djmp69

Not sure if this is the right forum, but the manufacturer lists the aircraft in question as an "ARF-QB", so here goes...

The plane is an Aeroworks Edge 540, 50cc. Absolutely gorgeous plane, and the build is really easy and straightforward, especially with all the hardware supplied. HOWEVER, in the manual for the aircraft, it shows and instructs to mount the servo just in front of the tanks, just aft of the engine box. Of course, they also specify to place the ignition just on the other side of the firewall, and the main ignition switch, well, we all know where that usually ends up.

The problem is that every gas engine mfg, and even servo mfgs say specifically (some in bold red print) to make sure the ignition and switch are at least 12 inches away from the receiver and any servos. No problem, just modify and improvise, right? Not so easy. I could easily mount the servo further back, BUTthe wing tube gets in the way of a straight solid run to the throttle lever. Any position in front of the wing tube leaves a distance of only 8-10 inches away from the switch in any direction, and the angle is bad. Nyrod is out of the questionthe amount of bends and curves and braces I'd have to make just to get it to fit right would be a bit over the top.

I and everyone that I know that flys gas swears by the 12 inch rule, and have had no problems with it, but Ihave witnessed throttle problems including crashes due to suddenly erratic throttle when this rule was broken. Yeah, Icould go ahead and do it the easy way and do it like the aircraft manual says, and check it all the time, but I would rather do it right the first time, and not waste gas checking a servo. And we all know that interference never happens when we need it to (testing, range checking), butt pops in when we LEAST need it to.

Any ideas on this?

djmp69

Well, figured out a solution, works great!  Got the mount behind the wing tube, and there's enough clearance between the wing tube and canopy for the pushrod to go in a str8 line to the throttle lever.  Just had to build a platform onto the receiver tray.

I still would like to know if anyone has had the same issue, how they got around it, or if the specified throttle servo placement ever ended up being a problem.

Engine is DLE 55, NGK CM-6 spark plug

Zeeb

My Feedback: (41)

Any ideas?

Yeah....

Nope, on second thought I'm not 'gonna get into this discussion/argument AGAIN. Use the RCU website search engine.....

ahicks

My Feedback: (2)

Just me OK? Sharing what I'm doing. I used to read all those cautions, and abide by them. Not any more. I now work from a much more practical perspective. I run the stuff where it makes the most sense from an operational/functional/clean install standpoint. Haven't crashed anything yet because of that. The only reasons I can come up with for this is better shielded electronics, and the fact I'm on 2.4. -Al

BarracudaHockey

My Feedback: (11)

Actually, I think you will find that most of us that fly gas don't give a flip about the 12" rule, esp with 2.4 systems.

allans

My Feedback: (11)

Try using a Igition BEC (like TecAero for one) it completey isolates the igntion from everything else.
Bullit proof.

Problem solved.

djmp69

Really?

djmp69

Actually, maybe that's why I'm having the doubts, because everyone that Iknow that flys gas sticks to it, and thats among 5 different clubs...

Truckracer

My Feedback: (19)

+1 on that simple statement! On one of my 30 sized planes, the receiver battery is on one side of the motor box, the ignition battery on the other side and the ignition box is on top of the box. Then, the throttle servo is inside the box just behind the firewall .... zero problems.

Heck, I still have several older planes that fly on 72 MHz. These use a combination of CH and Rcexl ignitions and absolutely no problems with ignition interference and in several cases the ignition box, receiver batteries and throttle servos are all very close together.

gade600sdi

Yes I think all those old rules dont apply as much anymore with modern equipment, still good rules to keep in back of your head. I would not worry about it I would set your servo where it needs to be and use a solid wire pushrod. If an installation on 2.4 lends itself to getting the radio equipment, switches, batteries etc. away from the ignition, do it, but if it is not practical or will throw your cg way off I wouldnt worry about it many manufacturers put the throttle servo 3 inches from the ignition and even provide you a solid wire pushrod, and strap the ignition battery right against the Rx battery.

Go to the Hangar 9 website and look at the instruction manual pictures for the new Tiger Moth 20cc. You basically have the throttle, elevator and rudder servos, the ignition battery, the Rx battery, switches, the Rx, AND THE IGNITION box all within about 8 inches of each other. In fact, they have the RX like 5 inches or less from the Ignition. There is no way to do it any other way in that model, because they havent allowed any space for it.

Luchnia

My Feedback: (21)

I know a lot of gas flyers and I don't think any of them adhere to the 12" rule. Most of them strategically place the throttle servo for best operation. My throttle servos are usually in the area just between the fuel tank and engine or right to the side of the front of the fuel tank.

I make a servo box or plate and mount them with less pushrod bend as possible. I don't like slack in my throttle setups and some of the longer rods don't work as well. The smaller planes I just place them were they fit best.

Zeeb

My Feedback: (41)

If you've already made up your mind, why are you here asking questions?

Like I said, use the search engine or continue with the course of action you've already decided on.

captinjohn

Google search= this http://www.tech-aero.net/ultra-ibec Some good reading for ya anyway! Capt,n

djmp69

[/quote]
If you've already made up your mind, why are you here asking questions?

