Author Topic: Inspiration for new air motor  (Read 22755 times)

Offline Brian Rupnow

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Inspiration for new air motor
« on: April 01, 2018, 03:26:27 PM »
I really, really, don't want to start another build right now. However--I have been researching all of the many different flamelicker engines, and ran across the Bengs unit. My God--It's awesome!! I wouldn't want to build a flamelicker engine, as I now have finished the Poppin by Dr. Senft, and a Stirling engine which was 75%Moriya fan and 25% me. I have I.C. engines out the ying yang. and a goodly number of air/steam engines. I really like the style of this engine, and may design a single acting air motor based on this.

<a href="https://www.youtube.com/watch?v=0G4OuBVb7NY" target="_blank">http://www.youtube.com/watch?v=0G4OuBVb7NY</a>

Online Jasonb

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Re: Inspiration for new air motor
« Reply #1 on: April 01, 2018, 04:19:34 PM »
Another similar one here you may be able to take some details from

http://www.dampfundmehr.de/bilder/hugo/hugo-1.htm

http://www.dampfundmehr.de/bilder/hugo/hugo.htm

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #2 on: April 01, 2018, 04:44:43 PM »
I find it strange that the rocker arm isn't set at a 1:1 ratio. It looks like the distance from the piston rod to the pivot is twice as long as the distance from the pivot to the connecting rod. I'm trying to wrap my head around that. I don't think it changes the number of flywheel revolutions to cylinder strokes. I think it just means that you can get away with a shorter throw on the crankshaft.

Offline stevehuckss396

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Re: Inspiration for new air motor
« Reply #3 on: April 01, 2018, 06:40:08 PM »
I find it strange that the rocker arm isn't set at a 1:1 ratio.  I think it just means that you can get away with a shorter throw on the crankshaft.

Most if not all full size engines I have worked on have a rocker ratio greater than 1:1. I think small Chevy is 1.5:1 and big Chevy is 1.7:1 ratios.

You suspect correctly. You can get greater valve lift with a smaller cam lobe.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline crueby

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Re: Inspiration for new air motor
« Reply #4 on: April 01, 2018, 07:25:44 PM »
That sure is a pretty engine. How can you not build one! 

Offline b.lindsey

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Re: Inspiration for new air motor
« Reply #5 on: April 01, 2018, 09:05:32 PM »
I love that one Brian. That little ball valve on the top of the cylinder is rather interesting too.

Bill

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #6 on: April 01, 2018, 09:11:42 PM »
Bill--that little ball valve is the exhaust valve for a flamelicker. Theory is that a Poppin doesn't need one, because pressure in the cylinder will just lift the .002" valve off the cylinder head and let pressure escape. On the flameaters with a rigid guillotine type valve, you need that exhaust valve.

Offline b.lindsey

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Re: Inspiration for new air motor
« Reply #7 on: April 01, 2018, 09:21:04 PM »
Yes I figured as much, but I also like the more rigid look of the guillotine valve as compared to the Poppin. Just gives the engine a more solid look overall.

Bill

Offline yogi

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Re: Inspiration for new air motor
« Reply #8 on: April 01, 2018, 10:58:01 PM »
Brian, flamelicker engines like long strokes. A 1:2 bore/stroke ratio is not uncommon. I would say the ratio on the rocker is to keep the crank more reasonable.

Yogi

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #9 on: April 01, 2018, 11:37:01 PM »
My Poppin runs-- Ahhh---good. It is very delicate, and very fussy about just where the flame is positioned, but it runs. The larger more complex flame-lickers I have seen with a rigid sliding gate valve, mechanically operated, seem to be a lot more forgiving of flame position and run a lot stronger.

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #10 on: April 01, 2018, 11:50:03 PM »
I have the engine all designed---in my head. The only thing I'm not sure of is the valve mechanism. Since it will only be a single acting engine, it doesn't really require a sliding admission valve like you would find on a double acting cylinder. Probably a simpler valve driven by an elliptical cam through a couple of bell crank mechanisms would work. I have an old Chuck Fellows single acting engine that I converted from it's original design to operate with a valve like this. I'll have to see if I still have the drawings of my design changes to Chucks original valve mechanism. Other than the double acting twin Stewart engine I built this winter, it's been a long time since I messed around with air/steam engines.

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #11 on: April 02, 2018, 01:55:07 AM »
Ah Rats!!! I can't find the files I need. I thought I had them on a disc, but after a massive disc hunt I can't find them. I do have the original files of Chucks hit and miss engine, but not the changes I made to the valve system.--However, it's not a major issue. I have the engine here on my shelf and I can pull it apart and reverse engineer it.

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #12 on: April 02, 2018, 03:26:30 PM »
Okay---We're good!! I took the old single acting engine down of the shelf and did a little reverse engineering. Now I know exactly how the valve for a single acting engine works. (I had forgotten). This is the valve my new creation is going to use. It is a very versatile valve that can be mounted any number of different ways.

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #13 on: April 02, 2018, 04:50:26 PM »
Where do you start with something like this? Well in my case, I happen to have a pair of 4" flywheel rings that at one time were mounted on my Kerzel engine. They didn't improve the hit and miss action of the Kerzel, so they were saved for a future project. This may be it. Second consideration is ratio and proportion. If you look at a side view of the flame-eater engine I am copying the style of, you will see that there is a ratio between the outer diameter of the flywheels, the outer diameter of the cylinder, and the length of the cylinder. There is also a relationship between the center of the flywheels and the centerline of the cylinder, both vertically and horizontally. This is somewhat subjective. And of course we know that the flywheels have to be placed far enough from the center of the cylinder that they won't rub on it.--So, for now we place them where they won't hit the cylinder as they revolve. That's what is involved in the "starting point" of a layout .

Offline Brian Rupnow

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Re: Inspiration for new air motor
« Reply #14 on: April 02, 2018, 05:13:56 PM »
Of course we are going to have to have a couple of supports to hold this engine up off the tabletop. This calls for milling a couple of 1/2" wide slots in the bottom of the cylinder and making up a pair of stands that will bolt to the cylinder. Right now the supports look kind of long and skinny, but the reason for that is to let the ends of the mount stick out far enough past the outside of the flywheel that I can reach down beside the flywheel with my screwdriver and put a #8 woodscrew through each of the four holes to mount this puppy to my workbench.--Don't want it to walk away on me when it's running.

 

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