This is Les' rendition of the ELF "Goose Egg Four", a flat four cylinder two-stroke, which means it's two simultaneous firing boxer twins, arranged to fire 180° apart. The engine is fully piston ported and the name derives from the shape of the fuel tank suspended on the underside of the engine. The designer is Dan Calkin and I really recommend the book about him and his engines by John Brown, titled Dan Calkin and His ELFs (he never called them Elves). As the two twins are alternate firing, the engine requires a distributor, which can bee seen at the rear. Above the egg is a spider of piping which carries the fuel/air mix from the filtered air inlet to each cylinder. Like all Les' engines, the Goose Egg is a runner, which makes it even more amazing, after you study its construction as detailed in the John Brown book.

Les and I, plus doubtless many others, have very fond memories of our departed friend, Roger Schroeder. Roger did more than anyone else I can think of to foster the resurgance in model engine making through his very inexpensive casting kits. This is Les' recently completed (as of July, 2013) Junior Brown Junior, from one of Roger's casting kits, sent to Les in September, 1986, making it almost as vintage as the engine it is based on was when Words and Music for building the engine appeared in The Engine Collectors' Journal, Numbers 81, 82, and 83 of that same year.

The actual Brown Jr, designed by Bill Brown, had a displacement of 0.61 cuin. For his "junior" version of the engine, Roger scaled this down to 0.199 cuin with a bore of 0.625", and a stroke of 0.650". This changed the bore/stroke ratio from 0.96 for the original, to 0.875, resulting, Roger believed, in a better running engine, small enough to make on modest equipment. Les built a Hurelman style timer for his engine, following Roger's recommendation that the standard timer was fussy and hard to make. As we see in the last shot, the engine runs just fine with it.

With this engine, Les completes the set of engines pictured on the original Motor Boys Plan Book. The new arrival is the 1938 Trojan Jr, a 0.192 cuin spark ignition, piston ported engine with a roller bearing crankshaft. The original engines had a complex cast iron cylinder, which Les has faithfully replicated.

The Trojan Jr was introduced in 1937 and is very rare today. It featured a cast iron cylinder with a brazed on bypass cover and intake mounting flange. The completed assembly was painted a bright red and the aluminum cooling fins were shrunk onto the cylinder. The main change for the 1938 model was at addition of cooling fins to the top of the head, a metal fuel tank, and use of the new-fangled 1/4" spark plug (the '37 model had a 3/8" plug, which substantially increased the size of the engine).

Les' rendition is faithful in every respect, and like all of his engines, runs just fine—better than original most likely, reflecting Les' skills, experience, and attention to detail. If you look in the background of the action shot, you'll spot the motor cycle coil Les uses to test his spark engines. This delivers a good hot spark which is exactly what you want when testing a new engine.

Les insists that the first order of the day is a big thank you to Don Brymer of Australia for sending photos of machining sequences he used in making his Fig Tree Pocket Twin (a picture of his twin can be viewed in Model Engine Builder Issue 27, page 9). The brass plaque on the engine's mahogany base echoes the description in the Motor Boys' Plan Book. The designer was Russell Watson-Will, who resided in a suburb of Brisbane, Australia, named "Fig Tree Pocket". Russ would be rolling in his grave right now insisting he did not design the engine, he simply copied the ideas of several others to construct it! I call it all academic, as without his work, beautiful reproductions like this and other could not exist.

Like all experienced builders, Les made some changes. The first major internal change was a reduction in crankshaft diameter. The massive 0.375" central shaft was dropped down to 0.250 diameter. It was further reduced through an 8° taper to hold the drive washer, then down to the final diameter of 0.188 for threading 10-32 for the prop nut. Les liked the 10° outside taper on the headsand the recessed mounting screws. He also liked the appearance of Russ' simple R/C carburetor, so he to followd this approach, extending the carburetor venturi a small amount to incorporate a shaped trumpet/trombone effect. He did change the fin size and spacing on the cylinders giving one extra fin on the head plus one extra on the cylinder—there's always room for more cooling!

