Bass1

Recently had a mishap (crash) with my 50cc Extra 330. The engine suffered some damage and the plane was totally destroyed.The carb was badly damaged as well as the linkages for the throttle and mechanical timing. The engine is an older Brison 3.2 with A C&H mechanical advance ignition. I installed a new carb and fabricated new throttle and timing linkages. Got the engine mounted a new 5occ plane and could not for the life of me get the engine to run smoothly at max throttle. Chased around cooling and possible timing issues and retimed and double checked everything . Still no luck. Along comes a poster here on RCU that goes by the screen name "gr8flyer55". He tells me he rebuilds the C&H units, modifies some with his own custom built circuit boards and also builds his own brand of ignitions. I figure I have nothing to lose as it's nearly impossible to find a "mechanical advance" C&H ignition. Sent it off to him and in less than a week it's back im my mailbox labled as repaired. I install the ignition back in my plane and set the plane up to give it a shot. Darn thing fires right up, idles beautifully and runs smoother at full throttle than I can remember. He sends me a PM describing what he found wrong with it. It was a broken coil wire and the positive battery lead was broken at the solder joint. He repaired the unit and sent it back for "no charge". I asked why no charge and his reponse was "no parts needed' so no charge!! On top of that, he is sending me a spare rebuilt C&H mechanical advance Ignition to have should I need one for any future mishaps. Anyway, John (gr8flyer55) is truly an asset to this hobby. He didn't have to do any of this and said he just enjoys doing it as a hobby and the pleasure of keeping RC enthusiasts happy. I will probably purchase one of his Auto Advance designs to have in case I ever want to ditch the mechanical advance. Thanks a million John!!

gr8flyer55

Thanks for the kind words Bass1 !
Working on the older CH ignitions is something I seem to do more of these days. While they were extremely reliable and well thought out designs, even the most robust designs can be rendered useless in a bad crash. Took a little probing and some freeze mist but found the problems and yours was up and running in no time. We all owe a debt of gratitude to Bill Carpenter for his life long work supplying us in this hobby with the marvels of CDI ignitions.
I for one, love the design. Easily repaired if you doink it in a crash. I can't improve on perfection, just offer new life for otherwise inoperable ignitions. CH designs were mirror image copied by RCexl a few years back, but there is nothing like a CH !!

By the way Bass1, goodies inside your returning box this week, couldn't help myself. Lol
Trial units for your next project!

John

WhiteRook

My Feedback: (38)

ive got a CH on a Q100B , and it has the 3w type , three prong hookup , can i use it on my 3W70i ?

its good to know someone knows how to work on these

gr8flyer55

If you are referring to the hall sensor plug having 3 pin connectors, yes it should work. Does your engine have throttle coupled spark advance? If it was a standard ignition without a Syncro Spark module, you can plug it in between the hall sensor and the ignition.

On the 3w 70, I would have to see some sort of picture of the sensor plug and wiring to be able to decide if it will work. There's nobody in my club locally that has one for me to look at. Just did an Evo 50cc today doing away with the complete old hall sensor mount, put a universal bracket on it and a new sensor. Working great.

We'll figure yours out.

John

Bass1

In that case I'll have to start thinking about a new project!

dirtybird

My Feedback: (5)

I would like to have a unit that works on 3V
I have found a small chip that takes 2V input and puts out 5V but it is limited to 200ma. As I recall the old C&H units used about 250ma. I was thinking of using two chips in parallel. That way you could use just one 3.3v A123 cell.
This is for small (10cc) gas engines.
The specs for the RCXEL ignition list 600ma current requirement. Its simply not usable.

MTK

DB,

I think I understand what you are saying....extra battery weight in the smaller aiframe of a 10cc gas engine is too much panalty.

Have you considered the Tech Aero IBEC? This is a great gizmo that connects directly to your airborne battery. I use it on every gas model I own. My typical battery is a 1800-2200 ma LiPo regulated (also using a Tech Aero regulator to get voltage down to 6.3V) powering 6 high torque/speed servos and the IBEC-CDI unit. I get 75 minutes flying time in my style of flying (not 3D) which drops the voltage from full charge, 8.4 V, to 7.4 V, which is nominal voltage for a LiPo. The IBEC weighs in at a scant 1/2 ounce and features a settable voltage to the CDI. I set volts out to 5.4 V to the CDI. Cost is around 40$. Check the Tech Aero website

dirtybird

My Feedback: (5)

A lipo and a regulator are two items I will not use in my aircraft.
I want an ignition that works on 3V so I can use a single A123 battery to power it.

gr8flyer55

Minimum power requirements for the most used hall sensors is 3.7 volts. You may have to rethink your project. I have ignitions functioning at that voltage with one Lipo cell but that's about my limit for reliability with lower voltages.

