scrambow

My Feedback: (3)

I am having a heck of a time with an electronic ignition gas engine. I have the 2.4 Spectrum that will not work with this engine. I have one of the RVSC 26 engines from TroyBuilt models. The radio is rock solid as long as the engine is not running. I have read the 2.4 does not suffer from RF interference. I sent my radio to Horizon thinking it is a radio problem. They replaced the transmitter and receiver. I reinstalled the receiver and went to the field today. I charged up and did a range check. When I began flipping the motor, the servos all went hard over and were unresponsive. The LED in the receiver was flashing very fast. I cycled the flight pack battery switch off then on and the receive rebound to the transmitter. Again as I flipped the engine the radio went hard over. Thinking maybe the flight pack switch had failed, I connected the battery straight to the receiver. Same results. Next I tested my theory. I rebound the receiver with the ignition battery switch off. With the radio responding normally, I turned on the ignition switch and checked the radio. It worked fine. Then I pulled the prop through slowly and as soon as the magnet on the prop shaft passed under the ignition pickup sensor, the servos glitched! This happened every time I pulled the prop through. The receiver is well over 12 inches from the ignition module.
I am at a loss of what to do.

WILDCRASHWILLY

Scrambow,

Please forgive me as this will sound like a stupid question but with numerous wires in the fuse I could see this happening. Is there a chance that you have the wire from your throttle servo plugged into the ignitions switch and as a result have your ignition power wire plugged into your rx? As I said, I've seen some planes where the cabin is filled with wires to the point where they could easily be switched if not marked properly. I sometimes mark mine with a piece of masking tape as to what channel to plug into th RX. You probably did not do this but sometimes stuff happens.

Charlie P.

One common error is to put a throttle servo too close to the EI module or magneto and it picks up a signal through induction and feeds it back to the receiver. Keep the throttle servo a foot away and use a nylon rod for the carbureator arm attachment.

And you are using a seperate battery pack for the ignition vs. the flight pack battery? Can't use just one.

Edwin

My Feedback: (2)

Sounds like your spark plug sheild is not grounded. And no, 2.4gh doesnt eliminate all RF interference. It reduces it quite a bit. You still need to follow the age old gasser setup rules.
Edwin

Rodney

While not a common thing with 2.4 GHz, it does happen. In the two cases I've seen, it was caused by an excessively noisy ignition module. Swapping out the electronic module solved the problems. As stated above, you still need to take all the regular precautions such as "resistor plug", "non conductive throttle push-pull", "no metal to metal contacts that can vibrate", "separate ignition battery", etc.

cuwaert

Quite so, one shouldn't think of 2.4 asif now you can mess around with wires and stuff freely, the basic rules still apply.

. sparkplug wire shielding only contact is the sparkplug and the ignition module, check if not damaged
. watchout with kill switches , if use one, take it out to check
. do you have any electrical contact from the CDI circuit with your radiocircuit? if so remove it.
. keep ignition wiring/battery/CDI as compact as possible and as far away from the radio as possible, 30 cm should be anough but more is better.

As a test you could deconnect the throttle servo and see if it still glitches.
If you can solve this in any way, to realy test it is to put in an old simple cheap ppm fm radio and when it doesn't glitch with
this one your system is clean.

aslan

Came across this twice before, and Edwin.....imho..... is on the money here. I would strongly recommend you try this first Scrambo. The quickest and easiest of things to do,just before you try the other guys suggestions.

Matt

My Feedback: (1)

Is there a website on there or a document, with ALL the rules for setting up a gas engine in an airplane by any chance? I have one gas airplane and knew really nothing about it. I figured i would just set it up like i do any other glow model. (i soon found out a truck load of information of what NOT to do when you have a gasser -AFTER- i flew it...lol) But I've had it for a season now and have no problems with it. And i'm flying on 72mhz with a pcm reciever.
** one more question, what do you guys think about using 'Y' extentions in gas airplanes? Do they put your plane at risk for interference issues??
thank you so much, and sorry for butting in like this...

Edwin

My Feedback: (2)

Dont know of a site that has all the gasser rules. Just ask here to get the latest. Every time I think I've seen it all, something new somebody else runs into, pops up. I use extention Y's on my elevators and ailerons. But remember I'm just an amature. General rule of thumb is to keep about 10" to 12" distance between your ignition and receiver. Use separate batteries. Separation it the key here. Having said that, some guys get away with having a throttle servo on the firewall. Seems to work for them, but I dont do it. Vibration isolate batteries, ignition, and receiver. I use nyrod for throttle linkage back to the servo, again way back away from the ignition. Do the same for the ignition switch if you use a servo on a mechanical switch. Opto isolated ignition switches exist if you want to spend the money. You dont want anything that can pickup or radiate back to the receiver. A good test is to run the system on FM to see what happens. If theres a problem, it should show up worst there. Fix it then go back to whatever you want to use for a receiver. And make sure you use the right spark plug. Some dont need a resister, some do. If there is a metal spark plug cap, make sure its snaps tight around the plug and is grounded real good. Sometimes the braid around the plug wire can break near the cap. Clear as mud? Good! Test is tomorrow!!
Edwin

Matt

My Feedback: (1)

Yep...that's EXACTLY what i did. (except for the ppm reciever first to check with) nobody told me that...but i did find out my interference problems when i flew with it....lol But my first gasser that i have it litterly a piece of flying crap! it weighs 20+ pounds and it's a low wing trainer. I'm actually thiking about getting rid of it MAYBE...
But thank you for the info. That's what i did for my first gas plane, and it worked out well in the end.

