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STEAMPROPULSION
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Joined: 10 Jul 2009
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Location: TORINO. ITALY
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 Posted: Sun Apr 01, 2012 9:34 am Post subject: BOWMAN BRYANT VALVELESS ENGINE |
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Many of you have the priviledge of owning one, but how many of you know exactly how it works?
I had clear idea of its working principles: the pistons rotate and uncover the ports.
OK
BUT how and why the piston rods rotate with the pistons was the question asked to me by Calin (kno3), late in the night, yesterday.
No drawings are found, and no really detailed explaination is found in details. So more than one guessing was thrown around without really understading why and how these pistons rods rotate.
I had promised Calin an answer.
A chat on Skype with my friend Marco, putting together our knowleges, solved the enigma at 1:30 AM, and we went to bed happy for not having anymore a valveless engine nightmare.
I do not want to bore you discussing this matter (once more on this forum) if all of you know already everything there is to know about this engine.
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GIOVANNI
SKIPE name: ark.gsorrentino |
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Roly Williams
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Joined: 02 Aug 2006
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Location: Lambourn, Berks.
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| Posted: Sun Apr 01, 2012 9:47 am Post subject: |
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Well, I know the answer but I won't spoil it for anybody who want's to guess 
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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STEAMPROPULSION
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| Posted: Sun Apr 01, 2012 9:56 am Post subject: |
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Roly,
I am very glad that you know the answer. A portable X-ray equipment would have saved a lot of brain effort. But this is a good exercise at my age.
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GIOVANNI
SKIPE name: ark.gsorrentino |
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Bugsy
Steam Supreme Being
Joined: 28 Jan 2009
Posts: 11106
Location: Sala, Sweden
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| Posted: Sun Apr 01, 2012 9:56 am Post subject: |
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I'd like to know the answer, preferably with drawings and diagrams.
On account of my comprehension abilities are dwindling with old age...
Phil |
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Roly Williams
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Location: Lambourn, Berks.
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| Posted: Sun Apr 01, 2012 10:23 am Post subject: |
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| Bugsy wrote: | I'd like to know the answer, preferably with drawings and diagrams.
On account of my comprehension abilities are dwindling with old age...
Phil |
PM sent
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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The Denying Dutchman
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Joined: 01 Jun 2010
Posts: 6502
Location: Assen, The Netherlands
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| Posted: Sun Apr 01, 2012 10:41 am Post subject: |
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I have an idea how it works, but that's only a theory since I, unfortunately, don't own a Bowman valveless.
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Roly Williams
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| Posted: Sun Apr 01, 2012 11:13 am Post subject: |
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| The Denying Dutchman wrote: | | I have an idea how it works, but that's only a theory since I, unfortunately, don't own a Bowman valveless. |
Neither do I but I've seen the Moose's 
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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kno3
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Joined: 21 Mar 2009
Posts: 816
Location: Bucharest
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| Posted: Sun Apr 01, 2012 12:22 pm Post subject: |
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Do tell, please, don't keep us waiting...
I'm wondering how many think they know how it works and how many do know. I have had a Bryant valveless for a couple weeks now and took it apart, but the piston turning mechanism isn't visible. It is hidden inside the piston, which is a soldered-up job, not easy to disassemble. The piston rod can't be taken out of the piston without unsoldering either.
I assume the piston rod has a sort of protrusion (pin) that slides in a small curved channel inside the piston to make it turn a few degrees, but I might be wrong.
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Bugsy
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Location: Sala, Sweden
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| Posted: Sun Apr 01, 2012 12:24 pm Post subject: |
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| Roly Williams wrote: | | Bugsy wrote: | I'd like to know the answer, preferably with drawings and diagrams.
On account of my comprehension abilities are dwindling with old age...
Phil |
PM sent |
Now I know, thanks Roly!
Phil |
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Roly Williams
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Location: Lambourn, Berks.
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| Posted: Sun Apr 01, 2012 12:35 pm Post subject: |
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| kno3 wrote: | Do tell, please, don't keep us waiting...
I'm wondering how many think they know how it works and how many do know. I have had a Bryant valveless for a couple weeks now and took it apart, but the piston turning mechanism isn't visible. It is hidden inside the piston, which is a soldered-up job, not easy to disassemble. The piston rod can't be taken out of the piston without unsoldering either.
