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Thumper---A new 1 3/8" bore i.c. engine

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  • And that's all she wrote. Time to move on to a different project.---Brian
    https://www.youtube.com/watch?v=BZjt...ature=youtu.be
    Brian Rupnow
    Design engineer
    Barrie, Ontario, Canada

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    • Unless the throttle is at least half open, I don't think it would be correct to say the engine does not have enough power to run the edger. It is simply starved for fuel. An easy way to measure performance is to hook up a DC generator (treadmill motor) and a bank of light bulbs or power resistors (heaters). You can add to the load 40, 60, or 100 watts at a time and open the throttle to get the desired RPM. Measure the voltage and current to get power, and you can then compute the torque.

      This could also be a way to provide a sort of governor. Add maybe 500 watts of load, and then run the board through the edger. If that is only a 1/4 HP (200 watt) load, the added load will be a smaller proportion of total, and it should be able to do the job.

      Brian, it does seem that you mostly enjoy the design and machining of gas engines, and their ability to run smoothly at idle and rev up with no load. And also, perhaps paramount, is the aesthetic beauty of the finished product, to be displayed proudly on a shelf. And that is certainly understandable and admirable, and I enjoy reading about your progress with these engines. I'm a more practical oriented electronics guy, so I'd be working on an engine analyzer and computer-controlled engine management.
      http://pauleschoen.com/pix/PM08_P76_P54.png
      Paul , P S Technology, Inc. and MrTibbs
      USA Maryland 21030

      Comment


      • Paul--I'd say you have that about right. I enjoy the design and building, and no load smooth running. I like them to be "pretty". I don't care to invest a lot of time "tweaking" the engine after the fact. I'm ready to move on to my next project.-----Brian
        Brian Rupnow
        Design engineer
        Barrie, Ontario, Canada

        Comment


        • Thank you Brian for the enjoyment of following you on your adventure with "Thumper". John

          Comment


          • Brian you are of course correct. The engine is a smooth running one that is very appealing and aesthetically pleasing as well.
            Not only has it been a treat to witness the build but it is also one that showcases your design and machining talents on a job very well done.
            This is of course a home shop machining forum and not one that addresses internal combustion thermal and volumetric efficiency, we can leave that to another thread.

            Take a breather Brian, and a bow to a to another incredibly beautiful engine. I think anyone here would be proud to claim it as their own creation, I know I would!
            Home, down in the valley behind the Red Angus
            Bad Decisions Make Good Stories​

            Location: British Columbia

            Comment


            • Brian
              I always follow along and really enjoy your builds. You would need to open up the throttle when you in the cut if you want it to work. Raising idle speed will not help. If it still stalls out at wide open throttle then you are definitely out of luck. Can’t wait to see what you dream up next

              Comment


              • Brian, This engine deserves better. Shelving it without even an attempt at manual throttle control makes no sense.
                Allan Ostling

                Phoenix, Arizona

                Comment


                • Originally posted by aostling View Post
                  Brian, This engine deserves better. Shelving it without even an attempt at manual throttle control makes no sense.
                  I certainly agree, but it is Brian's engine and his decision.

                  Maybe he will come back to it later. It would be very disappointing and discouraging to me if I spent a long time on a project and it did not do what it was intended to do. I understand being "done with it" at least for a while.
                  CNC machines only go through the motions

                  Comment


                  • Originally posted by J Tiers View Post

                    I certainly agree, but it is Brian's engine and his decision.

                    Maybe he will come back to it later. It would be very disappointing and discouraging to me if I spent a long time on a project and it did not do what it was intended to do. I understand being "done with it" at least for a while.
                    Yes, it was intended to run the edger, and it failed, possibly for something as simple as not increasing the throttle under load. Brian often chooses to totally ignore extremely valid suggestions others make to refine his builds, its his builds, his threads and his engines. Everyone has different quality standards they work to achieve, its a personal thing. I follow many engine builders out there, Brian, Gbritnell, Sid and many more.... all of them are interesting and quite different at times in their approaches and finished products. Variety is always a good thing.

                    Kind of reminds me of looking at cheap used cars, the statement "it runs" covers a LOT of territory !

                    Comment


                    • These engines are built for Brian's own interests. All of you are able to buy his plan set, build your own, modify it, improve it, and post on here about it. I would assume Brian has grown tired of this engine.

                      Comment


                      • Originally posted by RB211 View Post
                        These engines are built for Brian's own interests. All of you are able to buy his plan set, build your own, modify it, improve it, and post on here about it. I would assume Brian has grown tired of this engine.
                        As I also mentioned, yes it is his, and his to do with, or not do with, as he desires.

                        I admit that I, in common with others, I am sure, end up feeling a bit let down when there is a long build thread (your post was #385) about an engine, and then it stops short of what was the original goal. It's like reading a good book, and finding that the last half of the last chapter is missing from it.

                        It feels a bit different when you have been following the build, and then....... Yeah, I get it, I already said so, but you know.....
                        CNC machines only go through the motions

                        Comment


                        • Originally posted by J Tiers View Post

                          As I also mentioned, yes it is his, and his to do with, or not do with, as he desires.

                          I admit that I, in common with others, I am sure, end up feeling a bit let down when there is a long build thread (your post was #385) about an engine, and then it stops short of what was the original goal. It's like reading a good book, and finding that the last half of the last chapter is missing from it.

                          It feels a bit different when you have been following the build, and then....... Yeah, I get it, I already said so, but you know.....
                          Perfectly understandable

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