new propulsion system ?

[spiney]

I saw this on cover of latest New Scientist, and couldn't believe it, sounds just like sci fi, but apparently it's completely serious!

http://www.shelleys.demon.co.uk/fdec02em.htm .

The idea that sending a magnetron output into a special waveguide section produces thrust, at possibly 70% efficiency, just seems mind boggling. If it works, will change things a bit.

I still don't believe it, I just can't!

[Channel Hopper]

Odd that they haven't tested a parabolic reflector with a magnetron at the focal point. The total spectrum of microwaves is expelled in a single direction, any interaction between differing waves could be tested between different frequencies using aperture filtering, and in a final design, directional stability and efficiency is perfected by use of a gimbal system to move the whole drive surface.

I am worried however that there is a possibility for more 2.4-2.5 GHz devices to be used in the vicinity of people, as if there aren't enough brain frying systems already in the home.

[mhku]

I can't be arsed to read an article on the web written in Times New Roman without a summary.

Does it suggest using the cooking part of a microwave (magnetron) for propulsion?

[Channel Hopper]

Does it suggest using the cooking part of a microwave (magnetron) for propulsion?

It suggests using the whole 9.5kg microwave oven as a spaceship, any volunteers ?

[mhku]

Hamsters or squirrels in spacesuits then?

[spiney]

They'd probably get their bums burned, but have frozen heads and feet.

More seriously, if feasible. it would make possible "hovercars", as for example seen in film 5th Element, and similar sci fi .....

I stilll can't believe it.

[spiney]

Photons don't have mass, but they do have energy, and hence can - in the right circumstances - exert pressure. Several tonnes per square mile, from sunlight, on earth's surface, I believe.

Hence the idea of "light sails", often mooted as a possible space propulsion system.

But this is different, basically a photon rocket! From the rocket equation (look it up, via google!), efficiency rises with exhaust velocity, and nothing goes faster than light!

But, it's so far fetched ..... I still can't believe it.

If true, this would be the sought after "space drive" (alas, still not warp speed, but that's probably impossible).

[Channel Hopper]

An update
http://www.theengineer.co.uk/Articles/Article.aspx?liArticleID=295931

and an earlier hybrid

http://www.sciencedaily.com/releases/1999/10/991018080035.htm

[2cvbloke]

Can't beleive I've not noticed this thread yet!!!

Anyway, I'm not so sceptical about things like these, I think that it is entirely possible to use things like these to drive space going vessels (maybe not the USS Enterprise, but something like a NASA shuttle, assuming they don't wreck another one!!!), and could mean another step into, yes I am going to say it whether you like it or not, the final frontier, as long as they work out how to get through the radiation layer around the earth...

But the thing that really interests me is that most of the world's population has access to the main device that makes this drive possible as it's in our microwave ovens, whether the intelligence is there or not to try and build an "Emdrive" themselves is anyone's guess...

Thing is, it may not use chemical fuel reactions, but how much power would an Emdrive need to power something like a satellite to keep it in a stable position?

[spiney]

Well, it DOES work, but I think the article said the thrust is "measurable" (ie, there's something there, but only just).
Even if made commercial, it would be impractical for satellites, cos of all that "heavy metal". As was discusssed in another thread, dbs sats are now using ion engines, extending their probable life.

Regarding land transport, also probably useless, as other technologies would still be more efficient. You just can't beat the good old wheel (bet the caveman who invented it kicked himself later for not taking out a patent).