Trojan Junior (oz13705)


Trojan Junior (oz13705) 1938 - plan thumbnail

About this Plan

1938 Trojan Junior. Model aero engine.

CAD drawings by Ron Chernich. Article by Bert Streigler.

Quote: "The 1938 Trojan Jr by Bert Striegler.

Trojan engines were made by the Trojan Miniature Products Company of Hollywood, California. The manager of this company was Mr Hal M Atkins and his first production engines were sold beginning in 1937 with the introduction of the Trojan Jr. Very little has come to light on the history of this company or the number of engines that were produced. What is evident, though, is that the engine was a modern design for 1937 and included features that were quite advanced. This engine is not well known and is very rare.

The first Trojan Jr of 1937 had a cast iron cylinder with a brazed on bypass cover and intake mounting flange. The shrunk-on cylinder fins and head were made of one piece from aluminum alloy. The head was fitted with a 3/8" sparkplug and no head fins were used. Two exhaust ports were cut into the rear of the cylinder just above the intake mounting flange. The exposed part of the cylinder was painted bright red. A metal fuel tank was fitted below the intake tube and the needle valve used a friction fit to prevent rotation when the engine was running. Ignition points were exposed and the operating cam was a flat cut off of the rim of the propeller drive washer. The engine had a bore and stroke of 5/8", giving a displacement of .192 cubic inches. A really unique feature was the crankshaft main bearing, which consisted of two small roller bearings running directly on the hardened shaft A seal was used between the two bearings to prevent loss of crankcase compression. This is surely one of the first production engines to utilize antifriction bearings on the crankshaft.

By early 1938, a number of small changes had been made to the 1937 engine. The head now had fins and some of the engines were fitted with a 1/4" sparkplug. The early 1938 engines had a metal fuel tank, while later production engines of that year sported a new plastic tank.. The Motor Boys used an early 1938 version as the basis for the plan in this book and at least one running example has already been finished, and is pictured here [pic 004]..."

Direct submission to Outerzone.

Note this plan (and article) is an extract from the MBI (Motor Boys International) Model Engine Plan Book, 2nd Edition. This was originally published through the MEN site run by Ron Chernich, see Also see Mary's page on RCLibrary which hosts a copy of the book as submitted from MBI by Ken Croft, in accordance with Ron Chernich's wish that from 2013 onwards the book should be available, freely, to everyone as a PDF download.

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Trojan Junior (oz13705) 1938 - model pic

  • (oz13705)
    Trojan Junior
    3.14 cc
    Engine Spark
    clean :)
    complete :)
    got article :)
  • Submitted: 01/03/2022
    Filesize: 1293KB
    Format: • PDFbitmap
    Credit*: EdHolly
    Downloads: 447

Trojan Junior (oz13705) 1938 - pic 004.jpg

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