Retrotech: Lofting and Machining Components for the T-38 Supersonic Trainer, 1958


A participant writes about the early days of numerical control machining and also discusses how definition of complex aircraft shapes was done prior to the computing era.  Imagine the labor intensiveness of that process, which descended from traditional shipbuilding techniques but surely required a much higher degree of precision when applied to aircraft production.

A Bendix G-15 computer was used for the NC work described at Northrop, with paper punched tape as the communications medium between the computer and the machine tool.  There is a Bendix G-15 at the American Precision Museum in Vermont, along with many machine tools and other interesting exhibits–see my post here.  Recommended visit for those interested in the history of technology.

Retrotech Event

The New England Wireless & Steam Museum is having its annual steam-up on Saturday, October 7.  I’m hoping to make it this year, which I haven’t managed to do previously.

Related posts:

Machine tools and glassmaking – visiting the American Precision Museum and the Simon Pearce glassmaking facility.

A retrotech adventure – the Essex Steam Train and Riverboat.

Retrotech, revitalized – a triple-expansion steam engine, built for municipal water pumping, has been restored to operating condition.

Retrotech event, west coast edition – Bill Brandt visits a lumber mill from 1914.

Retrotech: Making a Tunic, 1700 Years Ago

The tunic was found in the Norwegian mountains.  Textile historians recreated it using the technologies current when it was made–pulling the wool naturally rather than shearing, spinning it into thread (with no spinning wheel), and weaving it into cloth. The labor required was estimated by having skilled people do a sample amount of each task required and extrapolating to the complete garment.

Total labor requirement was 780 hours.  The linked post estimates the cost at almost $38000, apparently assuming Norwegian labor rates.

I don’t think anyone would produce such garments using such expensive labor, though (unless it was for some very affluent niche market) but would use cheaper Asian or South American or even American labor.  Maybe a reasonable number including overhead and supervision would be something like $5/hour. Which still gives a cost of $3800.

And if someone made it for their own use, or that of someone in their family, that 780 hours would represent a pretty large piece of their work capacity for the entire year.

As Paul Graham noted, clothing was very expensive right up to the Industrial Revolution.