P-47 Canopy and Grumman Goose Nacelle
The P-47 project has now incorporated the Canopy Basic Layout. This Basic Layout represents the surface derived from the table of ordinates, with dimensions that reflect the mold lines at the inner face of the skin. An allowance of 1/32″ is required to accurately represent the actual surface of the canopy glass. All ordinate points are provided in an Excel spreadsheet, as is customary.
Once the best-fit surface is determined, it undergoes a curvature analysis to check for low and high spots. The next part of the process is checking the alignment with the fuselage’s basic layout surface. The Table of ordinates includes the Waterline level for the tangency intersection point between the canopy surface and fuselage at each station. The dashed lines along the lower level of the canopy profiles represent this waterline.
Each tangent point in turn is then checked against the fuselage’s basic layout surface. As expected, there is some minor deviation which is less than 0.3mm which is within acceptable parameters. Of course, with CAD it is technically possible to get this absolutely exact (see next blog article for solution). The primary reason for doing this check in the first place is to ensure we don’t have any rogue ordinates that could create problems later on.
A similar exercise will be undertaken for the forward canopy section and windshield. When we have a satisfactory basic layout surface for each section of the canopy I will endeavor to profile the glass panels and supporting structural elements.
P-47 Cross Tie Wing Hinge/Engine Mount:
This is the preliminary arrangement for the Cross Tie that supports the Wing Hinge and Engine Mounts. A small point worth noting is that the actual vertical dimension to the Wing Hinge Centre is 24.378in, and the dimension to the lower datum point for the Engine mount is 24.375in. A small variation, almost imperceptible but nevertheless important. This is the reason why the matching holes from the Lower Engine Mount are to be match-drilled through the Cross Tie and not pre-drilled in the Cross Tie. Once I have established the final location for the wing I will cross-check the hinge locations to verify setting out dimensions.
Grumman Goose Update:
The Grumman Goose is already available as an Ordinate package (See CAD/Blueprints page) which though comprehensive excluded the Nacelle. While I await some information on the P-47 I jumped back into the Grumman Goose project to partially develop the Nacelle and general tidy up of the package as a whole.
The Grumman Goose is not my primary project but as I find time I will drift back to the project to apply updates. I will also do several analysis exercises on the fuselage and wing surfaces to check curvature and alignments. This will be an ongoing project over the next few months. If you have previously purchased the currently available Ordinate package for this aircraft I will send you the updates when they are complete.
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