North American P-51 Mustang: Air Scoop

North American P-51 Mustang: Air Scoop

Working with ordinates from these archive drawings can be a very time intensive operation. To give some idea of the content of this work I have just started working through the vast amounts of ordinate data for the Air Scoop and Oil Cooler.

2015-06-04_12-23-12 This is a scrap view of the original NAA drawings showing the main ordinates for the Air Scoop.

This drawing shows 2 tables, one of which is the listing for the external contours and the other the internal contours.

The external ordinates comprises a total of 664 points and the internal ordinates comprise a total of 928 ordinate points.

Each point is manually entered into a spreadsheet which lists the Inch dimensions and then converted to Millimeter dimensions.  The data has 3 values for the Station location, the Waterline (value along a horizontal axis relative to the ship ctr line at set intervals) and the Buttock line (value along a vertical axis relative to Frame Ref Line ).

2015-06-04_10-19-41       2015-06-04_10-17-50

These values are then processed using the concatenate function in Excel to extrapolate the required X,Y,Z coordinates.

The points are then grouped and imported into Autocad to derive a point cloud.

2015-06-04_16-57-59 2015-06-04_11-04-09

The first screenshot is all points combined with the local fuselage contours shown for reference; the second screenshot is the internal point cloud. All these points would then be contoured in Autocad to determine suspect locations and any orphaned points.

The external point cloud had 6 points prominently out of sync with everything else which turned out to be an error in the original data set. This is not uncommon and is usually quickly resolved.

Once I have an initial dataset that satisfies these primary requirements I would then import this data into Inventor or Solidworks for evaluation as a surface in each case.

At this stage I have spent about 3 days on the data preparation and would expect to spend at least a week to properly evaluate the surface definitions.

It can be very satisfying work when you see for the first time all these data points translated into something tangible as a 3D model depicting the end product first realized all those decades ago.

Update: Decided to pull out all the stops and complete the datasets and point clouds for this area:

2015-06-05_01-50-15        2015-06-05_17-11-51


About Hugh

BIM & Cad Manager/Strategist, 3D/4D, multi-discipline cad workflows, integration. Interests include photography and historical aviation.
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