Like I said, use the search engine or continue with the course of action you've already decided on.
[/quote]

I am not a know it all, nor do I or will I pretend to be, especially by berating someone who doesn't know everything there is to know about something is seeking answers of substance instead of snippy worthless comments as yours. If you read my original posts, even though I figured a way to do things, I still would like to know what other people do, what solutions have worked, not worked, etc. If you also read what I wrote earlier, you would see that I am seeking what is outside of what Iknow. What Iknow is all I can go on, but I am not so stuck on myself that Ithink that what Iknow is all there is. Ialso don't like to just know an answer, Ilike to know the reasoning behind the answer so that Ican actually learn, and know what I'm talking about or doing. I'm not just going to simply do something just because someone says to do it. As Isaid before, Ihave WITNESSED erratic throttle behavior in LOTSof planes when the servo was that close to the ignition and/or switch, and the problem went away when the servo was moved. In every single case. Yes, the majority of these situations was with a 2.4 system (Futaba, JR, didn't matter), and current engines. Or were you too engrossed in your search engine to read that?

Not to mention, EVERYengine and servo/recevier manufacturer clearly states the 12" rule in the instructions. By the way, if you have successfully produced a run of engines, servos or receivers,by all means, point me to them, or give me a keyword to use in your suggested search engine, and I'll gladly consider your product...

That said, I want to thank everyone ELSEwho provided substantial answers and opinions that actually addressed my question (which I apologize Iknow has been asked time and time again). Those of you that went further to offer actual solutions, or reasonings behind your solutions have helped greatly by giving me more insight to why the servo placement is usually no longer an issue.

Those of you that assumed that I ONLY came here, didn't use a search engine, or just simply feel that Iwasted your time, well, Iwon't apologize. Ask me, you wasted your own time writing such pompous and worthless responses, thereby getting into a discussion and writing that you're "not going to get into it AGAIN". Wow, talk about the attention span of a sparrow...

ahicks

My Feedback: (2)

Well sir, maybe I misunderstood you as well. When I read this, I took it to mean that those of us that were not abiding by this "rule" were incompetent - because YOUR seemingly extensive experience seems to indicate what we are actually doing doesn't matter? I mean with all those guys (5 different clubs!) believing it's necessary, I'm not sure why you bothered to ask the question either? Are you going to go back now and tell all of them that the guys here think THEY are incompetent?

Zeeb

My Feedback: (41)

Okay you've had your 15 minutes of fame, gotten a chance to voice your indignation over a perceived personal slight and gotten to throw out some personal slights, now go away.

captinjohn

Maybe Pleasant Grove Ut ...is not so pleasant !

djmp69

[/quote]

Well sir, maybe I misunderstood you as well. When I read this, I took it to mean that those of us that were not abiding by this "rule" were incompetent - because YOUR seemingly extensive experience seems to indicate what we are actually doing doesn't matter? I mean with all those guys (5 different clubs!) believing it's necessary, I'm not sure why you bothered to ask the question either? Are you going to go back now and tell all of them that the guys here think THEY are incompetent?
[/quote]

You most certainly did misunderstand me. You missed the point of what I wrote which was, that because Iknow so many people who stick so closely to this rule, and they have success, combined with problems I've actually witnessed when the "rule" was broken, is leading me to question if I'm missing something because, as I've read here, so many people "don't give a flip" about the "rule". If so many people are having no problems with the close quarters set up, I want to understand WHY, and find out any differences, even slight, that may explain why those who go within the 12" are not having issues.

I'm sure you have success with your way, and seriously, that's great. At this point, for you, it doesn't matter if you understand it or not (again, not making a judgement), the bottom line is that you know it works based on your experiences. I haven't had those experiences so I'd like a little insight on the matter, that's all.

INNOWAY did Isay, nor did Iimply that anyone was incompetent. Just because Istated my doubts based on my experiences does not mean I am questioning anyone's compentence (how you got that I don't know). Like Isaid, Iam no know it all, but my doubts have served me well. I have, with this hobby, had some doubts removed by clear explanations and understanding, but I didn't just blindly forget about them just because someone didn't give a flip. Ijust want to make an educated decision.

So no, I'm not going to say to you that you're incompetent, nor am I going to tell the other guys they are. I'm going to continue to seek the answers I need, and in the mean time stick with the method that, from what I've seen, works.

djmp69

LOL, perhaps!

tomfiorentino

kumbayah my friends...kumbayah...

BarracudaHockey

My Feedback: (11)

FWIW, I'm not "winging it" and getting away with it. I worked on some very high end electronics systems in the Navy and I've been flying RC since my first Cox 2 channel glider radio and have a lot of experience with different facets of RC including gas planes. I don't mount a reciever to an ignition box but I do install my components where they make sense and are convenient without regard to the 12" rule, simply because it doesn't matter and many installations don't allow you to obtain that. Heck I power my 50cc stuff with one A123 battery that runs the Rx and ignition. I have hundreds of flights in this configuration, it works. Bigger than 50cc I run 2 A123's to a Power Safe reciever, one battery is split to the ignition.

I've never seen an RF problem that I have had to move components (or one of my favorites, twist servo extensions) to fix.

Charlie P.

Well there you have it. Someone who has flown every possible combination of all makes and models of engine, ignition system andservosand can state inductive interference cannot happen regardless of your wiring orinsulation condition.

Whew! If we could just get him to smoke we make disprove cancer!

Charlie P.

[ Kidding - just kidding]

BarracudaHockey

My Feedback: (11)

Well of course not every combination but I am in a position to have my hands on a diverse range of equipment.

As for smoking, never happen

captinjohn

This may be a dumb question....can a RCXEL ignition be run on one A123 cell or is the voltage to low?