Finding the design of the compression screw on the recent BJ Cacada compression ignition engine appealing, Les incorporated it into his FTPT—times 2, with bronze compression screws and 0.093 diameter stainless steel Tommy-bars pressed in. The "BJ" qualification is for the designers, namely, Chris Boll and Rob Jenkins.

Les used 3-48 stainless steel, slotted philister head machine screws throughout and for the "First Run" trials, fitted his Schroeder "First Ohlsson" fuel tank, mainly because of it's equivalent size to the engine. The One Size Fits All Elf mahogany prop is 12x6-1/2, made in accordance with page 247 of John J Brown's Elf book. At the time of writing, Les is still running the engine in—slowly—as evidenced by the sludge on the mounting block. But believe me, at full song, the FTPT is LOUD!

With one Sugden Special in house, Les saw no need for another, but what to do with the magnificant die casting for the Sugden made by Vincet Chai Les had sitting around begging to be built? Rather than leave Vincent's casting sitting on a shelf, or in some dark drawer never to see the light of day, Les waithed for right engine to come along that would look good in this case and still be functional. This finally came along in the form of Mike Cook's "Whatzit Diesel" as seen in Engine Collectors' Journal, Volume 35, issue 200 of August 2010.

The bore and stroke are 0.500" by 0.562" respectively, which works out to 1.808 cc or 0.11 cuin. The connecting rod has a center between the holes of 1.062". Mike's engine has a large outside bypass as shown in the ECJ pictures, Les opted for an internal milled bypass. After burning up four tank-fulls of fuel through the engine, Les concludes it's an absolure SCREAMER. The one unusual feature which he liked about Mike Cook's engine was the milled slot in the top of the cylinder head for adjusting the compression which was incorporated into Vincent's composite diesel.

This rather unusual creation is based on a Magnum 91 crankcase casting and a Watzit that appeared in Engine Collectors' Journal #186, and in our own Watzit pages. Les completed the engine late in December, 2009 and had the following to say about it:

First order of the day is a thank you to Bert Streigler who supplied enlarged pictures of the timer for the 1938 M&M, along with a drawing of the engine a number of years back from the late Ted Enticknap. This aided in the set-up for the front end of the engine, with the timer forward done in the 1938 M&M motif. The bore and stroke of this new Whatzit is 1.000" x 0.875" respectively giving a displacement of .69 cuin, or about 11.3cc. The foundation for this engine is a Magnum 91 case which has been in a drawer here for 17 years. With some modification, the gear box has become the tank because despite the valve on the head, it's a two-stroke. I liked the old world appearance of the Deller spark plug, so replicated it to go in keeping with the antiquity of the Whatzit.

The timing given for the old Whatzit in ECJ is as follows: facing the engine from the front and flipping the prop to the left, the FRV begins to open at 90° BTDC and is fully closed again at 45° ATDC. The exhaust valve begins to open 90° ATDC and is fully closed again precisely at BDC. In my estimation, this timing, along with the spring loaded valve in the piston were the two main aspects which prevented the original ECJ Watzit from running.

The new timing figures I have come up with are as follows, the FRV begins to open 130° BTDC and is fully closed again at 30° ATDC. The exhaust valve begins to open at 120° ATDC and is fully closed again at 65° ABDC. The piston valve in this new Whatzit doesn't rely on a spring in the piston, but is pretty much conventional in that the inner piston slides freely in the outer piston with the top to bottom movement of .076 thou. The exhaust cam is separate and after checking it's proper position, it was loctited, then pinned it to the shaft with music wire. The hole behind the valve is the actual exhaust outlet.

