Weaver Construction Log.
In June 1952, the British magazine Model Maker began a series of articles titled "A 1C.C. C.I. Engine" describing a simple compression ignition engine (aka "diesel"). The design was called the "Weaver/Ransom" after the designer and draftsman, respectively. Model Maker was then part of the Model Engineer, Aeromodeller, etc stable but alas, ceased publication sometime in the early 60's. The engine however is still remembered in MICE circles, being often referred to simply as "The Weaver".
This little engine was built and described by Mr Ransom to a design developed over several years by Arthur Weaver for use in rail car racing. Now tether cars are not exactly my cup of tea, but the thought of a 1cc diesel powered tether car somehow seems very "gentlemanly" and very "British". The engine was fully described over three issues to be fully fabricated, that is, no castings were employed. While the original plans and instructions are now very hard to come by, they are probably still subject of copyright held by a succession of owners of the venerable names (currently, this is Nexus Special Interest Publishing), so I'll respect that right and post no scans of the text here.
Weaver's design was published with a flywheel, but I'd seen an example of this engine doing a good impression of a Mills .75 at our local free flight field - that is, starting on the first flip and swinging a large prop at whatever rpm the flier wanted; from a powerfull two-stroke to a comfortable, under-compressed, rich, low-rpm four cycle. The builder was Russell Watson-Will. Russell has built two Weavers. His second one is the red headed engine at the head of this page. You may have seen this shot before in color on the back cover of SIC, or black and white on the rear cover of MEW. At the time I first met Russell (1994), I was just starting into model engineering and he kindly sent me a copy of the article (he has a magnificent library) and the above photo, saying I should build one. Finally, I did, but was unable to stop an one...
The links at the bottom of this page will take you through the construction of my Weavers, embodying my (unfortunately) usual education-through-error approach. As part of this process, the original plans were redrawn in MBI format, correcting a couple of errors, adding some parts for airplane use and changing the timing to make the inlet and exhaust more generous. They also incorporate a few other minor detail changes to simplify construction as advised by Russell.
This caused an outbreak of Weaver Fever in the MBIs, resulting in examples from Roger Schroeder and Ken Croft. Roger wanted to see how it would look as originally designed, complete with flywheel. If you look closly, you can see that Roger's crankcase is a casting. Ken's example is the one without the flywheel, finished appropriately in British Racing Green. Ken also used one of Roger's crankcase castings, but machined it all over to replicate the original "hacked from the solid" look. He also improved the inlet timing and reports 10,500 rpm on a 7x4 prop. If you examine each of the engines closely, you'll see that we all interpreted the head shape slightly differently, as well.
From this index page, you can go directly to any of the building sessions. The pages also link to each other in sequence.
I've not bothered with any psuedo-legal voodoo mumble before, but as the hit rate on this site climbs, so does my pulse rate. Somewhere out there is a turkey, so I better state here and now that I am a professional computer scientist, not a professional machinist! If you follow any of my techniques you are probably as gullable as I am. What I'm actually documenting here are all the ways I've found to positively screw up, frequently in a very un-safe mannar. Finally, amazed at the amount of time it now takes to backup this site, I have to state the all material herin is Copyright (C) me. If you want to reproduce it elsewhere, please ask first. Only way I'll say no is if you're getting paid for it and I'm not!
