Ian said:
I like they left the launch fails in the video, such a refreshing video rather than slickly edited "perfect" videos.
CanobieFan said:
There are videos of Xcelerator at Knotts doing the same thing when it started testing. I guess rather than start off with a full speed launch, they do a few low speed runs to get things warmed up.
Martyn B said:
For a split second I had terrifying visions of the triple launch on Premiers......
Warmed up, failing, or multiple launch passes, is probably the wrong way of thinking about it.
To a launch system, a roll-back is the worst case scenario. A fail of power during the launch (power cut, controls failure, cable snap, fluid leak, etc) means the train won't be heading into the first element at full speed. If you were testing a coaster, you'd want to make sure that the coaster could stop from one of these scenarios first, before you went ahead and tested it at full speed.
The analogy would be: if you're testing a high speed car, what do you test first? The acceleration, to ensure you can get too 200mph? Or the brakes to make sure you can stop? I know which one I'd rather test first!
In doing these "slow" launches, they're making sure the controls system and hardware is capable of dealing with the "worst case" scenario. If the train doesn't make it past the first hill, the launch track has to make sure the train doesn't rush back into the station backwards. If the train can clear the first hill but then stalls, a set of sensors on the track should tell the software when the train hasn't made it to the next block, and therefore not launch the next train.
A "failed" launch is most of the testing of launched coasters, making sure a roll-back scenario is safe.