Model Engines of Unknown Origin
Page 3

Last update: Nov 30, 2005
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A Big Scary Watzit

This is a very nice looking item. It's a two blade prop with a diameter of 20", featuring adjustable pitch and replaceable blades. We can't see how those blades are retained. Presumably some sort of recess is involved, but given the way the grain would run inboard of that groove, I really would not like to be around when it's turning at speed, especially to the side of it!

Intially, it had the Motor Boys stumped. Let's cover what it's not. It's not an English "Elmic"--much too large and too contemporary looking. It's not a Johnson "Auto-pitch"--again too large and the Johnson used centrifugal force to reduce blade pitch at low rpm; a way of decreasing thrust when reliable idle speeds were higher than they are today. And it's not a Tatone; again it's too large. I seemed to recall ads for something like this from relatively contemporary times. Also, the size is a bit of a give-away as you'd need something like a chainsaw to spin it (and just when did converted weed-eaters become popular power-plants?) Finally Tim Dannels came up with the answer:
Click here for the answer.

German 10cc Sleeve-valve

These photos came from Dietmar Kolb in Germany. He has no information on the engine and reports that it has a 25mm stroke with a 20mm bore for a capacity of around 10cc (9.8 actually). The carburettor is missing and he has been told that it is a pre-WW I "Drone" engine. Have a close look at the photos before reading my observations below--remember I could be completely wrong (it has happened once before ).

First off, it's obviously a sleeve valve design, but then the heading gave that away, didn't it? Next, the cam that actuates timer points seem to be attached to the crankshaft, so the plug will fire on every stroke, but the gears that drive the sleeve valve appear to be the expected 2:1 for standard four-stroke operation. No harm done firing the plug during exhaust, but no point either (sorry for the pun).

The angled screws on the conrod big-end are unusual too. They would increase the volume occupied by the rotating rod over what it would have been had they been vertical. There would appear to be plenty of room in the case, so one wonders why?

There are two rings on the piston and possibly one on the "junk" head. We can't see if there is a sleeve ring in the cylinder. The spark plug looks to be a commercial item and relative to the bore, would appear to be a miniature one--possibly 10mm. As far as I know, sleeve valves did not appear until shortly after WW I (with a lot of early experiments being done by Harry Ricardo in the early 1920's), and commercial miniature spark plugs were later again--say the mid 30's. Finally, the point assembly looks distinctly modern automotive. All of which strongly argues to me that the "pre-WW I drone" conjecture is highly unlikely.

The engine appears to be very nicely made. The mounting indicates a "stationary" application, or more likely, that this was an experimental engine. Also note that the lack of any thread on the shaft indicating that some collet system was probably used to retain a flywheel (common practice with model boats allowing it to slip if the engine stopped suddenly due to a dunking, thus preventing damage). There is no indication visible of where the carburettor attaches, but it would have to be somewhere on the ring around the middle of the cylinder which must double as the inlet and exhaust manifold somehow. If anyone has information about this engine, we'd appreciate hearing from you--and so would Dietmar!

Unfinished Hungarian Watzit

Another one from Bert Streigler (he's just floating in Watzits!):

This came my way from Jim Dunkin and he got it along with a collection of hungarian diesels, so it was assumed to be a Hungarian engine. It is unusual in many ways in that it is a .46 cu. In. displacement with a fairly square bore and stroke, but the rod is very long and the cylinder is much taller than it needed to be. The bypass cover stands about .030 proud of the rest of the cylinder, which was laboriously (and beautifully) all milled away to allow this to be, all with a mill about 1/8" in diameter!

The head appears to have been a die casting that was cleaned up on all surfaces. I am guessing from it's shape that it was off of a Feldgibel (sp?) engine of German origin, but cannot be sure. The massive 8mm crankshaft is threaded 0.5mm! (yes, 0.5mm!). All the machine work is first class, right down to the cast magnesium crankcase - not a task for the faint-hearted. It is entirely possible that this was German rather than Hungarian, but I just do not know. It was never quite finished as the timer is incomplete. It would have been nearly impossible to mount the thing with the way the mounts were made and the holes were placed. Maybe someone out there knows what this thing was?

YAMS (Yet Another Mystery Sparkie)

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These photos were sent to
Engine Collectors' Journal editor, Mr Tim Dannels. It is a mystery to all of us, probably indicating that is is the product of a talented homebuilder from long ago--but we are not sure. The case is split vertically and the feature that has lept out at us is the excellent registration of the unusual rib around the join line. The quality of the case castings is very high as evidenced by the surface cleanliness and how well defined the fiddly bits like the screw bosses on the rear are. Some light "pimpling" indicates sand casting.

The Cylinder (apparently a blind bore; not having handled it, we can't really say) is nicely made and brazed, but the soft solder work on the spraybar and choke shutter are of a different, significantly lower class. This may indicate later repairs by a different individual.

Mounting would be tricky as the case screws would appear to be meant to act as studs, but are rather short--and the bosses for the rear cylinder hold-down screws are rather in the way too. My guess is that the builder most likely intended to use Calkin Elf-style steel frames.

That's all we have to go on. No dimensions; my guess would be in the .60 range for displacement (made popular by the Browns). If anyone has seen something like this before, Model Engine News would love to hear about it.

Who Made This RTF?

This shot came from Ken Croft in England and has us all totally stumped. Here's Ken's story:

Mike Beach bought a strange old model at Old Warden a couple of weeks ago. It is apparently about 5ft span and Mike says it was originally a control line model, but someone has attempted to put radio in it. It is very old, and Mike says that all the components have inspectors numbers and stamps, and for this reason he believes it was built either for, or by, the military, for an unknown purpose. He says the model was made by Bunch [of motors fame], although how he knows this I have no idea. It has no engine, so he has been through his extensive collection to see what might fit. The only engine that fits, and fits exactly, is the Bunch Tiger Aero, and perhaps this is the reason he thinks it was Bunch built.