I tried a 14-5 Rev-Up prop for the initial trials, but decided very quickly that it wasn't enough prop after getting the fingers wrapped a couple of times, even with the spark set at TDC. Moveing to a much more user friendly Top Flite 16-6 Super M (maple), it started relatively easy, but didn't break any speed records!

This work is dedicated to memory of the late Roger J. Schroeder, 1931 2009. His model airplane engine casting kits assured my smooth transition from steam into internal combustion.

Les completed this one in July, 2009. It's a replica of the 1946 Atomatic 4 designed by Uberto Travagli. The original had a bore of 15.5mm and a stroke of 22.8mm, accounting for its tall appearance. It features a very streamlined look, assisted by the coaxial fuel tank fitted behind the prop driver, and a front rotary valve induction fed from a fixed jet fuel feed with a variable air valve, like the Pepperells from New Zealand (Les has made one of those, too).

Induction metering aside, the Atomatic was conventional enough although it did feature an alloy wristpin carrier, covered with a thin cast iron piston sleeve retained by a countersunk screw in the crown. Les has deviated slightly in the engine mounts by adding three mounting ears (the original had a rather complex screw in rear plate (not a backplate as the case is blind bored from the front) that totally hid the mounting screws. One hundred points for style; somewhat fewer for practicality.

Les wants to send his thanks and appreciation to Giacomo Mauro, technical advisor for Italy's SAM 2001, saying that his help, pictures and ideas were indispensable and paramount to the successful culmination of the Atomatic 3 cc project, which would have been virtually non-existent, had he not stepped in with his kind assistance.

• Ken Croft who made the rough sketches of the ACE
• My humble self who transformed these sketches into trademark MBI CAD drawings
• Roger Schroeder who made patterns and poured the castings
• David Owen for commissioning and providing the moulded plastic tanks

Les notes that he was further inspired by the shot of Graham Podd's example on the ACE page (the one with a transparent green plastic spool up front). He liked the factory die-cast appearance of this version, so replicated on his. Always with an eye to presentation, Les machined the cylinder to have five thin cooling fins instead of the traditional four. He also added a radius on top of the comp-screw post instead of the little flat, chamfered at 45 degrees. As the prototype case casting he was working from had an over-generous draft on the main body (my fault), Les worked it from a tiny radius that starts from the mounting lug and gradually gets larger before it terminates at the cylinder flange hold down screw. And last but not least, the serial number 1110 stamped on one side of the engine which is the number of his street address in Erie, PA.

The last shot shows Les' ACE spinning a massive 8x6 TopFlyte nylon airscrew. Remember this is a 0.5cc engine. That's just 0.030 cuin. Think how well your average .049 Cox Baby Bee would do if fitted with that prop. But that's one of the strengths of diesels; their ability to turn big props at a wide speed range by adjustment of compression and fuel mix. Then there's that lovely smell...

By 1931 there was a demand for a more powerful engine to power a small two-seater aircraft. Cylinders with overhead valves were fitted to the original crankcase, increasing the horsepower to 36 h.p. with 2,500 r.p.m. and a weight of 120 lbs. The engine was re-numbered E-113 and the aircraft renamed the C-3.

Aeronca engines were manufactured in England under licence by J.A.P. (J. A. Prestwich & Company Ltd.) These had a redesigned rocker box and cover to accommodate two spark plugs per cylinder with two magnetos for dual ignition placed at right angles across the rear of the engine and a power increase to 40 h.p. with 2,540 r.p.m. But the engine had reached the end of it's growth potential and was superceded by a variety of more powerful engines.

The model is a 1/4 scale twin cylinder horizontally opposed aero engine

• Anti-clockwise rotation looking at front
• Coil ignition
• Contact breaker and distributor housed in a dummy magneto casing
• Gear type oil pump
• Oil pressure relief valve set at approximately 40 pounds per square inch

Les completed this engine in March, 2009 after nearly a year of construction. Despite the imaculate presentation, it's no show pony. In the final picture, it is seen turning a Zinger 18x6.

