Author Topic: Gearless Mechanism--4 stroke i.c. engine  (Read 13808 times)

Offline Brian Rupnow

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Gearless Mechanism--4 stroke i.c. engine
« on: September 02, 2015, 08:27:00 PM »
I have long been fascinated with the old hit and miss engines that were 4 cycle engines, but used no gear to drive the cam shaft at half the speed of the crankshaft. I have studied on this, and they break down into two main types. The kind I can not reproduce on a manual mill is the type which had cam tracks cut into the face or periphery of a disc. Chuck Fellows did a really nice job of reproducing one of those last year. The other type, which I can reproduce on my manual machinery, is the "star wheel" type. I don't want to start another engine build right now. However, I will attempt to create one of the mechanisms, post drawings of how I made it, and build the mechanism and make a video of it operating. I might fall on my face here, but follow along if you are interested. The one I make will be sized to work on a model engine.

Offline Jasonb

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #1 on: September 02, 2015, 08:38:24 PM »
Brian, now that you have your DRO I wonder if it would be possible to use CAD to plot out say 360 different Y positions that could be used to plunge cut with a small milling cutter as the work is rotated 1degree at a time on a rotary table, with a bit of clean up you should be able to get the right sort of shape groove. I have something similar to make for teh coiling gear if I do my Ploughing engine and had thought that may be a way. Not unlike cam cutting but moving teh tool sideways rather than up and down.

Look forward to seeing the star wheel develope

J

Offline jadge

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #2 on: September 02, 2015, 09:56:01 PM »
Presumably these mechanisms were used because they were cheaper than gears at the time the full size engines were being manufactured. Can we assume that the original parts were made on manual machines, and if so, how did they do it?

Andrew

Offline kvom

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #3 on: September 02, 2015, 10:49:59 PM »
Very possibly use a duplicating mill that worked like a pantograph.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #4 on: September 02, 2015, 10:54:45 PM »
Got to have something to mount the star wheel in----

Offline Myrickman

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #5 on: September 03, 2015, 01:04:51 AM »
Brian- these types of mechanisms also hold a soft spot in my mechanical interest. The one you show above is fascinating to watch on both models and full sized. The slots on the ones I've seen have been cut using a square cutter where the valve contacts. Makes fabbing it on manual machines way easier? Have you seen this one which was on the Wright bros shop stationary engine?  Don't mean to be a thread hijacker, but I thought you'd like this one and so I toss it on the pile. Very clever....  <a href="https://www.youtube.com/watch?v=M7H-wnHxxXU" target="_blank">http://www.youtube.com/watch?v=M7H-wnHxxXU</a> I saw it on a report on their early engines and had to make a mockup.. Forgot if I posted it in an older post .

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #6 on: September 03, 2015, 01:07:38 AM »
Myrickman--Yes, I seen that on an earlier thread, but it was never used on any engines I know of. It is however, ingenious.--Brian

Offline Alan Haisley

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #7 on: September 03, 2015, 02:47:56 AM »
Brian, is this similar to a Geneva mechanism?

Alan

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #8 on: September 03, 2015, 11:55:50 PM »
These mechanisms seem to do a lot better with a roller on the end which rides on the cam. I am assuming that this is because #1--it will be moving twice as many times in a complete cycle as a lifter which runs off a camshaft---and #2---it will be moving twice as fast, and #3--it has more mass than a standard "valve pushrod".

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #9 on: September 03, 2015, 11:56:40 PM »
Brian, is this similar to a Geneva mechanism?

Alan
No

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #10 on: September 04, 2015, 01:50:03 PM »
At this point, I have to decide whether the engine cylinder will be horizontal or vertical. The gearless mechanism will work on either, but for illustration purpose, I will use vertical. I also needed to show the exhaust valve that will be acted on (the intake valve is atmospheric)----and what better to use than the valve body/carburetor that I so recently designed for the oscillating i.c. engine.
----Now, to get into the science of how this thing works. Immediately below the stem of the exhaust valve, you will see the 4 lobed brown "star wheel". This star wheel has 4 "lobes" that will contact the bottom of the exhaust valve and lift it, if the entire gearless mechanism is lifted on a cam. It also has 4 "relieved areas" between the "lobes"  (as shown) which will NOT contact the valve stem if the star wheel gets rotated 1/8 (22.5 degrees) before it gets lifted again!! So--Stay with me--the cam is attached to the crankshaft. That means that with every single revolution of the crankshaft, that gearless mechanism will lift up on the cam lobe and then return to the "down" position--(There will be a tension spring attached to the gearless mechanism to ensure that it does return to the "down" position and stay in contact with the cam. So---as long as we are able to rotate that star wheel 1/8 of a turn every time the mechanism goes up and down then the valve will only get lifted EVERY OTHER time the gearless mechanism is lifted.--That nifty looking green ratchet wheel with 8 notches on the same shaft as the star wheel is the component which ensures this will happen.

