Unpacking Day!
Wright Whirlwind Radial Engine 5 Bears Home

13 Dec 2004: Continuing with the unpacking of the Whirlwind castings, which arrived from Sweden.

The remainder of the pictures (besides the gears) consists of major crankcase section castings. The Hodgson crankcase was divided into three sections. In this engine, there are no less than 4 sections plus covers.

I'm pretty sure these too are die castings.

We start with the front crank case. On the reverse of this casting (interior) is an asymetrical webbing, one portion of which will contain the oil tank. The engine uses a drip oil system, unlike the Hodgson, which is a dry-sump, full pressure and scavenge system. Both have their advantages. In the case of the Wright, simplicity is the prime advantage.

The major section is called, simply enough, the crankcase. Here, the cylinders mate with the engine.

Each of these major sections has a nice finish. I'm already thinking ahead a bit and am imagining that these can be finished on the exterior with some type of bead-blasting, resulting in a finish similar to that of the heads and rocker boxes.

The blower housing, a complex casting. The round bosses are a portion of the intake system, whereby the fuel-air mixture is ejected from within the housing, making its way into the cylinder heads.

Of all the castings, this one had the most flash and the greatest discoloration.

Probably the most impressive cast piece is the planetary gear housing. The square boss at 2:00 in the photo accepts the carburettor. This casting mates with the blower housing. With the impellor installed, these two parts combine to form the bulk of the induction system.
I struggled a bit with the decision to buy the gears, as they are fairly expensive for the set. In retrospect, I am glad that I did. There are quite a few, and, of course, they are of metric form and diameters. If I attempted to substitute Imperial gears, the change would result in a horrible cascade of pitch diameters and tooth count. Since the diameters would necessarily change, the gear center location within the engine would likewise have to be adjusted. Finally, the gears exhibit quite a bit of machining to correct form, including the very nice addition of lightening holes in a number of them.

This set (I am guessing) is for the front of the engine, creating an 8:1 contra-reduction to drive the cams...

...while this set is probably for the rear.
This smallest set, with a different DP, is for the distributor 2:1 reduction

Some of the gears were stained slightly with rust which is not deep and will clean easily with a wire brush.

Time to get to work!

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