|foam being fitted|
All of the supporting structure and the eventual sanded foam blocks are designed to slip off the front of the engine after they are shaped and a layer of glass is added. The surfacing of the cowl will be done while it is attached. This will all be later removed and plaster splashes will be taken of the plug master. the cowling will be split horizontally through the center line of the prop hub. In addition to the actual cowling, there will also be two "cheek" cowls added after the finishing operation.
Blocks of foam are fitted to the templates. Care is taken to ensure the internal foam is cut out to clear the engine when the plug is removed.
|upper foam in place|
All of the foam for the upper half is in place. if you have any gaps, stuff wedges of the foam to fill these voids.
|initial shaping begins|
|Vertical template sanded to the edge|
|initial shaping of the foam|
After the templates are sanded to the edges, you can start to carve away the foam in between them. Use a saw or a butchers knife for this. Do not over cut, be very generous at this stage. Once the foam is trimmed, the real magic of this process happens. Scrap foam blocks are used to sand the foam. Both materials will equally abrade each other and transfer the contour back and forth. This creates a spherical interface and it is the same principal that Telescope hobbyists use to grind their lenses, they use glass to grind the glass.
Here is the final outcome of the foam shaping. This is a beautiful wave and dimple free surface the cleanly blends between the firewall and the spinner. The "P-51" look of the nose is now evident.
Next is the bottom surface. That will be the next blog entry