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HelicopterGasser Model RC HelicoptersOther › RC230 Surge - Fixed!
08-13-2007 05:39 AM  10 years agoPost 1
andrewp28

rrApprentice

Toronto, Ontario -​Canada

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I was flying my Benzine a while back and was having a surge problem. About every 7 seconds or so the engine would speed up like it was going lean. I thought - tuning? insulator? RF? Bad Stator Gator/GV-1? Color on the plug had been good so I was hesitant to re-tune. I had just installed a new Champion RZ7C spark plug. Did a little testing - governor off: no surging; governor on - surging. So, was it stator gator, GV-1 or throttle servo?

None of the above - as a quick test put in an NGK CMR7H and problem disappeared for good. I could have spent many pointless hours troubleshooting other components. Sometimes it is easy to forget to try the simple things first. Just thought I would pass that on.

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08-13-2007 01:50 PM  10 years agoPost 2
chinnook

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Corpus Christi TX​USA

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Glad to hear everything is good to go. I installed the NGK type plug, and could not get the surpressed cap to fit properly, so I am sticking with the champion, no surges so far. Rene.

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08-15-2007 02:19 AM  10 years agoPost 3
Disciple4123

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USA

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Glad to hear you have it fixed, while we are on the topic of suppressed caps and plugs: I had the NGK suppressed cap, and an Iridium long plug for a while. I got a failsafe activation, several acutally, and eventually found that the NGK suppressor had unscrewed off of the wire, and was thus adding a spark gap at the wire and at the plug. It ran strong, but failsafe'd and I caught it before it separated.

Is this a common problem, looks like a flimsy way of joining wire, esp when the factory wire is already a bit short. Also let us look into it deeper, is there anything about the NGK cap that is special? Can a black rubber plug boot from a car, slipped over the stock assembly, Do the same thing? I recognize that Iridium plugs have less resistance than Champions, but are reportedly better quality. Now if I want to run a slight EMI sheild effect, I can experiment, such as by putting a grounded aluminum box/sheet-curve around the entire plug area of the engine, etc. Any thoughts?

I posted-->
http://runryder.com/helicopter/t239297p1/?highlight=rfi

a year back, just trying to get the current climate of opinion on this.

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08-15-2007 05:11 PM  10 years agoPost 4
AceBird

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Utica, NY USA

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a year back, just trying to get the current climate of opinion on this.
I am sorry to say but this concept is all wrong (my opinion). Eric, I removed your coil with the wrapped wire “ground” and bought a new one. First I tried to replace it with an automotive wire but I couldn’t even get a spark. The voltage from a magneto must be too weak as compared to the high energy ignition systems of today’s automobile to get through the carbon conductor.

Why do I say the concept is wrong? Because shielding is normally done on the receiving wires not the source wire causing the RF. You would have to shield every wire within the radio system to do any good with shielding. What is normally done to the source wire is insulate. After I cut your shortened wire I spliced on an ordinary #12 copper wire to the plug so I could at least run the engine. Over the whole length of wire I slipped a heavy walled silicone tube as an insulator and flew a short while with it like that with no RF problems. Either with the APi or the FS8 I always monitor frame losses. The #12 wire has an insulator plus the air gap and then the heavy walled tubing which is enough to prevent RF but it doesn’t look pretty so I bought a new coil. Your “ground wire” could very easily have been some of the reason for your vibration problems. If it robs the plug of energy by grounding you would be getting misfires or inconsistent weak explosions. Grounding / shielding the HT wire is a mistake (my opinion). It is the last thing you want to do on a Zenoah engine. If you want to improve the insulation on the HT wire you can slit a rubber hose so you can get it over the wire. Face the slit part towards the engine cylinder and tape or tye-wrap it in place.

I am not in favor of cutting the wire but I am in favor of moving the coil.

Ace
What could be more fun?

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08-16-2007 02:05 AM  10 years agoPost 5
FCM

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Surrey, England

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Before you shield and ground your HT lead, make sure the lead and plug have good insulation properties i.e. you don't want any 'leakage' from the plug cap/HT lead joint. The suppressed NGK plug cap I use comes with a nice rubber boot that does not 'leak'.

I then apply self adhesive aluminium foil to the plug cap and the braiding from inside a length of coax cable. This is then attached with tie wraps to the HT lead with a length of solder braid grounding it to the engine casing.

The whole thing can be tested using a simple ohmeter to check for continuity and provides nearly 100% shielding for the HT lead and plug cap. The next test is to run the engine and use a testing probe to check for leakage. The probe I use is for testing microwave oven door seals.

You should then do a engine-on ground range check and compare the results with engine-off. Using this method of shielding has meant I get similar range with engine on or off.

Hope this helps,

Paul.

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08-16-2007 07:00 AM  10 years agoPost 6
Disciple4123

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USA

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Brian: I have a foggy recollection as to the events pertaining to the Predator I sold you, but I recall the out of round HD clutch as being the clear source of vibration, not a plug wire modification. I welcome your comments in my library of notes on the subject, I hold no degrees on radio engineering, just a cursory understanding of the principles. I'm just an end-user trying to ensure safe operation.