Offline Alan Haisley

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #11 on: September 04, 2015, 04:54:12 PM »
The fog lifts. Thanks, Brian.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #12 on: September 05, 2015, 12:33:44 AM »
Toolguy raises a very good point.--What keeps the star wheel and ratchet wheel from drifting out of the proper rotational relationship to the valve stem. I have seen it done two ways, and know of a third. The third way which I know of, is a spring loaded detent ball and eight detents in either the star wheel or the ratchet wheel. This might work fine for something that only sees occasional use and slow moving components, but it wouldn't live with something like this application.  I have seen the following method used on a model---A piece of rubber or vinyl tubing is slipped over the axle  between the ratchet wheel and the blue "fork" supporting it, and is a bit longer than the actual space provided there. This acts as a friction brake to keep the star wheel from rotational drifting out of alignment. The third way, which is used by Philip Duclos on his gearless engine design, it to have a piece of spring wire laying tight against the flat face pf an 8 sided octagonal wheel which rotates with the star and ratchet wheel.  When the star wheel and ratchet wheel and octagonal wheel rotate, the spring wire is bent away from the flat it lays against and after the 22.5 degrees of rotation another flat face is presented and the spring wire snaps into place against the flat to keep it from drifting rotationally until the next cam action turns it again. I like the Philip Duclos method best, and will investigate it farther---The only thing I don't like about it is that it begins to get very "busy" around the star wheel. If anyone out there knows of a better/different way, please step forward and tell me about it.---Brian

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #13 on: September 05, 2015, 01:42:28 AM »
I just found this video, which shows the action of the starwheel very clearly at 2:18 into the video.
https://www.youtube.com/watch?v=dneJKmdRbu8
« Last Edit: September 05, 2015, 01:49:46 AM by Brian Rupnow »

Offline cfellows

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #14 on: September 05, 2015, 05:06:32 AM »
Here is another gearless valve mechanism...

<a href="https://www.youtube.com/watch?v=Q3xlUbMB4Jc" target="_blank">http://www.youtube.com/watch?v=Q3xlUbMB4Jc</a>

This type of horizontal shuttle and cam arrangement is pretty easy to make using a vertical milling machine...  I made something similar for a flame sucker engine a number of years ago using my vertical mill and my indexing spin jig... no CNC involved.

Chuck
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Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #15 on: September 05, 2015, 01:28:49 PM »
In the last video I posted it shows a couple of really top notch ideas that I have been wondering about. First, instead of a spring holding the gearless mechanism in contact with the cam, the large end of the rod which runs to the cam totally encircles the cam, similar to early steam engine valve rods. This means that no spring is needed. The revolving cam can now not only push the rod in it's upward travel. but also pull it back down again. Secondly, instead of some strange shaped cam, the cam is a perfect circle, simply offset by some calculated amount from the central axis of the crankshaft. And---(best of all) it has a true ratchet and pawl system to turn the ratchet wheel with a nice positive action, and then hold it by spring pressure to prevent rotational drift of the star wheel.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #16 on: September 05, 2015, 03:19:45 PM »
I have decided to use the Duclos method to keep the star and ratchet wheel from getting out of rotational position. I have machined an 8 sided shape onto the side of the ratchet wheel and used a piece of .030" diameter spring wire (in red) held in place by a washer (dark blue) and #4-40 shcs. (yellow). When the ratchet wheel is forced to rotate 22.5 degrees (by a mechanism not yet shown), the wire will spring away, then snap back into place against the next flat face. The light blue "fork" that supports the star and ratchet wheel has had a small "ear" added to one side to provide a place for the #4-40 shcs to thread into. It also has a very slight groove machined into it for the .030 wire to set in to keep it from moving.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #17 on: September 05, 2015, 03:28:37 PM »
To give some idea of scale, here are the parts we have been looking at with a "to scale" model of my hand.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #18 on: September 05, 2015, 11:33:18 PM »
I'm getting to the "hinky" part of this design now. Assume for a moment, that the gearless mechanism has not yet stopped moving down---The star wheel is clear of the bottom of the valve-stem so it can rotate, but it hasn't rotated yet. The spring loaded pivoting "pawl arm" is swung in by the spring pushing on the back of it and you can see that the bent end of it is going to catch the tip of the ratchet wheel below the centerline of the ratchet wheel. If my downward travel is calculated correctly, then when the gearless mechanism continues it's downward travel and is fully bottomed out, the ratchet wheel and consequently the star wheel is going to be rotated by an amount equal to 22.5 degrees of rotation. --When that happens, then the gearless mechanism will move upwards due to influence from the cam, and since it has rotated 22 1/2 degrees, one of the lobes on the star wheel is going to contact the stem of the valve and lift it.---Clear so far??:eek::eek:

