by: Stephen T. Lawson [ ]
Originally published on:
An overhead camshaft (OHC) engine of 1914-1918 (also informally called pushrod engine) is a type of piston engine that places the camshaft running above the cylinder heads (with the the crankshaft in the block below), and uses lifters to actuate rocker arms above the cylinder heads that in turn actuate the valves. The lifters or tappets are located in the above the engine camshaft that runs above the tops of the cylinders. The Mercedes D.IVa was an six cylinder, liquid-cooled inline aircraft engine built by Daimler Motoren Gesellschaft (DMG). The D.IVa replaced the failed Mercedes D.IV inline eight cylinder engine. The D.IVa was primarily used to power bombers and large reconnaissance aircraft. Its design was relatively advanced, including four valves per cylinder powered by an overhead cam, also used on the earlier two-valve per cylinder D.I through D.IIIa series powerplants.
Designed specifically to be installed within a gondola or fuselage, the engine featured a number of design elements intended to reduce its width. For instance, the carburetor was placed behind the engine, feeding fuel to the cylinders via a long pipe. This had the disadvantage of poor fuel distribution. Two versions of the engine were produced in mirror copies, running in opposite directions.
Taurus Models makes high quality details its forte. Now they spring into action with a set of rocker valve lifters / tappets and springs and over head camshaft for the 1:32 Mercedes D.IVa motors in today's popular kits. As of this writing its available in the "Easy to build version".
#D3206 an "easy to build" option with the rocker box tops moulded on the over head camshaft. There are six blocks of resin with 53 items packaged in a Ziplock bag. 3 block of springs, 2 of rocker arms, the overhead camshaft with rocker boxes moulded to it. There are enough parts to do one motor with some extras included. It has a simple easy to read instruction sheet showing what needs to be removed from the main kit and locations for the replacement resin pieces.
This set is an ideal set to detail any kit that uses the Mercedes D.IVa powerplant. In the WNW range this includes:
Gotha G.IV #32005 (Needs 2 sets if detailing both motors.)
Rumpler C.IV #32023 early version.
Rumpler C.IV #32037 late version.
The builder might have to experiment with the applications. It seems the best method is to add the Over Head Cam first then the springs loaded and unloaded according to the provided diagram. Then use gel cyano to add the rocker arms.
Here is something for "larger scale" modellers containing timing gear, lifters & springs in 32 scale. A very simple product and very useful. WNW models don't have detailed items like this in their kits. Note the images of the actual engine are from the Taurus Models website.
Please remember, when contacting retailers or manufacturers, to mention that you saw their products highlighted here - on AEROSCALE.
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