PacificNWSkyPilot

My Feedback: (19)

Good! I guessed right. Yes, I saw that post after I posted mine.

~ Jim ~[8D]

pettit

My Feedback: (23)

I had a failure on my ignition box yesterday.  I have used an A123 2 cell pack with a 3 amp diode (600 mv drop) in series with the power lead to drop battery voltage down to about 6.2 volts. 

Now all my ignition does is just whistle with no spark.

The ignition is branded "RCEXL" on the case and all RCEXL ignitions can use UNREGULATED A123 2 cell or LiPo 2 cell batteries, according to manuracturer.  Date of manufacture on the box is June 2012.

What's up?

ahicks

My Feedback: (2)

jedijodi published an Rcexl troubleshooting guide up in the rookie post at the beginning of the gas section. It's post #24. Just reading through the steps may give you some ideas.

http://www.rcuniverse.com/forum/m_8673009/tm.htm

I've had 2 modules quit, both run since new with a diode in the supply line, and both found to have bad spark plug boots in the end. That's just my experience though...

PacificNWSkyPilot

My Feedback: (19)

When I talked to the manufacturers, they said that 6 volts (or higher) is hard on the ignition modules, and that they're really designed for 4.8 Volts. Pgmeyer is using the A123s and has been trying to get me to make the move over to them. I don't know what he's doing in the way of adjustments for the spark voltage, if anything.

Paul, are you out there listening?

I don't recall whether Todd told me to use 4.8 Volts or not for best results. But that's what I use.

I should mention that I haven't talked to any of the gas engine manufacturers for over two years, so my information could be as old and useless as I am.

~ Jim ~

Joystick TX

Anything over 4.8 volts on theignition module is just wasting current.

Most electricalitemsare designed for a certain voltage range.Normally, operating the item at the top end of the range willnot make it "work better." Most of the time, it will just generate moreheatwhich needs tobe removed. Any excess heat will be harmful to the components and will shorten their life.

When dealing with high voltage or high current devices, the situation is even worse, a higher voltage is almost never"better."

Most electrical design engineers (like me) "derate" components from 25 to 50%, depending on the reliability requirements, to avoid stressing them and causing early failure.

An example of "derating"would be tolook at your car engine, it may be able to run at 5,000 rpm. If you run it that fast all the time, it will not last as long as if you run it at 2,400 rpm.

Two cents from another old anduseless old man. At least some of my designs are still going strong after 40 years.

PacificNWSkyPilot

My Feedback: (19)

As opposed, to, say, your knees, Steve? lol

~ Jim ~

PacificNWSkyPilot

My Feedback: (19)

Okay, Syssa manual, Page 10, states:

Use a 4.8 Volt battery for the ignition.

~ Jim ~

tele1974

Guys the glass pack was a success. Their is significant reduction in the sound. IT WORKS!!! I will have it tested at the St. Clairsville contest this weekend.

Joystick TX

My kness did take a beating for sure due to old ageandduring my timein the Marines. Getting shot in one, "friendly fire",didn't do any good for them either. Favoring the bad knee took out the good one later, so much for redundancy.

pgmeyer

OK,
I use the following components: Dual A123 packs into dual power switches into a SmartFly BatShare diode matrix, into 2 ports on the receiver. I use the power port on the receiver and 1 extra channel. I run an AeroTech IBE into the ignition on my Syssa or the ignition on my DA engines. That regulates the voltage and gives me a switch to kill the engine remotely. Thats it, I use the same system with different capacity A123 packs on my 30cc and 50cc birds - never a let down and complete redundancy.

I recommend looking at www.hangtimes.com to learn about internal impedance of different chemistries, and how to care for A123s.

PacificNWSkyPilot

My Feedback: (19)

Thanks, Paul.

The IBE regulates the voltage to the ignition, but do you know what voltage it regulates it to?

I'll need to have a look-see at your A123 setup and see what all the fuss is about. How many years are the A123 packs good for on average?

