ME Vol 48, No 1136 of 1923

[JasonBModerator @jasonb]

I was just wondering if any member has a copy of the above mag which was dated 1st feb 1923.

I have an engine on it’s way that is a non runner and believe it gets a mention on page 116 as part of the write up of the ME Exhibition. A scan or photo would be most helpful.

It is the “G 1 Uniflow” high-speed Dynamo Engine. by Jackson-Rigby Engineering Co Ltd

 

[David SeniorParticipant @davidsenior29320]

It’s mentioned on pages 118-119

Hopefully that’s what you want

Dave

[JasonBModerator @jasonb]

Thanks very much for that David. I think the p116 was where the article started and was what I found in the online archive.

If I can get it running, I will post a video.

There is also a Bassett-Lowke Uniflow from about 1949 coming with it that is also not running a sit should. It is said that they melted down old Merlin engines to produce the castings as BL were located next to a scrap yard.

[Michael GilliganParticipant @michaelgilligan61133]

Swords into ploughshares !

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

https://www.worldradiohistory.com/UK/Practical-Mechanics/50s/Practical-Mechanics-1950-01-S-OCR.pdf

 

… et seq.

MichaelG.

[JasonBModerator @jasonb]

Thanks for that Michael, I do already have all parts of that build. Not sure if I will make one myself but will check a few dimensions that are not very clear on the scans before the engine goes back to it’s owner. I wonder how 3D printed aluminium would compare to melted down old Merlin engines?

What would be interesting is to find details of the “Don” engine. Do you have that issue David?

Well I’m happy to report that within 15mins of opening the box both engines are running and at least 5mins wa sspent sorting out suitable adaptors to connect the air line. Better videos to follow once I have done a bit of fine tuning and measuring.

[David SeniorParticipant @davidsenior29320]

The DON engine article from 1922 (not sure why they have come through in a strange order!)

[Nigel Graham 2Participant @nigelgraham2]

It’s very pleasing to see these old designs have not been forgotten!

I wondered how they obtained those indicator diagrams (in the 1922 article) until spotting the word “Estimated” in the caption – so they must have been calculated and hand-plotted. I don’t know if anyone has tried making indicators for miniature engines, though it would be difficult to connect one to those enclosed, uniflow machines unless the engine is designed to accommodate one. Usually it uses the drain-cock connection.

There are some intriguing design details, such as the eccentric crank-web mounting and the cutting of the port in a blind-ended cylinder wall, and the comprehensive tests on Mr. Don’s engine appear to have included using a weight-loaded, rope-brake dynamometer. What we read there does not mention that, but can be gleaned from what is written.

Neat way of making the connecting-rods too, as slices from a side-on profile. I think I’d use hot-rolled steel there to minimise the risk of distortion. The technique is also applicable to other components.

Despite the mentions of castings, these machines could well be built from bar stock.

 

I am tickled by one model engine’s specification given: “seven-sixteenths of an inch by 20mm”. A bit of dimensional bet-hedging there? Well, the year being 1922, the UK might go metric soon.

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Thankyou Jason & David for bringing these to our attention!

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Aside from these engines, I note two tragedies are mentioned in those pages. One, the awful death of a boy who connected a low-voltage motor to the mains. The other, which would have been known to contemporary readers of the magazine, is a reference to the loss of an aviator trying to fly to Australia. I wonder what happened to him – or if his fate was known?

 

[Nicholas FarrParticipant @nicholasfarr14254]

Hi JasonB, I’m not sure if this scan is any clearer.

I can’t help with the April one though, which seems as if it should have been in the March issue, but it isn’t.

Regards Nick.

[duncan webster 1Participant @duncanwebster1]

The Don engine is rather interesting, but we’ve had previous discussions on why uniflow engines don’t work very well at low pressure ratio. I’d put money on if working better with separate exhaust valves.

Pity we don’t see stuff like this in modern MEW, is no-one making anything out of the ordinary?

[duncan webster 1Participant @duncanwebster1]

Nicholas, the scanned article refers to drawings in the previous and subsequent months. Do you perchance have those?

