I use Futaba and like I said- 100+ YARDS is what I always have before I quit walking. Even though the manual states a much different distance.

The Proper way to do a range check is to perform a check with the motor off (record number), repeat check with it running at different throttle setting and record that distance.
If the difference is approx. 10% or more find out what is causing it. Plenty of good informations in above posts as to how to diagnose the problem. (be sure to at least meet manufactures min. distance)

I know from checking various planes that if MY radio does not at least give me 100+ YARDS something is wrong. Now I just walk out about 100 yards and if everything is fine with the engine running I am good to go.

Now that being said, Silversurfer watched me do a different type of range check once before.

Silversurfer, I think you put the best advise on here when you suggested starting out with a regular FM (PPM) receiver. Seen a few go in from somebody masking a problem by sticking a PCM in and thinking all is well.

Ed M.

Hello,

I am installing my first gas engine and was wondering whether any of you think using a metal push/pull rod to control the choke is a bad idea? It would be metal-to-metal contact and would have to have some looseness to operate correctly, so it doesn't sound like a good idea, but I have not seen this specific issue addressed on these boards.

Thanks,

Travis

The short answer is get the metal plug-cap. I had the Brison 3.2 and tried all the little fixes with wiring, chokes, etc. It didn't get cured until the Bosch cap went on. It's a simple fix to do at home if you buy the part, but since this one's been sent in, you might as well have them do it. It was the difference between a glitchy mess and a radio as dependable as a nitro install.

Not only do you need to check the plane running and off, but it needs to be tested in all attitudes( or as close to that as is reasonable) of both the plane and the transmitter. My interference would only show up in ground check when the TX was held a certain way and the plane was pointed a certain direction in relation to the TX. I flew a couple times and had hits before we found the "magic spots" that would cause interference. It made sense, since it seemed like the hits only occured over specific parts of the field.

Now I like to go out 100+ feet ad have an assistant slowly rotote the plane on it's gear as I repeatedly rotate the transitter thru an arc 180 deg from shoulder to shoulder and from below the horizon to straight up. Yes, ya gotta do that with the engine running.

BlueMax,

There is noting wrong about using a metal rod on the choke, but I would like to suggets that you use either a nylon clevis to attach the rod at each end or use any type of ball link that uses a plastick or nylon housing to thread onto the metal rod. The plastic or nylon breaks the possibility of conductivity and pretty much eliminates RF.

I know that using a ball link requires the use of a metal screw to pass through the assembly somewhere, but the fit is usually tight enough that problems will not arise from that part of the assembly. I have been installing gassers this way for a long time using a metal or carbon fiber rod on either or both of the choke and throttle without issues. But I DO follow the same principles noted above.

Another item of note is that gassers have a different vibration frequency and are well known to vibrate fasteners loose. The use of a thread locking compound or something else is highly suggested to prevent this from happening EVERYWHERE on the plane.

Good luck and enjoy your project!

Pat

RTK your the man i will do as you say from now on . I only have one question how do you get the 10% with motor running and motor off? I have tried that and i can never get the 10% its always like30-40%. What do you think my problem is? I never have any metal to metal and my antenna wire is never near any servo wires. But like i said before if i normaly get 100ft with it running i fly it, and so far i have never had a problem. I guess i have been lucky so far. I'm not an old dog i can learn new tricks. When i posted the 1st one on here i was only telling my experience from what i have done and what i see done on a weekly basis. I was not trying to call you a lier like Silversurfer is emplying. Sorry and thanks for not being so negitive toward me like some people are.

Thanks
smallplanes

Pat,

Thanks for the helpful information. I will figure out an arrangement that provides a plastic to metal interface on the part of the push/pull rod that needs movement. If you don't mind one more question: I have been using blue locktite on all of my fasteners as I assemble the plane. Do you think it is a good idea to use this on the screws that hold servo control arms to servos? I have never done this before with glow engine planes, but perhaps it's different for gas engine planes?

Thanks,

Travis

Smallplanes- The more think about it, I believe it is more like 15% but now I am even questioning if it might not be 20%. Probably should have kept my mouth shut.

But I do know that at one time a manufacture told me there should not be that much of a difference. I would feel uncomfortable at 30-40% decrease.

I am currently using a 9z and I can always get out to 100 yards before I quit walking. With my last 3 planes I never checked the difference between engine running and off. I know shame on me. I just felt 100+ yards (engine running) is probably good enough, and it is 3-4 times the distance stated by the manufacture.

As for silversurfer, he's actually a good guy. I don't think he tried to call anyone a lier, it just probably came out wrong.

OK there is still mis understanding what this is all about.
The "RULES" we developed at CH Electronics were developed when we were flying AM radios, yes we have been around that long. It was critical to do things right. No metal push rods (they generate metal to metal noise AND will also act as an antenna and transmit noise from the engine into the throttle servo which sends it to the RX and Bang-boom), lots of distance from ignition to RX, lots of distance between batteries and switches, no complete loop with the tail braces
Then came FM and all our problems were "solved" only they wern't and later came PCM but still not perfect.

If you have a "perfect" RX to begin with, evey time you broke one of the RULES it would be a little less perfect, break several rules and its a lot less perfect. EACH time some one turns on their radio your RX becomes even more less perfect, even if they are on a different freq. Your flying low and farther away than normal, your RX is even more less perfect than before. Point your antenna at your plane and guess what, even more already less perfect. To many less perfects and your PPM plane crashes, your PCM plane goes into lock out and then crashes .
Some of the above is really perceved TX strength, but the result is still less perfesct.

So give your self an extra edge and follow the RULES and then do a range check using the 15% rule before the first flight. Then later you can do the 200ft and all is well type check.

