Author Topic: Self Starting Wobbler  (Read 1095 times)

Offline JC54

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Self Starting Wobbler
« on: July 31, 2018, 11:07:40 AM »
After successfully building my first motor, a simple single cylinder oscillator, I am modifying it to double action.  Now my question is, if I mount two double acting oscillators in a V formation should that configuration be self starting? I want to mount it in a very simple R/C Clayton steam lorry model. Thanks for any help that you can give. John

Offline Thor

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Re: Self Starting Wobbler
« Reply #1 on: July 31, 2018, 12:12:25 PM »
Hi John,

 Two double-acting oscillating cylinders in a 90 deg. V would be self-starting, I have built one, see here

Thor
« Last Edit: July 31, 2018, 12:17:08 PM by Thor »

Offline JC54

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Re: Self Starting Wobbler
« Reply #2 on: July 31, 2018, 09:49:26 PM »
Thank you Thor for the answer and the link. I have downloaded and it will help me enormously. I want to run on steam so some different materials would be needed in places I think. John

Offline Thor

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Re: Self Starting Wobbler
« Reply #3 on: August 01, 2018, 12:12:32 PM »
Hi John,

 Glad to hear I could be of help. I used mild steel for the standard, a freecutting stainless steel or brass would have been better. If using brass for the standard you might try freecutting stainless steel for the cylinders, I don't think you should have any problem fabricating cylinders using silver soldering (brazing). Good luck.

Thor

Offline Gas_mantle

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Re: Self Starting Wobbler
« Reply #4 on: August 01, 2018, 12:23:18 PM »
The position of the crankpins needs to be considered, if the cylinders are driving the same crankpin then a 90o V makes sense but if each cylinder drives its own crankpin then you can use any angle of V from 0o to 180o by setting the crank throws to the required offset in order to all the smoothest self starting configuration.

Offline Thor

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Re: Self Starting Wobbler
« Reply #5 on: August 01, 2018, 02:13:05 PM »
The position of the crankpins needs to be considered, if the cylinders are driving the same crankpin then a 90o V makes sense but if each cylinder drives its own crankpin then you can use any angle of V from 0o to 180o by setting the crank throws to the required offset in order to all the smoothest self starting configuration.
When I made my V twin both cylinders drive the same crankpin.

Thor

Offline JC54

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Re: Self Starting Wobbler
« Reply #6 on: August 01, 2018, 09:46:54 PM »
I was intending to use one crankpin for both cylinders, easier to build for a novice... :smokin2: It took 5 attempts to get the piston right for the original motor.. :shrug: :old: :headscratch: John

Offline JC54

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Re: Self Starting Wobbler
« Reply #7 on: August 03, 2018, 09:18:33 PM »
Many thanks for the input folks, it gives me somethings to think about. I do have a question, Thor how did you manage to drill the long steam/exhaust ports? If I try to drill such small holes so long I end up with a ruined piece with a broken drill bit in it. I am using the mill with an ordinary chuck to drill with. John

Offline Thor

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Re: Self Starting Wobbler
« Reply #8 on: August 04, 2018, 10:12:08 AM »
Hi John,

 In my write-up there is a photo of how I drilled the long steam passages in the standard. I have a webbed angleplate that fits the T-slots in my lathe cross-slide (both ways), and I clamped the standard to the angleplate. I could then mount an ordinary drillchuck in the lathe mandrel for drilling the holes for the steam passages. First make a spot using a centre dill, then drill a short distance with a 2mm drill (first ordinary, then using a long one) removing swarf often. Then opening the 2mm hole up to 2.5mm with bigger drill. Then back to the 2mm and drilling a short distance (5 to 8mm I think) removing swarf often. Then back to 2.5mm drill and so on. When the hole you are drilling is horizontal, it may be easier to get the swarf out. A free-cutting steel or brass would probably be easier to work with, but I did manage to drill all the long passages without breaking a drill.

Thor

Offline JC54

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Re: Self Starting Wobbler
« Reply #9 on: August 05, 2018, 10:04:10 PM »
Thank you very much for this method of drilling ports. :ThumbsUp: I will give it a try on some scrap first to see if my 110 year old lathe :old: will run true enough. :thinking:  John