Author Topic: Throttle governed engine  (Read 7943 times)

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #30 on: December 24, 2019, 01:42:16 PM »
Since the arc is just a tad to big to turn on my lathe faceplate, I will cut it out oversize and then drill a chain of 1/4" holes thru as shown, then cut it out on the bandsaw, then use my vertical oscillating sander to clean up the stubs of material left between the holes.

Offline Jasonb

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Re: Throttle governed engine
« Reply #31 on: December 24, 2019, 07:06:20 PM »
As Chris says Rotary table would do it easy enough, just clamp to a bit of scrap.


Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #32 on: December 24, 2019, 09:48:52 PM »
This went much faster than I thought it would. Of course when you have a cad system that gives you all of the ordinate dimensions, it's just a matter of turning cranks and watching the dro numbers. Merry Christmas to all of you guys and girls that may be following this thread.---Brian

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #33 on: December 25, 2019, 07:02:38 PM »
Well Dang!! I'm impressed. Christmas is being celebrated a day late here because of various sons and daughters "in law obligations". This gave me a chance to sneak down to my machine shop and build the main governor body. A bandsaw, milling machine, and oscillating cylinder sanding machine makes short work of something like this.  The old guy with the white beard and red suit and bag full of presents will show up here tomorrow along with all of my kids, spouses and grandkids.

Online crueby

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Re: Throttle governed engine
« Reply #34 on: December 25, 2019, 07:33:45 PM »
Coming together quickly! Makes a nice bell-tower on top.   :popcorn: :popcorn: :popcorn:

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #35 on: December 29, 2019, 05:29:08 PM »
Moving forward things seem to be mounting the way I wanted them to. I am finished with the governor body main parts. Next up will be the linkage which connects things to the carburetor.


Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #36 on: December 30, 2019, 11:40:05 PM »
Today was governor linkage day. The brass lever is moved thru it's arc of travel by an internal rod that is acted upon by the governor weights. Yesterday when I mounted the governor body to the steel hoop around the flywheel/fan, I somehow got it as crooked as a dogs hind leg. So--Part of the day was used up dismounting it, lining it up correctly, and then drilling/tapping new mounting holes in the hoop.

Offline Ye-Ole Steam Dude

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Re: Throttle governed engine
« Reply #37 on: December 31, 2019, 12:13:40 AM »
Hello Brian,

That looks really good   :popcorn:

Have a great day,
Thomas

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #38 on: December 31, 2019, 09:45:14 PM »
This morning I made  the adapter which goes between the intake manifold and the carburetor, and the link which ties the governor lever to the carburetor throttle lever. I am not really sure what I'm doing here, and the more I do, the less sure I am. (That is not as unusual as it sounds!!). In the attached picture, my hand is holding the spring in tension, and the levers are pulled  into what is actually a "wide open throttle" situation. As the engine runs and centrifugal force makes the governor weights swing out away from the center, it actually pulls the throttle lever against the spring tension, until the carburetor is in an "idle" position. I have to adjust the spring tension to a point where the engine will settle in and run at 2000 rpm. but not so far that the engine idles. Now, if a load makes the engine slow down, the governor weights won't have as much centrifugal force, and the spring tension will pull the lever into a more "open throttle" position, causing the engine to run faster and bring the speed back up to the magic 2000 rpm.  So--The magic here seems to be my ability to adjust that spring tension so the engine runs at 2000 rpm but not any slower. However, that is only part of the equation. I also have to have the capability to completely over-ride the governor weights and bring the carburetor into a "full idle" position for starting. I THINK perhaps I need a counter spring pulling in the opposite direction to the spring I am holding, so that when it is engaged the carb throttle moves into a "full idle" position.

Offline Roger B

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Re: Throttle governed engine
« Reply #39 on: January 01, 2020, 08:41:23 AM »
How did your engine respond to the throttle when you measured the rpms? I found that my twin will run and take up a load over a wide rev range but gets unhappy when I open the throttle under load. I will need to consider a more complicated carb.
Best regards

Roger

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #40 on: January 01, 2020, 12:29:19 PM »
Happy 2020 Roger. I haven't yet tried to run the twin cylinder engine under any great load. I believe that the reason these small engines falter when being accelerated under load is that the mixture leans out. I will know more when I finish the governor. When this engine was finished a few years ago, I put up videos of it idling at about 8 or 900 rpm, and accelerating under no load. It hasn't been really used since.

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #41 on: January 01, 2020, 01:47:34 PM »
Update time---I really didn't want to cut the exhaust stack off on the governor side of the engine. Sometimes as I design and build these things, I see a way to change the design a bit and save myself some headaches. By brazing a piece of round 3/16" brass rod to the far side of the governor arm, I can move the spring over closer to the fan shroud to clear my exhaust stack. I have removed the pull cable and extra spring that showed up in a previous 3D model and went to a simple lever which I can move back and forth to determine the tension of the red spring. When I reach a point where the spring tension is strong enough to limit the motor rpm's to where I want them to be (about 2000 rpm governed) then I tighten the yellow threaded handwheel on the far side of the hand lever to lock it in place. I do have an idea for the mechanism that will completely overcome the governor and move the throttle into a closed position to make easier starting, but I have to chew on it for a while before I model it.

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #42 on: January 01, 2020, 08:10:30 PM »
Today seen significant progress on the governor control lever. I can loosen off the knurled handwheel and swing the brass lever into whichever position gives the best spring tension. The spring tension is what sets the "governed speed". I was able to position everything so that I didn't have to butcher my exhaust stack. I still have to work on a mechanism to over-ride the governor and set the engine throttle into it's "idle" position, as that is the best position when starting the engine.


Offline Craig DeShong

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Re: Throttle governed engine
« Reply #43 on: January 02, 2020, 01:34:46 AM »
Getting close Brian.  We’re all waiting to see the chips fly with your reworked power plant  :pinkelephant:

 :popcorn:
Craig

Offline Brian Rupnow

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Re: Throttle governed engine
« Reply #44 on: January 02, 2020, 04:34:47 PM »
Happy New Year Craig. Your engine looks marvelous.---Brian