From: Charles J Knight (c.knight_at_juno.com)
Date: 03/21/00
Date: Tue, 21 Mar 2000 15:44:59 -0800 Subject: Re: ball connection Message-ID: <20000321.154537.-229719.4.c.knight@juno.com> From: Charles J Knight <c.knight_at_juno.com>
> I don't know, for sure. I know that domes are strong, but I
> figure it's better to err on the side of over-engineering than
> under-engineering. Remember that Bucky's first dome was ridiculously
Reasonable. But, if we're talking about mass manufacturing these
hubs by the billions, extreme overengineering will be very costly.
> have to trim some excess later, so be it. But I'd rather that than
> have failures in the field that cause injuries or cost lives.
Oh, absolutely. I agree completely. I'm just asking basic engineering
questions...
> Remember also that we want to pick these things up and fly
> them around, with thousands of pounds of people-stuff in them, and
Agreed. But, we don't necessarily have to hook to a single hub in order
to do this. A distributed load (like the 4-corner tie-down points for a
car)
could serve us easily, and still allow the individual hubs to be less
heavily
engineered.
> If anyone knows of ways to measure, or wants to figure out
> how to
> devise those ways to measure stresses on domes, (and also on
It's also not just stresses ... it's the direction of that stress.
> Perhaps the best way to frame this concept is to think about
> automobiles and airplanes. When you buy a car, do you have the
> Sheet-metal Workers Local #342 come to your driveway and start
> pounding out body panels? Do you have the Upholsterers Union #128
> set
> up over by the mailbox, sewing your seats out of fabric and foam? Do
Good analogy. Here's one for you. We're talking about mass produced,
interchangeable parts. Sticking with the automobile analogy, tires are
such a part. I *do* take the car in and have a new set of mass produce
tires put on...tires which I can choose to complement my car. Same with
the rims...I can buy aftermarket parts to "customize" the car.
I also do this *after* the manufacture and delivery of the car.
> drive it away, or have it delivered to you after they order it from
> the factory with the options you specified.
So long as customization is possible...people won't stand for "any color,
so long as it's black" anymore.
> strengths. (Domes get stronger the more elements you have to
> disperse
> stresses, so a 4 is stronger than a 3, a 5 stronger than 4, etc.) I
Agreed. I was just picturing shipping them to Peru, and saying that
it's supposed to look like a big soccer ball. Simpler, from the point
of view of writing instructions and training construction crews.
I happen to agree with you...higher frequency is better. But, there
comes a point of diminishing returns.
> 4F also divides cleanly at the equator. (All even-frequency
> domes do. Whereas my 3F dome is really a 4/9ths sphere, resting atop
As do all octahedral domes. There are always simple ways to make
sure this happens.
> Another thing to remember is that mass-production reduces
> price drastically. I don't even want to THINK about what a prototype
Probably less than you think, if the designs are kept relatively simple.
> -I wonder if an "advertising" model, something like Juno and
> NetZero,
> -would allow for genuinely free houses?
>
> Ick. I hate web-advertising. And it's not genuinely free, as
You may hate it, but it's proved to be an efficient and effective
business
model. Might be viable to give away homes this way.
Just a different way to think about such things...
-- Chuck Knight
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