Page 54 of 55 FirstFirst ... 44452535455 LastLast
Results 531 to 540 of 543

Thread: Design and build Side-shaft hit and miss from barstock

  1. #531
    Join Date
    Jan 2004
    Location
    Missouri
    Posts
    30,700

    Default

    The ratio may be different from calculated, especially with small chambers and higher ratios, because a small error of chamber volume makes a bigger change in ratio.

    And any leakage drops the "effective" ratio, even if the calculated ratio is 100% correct.
    1601

    Keep eye on ball.
    Hashim Khan

  2. #532
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    The counter-spring for the governor has been built and installed. It works. You can definitely change the rpm at which the governor engages. It is a very delicate adjustment. Now I need to address the carburetor one more time, because it is running on a borrowed carburetor. This engine does not have a great "coast" mode. I'm not sure if it's simply a matter of flywheel diameter and engine bore, or if there is just too much inherent friction from the helical gears running the sideshaft and the bevel gears which operate the governor weights. This is basically the same engine as was built by Craig Deshong, based on a 1905 Myers hit and miss engine. His model has 8 1/2" dia. flywheels and I "think" a 1.25" bore cylinder. His engine runs marvelously, and has a much longer "coast cycle" than this one does.
    Brian Rupnow

  3. #533
    Join Date
    Jan 2004
    Location
    Missouri
    Posts
    30,700

    Default

    A classic hit and miss at a show, even very large ones with 6 foot flywheels, often will take only one or maybe two "hits" to be up to speed, and then will coast several revs before another hit. My Jaeger certainly does that.

    Things that seem to affect that include:

    the power in each hit, the rpm gain from a hit.

    The inertia of the flywheels

    the hysteresis of the governor, which is usually set to be large for show engines, but is considerably smaller for work engines, to avoid an uneven speed. The "pick up" speed for a show engine still has to be enough to easily get over compression for the next hit, though.
    1601

    Keep eye on ball.
    Hashim Khan

  4. #534
    Join Date
    Apr 2009
    Location
    Ashburton, near Christchurch New Zealand
    Posts
    6,638

    Default

    May I suggest a look at the 'pumping' losses, the miss period has to pump the cylinder volume in and out through that long exhaust tube and the intake stroke has to draw though that long intake tube. I suggest shortening both.

    John

  5. #535
    Join Date
    Jun 2007
    Location
    Anderson SC
    Posts
    1,316

    Default

    Quote Originally Posted by J Tiers View Post
    A classic hit and miss at a show, even very large ones with 6 foot flywheels, often will take only one or maybe two "hits" to be up to speed, and then will coast several revs before another hit. My Jaeger certainly does that.

    Things that seem to affect that include:

    the power in each hit, the rpm gain from a hit.

    The inertia of the flywheels

    the hysteresis of the governor, which is usually set to be large for show engines, but is considerably smaller for work engines, to avoid an uneven speed. The "pick up" speed for a show engine still has to be enough to easily get over compression for the next hit, though.
    Here is a video of the scale Myers engine that Brian referenced built by Craig Deshong. Although its built from a castings kit, its basically the same engine as Brian stated. Note how the engine hits and then coasts for a good many cycles before hitting again, much like its big brothers. So..... small model hit miss engines CAN hit/miss in ratios similar to their big brothers.

    https://www.youtube.com/watch?v=m8OuiR1chWo
    Last edited by Sparky_NY; 03-15-2019 at 06:39 PM. Reason: spelling

  6. #536
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    Just so ya know I'm not being totally slothful up here---Newest carburetor with 0.156" bore and bag of 100
    3/32" steel balls in a plastic bag. I'm having a terrible fight with my arthritis this past week, so I'm not moving quite as fast as I usually do.--Going in on Monday for a cortisone shot in my left knee. Hope to have new carb mounted and new anti backflow made sometime over the weekend.--Brian
    Brian Rupnow

  7. #537
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    Going to a 0.094" (3/32") diameter steel ball lets me make a much more simplified anti-backflow valve.
    Brian Rupnow

  8. #538
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    Very happy to report that new carburetor works fine. Engine is running and starting consistently with new carburetor. I will post details of new carburetor tomorrow.---Also hope to finish new anti-flowback valve tomorrow.---Brian
    Brian Rupnow

  9. #539
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    Finally--With the 3/32" steel ball in the anti backflow valve and the new carburetor with the 0.156" throat diameter, we are running off the main gas tank in the base and getting sustained runs. I am going to post drawings details of the new carburetor, take a final video, and then this thing is done like dinner.
    Brian Rupnow

  10. #540
    Join Date
    Mar 2008
    Location
    Barrie, Ontario, Canada
    Posts
    9,223

    Default

    As promised, here is the new carburetor drawing. It actually has a total of four sheets to it. I am posting an image of the first page here. The full four pages can be downloaded from the attached link.---Brian

    http://www.mediafire.com/file/7b03o2...FFSET.JPG/file
    Brian Rupnow

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •