Using CAD to Sanity Check Legacy Aircraft Plans

For those of us working from plans created long ago for airplane designs that are less common, having the ability to detect inaccuracies is very important.
While still a newbie with SOLIDWORKS, I was able to quickly sketch up the next part that I'll be working on. Sure enough, some critical dimensional inaccuracies were caught. Drilling wayward holes in my spruce spars would have been very expensive.

I'll attach a couple of screen shots via links.

Original Plans:
http://zoemertech.com/ad/discrepanci...tt_Fitting.png

SOLIDWORKS:
http://zoemertech.com/ad/discrepanci...ment_holes.png

Even with CAD drawings you can have problems. Back in the 90s the company I was working for contracted with a local firm for extra drafting help. I made some dimensional changes (red pen) & when the drawings came back I was having difficulties with things not lining up. I discovered the draftsman (who had been using ink on paper for years before learning Autocad) had manually changed the dimensions without changing the actual drawing. To this date if I run across a drawing with the initials "DOG" in the revisions I don't trust it.

Several years ago I put most of the drawings for the Long EZ into Autocad since I was planning on making some changes. I don't recall finding any discrepancies.

Quote:

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Originally Posted by Mike Switzer

Even with CAD drawings you can have problems. Back in the 90s the company I was working for contracted with a local firm for extra drafting help. I made some dimensional changes (red pen) & when the drawings came back I was having difficulties with things not lining up. I discovered the draftsman (who had been using ink on paper for years before learning Autocad) had manually changed the dimensions without changing the actual drawing. To this date if I run across a drawing with the initials "DOG" in the revisions I don't trust it.

Several years ago I put most of the drawings for the Long EZ into Autocad since I was planning on making some changes. I don't recall finding any discrepancies.

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Yes indeed, in the case of both hand-drawn and CAD, it's error-in, error-out. For critical parts of the airplane, a careful scan and double check of dimensions is essential. CAD systems make doing a quick ad-hoc measurement trivial.