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Ron's Rudy's Radial Five

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RReid:
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!

crueby:
Great project for the new dividing head, will be following along.


 :popcorn: :popcorn: :popcorn:

Kim:
Yes!  I think you'll enjoy building this one.  I certainly did!  :ThumbsUp: :popcorn: :popcorn:

Kim

RReid:
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:

crueby:
Time to add the sector arms!   :paranoia:

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