FCM: OK, I use the same NGK plug cap, now has yours unscrewed from the wire yet? That was my problem. If I get the time I may get an old ascilloscope and do some testing. RFI is something that we can never take too seriously. If a remedy other than the NGK cap that came apart, can be had I'd like to hear of it.

Thanks,

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08-16-2007 01:45 PM  10 years agoPost 7
FCM

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Surrey, England

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I use NGK supressed caps on both of my Benzines and have never had a moments problem with them. They work very well with NGK plugs which is all I will use on my engines as the Champions I can get are very poorly made and have caused RF issues due to their resistance suddenly breaking down.

I have replaced the HT lead on both of my coils as the standard length is too short. This may explain my lack of problems with the NGK cap?

Paul.

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08-16-2007 09:36 PM  10 years agoPost 8
AceBird

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Utica, NY USA

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The whole thing can be tested using a simple ohmeter to check for continuity
Checking for continuity with a VOM doesn’t really tell you much because the voltage source is flee power. The industry standard for checking the integrity of the insulation on a wire is a high pot test. Just because a rubber boot doesn’t leak today doesn’t mean it won’t leak tomorrow. Because of ozone oxidation over time it will eventually leak. That is why you replace your ignition wires in your car when you do a tune up. Putting a physical ground (shield) next to the insulation will insure degradation of spark over time.

Eric you are correct the primary cause for the vibration in your Predator was a messed up clutch. I vaguely remember that you had some tuning issues with this engine and that is what I was referring to in your attempts to remove vibration. Maybe I am misconstrued.

Ace
What could be more fun?

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08-17-2007 12:30 AM  10 years agoPost 9
Disciple4123

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USA

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I have replaced the HT lead on both of my coils as the standard length is too short. This may explain my lack of problems with the NGK cap?
I looked at some picutures in your (FCM) gallery of the plug wire, too small to examine. What did you do to replace the plug wire? I've read another post of a person yanking the wire out and replacing it, but is the replacement wire cemented in, or how is physical integrity maintained?

Apart from Brian's indicated failure using an automotive plug wire as a replacement on the Pred I sold him, I think that some further investigation in that area is warranted. The typical 8mm silicone jacketed wire, connectors, and boots used in automotive applications have the appearance of being better made than the brass strand wire job Zenoah offers.

The reason I am getting paranoid with RFI this week is because I'm about an hour of build time away from completing the twin engined Vario, 2 sparkers must be worse than one , and I don't want any problems. For now I have two NGK suppressor caps, 2 iridium plugs, and 4 Denso U-groove plugs, so there's a little hardware here to play around with if something should come up.

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08-17-2007 01:44 AM  10 years agoPost 10
FCM

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Surrey, England

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My replacement HT leads are from some stock I aquired from a hardware shop of unknown origin. It is of similar design to the Zenoah lead but slightly smaller in diameter which I fix by using shrink sleeving. The HT lead on the G230RC engine is just a screw fit - it is not bonded in and after removing the little sleeve from the coil, the lead screws out and a new one can be screwed right back in.

I would imagine a good lawn mower shop might keep copper cored HT lead?

Ace, the correct way to test the insulation on HT leads is to use a high-voltage insulation tester. I don't have one of these and my way works fine thank you. I have used this system for years now without any issues at all. You can find as many 'faults' with it that you can think up but it doesn't change this fact.

Paul.

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08-17-2007 09:21 PM  10 years agoPost 11
AceBird

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Utica, NY USA

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Ace, the correct way to test the insulation on HT leads is to use a high-voltage insulation tester. I don't have one of these and my way works fine thank you. I have used this system for years now without any issues at all. You can find as many 'faults' with it that you can think up but it doesn't change this fact.
A high-voltage insulation tester is called a “high pot” tester. Yes we agree.

I express my opinions because it goes against everything that I have learned about shielding and grounding. The temporary OK that you get with your method of testing does not guarantee that you haven’t created a problem somewhere else. Or that it will not create a problem somewhere else in the future. A search on your screen name will bring up posts where you have had RF issues like maybe most of us have. Your engine coil is also different than many of the coils used on other RC helicopters. There is no good way of lengthening the HT wire on a Zenoah 231 or 260. It is better to move the coil than lengthen it. The wire on my coils look to be steel not copper.

For somebody new to gassers I feel you are better off not veering away from OEM engine parts until you can recognize and solve the common problems. And once you can do that you won’t find the need to modify those parts.

Ace
What could be more fun?

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08-17-2007 09:29 PM  10 years agoPost 12
AceBird

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Utica, NY USA

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I'm about an hour of build time away from completing the twin engined Vario,
Way to go Eric, you went for a twin engine Vario! I would like to see some pics on that. BTW what diameter mast do they use on that?

Ace
What could be more fun?

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08-18-2007 02:15 AM  10 years agoPost 13
FCM

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Surrey, England

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The temporary OK that you get with your method of testing does not guarantee that you haven’t created a problem somewhere else.
It works for me and everything is temporary.
A search on your screen name will bring up posts where you have had RF issues like maybe most of us have.
Yes, and they are fixed now thank you
There is no good way of lengthening the HT wire on a Zenoah 231 or 260. It is better to move the coil than lengthen it. The wire on my coils look to be steel not copper.
True, but we are talking about G230/260 engines here. Your HT wire is probably tin plated copper.

