Small Horizontal Single Governor

[Superfast]

Alright here goes the experiment. As may of you have seen, I built a smaller version of Chuck's Horizontal engine, a 2 cycle version. There is some pics and video of it in the Photos section. Now I am attempting to make a flyweight governor for it, very similar to what is on a hit or miss engine. The governor required me to build new flywheels, crank shaft and of course the governor itself. Here is a pic of the parts built so far. The flywheels are 2" dia made from steel, turned on the lathe then drilled using a rotary table on the mill. The crankshaft is also steel and silver soldered together. The rest of the parts are all brass and the hardware used is 0-80.

<a href="http://scottsrc.com/machining/newparts.jpg"><img src="http://www.scottsrc.com/machining/thumbs/newparts.jpg"></a>

Now for the governor parts detail, shown next to a penny for size reference. This picture shows the governor assembled without the flywheel. The 0-80 cap screw you can see on the right hand side that is inline with the shaft is the "cam" that operates the valve linkage. With the weights "in" like shown, the cap screw will engage the linkage.

<a href="http://scottsrc.com/machining/governor1.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor1.jpg"></a>

This view shows the weights in the "out" position, the fingers move the cap screw away from the valve linkage and eliminating the "hit". The 2 small steps cut in the brass center piece are for the linkage fork and will keep it in correct alignment when the cam is pulled away.

<a href="http://scottsrc.com/machining/governor2.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor2.jpg"></a>

Here are a few detaill shots of the governor being assembled on the new flywheel.

<a href="http://scottsrc.com/machining/governor3.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor3.jpg"></a>

<a href="http://scottsrc.com/machining/governor4.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor4.jpg"></a>

<a href="http://scottsrc.com/machining/governor5.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor5.jpg"></a>

Here are is the governor installed on the flywheel showing the same action as above:

<a href="http://scottsrc.com/machining/governor6.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor6.jpg"></a>

<a href="http://scottsrc.com/machining/governor7.jpg"><img src="http://www.scottsrc.com/machining/thumbs/governor7.jpg"></a>

I am getting closer to trying this out, but still need to come up with some small springs to use on the weights. I may even try to test it using some small rubber bands.

Scott

 

[kustomkb]

Very nice work!

And small

 

[rake60]

Beautiful work Scott! :bow:

Rick

 

[Brian Rupnow]

Great stuff superfast. Hope to see more on this thread.---Brian

 

[Superfast]

I finished assembling the governor last night and did some testing using a small rubber band to put tension on the weights.

I think I kind of succeeded and failed at the same time

Success: The governor does work and regulates the speed of the engine. I played with different adjustments and was able to change the governed speed. The engine will not go passed the rpm setting no matter how much air you put to it. I know this cause I blew the air hose off it a few times!

Failure: No Hit or Miss sound. When the engine hits the governor it does skip cycles, but just one or two as needed to keep the rpm within range. I am thinking that since this is an air engine, the compressed air is not going to give the same "hit" as you would see in a gas fired engine, the kind of "hit" you need to fly the weights all the way out allowing the engine to miss multiple cycles.

Any ideas on getting a more powerful hit?

The only idea that comes to my mind is to modify the cam action. The cap screw head (cam) hits a flat that is milled on the end of the valve fork, this creates a kind of ramp action. The valve starts to open at TDC, is full open at about 1/3 rd stroke and closes at about 2/3rd stroke. If I make this a steeper ramp, say Open to close in the first 1/3 rd storke will it give me a more powerful hit? The valve action would be more instantanious.

A secondary idea would be to try and increase the intake port size ...................... maybe???? Or a weaker spring action on the weights ................... Lighten the flywheels a little ................ Guess this is in the correct forum :big:

I guess focus on the positive, the governor does work!

Scott

 

[cfellows]

Scott,

I think it's also equally important that the inlet valve be fully closed well before the piston gets to bottom dead center. You want to give the sliding exhaust valve plenty of time to open the exhaust before the piston starts back up. You might also also try using a stronger spring on the exhaust valve. If there is any resistance to the piston returning on the exhaust stroke, it will slow it down.

Finally, maybe try a longer exhaust valve so the exhaust port is completely covered on the power stroke before the inlet hole is exposed. This might give you a more powerful "Hit". I deliberately designed the original valve mechanism thinking part of the high pressure inlet air would go out the exhaust before the exhaust valve completely closed, causing it to make more of a pop.

