h a l f b a k e r yExperiencing technical difficulties since 1999
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We get so much stuff tossed along our small stretch of
roadside it seems only fitting that it should be compressed
into speed bumps suitable for slowing the tossers enough that
they can be identified for punishment by the authorities or,
failing that, slowed sufficiently to get a good shot at
them.
[link]
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//slowed sufficiently to get a good shot at them.// |
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Sadly, this is probably counterproductive. A car cruising
along at a steady speed is pretty easy to predict. You can
dial in the range and lead, pick out a couple of markers
etc. Even better, get alongside the road so the car's path
is almost parallel to the barrel. |
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Add in speed bumps, and you create the automotive
equivalent of running in zig zags to throw off a sniper.
Instead of steady speed, you now have all that speeding
up and slowing down that speed bumps compel.
This makes a side-on shot difficult. The pitch oscillations
caused by the acceleration and braking may also throw
off the aim if the target is ahead or behind the vehicle's
center of mass. |
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If the inter-bump zones are a mess of speed and pitch
oscillations, then the bump itself might be a natural
choice for the shot. After all, the car is slowest here. It's
also the most variable. People tend to brake all the way
up to a bump and release just as the car meets it, so you
move from deceleration to coast with the consequent
change in pitch. Then the car meets the bump, the car is
forced up and speed is traded for height. How much is
hard to estimate, because the suspension takes
variable energy from the system. On the down
slope the situation reverses. |
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This is a mess of height, pitch and speed changes. Worse,
it's complicated by variables like car length,
suspension, load and also how the driver will wobble
around in the car. I described the front wheels hitting the
bump, but the rear wheels will also, interacting in
complex ways. |
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Or just hose it down with 30mm cannon, if the car's not
worth saving. |
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^ Have you ever been on grassy knoll in Dallas, you can tell
us... |
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Sorry but my mother-in-law would not make a
reliable speed bump. |
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//People tend to brake all the way up to a bump and release just as the car meets it// - just to observe that this is the worst speed bump strategy. Under heavy braking the car 'dives' and the front suspension is compressed and, if the braking is continued right up to the speed bump, the suspension will then be further compressed and may 'bottom out'. A better strategy is to stop braking a moment before hitting the speed bump to give the suspension time to uncompress, ideally hitting the speed bump at the exact moment the suspension has actually bounced beyond its neutral point and is slightly extended. |
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The idea is to make speed bumps from anything tossed out
of a moving car. We appreciate the technical expertise of
your responses on suspension dynamics.
We are the recipients of a load of goodies including Bud
Light cans and bottles, Polar cups, banana peels(daily),
cigarettes& butts, car batteries(yes) and sundry other forms
of matter. Compressing this detritus into a revenge type of
obstacle tickles our fancy. |
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