Paul.

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08-18-2007 09:26 PM  10 years agoPost 14
AceBird

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Utica, NY USA

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Your HT wire is probably tin plated copper.
I am pretty sure it is not copper. It is about as stiff as throttle cable. It doesn't turn orange when you scrape it. They may have used stainless to increase the resistance which would help the RF.

Ace
What could be more fun?

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08-24-2007 06:26 PM  10 years agoPost 15
Disciple4123

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USA

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Some EMI control test results

Well I decided to do some objective testing this morning, using FCM's setup as an approximate guide. The results, pictures, etc are posted at

www(emi)aerialphotographyservices.com/emi

It appears that shielding the wires led to a great improvement

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08-24-2007 07:18 PM  10 years agoPost 16
Machinehead01

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Lower Michigan

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Plug wire shielding

When I was racing 1/4 scale cars many of us fought the same problems.
Our solutions were to go with a resisted plug, plus use the steel wire braiding over the plug wire. Those of us lucky enough to have a PCM radio didn't experience any glitching problems. Also the more isolated your engine is away from the frames and mounts(rubber style vibration mounting) the less RF noise you will have. I know that many don't want to buy a new radio, but the 2.4 gigahertz radios take care of this almost 99.9%. I have looked at some of the gasser kits out there and find that many do not have what I would say as enough isolational engine mounting. When the magnets on the flywheel pass under the coil it generates an electric pulse through the coil, this we know, but we don't take into effect is the EMP that goes along with the energy being produced in the coil and the the peak power of the pulse at the beginning of the spark. Times this by engine rpm and you have a very strong electro magnetic field that you are dealing with. The radio isolation rings sold at radio shack are also a very good option to eliminate any RF left after you have used everything else. The flyers of electric helis use these religiously.

Just my experience and 2 cents worth

Thomas

"You judge according to the flesh; I am not judging anyone."

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08-25-2007 01:18 AM  10 years agoPost 17
Disciple4123

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USA

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Yes sir, 2.4 is in my plans within a year, that is a major step ahead. And ferrite rings are in several positions on my heli, as well as NGK plug caps and resistor plugs. With two engines aiming left and right there was still a fair amount of RFI as the range tests assess.

Now I had both engines refuse to start later today, caused by a spark path from my foil job I have replaced the HT leads with automotive wires and will try to rubber wrap and then foil wrap them to have a similar effect. The Zenoah plug wire is just a bit to junky compared to automotive grade plug wires.

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08-25-2007 03:54 AM  10 years agoPost 18
rbort

rrProfessor

Franklin, MA - USA

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Sometimes you wish you could just make it​work stock...!

Never used sheilded spark plug caps
Never used the braided spark plug wire shield that came with the G,
Never used ferrite rings

I must be one lucky son-of-a-bitch!

-=>Raja.

MA 1005 Hanson 280, 4136 flts
Spectra 27 3DMax, 3200 flts
Whiplash V1 Hanson 300, 1430 flts
Whiplash V2 Hanson 300, 196 flts

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08-25-2007 05:36 AM  10 years agoPost 19
Disciple4123

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USA

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You are lucky Raja, and you're not the only one I've heard of running a stock heli ignition. Some people do fine like that. What needs to be looked at by all of us is 1) do these modifications actually improve safety, 2) is it worth the investment in R&D to reduce liabilities to society, preserve a reputation (business), and keep my equipment inservice rather than crashed. This Vario has been a night and day difference when compared to my previous gassers with regard to reliability, and I'm trying to keep it in one piece as long as possible

After I converted to twin engines I was having some minor servo glitches. I am running 8 servos, an AP2000, and downlink off of one power system; it all adds up. Being that I go 1/4 mile out on a regualar basis, it is imperative that I have the best range available. Add to that that the ign. is closer to the radio gear as a twin and you end up with more EMI. In a few months I expect to go with a XPS 2.4 system, I hear they are impervious to this, but for now the automotive plug wires came out great this evening, should be all set.

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08-25-2007 01:39 PM  10 years agoPost 20
AceBird

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Utica, NY USA

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I must be one lucky son-of-a-bitch!

-=>Raja.
Not really Raja, your just smart enough to realize there is no point in improving one problem at the expense of creating another.

Eric, if I decide to build a twin engine helicopter I will guarantee the radio gear will not be near the ignition system components. Switching to a 2.4 gh xmiter and receiver only makes that link reliable. It does not help all the servos that are taking a direct hit from the ignition system. Servos are not just motors and gears. If you add noise on top of the feedback signal it will confuse the receiver and as a result the receiver will make the servo go nuts. None of this is affected by using 2.4 gh technology.

If you believe in shielding than shield every wire and servo in your radio gear. Tie one end to the metal frame and leave the other end open. However I will warn you the concept is not fool proof. Sometimes it works and sometimes it doesn’t. You need an oscilloscope to measure the improvement not some half baked voltage detector that was meant for something else.

Ace
What could be more fun?

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