~ Jim ~[8D]

pgmeyer

Jim,
The Ultra IBE can be jumpered for outputs of 5, 5.3, 6.1, or 6.6 according to the user guide. I use the 5 volt output. I am not sure how long the A123s will last, my current packs started in a 50cc Yak I was flying in 2008 - all season and only 1 charge during layoff in winter - I did ruin one by leaving my power switch on - http://www.tech-aero.net/ultra-ibec

ahicks

My Feedback: (2)

I don't think anyone is feeding their ignition modules with higher voltage to gain performance. It's a matter of weight and/or convenience, has more to do with what's going on in the rest of the system.

There's nothing wrong with a dedicated battery setup, but if that not what you're running then you need to come up with something else, and that may involve running something closer to 6v to the module. Running an ignition module with a diode in the line powering it gives you a lot of options. Same story with an IBEC?

That Ultra IBEC comes set for 5v by default if I'm not mistaken. That's what Todd told me, but it's been a while...

NoBS Batteries is good reading... (Hangtime Hobbies)

-Al

Slow and Steady

I run the same set up as PGMyer on my 50cc planes, using two Life batteries on a Smart Fly bat share circtiut to the receiver and channel 7 on the reciever to power and control the Aero Tech IBEC, which I believe delivered 5.2 volts to the igntition. My Syssa is powered the same way, but with one Life battery supplying all power to the IBEC via the reciever. Two plus years with no issues yet, knock on wood. My first 50cc ignition may be showing some wear; after alittle over a year it is occassionally missing at full throttle. But that may be the plug, etc.

PacificNWSkyPilot

My Feedback: (19)

5 Volts shouldn't harm it, since a 4.8 volt battery fully charged is usually over 5 volts.

~ Jim ~

NJRCFLYER2

My Feedback: (42)

A 4 cell NiCad or NiMh pack puts out as much as about 5.5V and is over 5V for most of its useful charge. The factory default for the Tech-Aero Ultra IBEC is 5.3V, which is withinthe useful range of the discharge curve of a typical 4 cell pack with a 4.8V rating. 4.8V is a nominal rating, not an indication of what the battery pack is always putting out.

oldbassard

If they are in production thisis theengine I will put on a new 80" Stuka, santa told me I'm getting for christmas

PacificNWSkyPilot

My Feedback: (19)

Thanks for verifying that we're good in that range, Ed.

oldbassard,
At the time I ordered mine - last week or the week before - Todd was finishing up a new batch. If you're so inclined, now might be a good time to order.

~ Jim ~[8D]

JohnB96041

What a web site. Just took me 4:00 to get the web page to display. I suspect a router somewhere is needing some TLC. Now, to the test. I removed the cowl from my Funtana 125, opened the Low needle screw 1/8 turn CCW. Started the engine, started ok, let it warm up for about 2 minutes, slowly started opening the throttle. Engine sputtered and died. OK. Set the LS needle back to original setting, restarted, transition was excellent, but did the lag on going to full idle after throttle was closed. Killed engine, set the LS needle 1/8 turn CW to lean and restarted engine. Started Ok. Started to transition to high throttle and engine quit. Set LS back to where I had it to begin with, Started engine. Transition to full throttle is now back like it was to begin with. I quess I will just leave it alone and go fly. Just have to remember to bring the throttle back to idle a little sooner so the engine will be at full idle before turning on final. I will see how long it takes to post this response.

JohnB96041

Two minutes to post. Terrible.

PacificNWSkyPilot

My Feedback: (19)

Yeah, it's driving me crazy. err, crazy-ER. . . yeah, anyway,

I'm thinking that your low speed setting is pretty close, but you might have your high speed setting a little rich. Or lean, as the case may be, but after reading your post, my instincts say it's rich on the high end.

There might be some junk in the carb screen, or you might be in need of a new spark plug. Spark plugs can play havoc with an engine's tuning if they're not quite right. Junk in the carb screen is probably not the issue, but worth a check.

