Inventor wizard 6 Cyl Radial

[Jmccrack]

Hey All
I have spent the last few months building the 6 Cylinder Radial Pneumatic Engine. After assembly it will not run. So I started to try and analyze what the problem may be. I think it is in the air valve configuration. The crank has an offset pin that move a valve eccentricitly over a set of holes. As air is injected into the valve the therory is it pushes one pisrion down which exposes another port to the next piston on so on. After a “million hours” of machining I find that actually 3 ports are open at the same time. So air is trying to get into 3 cylinders at the same time. So in my opinion the drawing is wrong and I am not sure if there is a fix for it.if this is the case I would caution against using Inventor Wizard unless you have vetted the drawing completely. If there is anyone out there than can help I would greatly appreciate it. Below are some photos of what I am talking about.

Any thoughts would would sure help

 

[rweber]

Is that brass-part in the 3rd picture that one from "Valve.pdf"? Looks different to me.

 

[Tim1974]

Really hope you sort it out I did the vertical Stirling had not to many problems but that’s not the best sight for there plains I beleave all unproven? I would not recommended also

 

[Jmccrack]

Yes the brass part is the valve pdf. I machined out the sectors to see if more than one power port was open at the same time. And indeed at tdc 3 are open. So when air is injected that should only drive that piston down the ports on either side are open as well. I triple checked my dimensions and they are right. It should be a very simple design. One hole opens drives the piston down and vents moves the crank around to expose the next hole and so on.

 

[rweber]

Ok, now I see. You are right, this cannot work. I would suggest moving the valves excenter a few degrees (30?) forward in spinning direction compared to the crankshaft. This assymetry would cause in sum more pressure in the down-moving pistons than in the upmoving.

 

[Jmccrack]

I will give it a try tks

 

[ally-oop]

Aircraft radial engines altho mostly 4 stroke just NEVER have even number of cylinders,..a similar problem with valve timing,..

 

[nel2lar]

That is one beautiful design with the square cylinders. I was wondering if you about the heat and just how hot it would become with the limited ventilation. There is not a lot of air coming of those spokes, I was just wondering if you give it any thought. I must say it is a sharp design being square.
Looks sometimes trumps.
Nelson

 

[mohavegun]

I would check the timing, an air engine would require valves to be open for most of the down stroke of the piston and the exhaust valving must be open for most of the up stroke of the piston. I would seriously expect to see three intake and three exhaust valves open at the same time. I would NOT expect three valves open on pistons that are not moving in the same direction, that is the valve timing would be a WAVE of air traveling around the engine followed by a wave of exhaust valve openings. As for comparison to a 4 cycle internal combustion engine, the number of cylinders has does not matter because there is NO compression / power stroke with closed valves. Each piston\cylinder gets a "power stroke and exhaust stroke" per revolution. I am fascinated with the simplicity of the design, your work looks very good!

 

[popnrattle]

here is the 6-cyl radial air engine. later, rt.

 

[John VL]

Not sure if you may already have an answer to the problem, but one defect in the Galba design is that it lacks a "master" conrod. Without it the engine will seize shortly after animation. I modelled this engine but modified it to include one conrod integral with the conrod hub and this allowed the engine to work perfectly (in the 3D model). See the engine in GrabCad (search under "van Leeuwen") and user the explode facility to view the modified conrod.

 

[popnrattle]

here is a vid where i scrolled thru a Word document with my camera. the cavities in the "brass pivot" are timed with the rotating steel hex manifold. At least 2 and sometimes 3 cylinders are pressurized at any given time. BTW, I changed my design from a radial to a rotary. The rotary spins a lot faster. Later, rt.

 

[Jmccrack]

John VL I have made one rod a master now I can get the unit to rotate with out jamming up. But this still does not answer my question of the air valve. When I inject air into the system the way the brass valve is made air is being injected into 3 cylinders at the same time trying to drive them all down at the same time. After all this machining I cant get the engine to run. Any help would be soooooooooo appreciated..