Model Engine News: January 2013
Winter Is Coming
Oil Grooves, or Something Else?
ME Heron Instructions
Very British Mayhem
PAW Relocates to the USA
In-Page Navigation Extended To Jan, 2007
New Books and Magazines This Month
Engine Of The Month: ROC
Tech Tip of the Month
Unless otherwise expressed, all original text, drawings, and photographs created by
Ronald A Chernich appearing on the Model Engine News web site are licensed under a
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Adrian! Do remember what I told you would happen if I ever found you running a diesel engine in the kitchen again? Actually, Lorna Duncan is not like that at all, and neither is she the rather aggressive redhead seen in the photo. The villain about to get his just deserts is however, our own Adrian Duncan, that noted engine collector, engine review author, musician, spelunker, and thespian—fresh from his latest triumph as the Town Crier in a local panto. What can we say? At least it's a step up from playing the rear end of the panto-horse. This month we get two doses of Adrian's extensive research with a review of an early and very rare Japanese glow engine, and a complete revision of an old favorite. In the new year—by the way, happy new year—we have some exciting things scheduled, such as the Frog 500, the Dooling Brothers, Mr Majesco's Marvels, more Fuji Story, the ERE, the BMP, and others.
I suppose I need to say a few words about our latest and largely successful journey around the Sun. Personally, I'm over it. The folk who celebrate the summer and/or winter solstice seem to have a better handle on reality than we have with some arbitrary point in time chosen to increment the year counter. But we are well and truly stuck with it and so it seems that celebrate like there's no tomorrow we must (where were you on December 21st, 2012?). Ruthie and I had some friends over on New Year's Eve for a roast goose—which is another story entirely—and to watch the kiddies' fireworks show at 8pm from our balcony. The big kid's show probably took place at midnight, but we were sleeping peacefully by then.
The best New Year's resolution I've ever made and kept, apart from no more champagne—ever, is no more New Year resolutions! But if I did, it would be to learn to say no the next time old colleagues tempt me out of retirement. It's not that I don't enjoy software development anymore, rather I like it too much, and it's cutting heavily into my time which should be spent busily doing nothing—trying to find lots of things not to do, if you remember the old Bing Crosby song. There's a lot of things I'd like to do in 2013, but it seems that the surest way to not get them done, is to list them—or even think about them! So I won't...
It's been an absolute furnace in the shop this past month, with humidity somewhere in the super-saturated region. Despite the heat, I have managed to complete a level and refret job on the fingerboard of an old Epiphone, making a new bone nut and learning a lot I didn't know about arch-top guitars in the process. From the amount the bridge sinks when tuned to pitch, I suspect the soundboard brace on the treble side has come loose, but the f-holes are so small, there's no chance of getting a mirror inside to check, so I've ordered a 7mm diameter USB borescope from an eBay seller. It has adjustable intensity LED lighting, so should allow me to look inside using my laptop. I suspect this $34 gadget will have model engineering application too, so more when it arrives. And now that we've managed to return to subject, on with the show!
Winter Is Coming
Back in November, Les Stone took a photo of a rather nice lathe, neatly installed on a concrete slab between large pine trees, outside the offices of H&H Machined Products (Erie, PA). Before you head out on a recovery mission, the lathe is a 1907 Lodge and Shipley, covered by patents issued between 1891 and 1905. Les concludes that given the turn of the century patent numbers and the large pulley in the center of the head stock, it was powered in early shops by over head line shafts and pulleys which in turn were powered by one central large electric motor or engine, whatever the case may be. It was such a nice shot that I asked Les if he'd mind revisiting the site later in the year. Les, helpful as ever, obliged and we have the second photo of our old lathe, covered in snow. For some reason that I can't quite put my finger on, H&H's tribute to machinery and machinists, and the effort they obviously go to in keeping the lathe bright and shiny, makes me feel good..
Oil Grooves, or Something Else?
The pistons of some model engines of old—and some full size ones for that matter—were sometimes machined with a number of "V" grooves spaced along their length. The drawing here, taken from our Motor Boys International Model Engine Plan Book, shows the piston drawing for the 1938 Trojan Jr, faithfully copied from an original engine, which contains this feature. I and others always called these things "oil grooves", but a piece in a recent issue of the Model Engineer (Vol 209, Issue #4443, page 746, repeated in #4445, probably in error) by Doug Hewson, says we've got it all wrong. I quote:
...we turned small grooves in the bobbins using a Vee tool. I keep hearing these referred to as 'oil grooves' but they are not. They are 'labyrinth grooves'. The theory behind these is quite interesting and logical if you did school science. Remember 'Boyles [sic] Law'? P1V1=P2V2. In other words if the volume increases then the pressure decreases proportionately. In our case if steam leaks past the bobbin it comes across the first groove so the volume increases and thus the pressure drops. If the steam still has the pressure to get as far as the second groove the same thing happens again so the volume once again increases and the pressure drops even further. If the bobbins are a reasonably good fit then the steam will not have enough pressure left in it to reach the third or any other groove, so effecting a good seal.
The "bobbin" which Doug is talking about is the valve in a piston valve steam engine, but pressure is pressure regardless of how it is generated (although Boyle's Law does stipulate ...for a given mass of gas at a constant temperature...). Thinking about this in the context of model IC engines, I'm finding it hard to accept. For one thing, given the nature of our fuel, those labyrinth grooves will probably contain an amount of incompressible oil! Second, we can't have just a local pressure drop, can we? Mr Boyle does stipulate ...for a given mass of gas... so the volume change must apply to the entire mass of gas and will be miniscule. And the piston is moving so the volume and temperature are changing too (Charles's Law), making application of Boyle's Law tenuous, IMHO. I'm not saying Doug is wrong, just that I, personally, can't see it.
An earnest search through my texts (IC and steam) failed to find any mention of labyrinth grooves, and only Dave Gierke's 2-Stroke Glow Engines gave passing mention to oil grooves. A Google search did however uncover the use of labyrinth grooves on pistons (and cylinders), but only in the context of air-compressors (3 references). Still, it's something worth knowing about and if anyone can come up with a reference in the literature, I'd like to hear about it.
ME Heron Instructions
Each month I receive optimistic requests asking where the sender can obtain spare parts for something which has not been made for more years than some of us have been alive. In most cases, I have to suggest they haunt eBay looking for a "junker" of the same type, but these days, even engines which seem to be only good for parts can be restored, so prices are seldom low. On rare occasions, we can supply a drawing for the part and a suggestion of who might be able to machine it at a reasonable cost. On even rarer occasions, the contact is not asking, but giving! This past month, Albert Hornby (UK) wrote, including scans of the ME Heron instruction leaflet. Arthur obtained his, new, from the renown Model Shop of Newcastle in the 1960's. We've updated the Heron page with the scans and thank Arthur for his contribution.
Very British Mayhem
Adrian's research into the Nordec and Dooling (and others) this past month led us to examine the Practical Letters column in the Model Engineer during period from late 1949 through the start of 1950. A rather innocuous article by one George H Stone described how he competed in and won the 10cc tethered hydroplane class in the Swiss International Regatta held at Geneva on August 21, 1949. The article appeared in ME #2524, dated October 6, 1949. About a month later, the fit hit the shan with a letter by RG Mitchell saying the article should have been titled, "How I Won the Swiss International Regatta", and that perhaps an acknowledgment to Dooling Bros of California would not have been out of place. After that, it was on for young and old, including Gems Suzor, and Arthur Weaver, with ETW taking part through an article of his own. The debate centered around Stone's shameless use of a commercially made engine in competition rather than one he had constructed himself, and worse—a non-British engine at that!
I've long been of the opinion that no race on the planet can hold a candle to the Brits when it comes to vituperous letters to the editor. One must admire their eloquent use of the English language to quietly express outrage and call into question their adversary's opinion, intelligence, honesty, breeding, parentage, patriotism, and right to exist! After the launch of no fewer than twenty paper missiles, the debate finally diminished in March 1950, and remember that the Model Engineer was a weekly publication during this period. The outcome seemed predictable: you can't halt progress.
Now think about all the times since when similar hot debate has erupted. The "Builder of the Model" (BOM) rule for National competition for example. That one was lost, but revived in recent times with grumblings against the use of completely finished and trimmed (and highly sophisticated) models, purchased at telephone book number prices from former Soviet countries, and used to compete and frequently win in international classes like F1A, and F1B (Wakefield).
With a few notable exceptions, the thought that a modeler should build the engine he will use for competition has long vanished. One person, no matter how talented, will have great difficulty matching for a single engine, the test and development hours which a company can invest in a project which will see sales—eventually and hopefully—in the thousands, or tens of thousands. All this has not stopped individuals (Bugl), and teams (Flores, Metkemeyer, and Visser) for example, from doing just that. Even today, we see examples like Brian Turner's F2B barstock engine. The common thread is competition driving development. It seems to me any rule which aims to restrict competition is a bad idea, and generally doomed to fail anyway.
The British 10cc Nordec racing engine was one of the first reviews Adrian Duncan researched for Model Engine News, back in June, 2008. In fact, the Editorial of that issue has a photo of younger versions of Adrian and I, fondling engines on his patio in Vancouver, BC, while I was visiting Simon Fraser U to present a paper (observant readers might like to identify what Adrian is holding). As you've already seen in this month's Editorial, Adrian has not aged much, while I on the other hand—as you'll see in this month's Tech Tip—have gained a degree of gravitas, or weight, or something. Anyway, the Nodec is rather a favorite of Adrian's and many others, and the intervening years since the engine review have resulted in him discovering quite a bit more about the engine. An update was necessary, but given the volume of data, we decided the best solution was to completely replace the Nordec page, illustrations and all.
This will result in a certain amount of dead weight in the off-line copy of MEN held by many MEN Members, as the new page comes with a complete set of new photos. I can tidy this up on the web site, and new Members' DVDs, but not your hard drive. If you feel adventurous, you can go the men/ad/images subdirectory and wildcard delete all of the
tn_nordec_*.jpg files. If you don't, nothing bad will happen except you'll have 46 orphan images, unreferenced by anything, just taking up about 1.4MB of disc space to no return. The choice is yours.
In-line twins are a thing guaranteed to get my attention. The sound made by a two-stroke (two two-strokes, actually), firing every 180° is music to my ears, though your mileage may vary. The engine here is the second effort of Dean Clarke (New Zealand), and guess what? His first effort was an in-line twin too! As it's a New Year, I've started a new Gallery Page on which you'll find Dean's twins and a few more words describing them.
PAW Relocates to the USA
Bet that got your attention and has British modelers all in a tizzy, yelling from the rooftops, tell me it isn't so! Well, ok, it's not. While updating the David R Janson Index to add a link to his review of the PAW .29 R/C diesel, I noticed that Janson gives the country of origin for it as the USA! The review itself however clearly places Progress Aero Works in the correct location, so we'll call it an ancient cut and paste error, or maybe he just meant there was a US based distributor. As he mentions, PAW have been making basically the same design for a long, long time, although incremental detail design changes have improved the engines from time to time. We already have a tribute page for Gig, and beyond doubt, the engines designed and built by he and his brother Tony deserve the full treatment, but until then, David Janson's review at least ensures they get a mention in the Finder.
New Books and Magazines This Month
Way, way, way back in the May 2004 MEN, our subject was Dave Gierke's 1994 book, 2-Stroke Glow Engines. This was in the days before I started handing out star-rankings to books, so I'll redress that and give Dave's book the full Five Stars, and a Koala stamp . It is quite simply the best book on the history, theory, and practical operation of model engines ever written; so there. A review of his follow-on book was promised in the July 2008 MEN, and even though it's taken a while, here it is. Just to spoil the surprise, it too is simply terrific, highly recommended, but despite being even more informative and thought provoking than his first book, gets only four and a half stars. As to why, read on...