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Duncan, no I’m sorry I don’t, either my father didn’t get those, or they have been lost.

Regards Nick.

[JasonBModerator @jasonb]

David, once again a big thankyou. I was only expecting a page or two at the most. I will download them and have  a good read later.

Nick that looks clearer, again I will download and see how it compares. It is intertesting to note that the drawings do not match the image of the engine in the steam plant. The image shows the engine that I have where the cylinder has a jacket which is part of the crankcase casting yet the drawings show an open steel cylinder much like you might find on a 2-stroke aero engine that just exhausts straight out the side(s)

Duncan the other two issues are the ones I posted earlier and in Michael’s link.

When I was first contacted by the owner my first suggestions based on Uniflow engines that I have built  were that they need a decent amount of pressure and a good flick of the flywheel to get them going. Even then they are not going to work the same on air as tthey would on steam.

Nigel, I have used the method of producing a “stick” of parts and then cutting them off several times. It is good for things like wedges and cotters and only a couple of weeks ago I machined two elliptical flanges onto the end of a piece of barstock.

[JasonBModerator @jasonb]

I may have spoken too soon🤐🤐🤐🤐  After getting the G1 to run and thinking my work was done it started to misbehave. It would run OK for a while then the speed would go up and down before it stopped rotating and just oscillated back and forth.

The cam position was adjusted a few times from below but it still happened as if stopped from oscillating I could hear air still flowing out the exhaust at BDC even if the cam was nowhere near the open position.

Off with the head to have a look at the valve. It did not look like it was really closing and a could feel it was in contact with the base circ;le of the cam if not actually lifting so 5thou was taken off the end of the valve stem and put it back together for another try.

Same again so another strip down and I thought the valve was sticking a bit, though hard to tell as the spring is held down by the head. Out with the Mic and the bottom of the stem is 0.127″ compared with 0.124″ just under the head so into the lathe and Emery it down parallel and put the engine back together.

Same again. Off with the head once more and the valve did not seem to be sitting down so my thoughts turned to the tappet that I could not see. So off with the flywheel, Big end cap off so the piston could be pulled, loosen cam and slide out the crankshaft. The tappet dropped out.

On closer inspection the top of the tappet is threaded for a push rod and there is a lock nut. This nut was loose!! Which was allowing the valve lift to alter while the engine was running and when the lift became too high air was passing all the time.

I reset the pushrod length and locked up the nut before putting the engine back together.

All seems to be running as it should now.

Will take a better video over the weekend as the base plate still has to go back onto the bottom of the crankcase.

[Michael GilliganParticipant @michaelgilligan61133]

Well-spotted, Jason

MichaelG.

[JasonBModerator @jasonb]

The G1 Uniflow is quite a chunky engine of cast iron construction and quite large for the cylinder size. The steel crankshaft runs straight in the iron, dural piston and conrod.

As mentioned the main problems preventing it from running were that the cam was in the wrong position but mostly that the pushrod was not locked into the top of the tappet so valve lift was altering as the engine was being run. I did not run it at full generating speed as there is no oil in the crankcase and no lubricator but a few drops of oil are enough for short test runs and all seems well with it starting fairly easily. The owner can sort out the damaged regulator valve when he gets the engine back.

 

[JasonBModerator @jasonb]

The Basset Lowke Uniflow would only run with a small bleed hole open. A complete strip down did not reveal much but the flywheel was not particularly tight. It ran Ok once put back together with a temporary screw plugging the bleed hole. I can only assume that as these engines have quite a kick when the valve opens that the crank was rotating but the flywheel was not picking up speed and just slipping so had no initia to carry the piston back up and compress what air was left in the cylinder unless it could come out the bleed hole.

The drawings posted earlier show the crankcase stopping at the bottom of the cylinder and the steel cylinder exposed but this engine is like the one in the full steam plant photo where the casting encloses a steel cylinder liner and a passage around the exhaust holes directs the steam to a single exhaust pipe.

Again I did not push it to the speeds quoted in the old magazine articles but am happy with how it now runs.

Thanks for all the help with the old magazines.

[renardiere7Participant @renardiere7]

I like the look of that G1 engine.

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