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Monday, October 25, 2010

Irvine 20 ABC Diesel and Dykes Ringed Glow Versions


Click the link Below to Browse the Diesel Book


Irvine 20 ABC Diesel 

Circa  1987







Design History:-
Designed and manufactured as a dieselized version of a nitro glow engine in England in the mid 1980's




Design Features:-
Front through the shaft induction; ABC piston/cylinder technology; advanced design carburetor and bolt on muffler without pressurization tap.


Specifications:-
Displacement 2.5 cc

Observations:-

"This is the latest and, perhaps, the most significant example of the diesel-ization of an existing glow plug engine, in that it was initiated and developed by the engine's manufacturer. Ever since they began producing their own motors in 1977, Irvine Engines have specialized in glow engines (the sole departure being their production of the Mills 75 replica) and the fact that Ron Irvine decided to press ahead with the production of this diesel version of the well-liked and very successful Irvine 20 series, obviously indicates considerable faith in its capabilities.
The Irvine 20 has not been extensively redesigned for diesel operation. It has a new crankshaft; otherwise, dieselization is confined to the cylinder head assembly, plus small modifications to the carburettor and silencer".

After describing the reduced-choke carburetor, the author continues....

"The reason for having this much reduced choke area is to enable the engine to be operated without the assistance of an exhaust pressurised fuel system, which is the reason why the diesel version of the silencer has the usual pressure nipple replaced by a screw-in plug.
Why no exhaust pressure feed ? Simple! Exhaust gases condense to form a certain amount of H2O when they come into contact with the cool fuel in the tank. A little water in the fuel does not matter in a glow engine; it is miscible with methanol-based fuel and a small amount can be tolerated...Diesel fuel, on the other hand, is petroleum based (usually kerosene, occasionally DERV). Ergo, the water remains separated and, having a higher specific gravity than that of the fuel, settles in the bottom of the tank, where it may be sucked up by the clunk weight. Not even diesels like running on water. Result: malfunction of one kind or another...".

The author was Peter G.F. Chinn.


Although it is generally regarded as a fine engine it is not my favorite by far. Looking for a practical RC Diesel to power a Kitty-Wake sport float plane, I settled upon the Irvine 20 ABC diesel to do the job. After a short ground run I made a very bad decision and decided to opt for a first flight. As I recall the flight did not last very long, nor did the poor Kitty Wake. The Irvine suddenly quit and I was faced with the worst of all situations for an RC flyer; a down wind dead-stick landing on a new model. Needless to say the landing didn't go well, ripping away the floats on impact.


 Irvine 20 Glow Engine

That Irvine it's self never ran again. All attempts to start it proved unsuccessful and the reason was obvious. There was almost no compression, the once tight engine had gone from lots of compression to none in the matter of a few short minutes (unbelievable!). The engine was thrown into a corner and forgotten for a number of years, until one day I got around to disassembling it for a close examination. What I found was the engine had eaten it's self. The piston and sleeve were severely scored, with deep vertical groves running full length in each. All attempts to find replacement parts (matching piston and sleeve) proved to be impossible so, I thought if I could find a used Irvine 20 engine for parts that would be the answer (not!). The other used Irvine 20's that I managed to find were ringed engines, with marginal compression and I knew from the beginning that they would never start as a diesel.


Watch the video below showing my attempts to start and run these engines.





MAKE YOUR OWN MODEL DIESEL FUEL- 
Browse book at;
http://www.amazon.com/dp/B00CIVP03Q

Browse below to see how an Irvine 20 Diesel can be rebuilt
Buy your own copy Here

Wednesday, October 20, 2010

Mk XIII Wen Mac 049



The Mk XIII Wen Mac 049 was designed and manufactured in The United States in the mid 1950's by Atwood. The same talented engine designer who created other great engines such as the Cox Tee Dee and Medallion series. The Mk III was introduced in 1959 and featured a wind-up recoil starter.

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WEN MAC MARK XIII
Motorenart:Glühzündung
Kraftstoff:Methanol/Öl
Taktklasse:2T
Daten
Zylinderzahl:1
Hubraum:0,817 cm³
Bohrung:10,67 mm
Hub:9,14 mm
Gewicht & Abmessungen
Sonstige Angaben
Modelljahr1964
Hersteller
Wen Mac Corp., Culver City, California, USA
Vertrieb
Wen Mac Corp., Culver City, California, USA


Observations:-
The engine was marketed under various brand names over the years including McCoy. It was almost exclusively produced for a line of ready to fly plastic control line model airplanes. The engine was produced to very high quality and machine tolerances.

Engines were picked at random, for a quality control check. Part of the quality check included running several engines for 8 hours a day for as long as 30 days. Piston tolerances were 15 millionths of inch for size, roundness and taper

The engine is now qualified for use in the old time 1/2A Nostalgia FF flying events consequently, the good ones are getting harder and harder to find.

The engine featured in the video clip is not mine, but I have owned a couple in the past; which were mounted as outboard engines on a Ju 52. During the early 1960's these engines were so numerous that American Hobby Center in New York City, was selling them for the fabulously low price of $5.95.

The glow heads were prone to burn out and replacements were always hard to find. People learned to pull  the steel contact out and drill and tap the old head for a 1/4 - 32 short glow plug which worked fine. These little engines will really turn up the revs when run on high nitro (to 30%), but you will see in the video clip that they do quite well on 5% fuel.

Click the object below for a demonstration video on starting and running the little Wen Mac.



Special thanks to EBay Seller Dadretreadand RC Network (Germany) for material shown in this page.