The photo of the engine in action illustrates a very practical idea: get a healthy spark from a big coil and bettery until the engine is sorted out and it's running, starting, and tuning characteristics are well understood.

The cooling fins, or rather the lack of them, is one of the things that leaps out when you look at the engine. But note that the fins are tapered which makes them better at heat dissipation than simple parallel cut ones. Les says you can touch the head right after a run, and while you won't get burnt, it's not a particularely fun thing to do. Tapered cooling fins, still used in full size air cooled engines and much favoured by Westbury are seldom seen in model engines these days where lots of slit fins are more the norm. I rather like the look of the old ones. As Les says, it's a Classic.

Les has built this one as a straight rear rotary valve diesel, but the plans show how it can made convertible for either diesel or glow ignition, and with RRV or reed valve induction. In the "bar-stock" configuration—simply known as the "Humbug"—it is rather pedestrian in appearance, but if Roger Schroeder's castings are used, the appearance is totally transformed. Plans are scheduled for a future edition of Model Engine Builder magazine and it's great to have Les' help validating the design so readers will ultimately benefit from his experience.

The other thing here that looks rather like a bathroom fitting is the nose piece. Again this shows Les' lateral thinking on how to make a complex part simpler. If it does not look simple, have a look at part 5-1 on the GA of the Monsun that shows the part formed and fitted as designed.

Les reports that the engine was initially a bear to start, but is loosening up nicely and really moves a lot of air turning a Top-Flight 13x5-3/4 wood. Try that with your average .15!

You may notice my head has an unusual shape as compared to Vincent's perfect sphere shaped head. In Andy's instruction booklet, he presented a table of coordinates, but I misinterpreted diameter for radius and dropped into the head too abruptly, so had to re-group if I was going to save it. There was enough previous machining on the head that I didn't want to go through this again. If you catch a side view shot it, the resemblance is that of a pith helmet—needless to say, the day was saved. It starts very easily, just one choke and it's off and running; 5,200 RPM on a 12x6 prop.

Pith helmet yes, but more like an acorn to me (not that we actually have such trees Downunder, so what would I know). For an example of how it might have turned out, have a look at the one made by Dr Battiwallah himself, Oz Motor Boy Vincent Chai. A picture of Vincent's example graced the front cover of SIC #78 and provided Les with the spark of inspiration needed to finish his.

Les says that the most significant change he made on this particular engine was to the ignition system (Unterbrecher). The magneto is a dummy concealing a distributor running at half engine speed off the center camshaft for number one cylinder.

The engine base is comprised of two one inch thick laminae of Black Walnut hardwood, which gives the base it's final thickness of two inches. Like all Les' engines, this is a "runner", not just a "looker". which raises the question of how does it sound? When asked this burning question, Les provided the following description:

I got 5 tank-fulls through the Mite today (2006-09-09). The photos show it together with Topsy, two real powerhouses so to speak. This is about as close to Gasparin building as I ever want to get! The diameter of Topsy's piston is 5/16" followed with the Mite piston being 3/8". The Mite swung a Top-Flite 8 x 6 white nylon prop at a very respectable speed. The side view shot shows the bypass cover on the Mite which is .020 thick stainless steel.

Les used no castings for his Mite. The basic case is hogged from the solid. The venturi was pressed in and a fillet of JB Weld used for added security. Les swears by this stuff. It dries grey, so he's touched it up with silver paint to resemble a first-class TIG welding job. If you look closely, you'll notice the fins on the engine are "thread form". Evidence shows that originals exist with this rather extreme example of tapered fins and more conventional straight fins. I think the tapered ones add to the period charm of the engine.

While using finished cylinder assemblies helps, no twin is all that easy to build when you get to the crankshaft(s). The Hinds Twin is alternate firing, so the central "spool" has two inlet ports 180° apart with a deflector piece that is angled between them, sealing them from each other and providing the alternating induction from the single venturi. This results in two bangs per rev and Les says it does not just howl, it positively SHRIEKS!

