A new engine for fall---

[GailInNM]

Great way to start the day Brian. Congratulations.
Thm:Thm:
Gail in NM

 

[Brian Rupnow]

As a matter of interest, I took my new laser aimed temperature sensing gun out to the garage after the engine had been running for 15 minutes at a mid range speed. The top of the cylinder head was 180 degrees F at the base of the cooling fins, and 150 degrees F at the tip of the fins. The exhaust pipe at 150 degrees half way down its length, but 195 degrees F right where it exits the engine.

 

[Brian Rupnow]

Here is a video taken from the other side of the engine, and a video in which the Chuck Fellows carburetor gets an honourable mention. The crankcase vent doesn't seem to have any effect on the way the engine runs, whether it is open or blocked.
[ame]https://www.youtube.com/watch?v=D4w1-NEzby0&feature=youtu.be[/ame]
[ame]https://www.youtube.com/watch?v=tJRQ2FaaMoM&feature=youtu.be[/ame]

 

[Swifty]

Congratulations Brian, another well designed and made engine.

Paul.

 

[Brian Rupnow]

Thank you guys. Sometime within the week, I will be posting a link to a download of all the updated drawings as .pdf files. Nothing would give me greater pleasure than to see someone else build my engine.---Brian

 

[gus]

Congrats!!!!!! Brian.

From faraway Singapore.

 

[canadianhorsepower]

Congrats!!!!!! Brian.Thm:Thm:
Nice work

 

[nowramfg]

Congratulations Brian, another very good build.

 

[Brian Rupnow]

After I went to bed last night, I realized that during the excitement of the first run, I had forgotten to put gaskets between the intake/exhaust flanges and the valve body. The exhaust gasket is not terribly important, but without an intake gasket it's a wonder that the engine run at all. I will start today getting all of the drawings ready for download.

 

[RonGinger]

A great job, and very well documented as usual.

Why did you make the two cam shafts and gears instead of rotating the cylinder 90 degrees and having one long camshaft, like the old Briggs and Strattons? I suppose a valid answer is simply because you wanted to do it that way, but it seems more complicated this way.

 

[Brian Rupnow]

I have uploaded about 40 drawings to filefactory.com. If you click on the attached link, you should be able to download then free. They are in pdf format, so you won't need any engineering software to open them. Somebody please let me know if this works okay and lets you download them with no hassle. If anybody finds errors in the drawings, let me know about that please.---Brian
http://www.filefactory.com/file/1dkn3uxr9xbx/RUPNOW ENGINE-2.zip

 

[dsage]

Wow !!
Great engine Brian. It runs very smooth. No missing sputtering etc.
If you should make another video perhaps you can demonstrate how slow it will run. It seems to have enough power and flywheel mass to run slow.
It amazes me how you can go from an idea, through drawings to a finished engine in only a few months. And carry on regular work too.

I have a couple of questions:
I guess you decided against using the nice pipes bends for transmissions shown a few posts back. I think it looks good like it is with intake and exhaust coming straight out. (nice and compact)

I will re-iterate Ron's question from a few posts ago. Why not a single camshaft. Other than the obvious answer - because you wanted to do it this way. And that's an acceptable answer.
(one should never ask why in the model engineering hobby

A question to all. How do you tell which way a fan is supposed to rotate. The one you are using Brian seems to have wing shaped blades (blades thick on one edge thin on the other)which perhaps are optimized to work better in one direction. In my mind I say the thin edge should lead because it might cut the air better but then there's the wing shape which might somehow improve flow if the thick edge leads.
Inquiring minds want to know.

