located near the engine? Is the throttle push rod non metallic?

I got thinking over lunch and realized I used a metal clevis to connect to the tail wheel metal control arm on the pull-pull steering system. Could this be a contributor? I don't know why I did that, and it's buried inside tail.
If the pull pull system is in a little tension then the metal to metal contact should ok. I doubt that this is your problem.
Are you testing with only the top center wing section mounted and the rest of the wing sections not on? Do the center section wing braces connect to wood or metal inside the plane?

On my plane all of the braces and flying wires use DuBro rigging ends with 4-40 screws to clamp onto the strut fittings thereby providing solid electrical contact.

My name is not Bill.

Good Luck

RE: Range Check Problem
 

Check your spark plug and make sure you do not have a carbon ball on the bottom. Make sure that your spark plug wire is not loose were it goes into the coil. Try changing your ignition/kill switch. Typically these are the culprets. As far as rigging goes any complete circuit of wire can block a signal. Example: tail wires all being metal. I will take 1 metal clevis and make it plastic. Any way try the above mentioned on the engine side and I bet you find your problem. And these days PCM always helps!!!!!!!

RE: Range Check Problem
 

Yes PCM can help. The trouble is you never know if it will help enough. If it don't then you have a real problem. its better to eliminate the problem if you can. Then use PCM.
The problem with flying wires is not shielding or reflections or multipath usually. They can be a problem but very unlikely.
The problem is vibration on the wires cause buildup of static electricity on the wires. This is the same thing as rubbing your shoes on a carpet. This causes a difference in potential between the wire and other metal parts. If this wire and the other metal parts are in intermittent contact there will be sparking at the contact area. You will not see it but your receiver can hear it.
The cure is to isolate the parts with plastic connectors, or bond the wire securely to the other metal part, or use non conductive flying wires.
This problem can come and go depending on the humidity.

RE: Range Check Problem
 

Well, my frustrations continue. The source of the interference is still eluding me and any more suggestions would be appreciated. Below is a list of what I have done to date none of which corrected the problem. Yesterday, I remove the engine and put it in a test stand. With the engine running, and the plane held a foot from the engine, there was no interference! This leads me to believe it is a vibration-induced problem in the remaining components of the plane, which there aren’t many.

Big Bird asked the question “Is the throttle push rod non metallic?” No it is metallic 6” long rod, but there is plastic clevis/ball socket on the throttle and a plastic control arm on the servo. Shouldn’t that be ok or could the metal rod by itself be a problem?

Chuck

By passed the switches for both the ignition and radio
Tried different batteries for both the receiver and ignition
Moved the ignition battery about 2’ from the receiver
Moved the receiver five feet away from the plane; this lessened the interference, but not much
Disconnected all the servos except the throttle
Disconnected all the servos except the rudder and manually adjusted the throttle
Switched receiver
Took off tail feathers metal bracing
Removed center upper wing section and rigging wires
Cursed

RE: Range Check Problem
 

I would get rid of the 6" metallic rod. I noticed that you never mentioned shielding the spark plug cap and ignition wire and grounding the shield to the engine. This is the first thing I wound have tried. It is about the easiest thing that you can try and it can be very effective. Using aluminum foil is only temporary to see if you need to go with a fully shielded ignition wire. Ralph puts together a really good ignition system but you will never know unless you try it. If you are slow, it should take you 5 minutes to do it.

RE: Range Check Problem
 

Ken,

You are right I forgot to mention shielding the spark plug. Early on, I tried the foil suggestion shown in your picture and there was no change. If the problem was an ignition spark issue, it should have shown up when the engine was running in the test stand while the plane was held right next to it. How would the metallic rod cause a problem if it is isolated on each end with plastic? That question has been running through my head all night, but I will try a non metallic rod tomorrow.

Chuck

RE: Range Check Problem
 

Where are your switches in relation to each other?I seen where you moved the battery packs around or something I wasn't quite sure on that deal.The metal carb rod needs to go south.
You said you unhooked all but one servo and it was still glitching ,the throttle I take it ?how far away are the servos from the CDI & battery 12!QUOT! min if possible.
This may sound crazy but one of my larger extra was glitching and I hadn't noticed but when installing the wing somehow the charging jacks had moved over to wards each other .no they wasnt even touching but it was plenty for it to glitch like a bugger .A shielded plug wire and resistor cap is standard equipment for my CDI planes .
I try as best as I can to get anything to do with the CDI away from anything that controls the plane ,Battery ,Switch and so forth.
Just for kicks what type of a radio receiver are you using I know its a PPM but what brand and model.

RE: Range Check Problem
 

I thought I finally found the problem. In removing the metal push rod, the solder joint for the clevis fell apart, it was a cold solder joint. My fault and it won't happen again. The replacement push rod was made from plastic push rod material, and much to my frustration, it didn't solve the problem. Since it is warm today, I was able to run the engine longer to do more diagnostic work. The plane uses push pull with coated steel wires for the rudder and tail wheel running off the same servo. Today, if I held the wires for the rudder, the interference pretty much went away, but not completely. Holding those same wires and touching the antenna sent the servos into a frenzy. This was all done with the wires for the tail wheel disconnected and sitting loose in the bottom of the plane. With those wires flopping loose in the bottom of the fuselage makes it difficult to say for sure what's the problem, but the next step will be the removal all four wires and see what happens. I'd rather not replace them with Kevlar because I hear it stretches, but if necessary I will.

Any comments?