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #19 on: September 06, 2015, 05:33:33 PM »
I have absolutely no intention of building an engine for this gearless mechanism to go on. That being said, it is such an interesting mechanical device that I'm sure someone will want to build an engine to try it on. BE WARNED---This is not for any kind of high speed engine. This type of device was used on either hit and miss engines or old stationary thumpers that sat all day running about 600 to 750 rpm. I am going to do a "quick and dirty" design of a 1" bore x 1.5" stroke engine to mount it on. This will purely be a "guide" for anybody who may decide to take the design and run with it, and to give me some frame of reference for placement of parts.---Brian

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #20 on: September 06, 2015, 09:39:53 PM »
I suppose if it was easy, everybody'd be doing it!!! This is getting complicated----and no, I haven't shown any fins on that engine. That's why it looks so skinny.--and the head isn't on it yet.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #21 on: September 07, 2015, 12:44:46 AM »
So----There we have it at about 99%. It ends up at about 10" tall, overall. The more I modeled, the more it began to look like the Philip Duclos engine. There is a good reason for that. Distance from underside of base up to center of crank has to be tall enough to allow for a flywheel. Overall cylinder length is determined by length of piston and stroke.  The carburetor/valve body has to be positioned so that it can feed directly into the cylinder head, and the length of the 4 round pillars supporting the cylinder is determined by the minimum amount of room required to fit something like the gearless mechanism into the space between the crankshaft and the stem of the exhaust valve.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #22 on: September 07, 2015, 04:45:39 PM »
So, here we have it. a single cylinder four stroke engine 1" bore x 1.5" stroke, air cooled, large enough to accommodate the gearless mechanism. Again, as I said, I don't plan on building the engine, only the gearless mechanism. However, I wanted to ascertain that if someone ever actually did want to use it on an engine, it would be possible. It makes a good looking model.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #23 on: September 07, 2015, 05:04:48 PM »
Someone has asked for everything I have done on this project as .stl files. You will need 3D cad software to do anything with these, and remember that nothing is proven here--it is all a "work in progress". I am confident about the gearless mechanism. The engine itself, is as I have said "Quick and dirty" but is sized to work with the gearless mechanism.---Brian
http://www.mediafire.com/download/o1x03gjh59119ak/OVERALL_GEARLESS_ON_ENGINE-X_-1.zip

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #24 on: September 07, 2015, 10:09:11 PM »
Not exactly huge, is it!! I wanted to make the star wheel, but didn't have any material the right size. I was able to cut this ratchet wheel from a short length of 1" diameter cold rolled.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #25 on: September 08, 2015, 10:19:45 PM »
It's a cute little devil, so far.

Offline Tennessee Whiskey

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #26 on: September 09, 2015, 12:16:57 AM »
Brian, you're moving so swiftly the new mill must really be working out for you.  You know,  it's going so good you might as well build the engine also  :stir:.

Cletus

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #27 on: September 09, 2015, 01:15:56 AM »
Cletus--I don't want to get tied into another large project right now. That is why I posted a link to all of the solid models I created so others could download them and build the engine if they wanted to. The gearless mechanism is a nice little (and very interesting) project, which doesn't require a large time investment. I have been intrigued by gearless mechanisms ever since I first heard about them, and by modeling and building one I get a much better understanding of how they work. Even within the last week I have learned a lot of things about them that I never knew before. I'm not inventing anything new here----these are all tried and proven designs that I am basically gleaning from other peoples videos, etcetera and putting them into  a context I can build from. I have built enough complete i.c.engines now that I don't have any interest in building another----right now anyways!!!----Brian

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #28 on: September 09, 2015, 03:38:57 PM »
Okay kids and turtles!!! Some folks are asking me (I post on three different forums) why I don't build the complete engine.---I don't want to build another engine right now. There is plenty of work involved in building the demonstration model---trust me. The demonstration model will be hand cranked, but it will most definitely show the complete operation of the gearless mechanism. Note that in this model, I haven't shown the springs which hold the gearless mechanism in contact with the cam.---Brian

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #29 on: September 09, 2015, 05:40:36 PM »
Following my policy of "Never throw anything away---ever!!" I hunted around in a box of junk and recovered a one piece crankshaft I made a few years ago that turned out too crooked to work in an engine----But---it will work fine for a hand cranked demo model. You can see the big strange looking cam setting on one end of the crankshaft.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #30 on: September 09, 2015, 11:03:41 PM »
Progress was made today. I don't think the crankshaft idea is going to work out, but it's not a big deal. The stand is almost finished, the cam is made, and the guide and capture plate are finished.

