# Sliding cylinder



## rickharris (Jun 17, 2008)

I am pondering a number of engine designs (at present still more 3D CAD exercises - I need the practice) - and the possibility of making the cylinder slide to act as the valve system seem to be a possibility i can't find any other reference for.

Has this not been done? Is it impractical? seems to combine the simplicity of a wobbler with the elegance of a shraight picton/cylinder

Thoughts?


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## zeusrekning (Jun 17, 2008)

I believe someone here has worked with a cylinder that rotates and travels up and down on a "cam" to work as the valving. Can't remember who or what it was called but I'm sure someone will. It may have been on another small engine site???
Tim


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## Bogstandard (Jun 17, 2008)

Rick,

It has been used for many years on ic engines. They are called sleeve valve.

In fact a UK company manufactures model ic engines based on this technology, and has a contract with the US military for developing pilotless drone aircraft engines.

http://www.rcvengines.com/

http://en.wikipedia.org/wiki/Sleeve_valve

I am sure with a little bit of looking at it could be used for air or steam.

John


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## SandyC (Jun 17, 2008)

Hi Guys,

Rick.... there is also 'Bodmer's sliding cylinder' steam engine Circa 1841.

Designed for use in paddle steamers, but also used for land based installations.

A model kit is available from : -

www.pollymodelengineering.co.uk

Look under 'Stationary models'

'Anthony Mount collection'..... about 4 picture down....Nice looking engine and a bit different.

It Might give you some ideas.

SandyC


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## rickharris (Jun 17, 2008)

Thanks guys I have had a look at your suggestions - and thought further about this.

I have tried to illustrate my thoughts in the 2D drawings below. The idea is the cylinder has a stop at top and bottom so the piston contacts the cylinder. This causes the cylinder to slide up or down changing the porting from intake to exhaust - in much the same way as a wobbler only the action is all linear rather than rocking or oscillating.

It may be better to run a second shaft from an eccentric to move the cylinder but a minor change.

The two engines sited above don't appear to do this as such.

Note the pictures show the cylinder NOT the piston. This is what you would see when it was running - The cylinder sliding up and down as it runs. I can see that there would need to be sufficient friction between cylinder and back plate to ensure that the movement only happened at TDC and BDC.







Perhaps the issue would be that the pressure may drive the cylinder up/down rather than move the piston/flywheel? Need a physical catch at top and bottom to hold until tripped perhaps.


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## HS93 (Jun 17, 2008)

can I ask what program you use for the drawrings

Thanks peter


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## rickharris (Jun 18, 2008)

HS93  said:
			
		

> can I ask what program you use for the drawrings
> 
> Thanks peter



The drawings were done in a CAD programme widely used in schools in the UK called 2D design it is soldby Techsoft but is rather costly for the individual to buy.






http://www.techsoftuk.co.uk/


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## Xlmyford (Sep 13, 2009)

Hi Rick.
Maybe you can take a look at this:
*Bodmer´s sliding cylinder engine*
It´s all German,but the pictures are multilingual. :
Found one more side,with a good drawing of the valve function
*More Bodmer*
Ralph


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## jagwinn (Sep 13, 2009)

Well...
The illustration shows that a large area flat surface is used as the guide/bearing, one for each cylinder.
What is the friction loss in hp per cylinder? and is it more efficient that a valve train?

Also, as with automatic shotguns that use partial propelling charge to work reload action, having the cylinder turn a crankshaft to propell the engine and pull or push the cylinder along with it is increasing the load per square foot of the power for each cylinder thus reducing the efficiency considerably.

How about an attachment of a cam to the crank to raise and lower each cylinder indipendant of the power making cylinder?

Just some thoughts.

.


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## Jadecy (Sep 13, 2009)

You may want to look ar this: http://www.agelessengines.com/sleeve.htm

There is a video showing a 1 cylinder test rig of the sleeve valve running.


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## jagwinn (Sep 13, 2009)

.

Jadecy,
Thank you for the video link. 
John

.


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## ChooChooMike (Sep 13, 2009)

Here's 3 short videos of a model steam engine with a sliding cylinder I ran across at a flea market. Don't know anything about it. The vendor wanted $900. That's about $850 more then I was willing to spend. 

[youtube=425,350]RGCjISBw2pU[/youtube]

[youtube=425,350]VwWXQPo7kgs[/youtube]

[youtube=425,350]AMzWEnm4HQk[/youtube]​


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## zeeprogrammer (Sep 13, 2009)

ChooChooMike  said:
			
		

> Here's 3 short videos of a model steam engine with a sliding cylinder I ran across at a flea market. The vendor wanted $900. That's about $850 more then I was willing to spend.



Yeah but you wanted it...didn't you? Come on...'fess up. You WANTED it. ;D


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## ChooChooMike (Sep 13, 2009)

I DID, I DID, I DID !! But I resisted :big:

Well, it was a flea market, I should have tried bargaining to see what he really would have taken for it. I prolly would have bought it for $150-ish. Of course, then after running it for a while, it would have been relegated to the shelf to collect dust. 

Mike


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