I wonder how often we should go over our carbs and replace the diaphragms, and such. I never got to find out with my other gassers. They were all stolen before any of them needed it.[]

~ Jim ~

ahicks

My Feedback: (2)

Here's what's going on when the engine hangs up in a high idle. The long version. You've been out running around and the engine is thoroughly warmed up. You likely have the high speed needle adjusted dead on for the conditions, no richer than necessary. You decide it's time to come in and pull back on the throttle, but the engine doesn't come down to the rpm you expect it to. That takes a few seconds - while it's cooling itself down. There's little to no load on the engine, and it's bordering on a run away condition at that point.

Shutting that throttle down to an idle has robbed the engine of a TON of cooling. That gas that WAS going through it was providing a significant amount of the engine's cooling. That gone, and you're now playing the waiting game.

How to fix? More fuel. To be specific, more fuel on idle. How much more? Depends on where you're at. You should see a difference with 1/8 turn richer. If that doesn't affect it, go another. If that doesn't affect it, something's broke. You have a restriction or something else is going on that's affecting the low speed fuel supply.

Here's something else to consider. Rich engines don't quit.... (without going to extremes).

John, when yours quit after going 1/8 turn out (richened), I have to wonder if it had been thoroughly warmed? Are you sure you went CCW? Especially in light of the fact it returned to normal when you leaned it. That engine quitting after that first adjustment goes against all logic.

Just FYI - We get into this same problem ALL the time with the DLE 20 and 30 engines. They do the same thing (especially the 20), but that problem is compounded by the screwy timing curve that changes from full advanced to full retarded somewhere between 2200 and 2500. Right about where you get into the hung high idle .... Makes tuning a bit of a challenge! At least we don't have that to deal with on the Syssa's!

Joystick TX

I'm pretty sure ahicks is right. I had this same problem and it took a while for me to get my carb right. I also found that sometimes the correct adjustment seems like only a blade width away, not 1/8 turn.

This is from a previous post. Words to live by.

"A slow reduction of idle speed to a lower value when you close the throttle is a dead give away to the idle being too lean.

"A too lean idle will result in the engine failing to respond when you advance the throttle from idle. The engine may even quit."

You should also check your HI adj. when you adjust the low end since they work together. How are you adjusting your HI end?

It sounds like you make all of your adjustments with the engine shut off, that makes them way harder to get right. If your engine is side-mounted with the carb screws facing down, you may be able to put the plane upside down in a cradle so the carb screws are facing up so you can get to them easier.

JohnB96041

JoyStick: my engine is mounted inverted, spark plug down. I value my fingers, so do not do any carb adjustments with the engine running. Just me. I think I will leave well enough alone as the engine does run just fine. I will try changing the spark plug since I am over 2 years on the original plug. I will try a new one and see what happens (lol, I will change the plug with the engine stopped). Joke.

PacificNWSkyPilot

My Feedback: (19)

I was just thinking that I'm still betting it's too rich on the high end. That John already adjusted it richer AND leaner on the low end, and both times it died on him.

Then I wondered if perhaps he adjusted full 1/8th-turns, with no increments in between. Something Joystick said made me go back and look again.

I know people say that you have to stay away from the prop, but to tune an engine, it has to be running, or it'll take you all day. A full 1/8th-turn is a good four, maybe five increments, or as Joystick so accurately put it, "screwdriver blade widths," which we use when we're dialing it in, and each one can make a big difference. I guess I took what you posted as working your way out to an 1/8th-turn in each direction before it died, but when I read it again, it doesn't appear it was done that way.

When you're trying to work your way closer to good transition, use small increments, and when testing the adjustment, advance your throttle lightly and carefully, until you know it's not going to die every time you advance it faster. That way you won't have to start it a hundred times. Usually it'll start to die, but you can back it off quickly, and try the other way. The high speed and the low speed mixtures compliment each other. There's a balance there. Whatever you do to one has a subtle effect on the other. That's how you find the best transition.

It doesn't take long to get a feel for it. Your engine will love you for taking the time to learn how.

~ Jim ~