A spark is an infinite number of harmonics, meaning its covers the entire bandwith so sheilding the spark plug reduces the amount of jamming it sends out.

Hitec tells you NOT to use Locktite of any kind on their servo screws. Something to do with chemical incompatability, I believe. I would use something, though. The achine screws used in digital and metal gear servos are VERY prone to loosening without some form of thread retention assistance.

Since I run all JR, I usually use a very small dab of blue locktite on all my servo and servo arm connections. Ask RTK what happens when you use the red stuff in those locations And since I brought him up, I was just as guilty of the same range check he was talking about earlier, but we got really lucky.

Smallplanes:

I was trying very, very hard to get your attention and have you note that you were telling the ignition manufacturer how his components were supposed to work. I don't believe that you knew who TKG was at the time you posted. In any case, I'm sorry if I offended you, it wasn't meant to offend. The up side is that you had something revealed to you that will more than likely keep your planes in the air a lot longer and save you a bunch of money. For that I'm not sorry at all[8D]

Your right i did not know that tkg was from CH IGN. if i had i would have never said anything. I've been flying gas for a few months now and i'm still learning. I've been flyng glow for a few years and i guess i always got by with the short range check. But after hearing what you guys are saying i'm going to go back tru my other gas planes and do another range check. I have a few thousand a piece in them and i don't want any of them to hit the dirt for my ignorance. I guess the old saying is rite you have to crawl before you walk. Thanks silversurfer and no hard feelings.

Thanks
smallplanes

That's one of the great things about this hobby, nothing is static. In 30 plus years of this hobby I have seen more things change than I would care to count. Because of those and future changes, none of us can ever stop learning if we are to be able to take advantage of the technological advancements as they occur.

A little dab of clear silicone sealer on the servo arm screws works very well..Sticks good to everything, no chemical incompatibility, and easy to get out when required...You can cover the top of the screw with it and the screw will never come out even if it gets a little loose...
Works fine on our 289cc race plane...Works on cowl screws too..[8D]

RCIGN1,

Thanks for the helpful suggestions. Sorry if I changed the direction of this thread.

Travis

I'm not sure I would ever get that far(100yds) with my Futaba 8U or 6XA with the antenna fully down. I would say I get somewhere in the 100- 150ft range when the servos start getting twichy(engine off). If I pull the antenna out say one section, it stops. I've never had any hits or losses with either radio in years. Maybe I'm not counting my steps accurately? I'm getting ready to use a Brison 2.4 and that's why I'm a little concerned with these numbers. Will have to try a more accurate range check at the field next time.

marty

The key here is the difference between engine off and engine running. I never got much more than you have with a 6XA, but always had solid range checks nevertheless. So if you get 100 to 150 feet with either one normally, engine off, but you only get 65 feet engine running, there's a problem. Now if you get the same or close to the same engine on or off, go fly.

Another way to view it is consider what kind of a range check you got in your glow planes for comparative purposes. If you are getting less with the gassers, you might want to start looking at things.

Different radios types have different range check distances. It's always helpful to know what your radio usually indicates in a good range check and use that for a baseline. In RTK's post, he was referring to a Futaba 9Z. I'm using a JR 8103, but I know that the 6XA won't normally range check as far as either one. That doesn't mean it has bad range, just different characteristics.

Thats exactly why Ch says 15% not an absoult number of steps.

I've got a Brison 3.2 with standard CH ignition that I haven't fired up yet. It uses the standard rubber boot on the plug. Does the Bosch plug cap improve the shielding from ignition interference? Maybe TKG can explain how it does this? Other brands of ignition use a metal braid shield that covers and grounds the whole length of the plug wire.

In my experience, yes the metal Bosch cap is so good, it should be standard equipment.

Magneto engines normally don't need shielded caps..There are literally thousands of magneto engines out there with no shielding at all...A proper set up is the key...
There were no shielded 10mm spark plugs until recently when Champion and NGK came out with the RZ and CMR series plugs..There is no current shielded cap made for the 10mm Champion and NGK spark plugs...All my conversions that have the ignition inside the mount use standard unshielded spark plug wires and caps with a resistor spark plug..No one has complained about interference....
C&H ignitions are not inside the mount, so the long spark plug wire radiates RF..C&H shields the wire from the ignition box to the end of the wire, where it's grounded to the cylinder..The Bosch cap is an extension of the shield, completely cutting off any RF radiation...
Other manufacturers MUST have shielded caps because until recently there were no resistor 10mm spark plugs...
The Zenoah G26 uses a 10mm resistor spark plug with no shielded wire or cap..Works fine..
It's the only magneto engine currently made using this setup..
I once put a 10mm CM6 in a G26 because it's way shorter than the RZ7C the engines come with..Used a DA shielded wire and cap..Made the engine shorter from the crank to the top of the spark plug..Lost rpm because the shorter thread on the spark plug lowered the compression ratio.....

So Ralph:
If I understand correctly, the standard CH ignition with rubber boot has a grounding shield that runs the length of the high tension wire. I assume it's hidden by the rubber insulation?

Yes the lead is shielded. When the Bosh cap is used the shielding is connected to the Bosch cap giving you a shielded ignition from the box to the spark plug gasket. This makes it the quietest ignition we build RF wise.

Thanks TKG. Now I understand the setup.

Terry, would you mind elaborating a little: (Quoted from Post #34)

Check.

Why would this make a difference, as long as Rx and Ign are electrically isolated, and rule #1 is followed?

Forms an antenna ground plane? Makes Rx reception directional? (My radio/antenna expertise is limited)
If I leave the segments connected together (one junction DC isolated) how much of the issue remains?