Cyberwolf,
The switches are about 18" apart. The interference did not stop when both switches were bypassed. Regarding the servos, with the engine running with only a rudder servo connected to the receiver, and not the throttle servo, the interference was still there. With only the throttle servo connected, the interference was also still there. The ignition module is built into the engine mount which is RCIGN's normal practice and is around 16" from the receiver, but again with the receiver five feet from the plane, there still was interference....used a lot of servo extensions. The radio is a Futaba 9C and I have tried both a Futaba seven channel PPM and a HiTec PPM.

Chuck

RE: Range Check Problem
 

What is your tail wheel hub made of ?

RE: Range Check Problem
 

Kurt,

The hub on the wheel is plastic and the support structure is very similiar to a Robart retracting tail wheel, but it doesn't retract.

Chuck

RE: Range Check Problem
 

Chuck, I keep learning things. From this comment I did not know that you are using metal pull-pull cables.
"I got thinking over lunch and realized I used a metal clevis to connect to the tailwheel metal control arm on the pull-pull steering system. Could this be a contribrutor? I don't know why I did that, and it's buried inside tail."

I never use metal cables for pull-pull because of a previous noise experience that I had with them. I only use Kevlar and have never had a problem with them stretching. Pylon Brand makes a set of Kevlar cables for U-control. Buy one real for about $10 and you will have enough for 10 years.:)

Here is something to think about for your present problem or for future use. I use Kevlar on all of the tail feathers on my 1/3 scale Bucker Jungmeister. In these photos you will see that I use red plastic outer sheath to guide the cables through the fuselage. This way the cables do not need to be in an exact straight line. The yellow inner rod acts as a sliding bearing. The Kevlar is tack glued with CA to only one end of the yellow inner rod. With this system there is never any chaffing of the Kevlar.

Hang in there Chuck, when you finally fix it you will have learned a lot.

RE: Range Check Problem
 

One other thing I have not seen mentioned is to wrap all of your long extension leads around themselfs, just twist um up,this at times will also stop a noise problem ,Your Futaba radio should be fine.
Something that really bothers me is the fact you can run the antena out on the wing and still get RF .I use metal cable for my pullpull all the time plus flying wires W.O. any ill side effects.

The kevlar thats been mentioned here is great stuff, I wished I could get my hands on a roll.HINTHINT*L*

RE: Range Check Problem
 

I'm making progress. With the wires removed for the rudder and tail wheel push pull, the interference was significantly better, but not gone. I then saw that the ignition battery extension was wired tied with the throttle servo, another dumb one. Separating them made further improvements but there still was sporadic servo jumping. Then the engine started to miss, backfire and die, repeatedly, can't get any rpm's out of it over about 2,500rpm, missing real bad. Ignition battery voltage was 4.9V. I think there is a problem in the ignition electronics that has been amplified by a bunch of other things on the plane. So, until the ignition gets replaced, I'm done chasing the problem.

In the mean time, there is a lot to put back together on the plane, plus getting some Kevlar. When the engine is back from repair, I'll post the results. However it may be a few months depending the turnaround time on the engine.

Thanks for the help.
Chuck

RE: Range Check Problem
 

You might have one of the older circuits that sometimes failed, send it back, turnaround is one day on free ignition repairs..[8D]

RE: Range Check Problem
 

Ralph,

This is the one we exchanged emails on earlier this week. I will mail it out to you on Monday.

Chuck

RE: Range Check Problem
 

HUmmmmmmmm you may have been chasing your tail all along here with a faulty ign to begin with.

RE: Range Check Problem
 

My G62 came back from Ralph today, talk about turnaround, mailed it last Monday and got it back today. The goods news is the interference is gone and all servos are stable at all engine speeds. Yes, may be I was chasing my tail, but the plane is better for it. There were more than my usual amount of hicups during the debugging, but then it's a more complex plane. The Kevlar recommendation cleared up some issues with the tailwheel/rudder operation.

Thanks for all the help and have a nice Holiday!

Chuck

RE: Range Check Problem
 

Thats good news I hope its flies well for you .Merry Christmas to you also and a Happy New Year.

RE: Range Check Problem
 

I have the exact same problem with my G-62 in a TF P-47. I've tried most everthing and of course I don't have the flying wires that you have. But I do have metal push rods and wires for the tail wheel. I have replaced the RX and the TX and plugged in one servo at a time. And I have reposiitioned the antenna. The Jump start (I'm on magneto ignitioin) connector and kill switch are 12 inches from the RX wiring. I'm getting servo jitter with the engine running at about 50 - 60 feet.

Someone at the club said to shield the spark plug wire????? comments

Help please.

/colin

RE: Range Check Problem
 

Just to add my simple $.02. I was having problems with a TF Mustang and a PAU Edge, both have 3.2 engines, one is a Fox the other is a Brison.Range check on either one was non-existant, and I was using a PCM reciever. I know it's a no-no, but it's what I had already installed, well after going over and over, and getting no where, I decided to start at the battery,(6 volt), to the switch, and by chance I had talked to a fellow modeler and he informed me he was running 6 volts straight to the reciever, so I unhooked the regulator that I thought would be a good idea. When I tried the range check again, the range check was over 300 ft. Then a month ago, I had been doing some work on the Edge, I decided to put the antenna wire back inside the fuselage,( PAU had installed a tube to run it through), took it to the field three days later, started to do a range check and the plane went berserk. Now being 64 and some what feeble minded, I went to my garage to check my other radios, to see if I had left one of my radios on, and it wasn't, the field is behind my barn by the way and on the way back I remembered I had put the antenna back inside the fuselage, so I rerouted it back out side,( just tape it to the bottom of the plane) I was blown away by the fact the plane was rock solid, so go figure! Really baffles the mind, that would make that much difference.

Dale