Author Topic: Another air powered (maybe) Radial engine  (Read 1266 times)

Offline galland

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Another air powered (maybe) Radial engine
« on: September 08, 2018, 08:46:24 PM »
A number of years back our EAA chapter was discussing radial engines and some of the guys had no clue how the crankshaft and connecting rods moved so I built a very small partial radial just for demonstration of that action. It was never meant to be a running model or even finished to look complete. The first 2 photos are of what is was. A couple of months back I got it out and wondered if it could be made to run. I had made it with screw on cylinders for simplicity and had put a hole through each cylinder between the first and 3rd fin at 90 degrees to the crankshaft pointing straight at the next cylinder. At the time I was picturing tiny exhaust pipes in those holes curving to the rear. Now I was saying that sure was a dumb idea because there is no room to get in there and do anything but each cylinder has a port in it in the wrong place. Any way I went to work thinking on how to change that and not make 9 new cylinders (I hate repetition. I will explain my fix later (any ideas out there). The other photo is some of my practice rear chambers where I checked to see if I had room to put flanges on like Dreeves and Bill did on their radials. I did not want to go smaller than 0-80 screws and with 9 cylinders I kept breaking through in to the next flange hole for the next cylinder until on the aluminum one I just made it but the chamber was larger than what I wanted for my engine so I decided to go another route. The fixture was so that I could screw on each cylinder and then rotate them to where I wanted for additional work.

     Gary

Offline Ye-Ole Steam Dude

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Re: Another air powered (maybe) Radial engine
« Reply #1 on: September 08, 2018, 09:47:23 PM »
Hi Gary,

That is a beautiful piece of art / work.

Have a great day,
Thomas

Offline b.lindsey

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Re: Another air powered (maybe) Radial engine
« Reply #2 on: September 08, 2018, 09:56:42 PM »
I hope you can finish it up and get it running Gary. Nine cylinders is a whole lot tougher than the five Dave and I did, and even then there wasn't much real estate to play with.

Bill

Offline zeeprogrammer

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Re: Another air powered (maybe) Radial engine
« Reply #3 on: September 08, 2018, 10:15:43 PM »
I just noticed the dime. Wow!  :o

Fantastic finishes too!
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline galland

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Re: Another air powered (maybe) Radial engine
« Reply #4 on: September 09, 2018, 04:33:31 PM »
After thinking on how I could go ahead and use the port holes I had already put in the cylinder/heads I came up with a solution. Unscrewing the cylinders would bring the ports back towards the rear of the engine so I started playing with gaskets to go between the cylinder and crankcase. Using a carbide scriber in the lathe and putting various thicknesses of paper and Teflon on a mini faceplate I found I could cut out good gaskets. The 9 in the one photo are .010 thick Teflon sheet. That got my ports pointing about 45 degrees to the right of center when viewing from the back. I found some .0085 thick paper and those got me about 45 degrees to the left of center. I still kind of liked the idea of mini fake exhaust pipes so I went with that thickness paper gaskets and using the fixture I made I tapped the original holes for air fittings and rotated 90 degrees and put in holes for exhaust pipes. Now the intake will be 45 degrees to the left of center and the exhaust 45 to the right. I then turned the fixture vertical and put in my 36 0-80 holes with my fingers crossed for luck (no broken tap)!!! Sorry about the lack of photos. I then needed 9 head caps so I thought I would add a little color and go brass and while at it I might as well make some fake glow plugs. Then for a break I tried my hand at making a prop. Enough for a while.

     Gary

Offline galland

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Re: Another air powered (maybe) Radial engine
« Reply #5 on: September 10, 2018, 02:40:02 PM »
I went ahead and made a stand so I could mount the engine on. The front cover and crankcase are one piece but I put an extension on it to make it about 3/16 longer and to give it a more unique look. The rear cover is threaded on to the crankcase and I had to make a new one for the cam (air valve) to pass through it. A couple weeks back I played with several attempts at making very miniature air fittings to take brass or copper tubing for the air lines. Since the cylinders screw on and off I knew if I soldered things together it would be permanent and would not be able to do a tear down if I needed to get inside. So I gave in and decided to go with rubber lines. Here is where it stands today.

     Gary

Offline galland

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Re: Another air powered (maybe) Radial engine
« Reply #6 on: September 11, 2018, 11:22:27 PM »
The little radial is finished. Dia. is right at 2 1/2 inches at the top of the brass head covers. Took some looking to find very small air lines. Got the tubing from Mcmaster Carr. Its .040 I.D. and rated 10 psi. max air pressure. Made a new counterweighted crank disk and its very smooth when running fast so I am happy with that. Looked at Rudy K's plans for ideas for the cam/valve. His appears to get intake air till  142.7 degrees  ATDC. I made mine to close off at just shy of the full 180. Anyway it runs but with that many cylinders and being 2 stroke I am not thrilled with the sound. Maybe a bit to busy. My 5 cylinder sounds much better but it also has 7 1/2 times the displacement.

     Gary

Offline Ye-Ole Steam Dude

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Re: Another air powered (maybe) Radial engine
« Reply #7 on: September 11, 2018, 11:35:18 PM »
Hello Gary,

The engine is absolutely gorgeous, what a beautiful piece of machining. Thanks for sharing.

Have a great day,
Thomas

Offline b.lindsey

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Re: Another air powered (maybe) Radial engine
« Reply #8 on: September 12, 2018, 12:19:48 AM »
Well done Gary. You made short work of turning it into a running engine. Love the stand too!!

Bill

Offline galland

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Re: Another air powered (maybe) Radial engine
« Reply #9 on: September 12, 2018, 03:21:20 AM »
Thanks guys. Just for a comparison here he is with his big brother.

      Gary

Online crueby

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Re: Another air powered (maybe) Radial engine
« Reply #10 on: September 12, 2018, 03:22:40 AM »
Beautiful job!!  Any chance you could put up a video of it running?

Offline galland

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Re: Another air powered (maybe) Radial engine
« Reply #11 on: September 12, 2018, 02:33:57 PM »
Made a video. I have commented that my expertise on posting them is not my strong point. I will try and see what happens. Am very pleased at how smooth it is because I just guessed on how much to cut off when making the counterweight. Don't know what rpm it was cranking but it never attempted to walk around on that piece of smooth paper. That was 8 psi max.      Gary

Offline b.lindsey

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Re: Another air powered (maybe) Radial engine
« Reply #12 on: September 12, 2018, 02:38:18 PM »
Its even more impressive running Gary. What a great little radial....one to be proud of definitely!!

Bill

Online crueby

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Re: Another air powered (maybe) Radial engine
« Reply #13 on: September 12, 2018, 02:39:22 PM »
That runs beautiffully smooth - very well done!

Offline zeeprogrammer

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Re: Another air powered (maybe) Radial engine
« Reply #14 on: September 12, 2018, 02:48:17 PM »
Wow! Great video. Cranking up the speed got pretty thrilling.  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.