I assume the piston rod has a sort of protrusion (pin) that slides in a small curved channel inside the piston to make it turn a few degrees, but I might be wrong. |
You've got me woried now because what you say is COMPLETELY different from my understanding  Take a look at your crank pins and see if there's something odd about them
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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Bugsy
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Location: Sala, Sweden
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| Posted: Sun Apr 01, 2012 12:49 pm Post subject: |
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OK, I couldn't stand the suspense so I had a look at Moose's sight.
I pinched this explanation, surely Odilon won't mind. 
| Quote: | "The designer's ingenuity centres on the fact that the engine has no traditional valve gear. Inlet and exhaust ports are drilled in the sides of the cylinders about half way down so that they are covered by the pistons except when ports cut in these pistons coincide with them. The little end of the connection rod terminates in a ball and socket joint within each piston instead of the conventional gudgeon pin. This, in addition to allowing the usual back and forth movement of the rod due to the crank also permits the pistons to move round horizontally in the cylinders. Movement of a few degrees each way as the pistons rise and fall is imparted by pins set in the balls at about 45 degrees engaging in slots in the pistons. On the down stroke the piston is brought into coincidence with the steam inlet by this movement and on the up stroke the exhaust port is uncovered. Special shaping of these ports give early cut-off and the engine is quite economical of steam. The action is not unlike a sleeve valve and the porting arrangements are somewhat reminiscent of a diesel fuel injection pump. The exhaust note has a nice sharp bark for a tiny engine"
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Roly Williams
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Location: Lambourn, Berks.
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| Posted: Sun Apr 01, 2012 1:47 pm Post subject: |
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Ah! So I was wrong
Now where did I get the idea that it was tilted crank pins that imparted the twisting action?
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Roly Williams
"Opportunity is missed by most people, mainly because it is dressed in overalls and looks like work" (Thomas Alva Edison) |
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STEAMPROPULSION
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Joined: 10 Jul 2009
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Location: TORINO. ITALY
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| Posted: Sun Apr 01, 2012 2:16 pm Post subject: |
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| Roly Williams wrote: | Ah! So I was wrong
Now where did I get the idea that it was tilted crank pins that imparted the twisting action? |
Roly,
You have got the idea from the same place where I have got it. (!)
And I am quite sure that you are right.
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GIOVANNI
SKIPE name: ark.gsorrentino |
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STEAMPROPULSION
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Location: TORINO. ITALY
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| Posted: Sun Apr 01, 2012 2:18 pm Post subject: |
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| Bugsy wrote: | OK, I couldn't stand the suspense so I had a look at Moose's sight.
I pinched this explanation, surely Odilon won't mind.
| Quote: | "The designer's ingenuity centres on the fact that the engine has no traditional valve gear. Inlet and exhaust ports are drilled in the sides of the cylinders about half way down so that they are covered by the pistons except when ports cut in these pistons coincide with them. The little end of the connection rod terminates in a ball and socket joint within each piston instead of the conventional gudgeon pin. This, in addition to allowing the usual back and forth movement of the rod due to the crank also permits the pistons to move round horizontally in the cylinders. Movement of a few degrees each way as the pistons rise and fall is imparted by pins set in the balls at about 45 degrees engaging in slots in the pistons. On the down stroke the piston is brought into coincidence with the steam inlet by this movement and on the up stroke the exhaust port is uncovered. Special shaping of these ports give early cut-off and the engine is quite economical of steam. The action is not unlike a sleeve valve and the porting arrangements are somewhat reminiscent of a diesel fuel injection pump. The exhaust note has a nice sharp bark for a tiny engine"
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Bugsy, can you show me the source of your quoted explanation?
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GIOVANNI
SKIPE name: ark.gsorrentino |
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Bugsy
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Joined: 28 Jan 2009
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Location: Sala, Sweden
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| Posted: Sun Apr 01, 2012 2:28 pm Post subject: |
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| STEAMPROPULSION wrote: |
Bugsy, can you show me the source of your quoted explanation? |
Basil Harley'st article in Model Engineer, December 1978,
It's on Mooseman's site so it MUST be right!
http://www.freewebs.com/odilon/bowmanluton.htm
Phil |
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