That's not a lot of real info to go on. I know that R/C drones were made in the US during WWII for gunnery practice, but this is not one of them (they were large and surprisingly sophisticated). And there's a big difference between R/C and C/L! The idea of standing in the middle of the circle while a bunch of recruits take pot-shots at the model does not bear thinking about. Next mystery is the RAF-like fin flash and roundel on the wing, plus an RAAF-like serial number on the fuselage. Bunch is American! But the wheels look like Trixler balloon inflatables which would be correct for the period. If anyone can shed any light on the model we'd be most appreciative.

An Embryonic Opposed Twin

This one has us all perplexed. The American owner of the castings acquired them, and five others just like them, with his lathe. The previous owner was going into a retirement home and through the passage of time, is no longer contactable to find out the origin of the design. Worse, the current owner has castings to burn, as it were, and he might as well as there are no plans of any kind with the castings! But figuring the engines are certainly buildable, he's willing to offer a set of castings to anyone who is able to provide plans--assuming they are part of a larger population of such engines and not a one-off, back-yard foundry job. Before we dissect the design from the scant evidence, look over the following pictures:

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There you have it. My guess is that is was a home design and no plans exist, 'though for the owner's sake, I hope not. If by any strange chance you can shed some light on this design, we'd all be most grateful, and if you can provide plans, there's a casting set in it for you. Send suggestions to me at this web site.

A Tough One

Here's a tough one for you to ID. At first glance, it may appear to be a one-off flat twin, nicely engineered and built by some talented model engineer of the spark era. There are no identifying marks on the engine, but it was acquired by the current owner with another engine, single cylinder, but somewhat similar in appearance bearing two sets of letters, "GAN" and "FAN" arranged to

intersect like a crossword puzzle on the "A". The GAN is horizontal and the FAN, vertical. That may be enough to give you the probable genesis of the twin. We can see that it's water-cooled, quite large, and we have good reason th suspect it may have been intended for marine work.

A Good Little Socialist Diesel

This nicely made little diesel (2.5 cc capacity) we believe to be possibly of East German origin. Bert thinks it may be an Elgin, but he is not at all sure. Another suggestion was that it may be an Alag, but all of those that I've seen have a bakerlite or similar early composite material backplate. In some ways it's like a Yin-Yan (check the similarities around the cylinder liner exhaust ports, venturi insert, prop driver, comp screw and general crankcase design), but the Chinese were good at engraving their dies and this one is clean, so we didn't think it's one of those either. Then Bert put it side by side with his Yin-Yan and as he said, the plot thickened:

Now the plot thickens on the ID of the blue-head "socialist diesel". Both engines have a 15mm bore and both cases have the same deck height. My original Chinese Yin-Yan on the right has much superior crankcase castings, thinner cylinder and slightly different exhaust port flanges. The crankcase backplate on mine is recessed .400, while the blue engine is recessed .480. The cylinder muffs are not interchangeable because of the thread diameter on the thicker cylinder of the blue engine. I know the Yin-Yan and the Alag were made from the same drawings, but with minor styling changes, and a version was made in Germany by Engel, again with styling changes.

Comparison of the two might not be fair simply because my Yin-Yan was one of the first (if not THE first) to ever hit these shores. A friend in Military Intelligence got it in Hong Kong for me on one of his diplomatic trips and was told they were something very new. The instructions with it were in sorta-English, and state that "This is engine we have made for you and is the engine you will use." I suspect that was directed at the locals over there. It hardly fits the western style of free choice. Serial on my engine is 0244. This engine is superbly made inside and out and has a fully machined alloy rod. The cylinder is turned to a very high external finish and internal fits are perfect. The blue engine is also well made. It has a serial number of 1O59 (that is an O, not a zero)on the underside of one lug, and 79 under the other lug. The rod in this one is a square section rod, also machined from the solid, but roughly finished. The quality of the casting is not nearly so good in appearance. The bearing webs are much thicker and there is only a rudimentary web on the intake. The bottom of the case is about .080 longer, which explains the .080 deeper backplate. None of this precludes it from being a later model of the Yin-Yan.

So, there you have it. The blue engine is definitely taken from the "socialist diesel" design, but the question remains, "who made it?"

Still with us? This mystery has been with us for several days now and you are reading a blow-by-blow, edited description. The next link towards positive identification comes from Jim Duncan:

Hi all. I have been digging in my stuff and found a little more about the mystery engine. In spite of it's similarity, I don't think it is a Silver Swallow, Yin-Yan or whatever. I think the name of it is "T.Y.C." whatever that stands for. I have found out that it was made in Chongqing, China. My example was made in 1984 and has serial #1084. I suspect that, while it might be a different factory, there must be some connection with other mfg's. There was a certificate for the engine issued by the Three Leaves company. The Three Leaves (S.Y.) company is located in Shen Zhen City, China. The Yin-Yan's were all made in Shanghai.

I have attached copies of some paperwork from the TYC (including the "certificate", the box top for the TYC and paperwork for the SY engines. I have sent a photo to Mr. Gao Guo Jun of CS engines to see if he can help with information. He took over the Yin-Yan line of engines after they folded. I will also show the paperwork to my daughter-in-law (who is Taiwanese) and our son who speaks Mandarin Chinese and can probably read some. I will see if any of it is useful information. More as I find it out.