US Navy electromagnetic mass-driver commences tests A prototype electromagnetic mass-driver, intended to hurl jet aircraft into the sky from the decks of aircraft carriers, has gone into operation at a former airship base in New Jersey. The new kit could be even more important to the Royal Navy than it will be to the US fleet. The EMALS aircraft mass-driver fires a ceremonial …
"Any chance this can be developed for commercial aircraft."
Probably not. This article http://www.americanheritage.com/articles/magazine/it/2006/4/2006_4_26.shtml
lists a US carrier catapult takeoff as roughly 160mph in 2.5secs. That's about 29ms^-2 or close to 3g. while a lot of people could take 3g for less than 3 secs (modern roller coaster rides can give this, and I imagine some do quite a bit more) it would still likely kill a proportion. And energy requirements scale with mass. The aircraft in the article is 78oooLb (c35 000 Kg). An Airbus would be 10 to 20x that.
Basically everywhere else other than at sea building a longer runway is a *lot* cheaper and simpler.
OTOH if you wanted a singel stage to orbit vehicle that could land *and* take off horizontally (looked at by the USAF in the early 90s to the point where Boeing were prepared to offer it as a *fixed* price contract) this would be a very good choice.
If it was land based presumably you could have a longer run, and so more gradual acceleration.
This would remove the problem of passengers all passing out on take-off, but would also have the advantage that the aircraft does not need to carry the fuel required to get it up to V2, instead it could be generated by a green technology like a nuclear power plant!
The personnel in the photo appear to be rehearsing a number from Guys and Dolls--what's that about?
Also, though the US lighter-than-air program had access to helium, and so did not risk gaudy fires such as consumed the Hindenburg, still the Navy's rigid craft did not fare well. As I recall both crashed in bad weather with loss of life.
... My thoughts exactly! I've been showing my children Eric Laithwaites 'The Engineer in Wonderland' recently since they expressed an interest in mag-lev/mag-propulsion (interestingly, my 7 year old son 'invented' mag-lev when he discovered magnetic repulsion, deciding that cars/trains would be much better if they hovered... hence Prof. Laithwaite's book came out!)
"I'm looking forward to seeing this deployed ... and it would also be nice to see something similar used to put stuff into space!"
Depends what you mean.
EM launch assist is one of several technologies that can help in getting a vehicle started horizontally or (in principle) vertically. This is the time of the vehicle's maximum weight, and is the point when the vehicle burns the most fuel to get the least increase in velocity. Improvements here (if incorporated in the design stage) should give a substantially smaller vehicle, or bigger payload for the same size. Note that it is the *dry* weight that you pay for in design and build. Smaller vehicle gives smaller tanks to make. I think the USAF programme was "Have region."
Launching a payload to orbit *soley* by EM launch is a mass driver or rail gun approach. This is a very different beast. For a practical size your looking at accelerations in the 100s of g (roughly 321g for a 10km pipe). This is either a high value fast launch system for sensors or weapons or a low price bulk goods launcher. Steering is a problem and you'll need some kind of rocket to fire at orbit to get it onto its orbital track. BTW when the payload exits its tunnel airlock (it's normally presumed to be evacuated) it will be moving at about Mach 23, giving some quite interesting shock wave effects.
It will be interesting to see what happens to the ships electrical system when they suddenly stick a few megawatts of load on it, and again when they dump those megawatts off it again after the launch. Cue the Bee-Gees - "and the lights all went out ..."
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