Webster I.C. redesigned as hit and miss----

[Captain Jerry]

Brian

You have designed and built a very attractive mechanism, compact and functional as well.

I hesitate to mention this because I brought it up before with your first governor but you might consider adding a dashpot. This would be a more workmanlike means of moderating the reaction of the linkage than using scratches or punchmarks. This might be more difficult on this version than on the previous one because this version is much more compact and there is less room to add another component in the linkage.

Another thought is some sort of "over center" toggle that would snap the lockout in and would snap it out only when the opposite force on the linkage overcomes the toggle spring. I'm thinking a very light hairspring.

Another approach might be to reduce the governor speed relative to the engine. Bigger pulley. If you look at examples of vintage steam engines, I think you see the flyballs stabilize at an angle of less than a 45 deg. The higher the balls are at the point of engaging the exhaust lockout, the more sensitive they are to speed fluctuations.

A third, and less attractive approach would be a larger flywheel. I think you did a good job of adding to the original flywheel and have probably maxed out in the present configuration but that is one means of maintaining RPMs through several "miss" cycles.

I hope you don't mind the comments from the back row, but that's why they call this a forum.

Jerry

 

[cfellows]

Brian, are you running the carburetor wide open? You want the engine to "hit" as hard as it can, one time, to run the speed as much as possible. If you remember, the original hit n miss engines had no throttle, they ran wide open all the time. With proper hit n miss operation, the engine should "hit" once, then coast through 4 or more cycles. Also, the governor spring, if made weaker, will cause the engine to slow down more before it "hit's".

 

[NickG]

Brian,

As soon as you mentioned it hits again too soon I immediately thought , needs a weaker spring. The balls then need less centrifugal force to lift and engage the lockout. As Chuck says, you might as well have the butterfly wide open - it's going to hit, with a weaker spring it will hit at a lower speed, but that's what you want, more coasting. Another way may be to make the pully on the governor smaller, but then you're playing with the gearing too and making it harder to turn so it will miss sooner but it will slow down more. I reckon it'll be a trade off between the drive ratio and spring stiffness - they are the easiest parameters to play tunes with. Have you tried it with no spring? That will give you the 2 marks in the sand as it were and you'll know where to aim for in between.

Just my 2 p worth.

Looking superb by the way and can't wait to see in action.

Nick

 

[Brian Rupnow]

Thanks guys, for all your excellent suggestions. The dashpot is a good idea. Before I start to add parts, I want to play more with the parts I have. It seems to me that to get the maximum number of revolutions from a power hit, I want to reduce the mass of the governor somewhat, making it easier to spin. I currently have a set of 5/8" diameter balls on it. I have a set of 1/2" balls left over from my governor build two years ago, and this morning I will try them. I will also try a weaker spring. in theory these two changes should let the engine get more revolutions per "power hit" and a weaker spring with smaller balls should delay the collapse of the governor and the consequent rapid decay of my miss cycle.

 

[Brian Rupnow]

I just tried it with the 1/2" diameter balls, and I see some improvement. I will be able to judge things much better come Monday, when I can get an o-ring the correct length and have access to some different and lighter springs.

 

[ariz]

Brian, what an interesting thread you started here, and what a brain you have to think and make things like that :bow:

as someone has told, only you could be able to transform a webster in an hit & miss engine

why you put this thread here? I seldom enter in the 'break room' because my english isn't so good to let me to read about stories and not engines, so I saw it only today...
I would have expected to see this conversion in the 'work in progress' section

oh, now I understand... for you this was a kind of diversion, not a real project, as it was for me ;D
many congrats, can't wait to see the video tomorrow

 

[jpeter]

Now you ought to replace that commercial carburetor with a simple homebuilt spraybar carb. It'd look more homebuilt and run as well too cuz now it doesn't need to deal with multiple rpm settings.

 

[Brian Rupnow]

This morning I rushed across town and bought a pair of o-ring drive belts the correct length, (one is a spare) and a weaker compression spring for the governor stempost. I had to fire it up as soon as I got home. There is considerable improvement in the hit and miss action, but its not quite where I want it to be yet. I know you fellows are anxiously awaiting a video, so here you go. This is not final, but it does very well to show the Webster engine running in "hit and miss" mode.----Brian

 

[Brian Rupnow]

Well, I think this is about as good as its going to get. The project is a success. I have turned a 4 stroke Webster I.C. into a hit and miss engine. The reality of the situation is that the governor is way too large in relationship to the bore of the engine. I kind of knew that when I set out to do this, but its been a fun project. On a "to scale" hit and miss engine with the governors set into the flywheels, the governors are much more sensitive to engine RPM than what I have here. Add to this the fact that I am limited in terms of how large a flywheel I can mount to this existing engine. The thing I like is that I can run the engine in normal non hit and miss form by simply removing the o-ring drive belt. I have to do a bit of tidy up now, and find a new location for the gas tank, but other than that I will call this project finished. Thanks to all who followed along and expressed interest.----Brian

 

[zeeprogrammer]

That is fantastic Brian.
This has been very enjoyable. It's given me some ideas I hope to apply soon.

 

[Brian Rupnow]

Zee---Thanks for your kind words. If I can help in any way with your next project, let me know.----I love your train!!!!

 

[ozzie46]

I was sure I had posted on this earlier today, but didn't see it here. scratch.gif scratch.gif scratch.gif scratch.gif So I went looking. Yep there it was in the "pictures and videos" section. Thought I was going batty there for a while. Sure had me confused for a little bit.

Nice project Brian and well executed. Thm: Thm: Thm:

Ron