View Full Version : Hit &Miss engine
08-31-2002, 10:18 PM
I would like to find the plans to a small hit and miss engine. Kits or from raw materials are fine. I am not familiar with the horse power ratings of the engines. So about the only way I can describe the size is by the fly wheel.....
I am looking for one with about a 12" fly wheel.
08-31-2002, 11:03 PM
Attached is a link to Purveyor, they have about 8 Hit & Miss kits listed in the 4" to 12" flywheel size, average price is about $450.
09-01-2002, 01:26 AM
In the older issues of Live Steam, HSM, and MW there were ads for a "little John Deere" replica. This was recognized as a hot kit and had a 300 or 400 pages of documentation with it. From what I have read in respectable mags this was a top notch kit with super qaulity castings - well worth your time (Limited edition run). Also, Stuart has some beautiful models (very pricey) all with super castings.
here are some good sites that may steer you that way:
These are all interesting sites - usual disclaimer - I have no fiscal interest in any of them.
09-01-2002, 04:36 AM
be sure to look at this site, he doesn't sell from the webTV site but you can ask for a catalogue.
I have plans for one of his engines and they, aloong with the detailed instructions, are excellent.
he also advertises in Live Steam et al.
There are scads of plans around, some using castings, some using barstock. There werre plans for at least one hit-and-miss described in Home Shop Machinist several years ago, to be made from barstock. Also check out Jerry Howell's web site at http://www.jerry-howell.com/ for some possibilities, though they may not be what you're looking for.
09-01-2002, 01:17 PM
The Shop Wisdom of Phil Duclos has several plans for barstock engines. Most are 3-4" diameter flywheels. I have seen them scaled down, no reason not to scale them up as well.
09-01-2002, 05:15 PM
I was just looking at the Bob Shores website a while ago, before checking the postings here on HSM. The recent issue of HSM had a short 'First Look' writeup on Bob's "EAGLE" engine, which is described as 'Great for Beginners" in his ad on pg 66. I'm kinda tempted to take the plunge and try my hand at engine building.
Has anyone here built that EAGLE?
Oops, forgot the main reason for posting here was to ask: What exactly is meant by the term "Hit or Miss" or I sometimes see it as "Hit AND Miss". Did I read somewhere long ago that it described an engine that just fires in random cycles when the rpm drops??
[This message has been edited by lynnl (edited 09-01-2002).]
09-01-2002, 07:28 PM
Yes - that is what the old John Deere Tractors did (reminds me of a harley...). The Tractor had massive flywheels on either side of the motor.
09-02-2002, 11:36 PM
The Home Shop Machinest had a series of articals on building a hit and miss engine. The articals appeared about 1983 or 84. As I remember the flywheel was about 5". It should be easy to scale up.
09-09-2002, 10:59 PM
I have a John Deere 1-1/2HP "E" stationary gas engine that is neat to watch and listen to. I have a couple movies I made of it at http://www.wheatfarm.com/jd_engine/index.html along with pictures.
How the engine runs is, it has an atmospheric intake valve that has a very light valve spring. It's opened by the vacuum created on the intake stroke, there's no rocker arm on it. There is a rocker arm on the exhaust valve.
When the engine is running, it accelerates up to it's governed speed, about 600rpm's, and the govenor then locks the exhaust valve open. Because it's open, no vacuum can develope in the engine, and no air/fuel mixture is drawn in. Once the engine slows down far enough, the govenor drops the exhaust valve creating a vacuum, drawing in the air/fuel through the intake valve, and at just the right moment trips the ignitor and fires the engine. With no load, one firing cycle is usually enough to get it back up to speed. If you put a load on it, it'll start firing much more often.
09-10-2002, 12:47 AM
Stationary Engine magazine has been running a monthly series on building a Fairbanks Morse 'Eclipse' 1/2 scale model. Appears to be a vertical engine. Started in issue #336, March 2002, still running. (the article, not the engine...)
The author got his castings and drawings from T&S Model Engineering Works, 470 North Lallendorf Rd., Oregon, Ohio 43616. e-mail: email@example.com He seems impressed with what he got.
10-24-2002, 08:20 PM
Jeremy has a fine explaination. nothing random about the egnines. I actual use they were very efficient (all things considered). No Very little anyway) vacuum except when on an intake stroke that will be followed by a power stroke. The thing runs unthrottled. Next engine show take a stop watch, time how long between "pops" (power strokes). 15 to 30 seconds is reasonable for engines designed to cost down slowly. Two pops in rapid order means the fly wheel is rather heavy (which stores more power) but should count as needing power twice as often. They are still in use in parts of the world. I think they would run on every thing from a beer/gas expelled slowly to hi octne av gas.
And thanks for the link. makes me want to make a model engine- but if I take a deep breath the feeling will pass. http://bbs.homeshopmachinist.net//smile.gif. looks addictive Lynn
11-16-2002, 03:16 AM
I purched the plans for Bob Shore little angel, And have gotten a good start on it. However it wasn't a good choice for a first project. The little angel is 1/8 scale of a whitt stationary engine, and the parts get very tiny. Hard to make really small parts even on my smithy. There is a really good website from the Florida model Engineering club www.floridaame.org (http://www.floridaame.org) It is a great forum on small engines and Bob Shores hangs out there all the time..
The hot/miss engines are facinating the work with and to watch run. There is a yearly event near my home called the "Old thrashers reunion" Over the 4th of july weekend every year, Where there must be 500 hit/miss engines. One guy even making ice cream with an old J.D. engine.
The operation of the hit/miss was covered very well by the other postings. They use a variance of a flyball governer, That is it is a centrifical governer to hold the exaust valve open..