Bowman valveless engine

[fcheslop]

Hi, Does anyone know how this valveless engine actually works
Iv read a few articles by Basil Harley and seen a few discussions on the web but still cannot understand how the piston is been rotated if it is indeed been rotated.
I think its a little like a two stroke and the piston has a port that aligns with ports in the cylinder wall.
I have Basil Harleys boat drawing and would like to build a near replica of the real thing. More for the the grandson than me.
Well he may get it after grandads finished playing with it
What do you think????

[Brian Rupnow]

The internet search engine is your friend---
http://modelsteam.myfreeforum.org/archive/how-the-bowman-bryant-and-quotbm-and-quot-valveless-works__o_t__t_20514.html

[fcheslop]

Thanks Brian, Iv read through the thread before and just not convinced.
Iv also noticed that on the cross member the cylinders mount to is a pin on the centre line of each cylinder
The way I think it works is a spiral either within the piston or on the OD but the big but for me is it was a toy engine that sold at a reasonable price and it all just seems to complicated or that it will wear quickly
I will reread and ponder a while longer.
I seem to remember Rex Tingey building a valveless traction engine.
kind regards
frazer

[ths]

Hi Frazer,

I can't help you at all, but share your interest in this engine. I think that there are so many people out there that would like to know how it works, I'd have thought that at least one example could be taken apart in the name of science at least!

I've never seen one, probably won't, but I'd like to have a go at making one.

Hugh.

[fcheslop]

Hi Hugh, I thought I had missed something obvious but judging by the replies maybe not
I want to build a Sea Jade look alike
Looks like only mee and thee
 

[Roger B]

I can imagine how this could work as a sort of 'uniflow' engine.

On one side of the cylinder there would be an exhaust slit which opens around BDC like on a 2 stoke IC engine. One the other side there would be two ports which would be connected together by a slot in the piston also around BDC. One port would connected to the steam supply the other would connect to the top of the opposite cylinder so each cylinder acted as the admission valve for the other.

[fcheslop]

Thanks Rodger, that was my initial thoughts on how it works
Delving a little deeper it looks as if the small end is a ball and cup allowing the piston to rotate ? just not convinced at the moment
Iv reread  Basil Harleys description of the engine and that doesn't ring true .
There has been a few threads on toy forums over how this engine works but nothing ever seems to be conclusive
I know it has to be simple as it was a toy and costs would have been a major factor.
The two stroke idea seems right in my mind in that the cross bar has the ports and the piston open and closes them but how Im not sure and the more I look into it the more my simple mind becomes confused.
Also just up from the big end is a pin as to its purpose Iv no idea at the moment.
Thanks again

[fcheslop]

Found these pics

[b.lindsey]

I am hoping this one can  be figured out. I have checked the links and seen the pictures and drawings and it's still puzzling to me. One of the links also pointed to and Oscillating Piston Engine I did over on the other site years ago, but that on is a much more obvious movement. I agree this one would make a fine smallish model.

Bill

[fcheslop]

Thanks Bill, I keep looking and pondering
Just starting to wonder is the piston and conrod pivoted in the big end and thats what that pin is doing.Allowing the rod to rotate but stopping it pulling out as that is a lot easier than the ball and cup idea
The quest goes on
Just had this link sent http://modelsteam.myfreeforum.org/archive/bowman-bryant-valveless-engine__o_t__t_49715.html
I think Dean W may be onto something.