So, apart from being an amazing feat of engineering, what's so special about this? Well, The Daily Mail reports in typical disregard for science that:
"The bike's makers claim that the G-force which the rider has to contend with is three times more than that faced by a skydiver during freefall."
G-force is a unit equal to the force exerted by gravity. It gives weight to a mass. The other way to look at it, is we are all being accelerated towards the earth by 1G (although strictly, that depends on where on Earth you are). 1G is about 9.8m per second (every second).
A skydiver in free-fall reaches a terminal velocity at about 120mph (200kph) due to wind resistance and never experiences any more g-force than if he were sat in a chair. The equations of motion for an object under constant acceleration, accelerating from a standing start are as follows:
The bike covers the quarter mile track (about 402 meters) in 7.8 seconds giving an acceleration of 13.2 ms-2 which is well below the brain-busting 29ms-2 acceleration claimed attributed to KillaCycle. There is something I'm ignoring here and I'll come back to that before you jump in and comment on it, but if KillaCycle really was achieving such acceleration it would travel nearly 1800 metres (over a mile) in the time.
So where does that come from? Clearly, KillaCycle is not accelerating constantly for the entire quarter mile. The 3G experience comes in the first shoulder socket-wrenching second and it's likely that most of that happens in a small fraction of a that second.
Cars, planes, motorcycles and pretty much everything that accelerates under power do so variably - the acceleration curve: but the Mail isn't interested in that and just runs the quote from the release.
Perhaps more interesting though is the boast that a four minute charge from wind energy is enough to power the vehicle (they claim) for seven runs. The energy may indeed by "green" but you can bet your CO2 emissions that those batteries are about as recyclable as George W Bush is climate aware
However, let's take nothing from the achievement, even if it is a bit of a white elephant. KillaCycle's team are now said to be working on a 1000BHP version. Presumably the Mail will be telling us next that it's twice as fast too.
In other news, someone stole my shaving cream so my face is sore.
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You need to do a bit better on your homework if you are going to hold yourself above other journalists.
ReplyDeleteIf you look at the posted timeslips, the bike does 1.14 seconds for the first 60 feet. This is 2.9 g's.
The bike is in the traction limit for a significant distance and pulls 2.9 g's until it hits 500 HP maximum output of the battery pack.
Abusing the News doesn't generally dip into this sort of thing, we're here to take the piss out of what the papers (Mail in this case) print.
ReplyDeleteBut you obviously didn't read the entire piece, now did you? Tut tut.
The difference between this blog and others, is we do actually read between the lines, using the figures supplied in the original article, I wrote (and you'll find in Google's cache):
You're alluding to this:
"...which is well below the brain-busting 29ms-2 acceleration claimed attributed to KillaCycle.
When, if you bothered to read the full post, goes on to say this:
"There is something I'm ignoring here and I'll come back to that before you jump in and comment on it, but if KillaCycle really was achieving such acceleration it would travel nearly 1800 metres (over a mile) in the time. The 3G experience comes in the first shoulder socket-wrenching second and it's likely that most of that happens in a small fraction of a that second."
Excuse me for rounding up. This is preeeety damn close to the 2.9g you've stated.
Perhaps I should have checked the accelerometer data, but I don't have it and but this is an entertainment blog, not a physics one.
Using your figures, 60ft in 1.14 seconds comes to:
60ft = 18.288 metres
Dropping that into the posted equations gives us:
Acc. = 2 x 18.288 / 1.14 x 1.14
Acc. = 28.14ms-2
Now, divide by 9.81ms to get the g force:
Acc. = 2.87gs
About 3g in the first second - which is pretty much what I wrote.
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ReplyDeleteWow. That is quite impressive, isn't it? Thanks for this tid bit of info.
ReplyDeleteThat is insane! Thanks for video as well.
ReplyDeleteThank you for sharing such wonderful and interesting article about world accelerated achievement .
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ReplyDelete