**So i should get an 'A' on the test right? lol

Edwin

My Feedback: (2)

Very good grass hopper. You do good!!
What plane and what engine. 20lbs may not be that bad depending on the wingspan, wing loading, and type of plane. If its an aerobate, I might not be much help for you. Mine is a GP Yak54 with a DL50. Warbirds are my passion, the Yak is just for practice and play.

Edwin

bkdavy

My Feedback: (1)

Using Y extensions doesn't increase your risk of interference, but depending on the servos and the plane, you can run the risk of trying to draw too much current through a single connection. The normal connectors are only rated at 4 amps. Digital High Torque Servos like the HS-7955 can draw up to 4 amps each under heavy loads, so you probably wouldn't want to use a Y on them. Having recently made the jump myself into the giant scale world with a 30% Yak-54 and a DLE-55, I did a lot of reading over at the Flying(synonym for large) (that is Giants) site. Lots of good setup tips combing through the site. There is also a Giant Scale forum here on RCU, but its not as active.

Brad

Matt

My Feedback: (1)

don't even ask on the 20 pound 'plane of doom'...lol it's for a person who just likes to fly around and do very few acrobatics.....i'll put a picture of the thing. I don't even know what to call it. People say that it's called a G-shark...and the engine i THINK is a US 42cc. (don't ask...it's a looong story)

Matt

My Feedback: (1)

in my 27% aircraft that i'm getting...i'm going to use HS-7985MG servos. But i will try my best NOT to use 'Y' harnesses at all.

TedMo

Looks like it may be a G-Shark. Ihad couple of them about so years ago. They flew great. Had a Homelite conversion in mine.

Matt

My Feedback: (1)

It would be nice to know exactly what this 'thing' is. All i know is it IS called a G-shark.
**was yours 20+ pounds though???[X(]

RCHubbub

Good info here.

http://www.rcuniverse.com/forum/m_86...anchor/tm.htm#

Matt

My Feedback: (1)

thank you...that will help...

Wilki01

HI, maybe I can help too, lol. I run gassers all the time now without issues. I run all my gassers with my JR 9303 2.4.
Basically I connect my throttle servo with no metal to metal contacts from the throttle servo to the carb linkage. I then install a Ferrett ring on the wire from the throttle servo to the receiver. I also always run seperate ignition and flight control battery packs with their own heavy duty switches, never cheap out on the battery switches. I also instal one ferrett ring per aileron servo wire. There are many other ways of setting a gasser up with the same results or no interference. This way works in all my setups with no trouble at all. As previous R/C Supporters mentioned above things such as a bad sparkplug wire, poor grounding for the ignition module, even a small crack in the sparkplug can cause the issues you are having. There is a lot of experience on this site that you will benefit from, when you find the actual problem please post it, others will learn from you as well. I hope I was of some kind of help. I sure can't wait to get to warmer weather here to go and fly, guess I will just build for now..

Matt

My Feedback: (1)

Would it be better or make any difference to put one farrid bead(sp) on all your plugs going into the reciever instead of just the throttle one?

Wilki01

No, you want to isolate the throttle channel, it is the only one directly connected to the main possible source. I also do the ailerons due to length of the wires. The ferrett rings are cheap and do help.

Matt

My Feedback: (1)

I'm into electronic circuits and i've heard they work wonders as well. So maybe i should ask this then. Should i use one farrid bead for each servo extention that's long? And which end do you put it on?...close to the reciever end, or close to the servo itself?

Wilki01

I only put mine on the throttle (all) and ailerons(only if 18inch extensions are used) I install the ferrett rings on a 12 inch extension looped through the ring 3-4 times, with the extension installed at the receiver end. I have yet to have any twitching or interference on any servo yet on my gassers. I also keep my receiver and remotes away from the engine, ignition module, throttle servo, ignition bat switch, ignition battery as well as the wire from the throttle servo to receiver wire. A well layed out wiring plan is a must. I also use the Spektrum flight data logger on all my aircraft to monitor signal loss, fades, frame drop outs and voltage check( for 30 bucks well worth it)

Matt

My Feedback: (1)

mmmmmmm...okay...i've read that neatness counts. I forgot if anybody mentioned about using those servo reversing 'Y'. Are those safe to use? I know regulat 'Y' harness aren't. Still not exactly sure why though other then the problem of running to many amps through one channel port..

Wilki01

not sure about the y-harnesses. I don't use them. Fortunately I have enough spare channels. I prefer to run all my servos on seperate channels, but I am pretty sure Spektrum may have that answer for you on their website. I believe it is under common setups or faqs, something like that.

Try this link

http://spektrumrc.com/Community/Inst...Practices.aspx