Offline b.lindsey

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #31 on: September 10, 2015, 12:35:02 AM »
Brian, I realize you are making this as a proof of concept display and judging from the pictures, this would fit a rather large engine at the scale you have modeled it. Do you think it can be made successfully on a smaller scale if someone wanted to use the idea in an engine of smaller overall dimensions? Nicely done by the way!!

Bill

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #32 on: September 10, 2015, 01:16:45 AM »
Bill---thanks for dropping by and saying Hi. This project hasn't raised as much interest as I expected it to. In all honesty, I don't think it could be made much smaller and still have a chance of working consistently. The smallest one I have ever seen is on a Philip Duclos engine called the Maverick.---You have to really look for it, it's so small, but I have heard reports that it didn't actually work very well.

Offline b.lindsey

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #33 on: September 10, 2015, 02:00:40 AM »
Oh, I've been watching the  whole time Brian,  just seeing where it was going with this idea and its quite a clever mechanism. I have been around this hobby long enough that I recall the Duclos Maverick and probably have the HSM issues squirreled away somewhere from years back.

Bill

Offline Perry

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #34 on: September 10, 2015, 10:33:32 AM »
Hi Brian, I like your fast design to build approach. Nice mechanism indeed  :ThumbsUp: P.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #35 on: September 10, 2015, 11:11:37 PM »
I just had my first "test drive" of this mechanism, and it's awesome!! Even though I know how it works, even through I have watched the video 25 times, it is just "awesome" when it comes to life from parts you have made yourself, from drawings you have made yourself. What a great thrill that even after having done this kind of thing for 50 years, I still get excited when I see one of my creations run. It is not my invention, it is not my intellectual property, and it's all been done before many times by many people---but I still get excited!! Video tomorrow, maybe.

Offline b.lindsey

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #36 on: September 10, 2015, 11:56:42 PM »
Would be a real hit at shows Brian...one of those things kids (of all ages) would just love to crank the handle on and see it  work. Nicely done!!

Bill

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #37 on: September 11, 2015, 01:41:16 AM »
Tomorrow I will make a "valve" to fit into the top plate, complete with valve spring and spring retainer to hold the valve closed. I have arranged things so that I can crank the mechanism by hand, or drive the mechanism very slowly with a belt drive from a power source. I will have to see what works best before I make the video.

Offline Brian Rupnow

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #38 on: September 11, 2015, 06:44:16 PM »
Here ya go fellows!! Hope you enjoy. If you want a set of drawings to build your ow mechanism, email me at brupnow@rogers.com ----Brian
<a href="https://www.youtube.com/watch?v=HuwlBj3YZMQ" target="_blank">http://www.youtube.com/watch?v=HuwlBj3YZMQ</a>

Offline wagnmkr

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #39 on: September 11, 2015, 06:55:31 PM »
Very nicely done Brian. That was not very long for you to do this wee project.

I hope we don't have to wait too long for your next project.

Cheers

Tom
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Offline Steamer5

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #40 on: September 11, 2015, 07:03:05 PM »
Hi Brian,
 Thats pretty nice! A fun project, cool to see how it works, not always possible in a complete engine.

Cheers Kerrin
Get excited and make something!

Offline Admiral_dk

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #41 on: September 11, 2015, 07:47:24 PM »
Yet another Rupnow Engineering project completed  :cartwheel:

Thank you for the show Brian  :)

Offline b.lindsey

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #42 on: September 11, 2015, 07:51:08 PM »
Well done Brian. And thanks for showing the video too!

Bill

Offline Johnmcc69

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #43 on: September 12, 2015, 01:09:40 AM »
Very cool Brian! Nice job!

 John

Offline Zephyrin

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #44 on: September 12, 2015, 11:52:50 AM »
This a very interesting thread, very  instructive, (as usual !) and I'm planing to incorporate such a device in the engine that I'm building now in lieu of its present setup : a classical camshaft, with a chain drive that I found too bulky and not tuned with its old style : a vertical 4 stroke engine on a two footed pedestal, (similar to a steam engine).
I think that I have to modify the cam profile, otherwise the exaust would stays open too long. 

Offline cfellows

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Re: Gearless Mechanism--4 stroke i.c. engine
« Reply #45 on: September 12, 2015, 04:39:46 PM »
Nice work, Brian.  I got an update to a thread on HMEM this morning.  Couple of videos of gearless hit n miss engines you might be interested in looking at...

http://www.homemodelenginemachinist.com/showthread.php?t=20159

Chuck
So many projects, so little time...

 

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