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Great video of building wooden propellers for early wind tunnels

richard newman

Titanium
Joined
Jul 28, 2006
Location
rochester, ny
Just discovered this video on a luthiers forum, pretty amazing! Making HUGE propellers for early wind tunnels, pre-NASA.

Construction of Wooden Propellers - Part 1 - YouTube

Part 1 is stock prep for laminating, nothing special, except a giant jointer

Part 2 has the most amazing glue up I've ever seen, with a synchronized clamping team, like the Olympics!

Part 3 has assembly of the multi blade fans, very cool!

I love these old videos, and often learn something useful, much better than arguing politics!
 
That was equal parts entertaining and fascinating to watch. Thanks for posting. I remember another you may have posted showing French(?) barrel makers and incredible hand skills prepping the wood staves and steel bands. Always fun to see the pre cnc problem solving techniques and skills on display.
 
Great post Richard.
I want that air powered rotary hand planer shaper tool!
I also wanted to see the fan powered up and blowing some air!
I counted over thirty men during the gluing operation, there was probably more than that.
 
Thanks for showing that. Really amazing work. Although not the most technical part, I thought “scrubbing the glue in” was particularly remarkable. I’ve spread, brushed and used my fingers and other tools to apply glue but never thought about scrubbing it in with a brush.
 
Glad you guys enjoyed that. The teamwork in the glue-up was really cool, I imagine they had many dry runs before they actually spread glue. I spend WAY TOO MUCH time watching this kind of stuff!

Here's an old film of hand forging chain in England, with a sequence of forging a huge anchor starting at 2:45. A bunch of blacksmiths are whaling away with big sledges on the white hot steel, really impressive teamwork. At about 7:15, there are 8 guys pounding on a shackle pin, wild!

Hand forging chains (1) - Blacksmithing - YouTube
 
Some thoughts on the propellor series:

One particular echelon of the glue-up team were (mostly) wearing hats or hairscarves, presumably because they were the ones that got dripped on.

The section depth cut technique is still useful today in non-CNC circumstances.

I liked the pneumatic "spokeskave" and "bench plane" used to rough out the areas between section contours, presumably both with rotary cutters. Interesting that they power roughed, hand finished to section cuts with conventional planes and cabinet scrapers, then power sanded.

The dual use scriber and boring bar bushing looks like a useful technique to remember, a key being that the rough hole doesn't remove the scriber line so it can be replaced later.

They were definitely serious about those props not getting loose: steel sleeves press fit in the wood prop butts, sleeves reamed in place mounted on the hub, and tight-fitting bolts driven into the sleeves. I wonder what the process of dismounting one of those props to reuse the hub was like.

This is the best filmed example I've seen of hand-boring (reaming in this case). If you go back in time far enough, man-powered (actually usually shop-boy powered) boring bars were a frequent thing for one-off jobs, leverage and time being substitutes for electric or water horsepower. However, given the number of bolts they had to fit, I'm really surprised NACA didn't make another pneumatically powered tool for the sleeve reaming.
 
A little fact about the Wright Brothers. The wooden propeller that they designed was measured to be 81% efficient.
Modern day propellers are 84% Amazing that they got so close.
 








 
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