Power: Beyond The Basics, by Dave Gierke, Air Age Media, CT, 2007, ISBN 0-911295-70-4, is named Volume 2 of 2-Stroke Glow Engines for a very good reason. First, it assumes the reader is fully conversant with all the material in Volume 1 and wastes no time nor space on descriptions of basic 2-stroke principles. Second, it does what it says, going beyond the basics, delving deeply into throttle design, fuel delivery systems, and fuel composition. My only disappointment in Volume 1 was the lack of math—even simple math—to back up the theory. Volume 2 addresses this omission providing both math, chemical formulae, and chemical equations, but don't be afraid—they are not anything that someone with a dimly remembered high-school level of understanding will have any trouble with. You can even skip them entirely and still understand 98% of what he's on about.
I find myself simply wanting to rave about this book. I truly wish I'd bought a copy back 2008 when I first mentioned it as it has clarified so many things for me, made me rethink things I already thought I understood, and taught me several new things of importance on the theory and operation of model IC engines. It begins with a history of the development of practical throttles for our model engines, introducing the reader to the problems in supplying the correct mixture required in the band between what Dave calls "WOT" (wide open throttle), and idle. He correctly (IMHO) identifies the important developments along the way to the current state of the art, these being the 1949 Jensen Channel Island Special (designed by Edgar T Westbury, although Gierke does not mention it), the barrel-type throttle designed and manufactured by Mills Bros in 1950 for their Mills 0.75cc diesel, and the mixture compensating "AutoMix" carb designed by Hi Johnson in 1962 for his Johnson .36 JBB R/C. He also covers other methods of throttling a model 2-stroke, such as exhaust restrictor devices, the use of twin sets of ignition points for advanced/retarded running of spark ignition engines, dual needle valve engines, idle-bar glow plugs, and other developments, good and bad, during the 1947-59 period.
The next chapter (2) covers developments from 1960 to "present day", which in this case, is 2007, although there have been no breakthrough developments between then and now. Starting with the AutoMix, he traces refinements of that idea, up to the Perry, with the three needle Fox, and many others including a garden of different designs from Duke Fox, in between. The Fox three needle he feels was the best carb ever, even if no-one but Duke himself could adjust it! With the groundwork laid, the next chapter delves into carburetor principles, introducing air/fuel ratios, atomization, pressure differentials, venturi action, and engine pumping action. Fuel delivery gets three distinct chapters, one for non-throttled engines—which will delight the control-line and free-flight enthusiasts, and another for throttle equipped engines. The latter includes developments such as the different types of pumps which have appeared over the years (Kavan, Perry, Robart, etc), and describes and quantifies the pressure differentials from atmospheric present in a standard 2-stroke (and how to measure it), as well as those utilizing muffler and crankcase pressure feed (timed, and un-timed). I hope you are beginning to see that this is one comprehensive book!
That brings us to chapter 6, the third on fuel delivery, where pressure carburetors (YS) and EFI (Electronic Fuel Injection) are covered. An interesting diversion in this chapter is the little known work by the AMA control-line Carrier fliers in general, and Harry Higley in particular in the use of on-off pressure and Perry-type fuel metering for the high and low speed phases of flight required by their rules.
Last five chapters deal with fuel. As succinctly noted by Graham White in his book, Allied Aircraft Piston Engines of World War II, it was the chemists who drove the development of high-power engines, ahead of the engineers. Dave now gets quite technical in tracing the development of model 2-stroke fuel blends, delving into detonation, anti-knock chemicals, the importance of outboard racing boats on fuel formulation and engine design, and both the facts and fiction—and there's truckloads of that—surrounding fuel blends. He even covers, if briefly, ignition-less operation: diesels! He devotes an entire chapter to methanol (CH3OH), another to nitromethane (CH3NO2, and note the extra oxygen this carries), and yet another to lubricants. I was surprised and delighted to see a box-insert in the lubricants chapter attributed to Motor Boy, Bert Streigler. The text follows, almost word for word, the advice Bert sent out to the group years ago, reflecting his knowledge as the Technical Services manager for Conoco, which you'll find cunningly hidden in our FAQ pages.
