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Building Tips and technical articles. => 1/2 A building. => Topic started by: John Castle on March 08, 2010, 11:01:56 AM
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Sullivan Hornet 1/2A Electric Starter:
Any of you have any experience with this starter.
My cox engines seem to flip start pretty well but the Norvel engines could use a little persuasion.
What do you think?
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I have found that nothing works better to grind off the front of my Cox 049 crankcases, and the backs of the prop drive washers, than my Astro-Flight electric starter.
It's aluminum to aluminum, like metal to like metal, and you have to press hard to get a grip on the prop.
Back when they were popular I heard that there were some Cox engines with brass prop drive washers (for cars?) -- these would apparently last much, much longer.
I have no idea what the materials are on the Norvel, but I'd check before I touched it with a crankcase-grinder-offer.
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The Sullivan has very little torque, I actually burned mine up on a flooded Norvel .049, piston locked up and burned up the motor. I picked up a larger model (Hobbico maybe?) for the same price and it works MUCH better.
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:! I guess I could just get a smaller cone insert for my larger starter...Save a few bucks.
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John, i only use the starter for my Norvel combat ships, the rest i use a spring starter. They are worth the investment and time it takes to find them. A little prime in the exhaust and or venturi and a good glo starter and my Norvel's are off and running. Same for the AP wasp.
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Gentlemen, I think you all may want to reread Tim Wescott's post once more. What he is trying to say is that electric starters can ruin a Cox engine in a hurry!!! :o And one of the reasons is that you have to press very hard to get the starter to do it's job well. Another reason you have to press hard is that there is so little contact surface between starter and prop. A large spinner would help some and most don't use a spinner at all. the tiny spinner found on the Tee Dees and some of the reedies are just not helpful here at all.
Most important is that most time the engines themselves do not have any spacer or washer of a dissimilar metal between the front of the crank case and the drive washer!
If you insist on using a starter, put a brass or bronze washer between the drive plate and the crank case! Please! A phenolic washer should do as well.
Robert
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Another caution for using electric starter on 1/2A engines ( especially a standard size one with a small cone insert)- be very careful not to overprime / flood the engine. With a spring starter or finger flip- if it's flooded it will bounce back off the compression stroke.
With a starter- if you have enough fuel to hydraulic lock the piston you either bend the rod, snap the crank pin, or twist the whole engine and mount off the front of the plane.
As usual- based on my own experience- your results may differ. Mine are usually the more expensive results!
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I wish that the spring starters for the Norvel's were easier to find or some body manufactured a replacement. Any ideas? Do they make a spring starter for the Wasp .061? I really prefer the springs for the sake of simplicity.
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I wish that the spring starters for the Norvel's were easier to find or some body manufactured a replacement. Any ideas? Do they make a spring starter for the Wasp .061? I really prefer the springs for the sake of simplicity.
I have fabricated spring starters for Cox engines from music wire. Even when you get the shape right they're inferior (music wire is only almost spring steel), but they worked fine.
So if you're good at bending it may be possible to make something.
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A friend uses Cox spring starters on his Norvel, and bends the ends as necessary. The Norvel springs were not as good as the original Cox springs.
Norvels, and the AP Wasp clones come with a washer between the case and drive hub, and can be started safely with an electric starter.
My Miller half-A starter works beautifully, and was recommended to me by Larry Renger. A bit expensive, but worth every penny.
I've also used it on OK Cubs, but it does wear the front of the case, if your not carefull. I've found that pressing the soft Miller starter cone against the front of the prop, centered over the prop nut, and giving it a very short blip approximates the action of a spring starter, and does not cause much wear on the case. Works even better on spinner nuts.
Bill
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I use the Norvel starter (similar in performance to the Sullivan, Miller and Ace units) on all my small engines. On the reed engines, I make a washer out of thin brass shim to go between the crankcase and engine. (Or if you can find them, Cox made them out of stainless steel, perhaps Xenalook will make them available?) End of problem. I have not found flooding to be a problem if you have a reasonable starting routine. (Prime Cox engines with the ports closed, for instance)
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I have not found flooding to be a problem if you have a reasonable starting routine. (Prime Cox engines with the ports closed, for instance)
Getting the prime just right is a lot less important with a starter, too.
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As has already been stated, just bump start the engines. I have seen so many people hit the starter switch and keep grinding away. That is what ruins engines. Remember these are not car engines, like in your family car. H^^
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Zenalook has steel washers to add between the prop drve washer and the crankcase ro reduce grinding off the front of the crankcase.
I prefer the old AstroFlight style starter. I can't find my old one, but there is a guy that does starter inserts that still sells old AstroFlight style starter.
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Zenalook has steel washers to add between the prop drve washer and the crankcase ro reduce grinding off the front of the crankcase.
I prefer the old AstroFlight style starter. I can't find my old one, but there is a guy that does starter inserts that still sells old AstroFlight style starter.
If I ever get around to modding my engines to not grind themselves up, I'm also going to put a NiMH battery pack on my Astro Flight starter. Should be able to do this with 600mAh cells. I'm not even sure if you really need a full 12V to get a reliable start.
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The Miller R/C starter is small and light weight, but has the power to spin larger engines than half A. I've started 15 size engines easily with mine, but haven't tried anything larger.
They have enough torque to spin any half A engine from a dead stop. I just press the cone against the front of a prop, and blip the switch. As Doc says, that won't wear the front of the crank nearly as fast, if at all.
I'm told Miller starters are made by Kavan, and I think those are top of the line starters.
The washers Xenalook is selling have too small an ID to fit OK Cub .049 engines, but a good reamer is all it takes to fix that.
Bill
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Miller R/C
Thanks, that was the name I couldn't remember. Nice starter cones for full size starters also.