Reminds me of the Gaea trilogy - John Varley.
Peri
------ Original Message ------
From: "Bill Dube via EV" <[email protected]>
To: [email protected]
Cc: "Bill Dube" <[email protected]>
Sent: 03-Dec-19 12:31:38 PM
Subject: [EVDL] OT: Re: Chrome-moly vs. Steel
Wood is still used today for construction of small airplanes. Unfortunately, it
must be cared for well, and inspected regularly for rot and bugs.
I suspect that DNA manipulation by CRISPR may well bring back wood as a competitive fabrication
material. It may even become an ecologically preferable material. Imagine trees that produce
finished "composite" products. Spoons, knives, forks, bowls, and plates are simple
examples that a tree's DNA could be "re-programmed" to produce. Wind turbine blades,
airline seats, rain hats, coats, are all possibilities.... It is not totally inconceivable.
< back to EV discussion mode>
Bill D.
On 12/4/2019 9:11 AM, Neal, Gary via EV wrote:
Interesting observation from the
https://en.wikipedia.org/wiki/Specific_strength table: Oak (wood) has a higher
specific strength than aluminum 6061-T6 and Chromoly (4130)! Balsa (wood) has
a higher specific strength than most metals and almost rivals carbon-epoxy
composites. Of course wood's strength depends on the grain structure
(non-isometric), but still. That's pretty cool. Maybe we need to go back to
the future and use wood in transportation.
Gary
-----Original Message-----
From: EV <[email protected]> On Behalf Of Bill Dube via EV
Sent: Tuesday, December 3, 2019 3:00 PM
To: [email protected]
Cc: Bill Dube <[email protected]>
Subject: [EVDL] Chrome-moly vs. Steel (was: Light weight electric motorcycle.
DIY)
Chrome-moly steel is about double the specific strength (ratio of ultimate
strength divided by density) of mild steel. That's why they often use
chrome-moly in airplanes, and never use mild steel.
https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FSpecific_strength&data=02%7C01%7Cgln103%40psu.edu%7Cf55cd34d8fed4ed144e708d7782b5ed7%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637109999974629230&sdata=GBD3treZq5TBYBHiwFt8V1JTheybre8Z3sqJ38vW2uk%3D&reserved=0
As you can see from the chart, mild steel has a specific strength of
71-85 kN m/kg, while low-carbon steel has a specific strength of 46 kN m/kg.
Looking further down the chart, you can see why they use carbon fiber composite
(785 kN m/kg) to build modern airplanes.
Chrome-moly (4130) is often chosen for its ease of fabrication and its
forgiving nature when abused. It can be welded (or brazed) without subsequent
heat treatment, and it deforms ~25% before failure. (It stretches like taffy
before it comes apart.) It also has a high fatigue resistance.
Bill D.
About double On 12/4/2019 7:31 AM, Paul Compton via EV wrote:
On Tue, 3 Dec 2019 at 03:27, Lawrence Rhodes via EV <[email protected]> wrote:
Using chromoly will reduce the weight.
Oh, is Chrome Molybdenum Steel somehow magically lighter than mild Steel?
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