Author Topic: Ron's Rudy's Radial Five  (Read 9967 times)

Offline RReid

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Ron's Rudy's Radial Five
« on: June 27, 2021, 01:06:12 AM »
I've been intrigued by possibilities of the compressed air, IC replica engines, such as those designed by the late Chuck Fellows. I became even more intrigued when I watched the video of his “Cirrus” V8 running, and heard what a realistic V8 rumble it has! I've even been doodling on an inline 4 cylinder engine combining elements of that V8 and his Opposed Four.

I also love the sight and sound of aircraft radials. Then I came across Kim's build log on this forum of the Radial Five as designed by Rudy Kouhoupt. I've been a fan of Rudy Kouhoupt's work since I read, at the age of 11, the article shown below in the August 1970 issue of Railroad Model Craftsman.


I have plans for several of Rudy's steam engines, but the combination of factors just mentioned has led me to choose Rudy's Radial Five as my next engine project.


A few weeks ago, while I was waiting for the materials to build my just completed dividing head to arrive, I got a start by turning the crankshaft and prop spinner. Today I made the brass “front plate”, which is used in through bolting the prop to a matching steel “back plate”. The 6 hole bolt circle gave me a chance to play with the new dividing head on a simple task.  YeeHaw!

The only brass stock I have big enough to get out the needed 0.875” diameter is a bar of hex stock. This  I chucked up, turned down, and drilled 1/4” to fit over the nose of the crankshaft. Then I mounted the DH to the cross slide and used the shank of the same drill to line it up and zeroed the dial.


Now I moved the chuck from the lathe spindle over to the DH spindle, and set up an ER collet to hold the #44 drill bit. From there I simply had to move over by the radius of the desired bolt circle, insert the indexing pin into a convenient hole (which I marked with a Sharpie), lock the spindle, and drill the first hole. With a 30:1 gear ratio, and a 30 hole division wheel, 5 full turns of the crank brought me into position of the next hole, and 5 repetitions gave me a lovely 6 hole bolt circle. So much easier and more accurate than laying it all out by hand!



Regards,
Ron

Offline crueby

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Re: Ron's Rudy's Radial Five
« Reply #1 on: June 27, 2021, 03:13:14 AM »
Great project for the new dividing head, will be following along.


 :popcorn: :popcorn: :popcorn:

Online Kim

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Re: Ron's Rudy's Radial Five
« Reply #2 on: June 27, 2021, 05:43:20 AM »
Yes!  I think you'll enjoy building this one.  I certainly did!  :ThumbsUp: :popcorn: :popcorn:

Kim


Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #3 on: June 27, 2021, 08:28:29 PM »
Thanks guys, glad to have you along. I am enjoying it so far!

Already found my first OOPS though. Yesterday I described using the DH to make the bolt circle on the brass front plate. This morning I used the same procedure to make the matching steel back plate. When I compare the two bolt circles, there is a great match - on 5 holes. One hole is slightly off. Close inspection shows the problem is with the brass plate. I apparently miscounted once, probably either going from hole #1 to #2, or from #5 to #6. Oh well, luckily it's a fairly small error. I could re-drill that hole and hide it behind the bolt head, or just remake the part. It's so simple, I'll likely do the latter.

Stuff happens. :facepalm:
Regards,
Ron

Offline crueby

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Re: Ron's Rudy's Radial Five
« Reply #4 on: June 27, 2021, 08:33:49 PM »
Time to add the sector arms!   :paranoia:

Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #5 on: June 28, 2021, 12:23:06 AM »
Quote
Time to add the sector arms! 

I hear ya Chris, but they wouldn't have helped in this case. They mark your place on the wheel, but can't count for you. Trouble is, I can't count for me either! I was exactly one full turn off.

After lunch I tapped all the holes in the steel back plate and assembled the front plate to it using the 5 “good” holes. I figured it was worth a try at re-drilling the bad one, so I held the assembly in a vise on the mill with the steel plate up. I lined up under a spindle using the shank of the tap drill. Since the tap drill is a #50 or 0.70 diameter, I switched to a 1/16 end mill to drill through the brass plate without touching the threads on the steel one. A little touch up with a needle file and I had a minimally corrected hole location that I think I can live with.




Regards,
Ron

Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #6 on: June 29, 2021, 12:20:03 AM »
With the addition of the crank disk and the crank pin, the crankshaft assembly is complete. Now I can go back a few pages to the beginning of Rudy's narrative and start working on the crank case.


Regards,
Ron

Offline Dave Otto

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Re: Ron's Rudy's Radial Five
« Reply #7 on: June 29, 2021, 01:16:26 AM »
Nice progress Ron, I have been following along here in the background.

Dave

Offline Don1966

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Re: Ron's Rudy's Radial Five
« Reply #8 on: June 29, 2021, 02:46:52 AM »
 :Love:


 :cheers:
Don

Offline joe d

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Re: Ron's Rudy's Radial Five
« Reply #9 on: June 29, 2021, 02:48:44 AM »
Looking good Ron, following along.

Cheers, Joe

Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #10 on: June 29, 2021, 02:45:45 PM »
Dave, Don, and Joe - Thanks for checking in. I'm very happy to have you guys along. :cheers:
Regards,
Ron

Offline Roger B

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Re: Ron's Rudy's Radial Five
« Reply #11 on: June 29, 2021, 06:36:49 PM »
Looks to be a fun build  :) I will be following  :wine1:
Best regards

Roger

Offline Johnmcc69

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Re: Ron's Rudy's Radial Five
« Reply #12 on: June 29, 2021, 08:14:56 PM »
 :ThumbsUp:

 Nice work!

Yep, one of my favorites as well. I CAD modeled it up some years back, maybe these will be of some help...

 John

 

Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #13 on: June 29, 2021, 08:25:25 PM »
Welcome along Roger.

Thanks for the drawings John! Those will be a handy resource, especially the exploded view.
Regards,
Ron

Offline RReid

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Re: Ron's Rudy's Radial Five
« Reply #14 on: June 30, 2021, 12:47:45 AM »
The first step in Rudy's crankcase construction is to make “fixture A”, as well as a pair of “caps” that work with it. This is a fixture that can be mounted directly to the lathe spindle or moved over to the dividing head/rotary table or chuck adapter plate for operations on the mill. The crankcase blank gets mounted to this fixture early on, and stays there until all the machining steps on it are completed.

My fixture started with a plain hub aluminum flange I had picked up at my favorite salvage yard sometime ago. Thinking it would make a decent light duty face plate, I had bored and counter-bored the hub, tapped it 3/4-16 to match the Taig spindle nose, and trued it up on the lathe. Then I never had much use for it, until now.



A piece of plate stock was cut and attached to the face plate with sunken 10-32 cap screws, and two steps were turned into it. The smaller step is the register for the crankcase blank. One of the “caps” (still to be made) and a 1/4-20 screw are used to fasten the blank to the fixture.


I'll need a piece of 1” x 2.75” x 2.75” stock for the crankcase. The pencil lines in the picture below suggest were it's going to come from.
Regards,
Ron

 

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