Hey guys.. I got a few questions about converting my US41 to electronic ignition.. hope you can help

Ebay has this Rcexl ignition system for $75 .. that seems like a great deal to me.. but I'm a bit nervous about a few aspects of the conversion

The listing states " You provide your favorite switch and 4.8 battery and a hub for the special magnet that is included."

Is there a place to purchase a hub that will work with my engine? and what "switch" would you recommend I use?

also... since the spring starter will be deleted...would there be an advantage to removing the aluminum motor mount and replacing it with standoffs? I'm trying to lose as much weight as possible.. I'll post a pick of what all comes with this ignition.. any help would be greatly appriciated!

I use small toggle switches from Radio Shack. You are also going to need a 4.8 volt 800 mah or larger battery pack, and a means to charge it.

Your best bet would be to contact Ch Ignitions at www.ch-ignitions.com and you can buy an ignition from them and probably the hub as well.

If you have already bought the ignition, then try www.wackerengines.com to see if he has or can make you a hub.

AV8TOR

I'm doing the same sort of thing to my Rowena engine (see other thread). But unlike yourself, I havn't thought it through Already bought ignition kit.

The magnet needed is tiny so can be glued into the 'hub'. As long as there is a bit of diameter on the hub (so it isn't super-critical on gap setup) I should be able to make it work. The hub itself is escaping me at the moment as I only have a plain ~12mm dia shaft on the front of my engine. So I'm looking for a plastic clamp/clip that I can drill for the magnet and clamp on the shaft.

If you've got a mag on yours, you should be able to put a nylon rod or similar on to the shaft to fit the magnet into. I've also read about hole-sawing the alloy core out of the flywheel and using that if you need to go onto a taper.

EDIT:- Found what I need......

another problem with the kit you're looking at is the spark plug that is needed and included with the kit, it has 10mm threads, and your engine most likely has 14mm threads. if you have a metal lathe or access to one, there's a simple solution involving a discarded car spark plug (I used one from a chevy 350), part off all but 3 threads, drill out the center to the size needed to tap the hole, tap the hole in the middle, then part off the rest of the plug just past the sealing taper and face it so the new plug will seal. or you can just buy the adapter from CH or get an ignition module that takes the right size plug...

Or just buy a plug for ÂŁ2.50 that fits the head

Thanks for the replies so far.. it's definately a help

I've got the flywheel off and I took a picture of the shaft.. the shaft is tappered.. and for this reason.. the idea of using a hole saw to cut a hub from the discarded flywheel sounds like a great idea.. (I'll use a drill press) I can just drill a hole in the fabricated hub and red loctite the magnet in.. drill and tap two small holes on the aluminum end cap to screw down the bracket that holds the EI's magnet.. and I'm off to the races.. unless I'm missing something.. I'm still grasping for all the advice I can get here before tackling this project..

the EI on ebay can be ordered with the 14mm plug also

one more question.. can the shaft that protrudes out the back be cut off flush in order to save more weight?

Don't see why you can't cut the rear shaft off. Unless it presents an obvious magnet-mounting position.

The taper has been turned off my motor and is a plain 12mm dia. So I'll be pressing or clamping something on there to drill for my magnet.



RangerFredBob. Sorry for earlier sarcy smiley

Well I ordered it.. I got the 14mm plug size.. this looks like it will be a fun project.. this US41 has always ran excellent.. it's just a heavy beast.. I'm hoping to shed about a pound of weight.. I'll probably use a 1450ma NiMH for the ignition pack.. It's installed on a Kangke Cap 232 that prior to this modification weighed in at 14.5 lbs... it flew pretty nice.. just had that heavy feeling.. 75 bucks is worth it to me.

When I start doing the conversion I'm sure I'll have more questions.. getting the timing right will be a big concern..

Thanks to everyone that responded!! anymore advice you can give will be greatly appriciated!

You can use the rear shaft to put the ignition sensor on, so the whole chebang fits in the rear of the engine.
Use 5mm rare earth magnets, and position the hall sensor so it will provide a spark. (it is pole sensitive, and can be turned around)
Set the ignition at 28 degree advance for best overall performance

not exactly that simple, I didn't find any that had the 14mm threads and fit the plug boot thing for the ignition that needs to be grounded to the plug body, they might exist, but I didn't have any in my posesion at the time it was easier to just make an adapter

Makes sense now.

A 10mm threaded plug with a 5/8 hex 14mm sized top is available, but havent seen a 14mm plug with a 10mm top..
The right size cap is the way to go.

I figured just adapt the plug, it was smaller and lighter, both of which seemed like good ideas, plus the adapter was free and easy , and I like playing with the lathe...

The seller on ebay has contacted me three times varifying information about my spark plug and making sure I am getting exactly what I need.. He seems very knowledgable.. his abay name is syssaaircraft and I can highly recommend purchasing from him.

I took all the parts off my motor last night and weighed the flywheel, magneto and spring starter.. They weighed in at 1lb 2oz ... I'm either going to use the original motor mount and lighten it up as much as I can.. or else use standoffs.. the ignition will probably add back 6-8oz I'm thinking.

has anyone had good luck using AAA NiCD or NiMH packs? I would estimate I fly much less than 2 hours at a time since I always take more than one airplane.. I'm thinking the next place to look at loosing weight will be in the pack used to fire the ignition.

An 800 mah pack should fly for an hour or so. The lightest option would be to use an 800 mah 2 cell LiPoly battery with a voltage regulator to bring the voltage down to 5 volts. (The regulator weighs practically nothing.)

AV8TOR

hmmmm... i have an etec 1200mah 2 cell sitting around.. is there a way to have a voltage cutoff to save the lipo from discharging too far? any suggestions as to where to get a good regulator? thanks

Yes, I have one that also has a set of indicator lights for the voltage. I can't remember where I bought it. It's at the office... I'll be there in an hour or so and I'll let you know.

AV8TOR

I have both the CH with built in syncro-spark in my Giant Spacewalker powered by a Zenoah G-26, and a CH-RCEXL that I run on a converted SuperTigre G51 in a 40 size SuperSportster. Both seem to use anywhere from 250 ma to 450 ma per hour of flight time. I am guessing that the variance is how hard I am running drawing more current for the increased rpm's. I have run the Zenoah on a 600 ma Sanyo NiCd pack for just over an hour and a half and it was still running. The pack needed 510 ma on my Triton to peak it when I got home. I now run Sanyo "Eneloop" 2000 ma NiMh's on both and never worry about how much I have left. Those will far outlast me. I am toast after about 2 hrs of flying.

That regulator I have is called the "Sport VRLI" and it is sold by FMA Direct. (www.fmadirect.com)

It doesn´t cut off the power, but it has a set of three lights for monitoring the power level of the battery. It regulates the power to 5 volts and is good for 2 amps continuous. I think that will be enough....

AV8TOR

What I do with a hub is I took a hole saw and cut the senter out of my fly wheel. put in a manet and used the prop hub that came off the engine. Works grate.

Paul

i was looking at UnitedHobby to see what they had to offer since i'm planning an order in the near future.. they have a 4amp UBEC with a warning "beep" when the battery gets to 3 volts per cell.. it costs 11 bucks before shipping... i'll also look at the fma site as well

[link]http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=2160[/link]

my 1200 2cell is an older 8C pack.so it should handle an 800mah peak draw just fine.. things are coming together nicely.. it's a little work to go through with an old "boat anchor" of a motor... but i'm learning as i go and knowledge is priceless [8D]

thanks for the info AV8TOR!