Yet Another Month with No Activity In The Shop! But the team and I have been writing a lot of good, solid code for the next release of DSTC's HotMeta metadata server, so I'm not unhappy. I am, however, exceedingly embarrassed. My gaff of a couple of months back regarding the simultaneous firing horizontal twin that turned out to be an alternate firing horizontal twin pales into insignificance against the latest and most public blooper: the current issue of Engine Collectors Journal contains an explanation of "normal" and "climb" milling by me that gets it exactly 180 degrees wrong! Worse, the smelly stuff rubs off on my friend Roger Schroeder in whose column this appears. For a while (about three nano seconds), I though this gaff may pass without notice, but not so. Oh well...
Magazines and Books of the Month
Apart from ECJ (which I've not seen yet, and now probably don't want to ), October past saw the arrival a new issue of Model Engine World, and another issue of Model Engineer continuing the well illustrated series by Mr Rowland Lowe on building a 1/5 scale Gnome Monosoupape from Les Chenery's plans. I was also loaned a copy of an excellent book on the Pratt and Whitney R2800 radial piston engine.
This is the third issue to appear since Andrew Neham took over the helm. The format now seems to have settled down somewhat with a technical article on a larger-than-model, but smaller-than-auto size engine with some unusual feature, a model engine related historical piece, an engine review, a technical article and an offering from past editor, John Goodall with, as usual, liberal use of the question mark as a sentence terminator. The technical piece relates to development work being pursued by Dave Bowes in Canada on solenoid activation of poppet valves in miniature four-stroke engines. Dave also published a construction series on this type of engine published in SIC, just before its sad closure. As an engine builder, I'm sad that construction features are not Andrew's policy, but the material he does print (with one exception) is interesting and of a high standard. I will certainly renew, when the time comes.
ME vol 189, no. 4175
The construction feature on the Les Chenery designed, 9 cylinder Gnome Rotary continued this month with details of the cams (one per cylinder), and their gearing. Mr Lowe's approach to machining these components is simple and pragmatic. In fact, he makes it look like anyone could build this complex engine with ease. His use of a pot chuck to grip a shop made gear on its OD to finish-bore the ID concentrically is inspired and will fix all that is wrong with the gears I've made — which suffer a small, but measurable (0.0015") loss of concentricity as the chuck holding the blank, turned to finish size on the OD, is transferred with the gripped blank from the lathe spindle to the dividing head under the mill for teeth cutting. Bob Washburn and SIC came under occasional fire for presenting projects that were too advanced for the average home machinist. This may be so, but I've always found that there's usually a gem inside them that IS
applicable to engine building, regardless of size and complexity. I look forward to the next installment.
R-2800 Pratt & Whitney's Dependable Masterpiece
This tome, generously on load from Russell Watson-Will, weighs in at a hefty 720 pages filled with photographs, line drawings, cut-aways, graphs, color plates and well researched text. It is the work of Graham White who also write Allied Aircraft Piston Engines of World War II
. How do you make a highly technical book on a machine fascinating? Just include background on the people who designed it, the political and economic drivers of their day, and conclude with the aircraft (civil and military) that this engine powered. Speaking of the latter, I thought I'd seen them all, but the book contains a photo of a Northrop P-61 "Black Widow" variant with a bubble canopy; very mean and sleek looking and an aircraft I've never seen before. The color section details the working of the Hamilton Standard hydraulic controllable pitch mechanism. Ever wondered what the domed protrusion in the propeller hub contained? Buy this book and find out—strongly recommended to engine loons like me.
Firing Sequences and ET Westbury
My little tale last month regarding the Siato alternate-firing flat twin prompted an email from Phil Coleman who is busy building another Model Engineering related web site. We tossed around the design for a while, drew out timing sequences and concluded the obvious: the engine will produce two power strokes, 180 degrees apart, every 720 degrees of rotation. This is why it is standard practice to design multi cylinder engines which have a single throw crank pin as a radial configuration with an odd number of cylinders, evenly spaced. This will produce evenly spaced power strokes, no other arrangement will.
With this revelation stored safely in my brain, I continued piecing together a compilation of the Late Edgar T Westbury's construction and engine related writings from Model Engineer, scanning old issues and doing a lot of reading in the process. To my surprise, I found one of his construction series where he wrote at length on this very topic. This was the "Seagull"; a 4-stroke, 10cc, twin cylinder, in-line, petrol/ignition engine with side valves and water cooling. As an in-line engine, it features a two-throw crankshaft, but he places both crankpins in phase (as it were), explaining that this produces evenly spaced power-strokes at the expense of having all his reciprocating mass going in the same direction at the same time. His reasoning is that the induced vibration can be largely balanced out, while un-evenly spaced power strokes cannot.
ET Westbury was most definitely a pioneer in our field of miniature IC engines. Born in 1893 in rural England, he served in the Royal Navy during the Great War, then as an instructor at RAF Cranwell in the late 1920's. Here he collaborated with Col. (then Capt.) CE Bowden (another aeromodeling pioneer) on IC engine powered free flight models. He also worked alongside Frank Whittle (later Sir Frank, whom some consider the father of the jet engine) and was friend to ET Shaw, better known as Lawrence of Arabia. Westbury was a prolific designer and builder of practical IC engines for home construction. He also had a keen interest in flash steam engines for high speed, tethered hydroplanes. One of his designs was later adapted for use an the air-tool industry. He passed away on Sunday May 3, 1970, but has left a wonderful legacy through his writings and designs in Model Engineer under his own name and several nomdeplumes ("Artificer" and "Kinemette" amongst them) and numerous books published under his own name.
Ken Croft has again kindly visited the great Midlands Model Engineering show on our behalf and taken photos of the engine related exhibits for our pleasure. Ken reports that the engine content was noticeably absent this year, although the show itself was strong. Oh well, next year, maybe. By the way, the odd little prototype was made by Tom Pascoe, a neighbor and friend of Ken's so if anyone has some special interest in this design, Tom can be contacted via Ken.
Weavers and Mites
Out of the blue (bad pun — see later) in late October, I received an email from Ken-ichi Tsuzuki in Japan. Ken-ichi bought a set of Weaver castings from Roger Schroeder, which come with a redrawn, corrected and slightly simplified set of Motor Boy CAD plans. Mr Tsuzuki describes himself (in perfect English) as a 53 year old novice and attached a photo of just about the prettiest little blue-headed Weaver one could imagine. He reports no problems getting it running and another photo shows it spinning a good sized prop with authority! If you read Japanese, visit his site here, then again, you can always just look at the pictures! I'd forgotten, but I did manage to complete an engine early last month. This was yet another Milford Mite 1cc "diesel", made as part trade for a pile of magazines I don't really need, by desperately wanted (the Model Makers mentioned last month). This month, I hope to do better...