Now read between the lines. Les' Hornet B exhibits all the skill and hallmarks of his Hornet C. They sure don't look like they were build 22 years apart. Next, look at all Les has produced in a mere 22 years! This page is by no means exhaustive; it omits all his multy-cylinder engines, including the pair of Furgerson boxers, an Elf Goose-Egg, a deHavilland Gypsy 1 and a Hodgson 9 cylinder radial!!

Impossible to see from the outside is the change Les made to the crankshaft. As shown on the plans, the Sugden featured a dual diameter journal, running partially bronze bushed, and partially unbushed in the case material. Les' shaft is a constant diameter, running unbushed in the case. Some simple re-design provided the same inlet timing as the "standard" Sugden. This sort of modification will make purists shudder, and pragmatists nod in appreciation.

Obviously the engine itself does not care, as it runs just fine. Incidentally, the case is a sand casting from Canadian Motor Boy, Andrew Coholic.

This is the only split pattern I ever made because sometimes the mating pins are effected by the moisture in the sand and you don't need any pattern that is reluctant to come apart at this stage for fear of destroying the mould, therefore my preference is the solid pattern with plenty of draft.

This engine should be familiar to all regular MEN readers, although the eagle-eyed will spot some differences from the "classic" version (as described in John Brown's excellent book, Dan Calkin And His Elfs). Here's how Les describes his rendition:

As expected, the engine bears Les' "trademark signature" finish, but take special note of the spark plug. This is shop made with a brass base that gives a beautiful contrast of metals. The insulator was turned from "Corian", a synthetic ceramic-like material that has been popular for kitchen tops (bad pun). It machines easily making it well suited to this function, although I've heard that it pits rather quickly with prolonged, hard running.

As Les says, with the bullet shaped spinner and tank, it's hard to tell if the engine is comming, or going!

This is a Cave Cobra, a .60 cuin sparkie from the glory days of tether car racing. More details below in the section that shows the Cobra side by side with...

...Les' Dooling .61 replica. Even without the name on the side, who could mistake the bypass bulge on this engine. More details below.

Both the Dooling 61 and the Cave Cobra share an era and a purpose: to drive tether cars around a track at speeds the eye has difficulty tracking.

Les reports that the Cobra was made from a casting kit that is still available from Art Dekalb (see the Suppliers page). The trombone venturi was turned from a lump of beryllium copper, which Les says was "very tenacious to machine but well worth the end result".

The 7-fin Dooling .61 replica was made from castings obtained from Denny Hitson—I don't know if these are still available or not.

Dropping in size a little, and not actually an internal combustion engine—or any kind of combustion for that matter—is this replica of an "expansion" engine of 1928 designed by Edward Pachasa, who was better known as Edward Packard of the Cleveland Model & Supply Company.

The original plan appeared in American Modelmaker. For a time, Roger Schroeder of Classic Model Engines was able to offer kits and plans for the engine, and Les' example id from one of those kits. The plan, and the history behind it was serialized in Roger's regular "Engin-uity" column, beginning in the March-April 1969 issue of the Engine Collectors Journal. Compressed air engines like this were the only alternate to elastic power for model aircraft during the first quarter of the last century. While the air tanks were quite bulky, they and the engines were light and produced a truly remarkable amount of power—though like rubber, they tended to produce a burst of power that tapered to near useless towards the end of the run.

The Etha, while less well known than the Dyno, is generally accepted as being the first commercial compression ignition engine to appear on the market.

A copy of the design drawings found their way to erstwhile SIC editor/publisher, Robert Washburn, way back before he launched his magazine. At the time, Bob was writing for Home Shop Machinist. The full plans and his very detailed article on building the engine (and jigs to assist this task) were published there. Ultimately, it was the lack of editorial interest in IC engines in general at Village Press that led him to found SIC. Robert says 42 sets of castings went out after the build article appeared in HSM.