Chuck

 

[GailInNM]

Scott,
I assume that your spring that holds in the weights in is near the weights. If this is true, then the weight position will be proportional to the RPM.

If it were possible to move the spring near the pivot point for the weights such that as the weights moved outward the spring would move toward the pivot points, then the returning force of the spring to the weights would decrease, even though the spring tension would still be increasing. Thing of the extreme where the spring action was through the pivots, then there would be no force applied to return the weights to the inward position. Of course we would not want this extreme condition, but it may help to visualize. Think of the break over action of a toggle switch or play with snap action household light swiths, but restrict the movement to less than the break over point.

By doing this, the weights would stay out until the RPM reduced considerably, then the weights would snap in to an inward position.
I don't know if you have the room inside the flywheel to do something like this.
I can sketch if you need help visualizing this.

Gail in NM,USA

 

[Superfast]

First off, thanks for all the great comments about this engine, and don't worry I haven't given up yet!

Chuck: I never even thought about the exhaust valve, I was too worried about the intake. Increasing the spring tension on the exhaust valve should also increase the air pressure required to run the engine, not by alot, by every little bit will help. I think I will try changing the exhaust valve spring first, it's an easy part to change. Then I can take a closer look at the intake port duration and make it close a little sooner, ensuring the exhaust port has enough time to close fully. I'll leave the valve length the same for now and see what happens.


Gail: I can see what your saying here. Yes, the rubber band I am using is near the weights. First I tried it around the outside of the weights thenselves, then slightly inside and finally up near the outside of the flywheel. I got better results the closer i got to the flywheel. The governor started to actually function up close with a weaker rubber band. I will take a look at it agin tonight and see if I can get the rubber band to fit behind the flywheel, which would put it very close to the pivots. The closer to the pivots I get, the more tension I should be able to put on it, the weights would have more moment and be able to overcome it a little easier. With the rubber band that close to the pivot, when the weights moved to the outer position it would actually place the band closer to the pivot.

Thank you both for the ideas on getting this to work. Now I can't wait to get home and do some tinkering. Maybe this will work afterall !

Scott

 

[Superfast]

Here are a few pics of the engine with the new parts installed.

<a href="http://www.scottsrc.com/machining/horizontal5.jpg"><img src="http://www.scottsrc.com/machining/thumbs/horizontal5.jpg"></a>

<a href="http://www.scottsrc.com/machining/horizontal6.jpg"><img src="http://www.scottsrc.com/machining/thumbs/horizontal6.jpg"></a>

Here is a close up pic of the inside of the flywheel showing the backside of the governor assembly. The thin black line around the backing plate is the rubber band that privides tension to return the weights to the "in" position.

<a href="http://www.scottsrc.com/machining/horizontal7.jpg"><img src="http://www.scottsrc.com/machining/thumbs/horizontal7.jpg"></a>

The exhaust valve spring was changed to a little stiffer one as Chuck suggested and the rubber band was moved to the inside of the flywheel near the pivots as Gail suggested.

IT WORKED ! The engine runs and sounds like a Hit & Miss engine. As I press my finger on the flywheel to add a "load" the weights will move inward and the hits increase, keep adding pressure and it will hit every stroke. Changing the exhaust valve spring allowed me to up the pressure a little to the engine, so now when it hits it has a little more power to get the weights moving. The placement of the spring (rubber band) is ideal, it wraps around the backplate like it was ment to be there. I still might play with a few more rubber bands. I tried one with less tension and it ran quite a bit slower, the one on there now seems to be about right.

Now that it is running I guess it is time to take it apart, clean up some tooling marks and put a little shine on it. I also have an idea in my head of maybe adding a water jacket to the cylinder, if it sounds like a hit & miss it might as well look like one!

If anyone would like a rough sketches of the governor and how it goe together I can draw something up. I say "rough" cause I would have to re-measure all the parts to get the correct dimensions, alot of them were file to fit. I also thought of a way that this governor could be adapted to the larger 4 cycle versions of Chuck's Single.

Check the Photo/Video forum, I will post a video of the engine running in a few minutes.

Thanks again for the help with the valving and spring position.

Scott