Rupnow i.c. Engine with governor

[Brian Rupnow]

Johnny--You are "sort of" right. The trick is that you don't set the length of the pivoting latch to hold the valve absolutely wide open. ---Maybe about 3/4 or 7/8 open. That way the engine can't develop any compression, so it doesn't fire, and begins to slow down.--However--every time the cam comes around it still "bumps" the cam follower bearing and tries to open the valve all the way. As soon as the engine slows down, the governor spring retracts the flyball arms and the pivoting latch wants to retract out of the way. At the next bump from the cam, the pivoting arm is released and falls back completely away from the L shaped latch. Then the engine can fire again and start the whole process over again.

 

[Brian Rupnow]

So----Five years ago, when all of this machining business was brand new to me, I built a ball turner. I only ever turned one ball with it (which can be seen on the end of the handle). I did a big write up and post of it on HMEM and now I can't find it. The ball turner has hung on the wall of my shop ever since, never used. Today I decided I would make three 5/8" balls from aluminum for the flyball governor. Damn---I couldn't remember how to set it up. I basically had to set and study on it and try to figure out how to set it up to turn balls instead of elliptical ogives. (Thank you Marv for that fabulous word.) Then when I took the top slide off my lathe to mount it, I see that I was smart enough at the time to trace around the perimeter of it with a scriber to show me where to put it if I ever used it again. Tomorrow I will see if I can make 3 balls.

 

[starnovice]

Brian,
Here is a link to your ball turning article.
http://www.homemodelenginemachinist.com/f31/ball-turner-mysteries-unveiled-3355/

Pat Wicker

 

[Brian Rupnow]

Starnovice---Thank you so much for finding that link for me. I spent half an hour looking for it and gave up. I have copied the link and saved it in a file of my projects so I can find it again .---Brian

 

[starnovice]

just glad to be able to give something back to someone who has given so much to us.

Pat

 

[Brian Rupnow]

Okay--I'm here to tell you---My future as a ball turner is very dim!!! I got one rather ball like part out of 3. Ugly damned things, to say the very least!!! The plan has changed as of right now to use 3 pieces of round 5/8" aluminum x 0.42" long. (That will have the same mass as a 5/8" diameter ball, or at least very close). Once I'm happy with the way the flyball governor works I will buy some 5/8" aluminum balls, as they seem to be a bit beyond my machining abilities.--So---The ball turner goes back up on the wall---this time possibly forever!!!

 

[starnovice]

The first time I saw one of these ball turners, one of our club members brought it and a ball to a club meeting. He was peacock proud of the 2 inch ball he had turned until someone asked him why it looked like an egg.

 

[Swifty]

You have the ball turner, don't give up so easily. I was planning to make my own ball turner when it comes time for me to start on the governor.

Paul.

 

[Brian Rupnow]

Paul--If the shipping didn't cost so much from here to Australia, I would send you this ball turner. In a world full of such exciting things to build, the last thing I want to do is drive myself crazy trying to make perfect aluminum balls.---Brian

 

[Path]

But Brian ...

They don't have to be perfect .... so what if they are a little egg shape.
That makes your engine unique ... give it a try.

Pat H.

 

[Brian Rupnow]

I haven't ran off---I'm just enjoying a couple of "machining free" days. The thrash to build this engine and prove out my drawings was pretty intense and I needed a break. Tomorrow I will put the new weights on the governor arms and make the latch extension, then see if we can get things into full "hit and miss" mode.---Brian

 

[GKNIPP]

Hello Brian, would you please post the PDF's of the catch lever and the bevel gears. I am thinking you forgot to attach them. Thank you so much;

Greg

 

[Brian Rupnow]

GKNIPP--If you have been following the thread you will see that in the last couple of days I have changed the catch lever and added a piece for it to engage. This is a change from my original catch lever drawing. I will have to make drawings and save them as pdf files and post them. I will do that right now.---Brian

 

[Brian Rupnow]

This is the new "catch lever" as I determined that the earlier design was going to 'hang up" and not release properly. Also shown is the new "latch extension" that the "catch lever" now catches on.



View attachment CATCH LEVER FOR HIT AND MISS ACTION--RUPNOW.PDF

View attachment LATCH EXTENSION-RUPNOW ENGINE.PDF

 

[Brian Rupnow]

This is a revised drawing of the valve lifter pushrod assembly. The only change is that I have added two 0.112" diameter clearance holes to the 3/16" square pushrod and removed the "notch" that was originally there for the first "catch lever" design that didn't work out.


View attachment EXHAUST PUSH ROD SUB ASSEMBLY-RUPNOW.PDF

 

[Swifty]

Brian, a couple of days break will renew the mind as well as the body. Always found that if I had a problem designing something, a break away for a short while allowed me to toss around the problem in my mind and then attack it with renewed vigour when I got back to it. Keep up the great work.

Paul.

 

[Brian Rupnow]

Thanks Paul. I get so deeply involved in one of these builds that they take over my life. Its fun, its exhilarating, but it eats me up too. I will be back in "machining mode" by tomorrow, and after that (hopefully) we will soon have a runner.---Brian

 

[gus]

Hi Gurus,
Made my own RT to turn out the governor balls for the American Popcorn Engine.4" RT from LMS or Arceurotrade cost "an arm n leg".
My first trial turned out pheasant eggs. Subsequent results were good enough.I cheated .Called my former machinist for advice.
See fotos of my DIY RT. And the American Popcorn Engine.

Lessons learnt, Cutter must be centred on the RT table and tool height also.

 

[Brian Rupnow]

This is the governor with aluminum weights (I can't really call them balls) in place of the 5/8" brass balls. The weights shown have the same mass as 5/8" aluminum round balls would have, and are almost exactly 1/3 the weight of the brass balls. What does this mean in terms of how the governor will work?-Well, for one thing, the resulting "downforce" on the central rod will only be 1/3 what it was before. This means that the adjusting spring will only have to be screwed down to 1/3 of the compression force it needed before to "balance" the governor balls. This in turn means that the friction between the end of the central rod and the brass lever below it should only be 1/3 of what it was before. I am rapidly get into the field of "Try it and see" engineering " here, so I will post the results after I try this.----Brian

 

[Lawijt]

Those weights looks also great. It is something other than Always those round balls.