Thanks for sharing Brian

Sage

 

[bmac2]

Wow Brian! The things I miss when you’re away for a couple of days! Another great job, and a very well documented build. That engine is running sweet.
Congratulations on another runner woohoo1
The download works fine only one or two sports popups, and the drawings look great. Thank you once again, that’s a ton of work. I’ve been using CAD in one form or another since my first AT computer (Generic CAD) but being self-taught most of my drawings look like pure gibberish to anyone but me. To create professional drawings that are meaningful to other people is an art in itself. I know you do this for a living so it must come as second nature for you but I can truly respect the amount of work that goes into them.
Question . . . If you design one more engine, don’t you have to wright a book?scratch.gif

 

[Brian Rupnow]

Very timely question dsage--I made up gaskets for the intake and exhaust flanges (I had forgotten to make them) and after a bit of tuning this morning, I got out my spanking new digital tachometer. This gave me pause, because at first it wouldn't work. Then I tested the batteries that came with it from the factory, and two of them were stone dead. After replacing two of the batteries and warming the engine up, I found that its lowest consistent idle was at about 800 rpm. It would idle lower, but then it faltered and threatened to stall. On the high speed end, it topped out at a whopping 1950 rpm. This is really about what I expected from the cam I designed. This is more of an "industrial" engine that likes a steady speed without wide rpm range fluctuations. It is really happy at about 1200 rpm, and would run all day at that speed without faltering. The heavy flywheel gives a good steady run, with a slow throttle response due to its mass. This engine is almost the exact opposite of the Canadian Cub (Malcolm Stride's Jaguar engine wearing Canadian clothes). I went to separate camshafts so I could set the cam timing of exhaust and intake totally independent of each other.--You simply can not do that with a one piece camshaft. On the question of cooling fans---I wanted a fan with a pitch which would push air over the cooling fins, rather than pull it, when rotated clockwise. (All of my engines are set up to turn clockwise). Unfortunately, the only fan I could find in the correct size range was designed to rotate counter-clockwise, thus the curvature (dished shape) of the blades. However---That doesn't mean they won't blow in the opposite direction if rotated clockwise. They just won't blow as efficiently. I don't need a whole lot of airflow---just enough to keep a steady flow of air over the cooling fins, to move the heat away. As for writing a book---I have had two of my engines published in "The Home Shop Machinist" magazine. I may see about publishing this one, because it is a very unique engine and seems to run very well.---Brian

 

[canadianhorsepower]

Wow !!

A question to all. How do you tell which way a fan is supposed to rotate. The one you are using Brian seems to have wing shaped blades (blades thick on one edge thin on the other)which perhaps are optimized to work better in one direction. Inquiring minds want to know.

Sage

The direction of the fan is to your discretion. You could have a push fan
the one we usualy have in a cooling fan at home or a pulling fan that is what we are using over the stove set up.

The way of action is pretty simple, you can relate the picture in your mind as a ice cream cup, the proper direction you would store air in the cup and throw it away(EI you would take cold air and throw it to the engine (push fan)or take hot air and take it away from the engine( pull fan)

In Brian's a second groove offset from the first one and twisting the oring around to create a "8" shape and it would be in the right direction:fan: this would reverse the fan roration

cheers

 

[Brian Rupnow]

A little bit of the reasoning in using a fan to "push" air over the cooling fins, rather than to "pull" it away from the fins. Right now, as things are, it wouldn't really matter which way the fan rotated, and it probably would move more air if it ran counterclockwise because of the cupped shape of the blades. The big difference comes when I put the shroud around the fan. The shroud does more than keep my fat fingers out of the fan blades. It concentrates the column of moving air and makes it more dense, and directs it in a "column" over the cooling fins, rather than dispersing it in a shallow cone over a much larger area. There are more sophisticated ways of explaining this air column effect, but it gets into an entire science of air-flow that I know only a small part of. ---Brian

 

[toolznthings]

Hi Brian,

Do you have to sign up to the site where your drawings are posted to down load ?

Thanks !
From another Brian

 

[gus]

Same question . Do we have to sign up.
No worry Gus is live and kicking.Itching to build your new engine.

 

[dsage]

I didn't have to sign up. Although it was quite a gauntlet of confusing pop-ups. I suspect all red hearings to get you to sign up.
When I chose the "fast download" option I was taken somewhere that I didn't understand like a full page ad. So then I chose the slow download and it worked. Although it fiddled around for quite a while apparently preparing the download before it presented a "download now" box.
All in all not a pleasant experience but mission (eventually) accomplished. There must be a better alternative.

Sage

 

[canadianhorsepower]

Thanks of letting your fans understanding the proper operation of both
different fan style

Cheers

Luc