Author Topic: Freelance Inline Twin  (Read 29535 times)

Offline 10KPete

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Re: Freelance Inline Twin
« Reply #15 on: November 12, 2016, 02:33:44 AM »
Yep, Yogi has it all figured out.....   :facepalm:

Pete, just waiting to see this one run!
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Offline yogi

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Re: Freelance Inline Twin
« Reply #16 on: November 12, 2016, 03:59:28 AM »
I hope I thought of everything Pete, but please feel free to ask questions, or if you have any input I sure would like to hear it. Right now would be the time to make a change to the design.

The design evolved over a long time. I have been working on it on and off for over two years. So there were a lot of design decision that had to be made. It's also my first IC engine I designed myself and I'm curious to see if everything is going to work out the way I imagined while drawing it up.

Regards,
Yogi

Offline Jasonb

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Re: Freelance Inline Twin
« Reply #17 on: November 12, 2016, 07:00:39 AM »
360degree crank should be OK The Nemett Bobcat which is a similar layout model engine runs OK with one, the designer did an article or two about crank layout Vs vibration and decided the 360 was the best for his engine.

Offline gbritnell

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Re: Freelance Inline Twin
« Reply #18 on: November 12, 2016, 01:01:59 PM »
Hi Yogi,
I'm guessing that the cover plate on the head is so you can create water passages in the head and then seal it off? If this is correct then you might have some issues with the valve guide alignment as they go from the head to the cover plate. I might suggest putting a couple of registration dowels in the head and cover plate so that the two pieces stay in exact alignment when machining and assembling.
gbritnell
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Offline yogi

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Re: Freelance Inline Twin
« Reply #19 on: November 12, 2016, 03:45:37 PM »
Thanks Jason, that is comforting to know.

George, thank you for your input. You are correct. The top plate is so I can seal off a cooling passage machined into the head. I came up with the following solution to the problem you pointed with the valve guides alignment: The holes for the valve guides in the cover plate will be machined over size, to allow for the machining tolerance. Also, the valve guides will be stepped down to a smaller diameter at the top. This would prevent the valve guide from working its way out of the cylinder head from the combustion pressure. Even though to common practice of pressing them into the head has proven to be more than adequate, I felt this would be worth while.





Best Regards,
Yogi


Offline Roger B

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Re: Freelance Inline Twin
« Reply #20 on: November 12, 2016, 06:14:58 PM »
Do you need the port tapered in towards the outside like that? Parallel and matching the manifold would be much easier to machine  ::)
Best regards

Roger

Offline yogi

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Re: Freelance Inline Twin
« Reply #21 on: November 12, 2016, 08:48:09 PM »
Roger, the exhaust passage is actually a straight hole, but it's at an angle to clear all the mounting holes. The section cut was done parallel to the plane, that's why it looks tapered. To better illustrate, I attached a couple of renderings.






Regards,
Yogi


Offline kuhncw

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Re: Freelance Inline Twin
« Reply #22 on: November 12, 2016, 10:15:39 PM »
Yogi,

I like your twin cylinder design.  It reminds me of the Bob Shores Silver Bullet I built.  I think you'll find you can easily start your engine with a hand crank.  Definitely add the over running bearing as George mentioned. 

Which solid modeling software are you using?

Good luck and I'll be following your build.

Chuck

Offline yogi

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Re: Freelance Inline Twin
« Reply #23 on: November 13, 2016, 12:17:33 AM »
Thanks Chuck!

I modeled the engine in Solidworks.

Regards,
Yogi


Online b.lindsey

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Re: Freelance Inline Twin
« Reply #24 on: November 13, 2016, 12:31:49 AM »
Very interesting project Yogi. I have been following along quietly and will be along for the ride.

Bill

Offline Art K

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Re: Freelance Inline Twin
« Reply #25 on: November 13, 2016, 03:13:12 AM »
Yogi,
Just caught your inline twin. It looks like the makings of a great engine. Your cad work is way above mine, I must admit. I look forward to seeing it progress.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline yogi

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Re: Freelance Inline Twin
« Reply #26 on: November 13, 2016, 02:21:00 PM »
Thanks Bill and Art!
I hope it's going to work the way I envisioned it...  ;)


Offline kuhncw

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Re: Freelance Inline Twin
« Reply #27 on: November 14, 2016, 03:57:08 AM »
Yogi,

What is in the big ends of your rods for bearings?

Since you are going for low rpm idle, don't hesitate to add some extra diameter to the flywheel.  If that makes the flywheel look a bit large, you could add an industrial engine style flywheel housing.

Chuck

Online steamer

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Re: Freelance Inline Twin
« Reply #28 on: November 14, 2016, 12:22:29 PM »
Looks very "Wallabyish"   8-)

I like the crank! 

Dave
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Offline yogi

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Re: Freelance Inline Twin
« Reply #29 on: November 14, 2016, 09:20:22 PM »
Chuck, the big end bearings will be needle roller bearings. A bigger flywheel is always an option. I think we'll have to wait and see how it runs, and make adjustments if needed.

Dave, I definitely used some design ques from Westbury's Wallaby. It is such a good looking engine...   8)

Regards,
Yogi