John

Tony Hallo

Call me crazy, yesterday I flew by 5.1 D&B powered One Design with a $5.41 Hobby King UBEC plugged into the radio battery (7.2 voltlipo)for ignition power without incident. The D&B uses CM6 plugs with resistor wires without caps. I have a Frsky 2.4 ghz telemetry module in my Futaba 9C radio and receivedno alarms. Last year Iflew with aGT80 with Rcexcel ignition and 4.8 NiM batteries that hadprovided more alarms for low/loss of signal. The ground check was good so I flew the plane twice before getting rained out. The only negative I found was the UBEC consumes 140 MA when the engine is off. I do have a Smart Fly iugnition cutoff installed.
Speaking of ignitions the two magnet system used in the D&B engines works great, other than cost I see no reason why it never became as popular as the CH/Rcexel brands.

dirtybird

My Feedback: (5)

There are two circuits in the CD!, one supplies the spark and the other provides the timing. I am told the spark circuit will work on 2.4V The timing circuit requires more voltage.
There exists a voltage doubler circuit on a small chip that will provide 5V @200ma with an input of 2.0 volts. This chip can be had for $3.
My plan is to run the spark circuit directly from the battery because it requires 600ma, while the timing circuit will be supplied 5V from the doubler.

dirtybird

My Feedback: (5)

I agree with your initial assessment.

SOLO_48

My Feedback: (8)

Can you repair RCXL ignition,got TWO that need work ,please let me know if you can..THKS

gr8flyer55

If you were referring to me, most of them are repairable if they didn't pot them in epoxy. If that is the case, I usually just build a new unit and install it in a case I have on hand.

John

SOLO_48

My Feedback: (8)

Can send it to you813-500-0231

gr8flyer55

Send the RCexl unit to:
John Weidman
341 Ontelaunee Trail
Hamburg, Pa. 19526

I'll take my best shot at it even if it's one of the potted ones. I usually have little problem repairing them.

John

SOLO_48

My Feedback: (8)

thks,will send it to you

Bass1

John, I received the goodies yesterday. The Auto advance timer board is a slick little unit. I also tried out your tiny ignition tester and it works great. About how many rpm does it simulate? Thanks for all the stuff. I will put it to good use. I'll probably swap out the old brown case C&H Ignition with my other Brison 3.2 for one of those nice and shiney silver ones even though it still works fine.

captinjohn

gr8flyer55, I found a small wood box to place the Neat ignition you sent. I will place a few photos on a web-site that has a lot of Guys looking for a Ignition system for the small hit & Miss enngines they run and display.My love for engines of all types kinda leads me too engine shows too that are non RC. I am sure they will like your "stationay" ignition system. Keep up the good work on all your various ignition building and repair.BestRegards, Capt,n P.S. The photo is my engine and you can see your ignition is a lot smaller.

gr8flyer55

The testers can be made to simulate a mid throttle range of about 3,000 rpm. I have a few that will go up to 12,000. Yours was about 3k. If you have an optical tach and are using one of my timer boards with the super bright LED, point the tach at the LED very closely and shield it from external light sources while using the tester. Get the reading from the tach and multiply it X 2 and you have the rpm simulation speed.
Most of these small ignitions begin to lose spark strength after about 10k. All depends on the plug used and if the plug cap had an installed resistor or not. My personal preference for my plane uses a non resistor plug, stranded copper plug wire core and of course braided RFI shielding.

I'm glad you are pleased with the advance boards. All hand made and tested.
Thanks for giving them a try.

John

gr8flyer55

If you would like an assembled set of boards to test your voltage step up chip on, PM me with your mailing address and I'll send you the separate boards. In theory, using a common ground between the boards and the signal wire from the advance board will work as planned. I've done this many times while in the process of developing my boards to isolate problems. Please use one blocking diode on the common ground back to the ignition though, it's needed. Ask me how I know!!

John

closetguy

My Feedback: (13)

do you know what the timing is on the auto advance CH units and can they be adjusted for different settings.i now they are set at 28* at WOT but what is the setting say at idle?
guy's that are in the know say 4* at idle and 28* at WOT.

gr8flyer55

You are correct with 4 degrees but it is before you flip the prop. At an idle speed of say 1400 - 1900 they are advanced to about 14 - 15 degrees and then do a linear climb with rpm till it reaches 28 degrees WOT. These settings are what I use for my advance curves also. Produces an easy no kickback hand start and great top RPM.

John

gr8flyer55

CH original units are not changeable. Mine can be reprogrammed if you are equipped with the programmer board, my info in the engine conversion forum, and the skills in editing. Most of this is explained in my construction articles. The use of excel spreadsheets, and the assembly language program editor is required to reassemble the file into a hex file and reprogram the Pic chip.
At the present time I am not offering to make changes to the curve. Being so busy here it would take up all of my free time. It is a good universal advance curve, and has been tested on many engines with great results.

John

closetguy

My Feedback: (13)

thats ok i just wanted to know what CH ignitions are set at.i have two of them that i got in trade with engines,the engines are gone with other ignitions,but i kept the CH's that came with them.Thanks