The final two chapters cover glow fuel blends, and mixing your own fuel. There are two appendices, one on stoichiometric air-fuel ratios, with the chemical reaction equations to show the hows and whys, and another on the "four-two break" beloved by control-line stunt filers, reflecting the author's background and unsung success in this event. The book concludes with a very extensive index, which is a great assist when you need to find something to refresh your understanding of a dimly remembered detail. The writing style is clear and peppered with anecdotes from the author's experiences as a life-long modeler, while reflecting his extensive work teaching engineering using sophisticated model engine test-rigs to measure and quantify model engine characteristics and compare these to theoretical values.
Rave, rave, rave. Ron really likes this one and says that both it and its companion volume should be on the shelf of every engine fanatic. So why has half a star been knocked of its ranking? Well a couple of reasons, one of which eventually annoyed the hell out of me. First, editing. There are typos which should have been spotted. I blame the editor, not the author. Second, the presence of gratuitous magazine illustrations, generally advertisements for fuels and fuel tanks, which have either tenuous relevance to the text, or none at all. Even worse, you need a magnifying glass (or Optivisor ) to read them! In one case, the text describes the claims made for the backplate mounted Perry Regulator and references Ad 5-7, which is an almost unreadable advertisement for Kraft polyethylene fuel tanks! The text goes on to to chronicle how Perry Automotive was sold to Bob Varsane, who removed the "flip-flop" circuit from the pump. This is illustrated (Ad 5-8) by an advertisement for the Kavan 6-channel tank! Obviously something has gone massively wrong and it's not mis-labeling. I'd have loved to give this book the full five stars and a Koala stamp, but simply can't.
Engine Of The Month: ROC
What? Never heard of a ROC? Where have you been hiding, under a...no—that's too cheesy even for me. A little more seriously, I doubt that many outside of Japan know of this engine, and Adrian suspects that even inside the Sacred Territory, few know or remember this very basic, but well made Japanese 5cc glow engine from the late 1940's. Adrian's research has uncovered FRV and RRV versions, and in the new ROC page he examines possible connections to other similar Japanese products of the time.
Tech Tip of the Month
What we have here is your common, garden-variety, Optivisor. It's (obviously) a headband magnifying visor which has been made since about forever by Donegan Optical Co (KS USA). On the off-chance you've never seen one, the light-weight ABS visor hinges on the adjustable headband so you can quickly and easily bring it into play as required. It has interchangeable ground and polished lenses which range in magnification from 1.5X to 3.5X. The downside to that being that as the magnification goes up, the focal length goes down, so a #2 lens (1.5X) has a focal length of 20" (508mm), while the #10 lens (3.5X) focal length is a mere 4" (102mm). Changing lenses is a bit tedious, so people generally pick a compromise lens trading off magnification for focal length.
I've had an Optivisor, fitted with a #7 lens (2.75X at 6") for as long as I've been a model engineer, but mostly it gets used for locating slivers of metal in my fingers, which is a pity because close examination of your work can be very beneficial. Enter reading outside your speciality, again. Here's an idea I saw on the Stewart MacDonald luthiers' supplies website. Pick just about any of their videos and you'll see Dan Erlewine wearing a modified Optivisor like the one seen here, fetchingly modeled for you by moi. The Stewmac shop apron is included as a tribute to Dan's idea which is just about the best assist to detail work for aging eyes I've ever seen (no pun intended, but feel free to groan anyway).
Dan's stroke of genius was to add a couple of plastic strips to the Optivisor so that a second lens could be fitted, below but in line with the normal lens. Dan used ABS plastic, which any well equipped luthier will have lying around for binding the edges of instrument bodies and fretboards. Not having any, I used a couple of strips of 1/16" Perspex, doubled up below the visor rim with super-glue to 1/8" thick to match the length of the lens snap-rivets. It's screwed to the lens hood with four countersunk 8BA screws (2-56 if you prefer) and fettled so both lenses can still be snapped in and out, though I doubt I'll ever need to now.
