Rowland Vacuum Engine

An engine made by Mick Cherry. This is the Nick Rowland Flame Engine or Vacuum Engine. They seem to be called by a number of names, but in the end they are all vacuum engines. It really is a good design, Nick told me it took him months to get it working OK. The most critical part is the gas jet, it is formed using .002 shim. Just as Nick says in his summary, you can perform the most exact machining with all parts a perfect fit, but if the jet is not made to drawing, the engine will not work.

All this must be achieved using the correct gas pressure, in this case between 3 and 5 pounds sq.in. The small shield to the right of the ignition tube sited on top of the cylinder head, is for the relight flame. This is a constant burning flame which is used to relight the gas, after the main ignition flame has been sucked into the cylinder. This is a brilliant piece of work, no matter how fast the engine runs, there is always an available flame for the next induction. You can see now why so much time was spent in the development of the engine. There is an exhaust valve in the piston crown,this is also made from .002 shim. The vacuum holds it shut, but when the piston goes back up to TDC any unwanted pressure is vented out through the piston to atmosphere.

The working principle is the similar to the a Hot Air Engine, in that heat is drawn into the cylinder, at BDC the inlet valve shuts the heat then cools down this in turn creates a vacuum, this vacuum plus air pressure then forces the piston back up the bore which gives the power stroke.

The only problem I had was when the postman delivered the castings, I had to pay him £28 custom and excise duty, which I have to admit never entered my head.

A modification to the lubrication

The following pictures show a modification to the lubrication system.

I have found the need for very thin oil to start the engine from cold, then when it has got nice and hot you can use a thicker oil. Even so this is still very thin, namely sewing machine oil.

Also I have now fitted a flow control valve on the gas feed. The engine works on 5lb p.s.i, and with the aid of the valve I can now adjust the flame and use this as a throttle.

Looking at the engine from the side, the lubricator at the front I would fill with WD40, I will continue to do this until the engine gets nice and hot. Then it’s just a matter of screwing down the needle valve and moving on to the main lubricator which has the sewing machine oil, this plus the heat of the engine which makes the oil just that little bit thinner, has done the trick. It would run all day without any trouble should you want it to.

About Nigel 119 Articles

Have been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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