As far as is known, apart from the ones Robert himself built, only two have been completed: Les' example seen here, and another by Ron Colona.

This is a 1/4 scale Anzani three cylinder, "Y" radial—as distinct from the Anzani three cylinder, "Fan" engine. With this engine, Les completes his renditions of the "collected works", as it were, of the late Les Chenery. The design is especially noteworthy for the way Anzani tackled the perennial problem posed the Big End of radial engines. The most common solution is the "master/slave" rod design. While the position error for the pistons connected to the slaves can be compensated for, the most correct (and complex) solution is to use "slipper" big end segments, concentric with the crankpin. Les comments that successful completion of this mechanism was one of the high points in building the engine. An even more complicated slipper Big End, comprising two concentric tracks, was used on the Le Rhone nine cylinder rotary, as detailed in Aviation Engines, by Pagé.

Back to Les' engine. The drawings (dated December, 1992) and castings had been sitting around the house for 16 years, so Les decided it was finally time to make a start. On one of the trips to England made by Les and his wife, they had the opportunity to spend a day with Les Chenery and his wife Alice. This made a lasting impression which has finally resulted in the construction of all six of the plan sets designed and drawn by Les Chenery. Later, Les and his wife received a letter from Alice Chenery in which she described her husband's fascination with the real, full-size three cylinder Anzani Y type Aero Engine that is mounted in the nose of the Depperdussin which forms part of the Shuttleworth Collection. This was his inspiration to design and build the 1/4 scale model. Les Chenery was allowed to take any measurements that were required, so it is fitting that some of his models were donated to the Shuttleworth collection.

Les' attention to detail is most clearly evident in the bottom four photos which show the engine fully completed, and running. Take special note of the oil tank with domed brass ends, and filler cap, which feeds a manifold that supports an oil pressure gauge. Behind the engine, on the baseplate (a work of art by itself), is a device which reminds me of an old glue-pot (the horsed hoof glue variety), except no glue-pot was ever that shiny. It is complete with a rather maritime cap lock. The device at the rear of the baseplate is an extension to the carburetor fuel regulator.

As he does on all engines, Les takes care to use metals and other materials which provide color contrasts. For example, the red distributor cap, and the oil tank mentioned earlier. Have a close look at the other engines on this page for more examples of this attention to eye catching detail.

And finally, showing this is no mere show pony, we see the Anzani doing what it was always intended to do, run!

Like many other model engineers, Les has built the Westbury Atom Minor Mk III, from the Atom Minor book. His castings were obtained in the US about 1997 from Fred Ellis' Power Model Supply (not to be confused with Coles' Power Models). Fred Ellis died in a firework explosion and fire at his shop circa 2000, so that source is no longer available. Although it is possible that Ellis had his own patterns, his catalog lists a number of other ETW casting sets, all of which were available from Woking Precision (UK), so Fred may have been their US agent. Woking changed ownership in 2003, but chucked it in 2006. However, the Woking's patterns and stuff were bought up by Hemingway Kits (UK) who plan to improve the quality as time and demand dictates. There is nothing basically wrong with the Woking castings, although registration of the bosses on crankcase and covers is a bit coincidental. That just means more care, attention, and experience are required to achieve the results obtained by Les, and Jan Huning.

In fact it was in response to Jan's report that that crankcase ran hot that Les decided to fire up his Atom and check the 'case temperature. Les reports that after a good run, he put a finger on the case, but it did not stay there long! The question remains, why? For the test, Les used Coleman's Lantern Fuel, mixed 3:1 with #70 weight oil. This is a petroleum naphtha product, historically known as "white gas", which is exactly what was traditionally used for sparkies in the old days, with a high combustion temperature and no additives, like tetra-ethyl lead. As we see here, Les' Atom Minor seems to like the stuff, just fine.