The idea is that by adjusting the angle of the visor and the nod of you head, you now have three levels of magnification available (or six if like me, you are short sighted and wear correcting lenses). Nod your head down and move your gaze up a little from unaided 1.0X vision, and you have 1.5X at 20", which is perfect for normal working on the lathe, mill, or bench. Nod your head and roll your eyes further and you have, in my case, 2.75X at 6" for really detailed, close inspection. I'm not suggesting this as a safety item, but the danger of getting your nose bashed by the work is reduced because it will hit the visor first—a tech training college machinist teacher I knew suggested wearing a baseball cap while working so the brim takes the first hit, and not your nose, or hair if you have any. Optivisor themselves take pains to stress that their lenses are plain ground glass and not a substitute for safety glasses, or face shields.
This photo tries, poorly, to show the two magnification levels provided by the #7/#2 lens combination, against zero magnification. While the clear Perspex extensions cause no visual distraction, they are a bit brittle and you may notice that I've had to cyano one side back together (twice). Dan Erlewine's ABS strips are lightly bent inwards at the bottom edge of the visor, trying, I guess, to keep the lenses perpendicular to your line of sight as you nod and roll. Seems like the right thing to do, but my straight version seems to work fine too. The best part is you can adjust the visor angle so normal straight-ahead vision is not magnified, while a tiny head/eye movement engages instant magnification—you don't have to touch the visor unless you really want to.
If you are short-sighted, your correcting lenses produce an image of distant objects inside your furthest point of distinct vision, but reduced in size. I often find myself looking over the top of my glasses and bending close to overcome the size reduction. I've found that looking over the top of my glasses through the #2 lens means I don't have to get embarrassingly (and dangerously) close to the work. This is good because the combination of myopia correcting lenses and Optivisor lens reduces the available magnification.
You can order an Optivisor with a #2 lens from Amazon for about $34. A #7 lens will set you back about $20 more from the same source. You can sometimes find them cheaper on eBay, but don't forget to factor postage and delayed gratification into the equation. A strip of 3/32" thick ABS plastic 65" long from Stewmac will set you back about $9, but I'll bet you can find something appropriate in your scrap box. I've had my Optivisor over twenty years, but hardly used it (apart from times when I needed to locate those painful metal slivers). Now it's practically never off my head, even though Ruthie says I look ridiculous.
In-Page Navigation Extended To Jan, 2007
In a sudden rush of blood to the head, another thirty-six (36!) MEN issues have been modified to add the New Navigation Feature. At the same time, I ensured that all the pages are 100% "tidy" as regards HTML encoding. This required a lot of effort, which meant that way more than those 36 MEN pages needed updating. You'll see them listed in the New and Updated Index for this month. Don't get excited or worried; the changes are "transparent" to the reader. If a page has content changes, it will be noted in the Briefly Noted section which follows.
This section is intended to alert you to little things that are hard to expand to a full news item, or cunningly wind into the Editorial, but are worthy of note never the less.
- The December MEN Issue was a whopper with the Members' zip update reaching almost 15MB. The number of files touched was large, too. Sadly, with so much going on, my pre-release testing missed a couple of boo-boos. Luckily, we have a legion of readers who jump on the page literally the second it is released and let me know about errors. I fix 'em quick, but in case you read it early, be aware that the Deller page had a duplicated plan scan page, and the BJ Cicada plan, was, as Charlie Stone put it, absent without leave. All fixed now.
- Another slight boo-boo found its way into the Members' Monthly Update for December 2012. This caused some problems in the menu and plans index page. The January 2013 update corrects this and thanks go to the Members who alerted me to the problem and helped test the fix.
- In the process of cross-linking this month's Book Review, I discovered that I'd spelt Dave Gierke's name incorrectly in two places on the How To Test Model Engines page. This has been fixed and the section on Dave's engine test rig has been updated a bit.
- The Katipo review has been updated with additional information and a new image.
- A search for something else entirely chanced across a photo of the fearsome Mr Hefin Davies. This has been added to the DC Ltd page.
- Finally, our Arnold Hardinge and the Mills Brothers History page was in danger of being lost in the noise, so it has been cross-referenced into the People and Companies Index, as it should have been, ages ago.