Has America created a Negative Density Aircraft?

Question

No stupid answers please. If you dont like this question then dont answer it.

Answer 1

if you meen lighter then air aircraft then yes but if you meen like a airplain like a cesna then i belive not

Answer 2

Actually I think Germany invented the Zeppelin, and France invented the hot air balloon. Both are "negative density".

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Answer 3

The Montgolfier brothers first demonstrated their craft publicly on the 4th of June, 1783.  They were French.

But Americans have since developed their own.  You might see one hovering over a sports event.

Now, these craft are simply lighter than air.  There aren't any materials that have negative mass.  There are solids, like aerogel, which have lower density than air, and so float around.

Answer 4

I don't know what you mean exactly by a negative density aircraft, but I'll assume you're talking about density as I know about it (i.e. as in mass over volume).

If you mean that an aircraft has been created out of a substance that has a negative density, then I don't see how that's possible as it can't have negative volume or negative mass (unless antimatter has negative mass, but I don't know if we can currently create anything large/substantial out of antimatter...)

If you mean that the aircraft overall has a negative density, I also don't see how that's possible as even if you use nearly weightless materials to construct the aircraft and make an aircraft that is absolutely HUGE, the overall density will merely be close to 0 - not negative.

Sorry if I've misunderstood what you're asking - I'm not trying to give you a stupid answer!

I just saw your edit, and I think that what you want to ask about is negative GRAVITY aircraft (since you mentioned repulsion of gravitational pull). Even in this case, though, I don't believe that such a craft has been created, as (again, as I understand it) every body that has mass (e.g. everthing we use as materials for aircraft...) attracts other bodies with mass towards it (this is 'gravity'). Again, antimatter might be an exception to this, but you've seen my thoughts on that possibility above. Perhaps an aircraft might be magnetically/electrically charged in such a way as to be repelled from the Earth, but that would take enormous energy (I would imagine) and would not have any significant benefits over 'usual' aircraft once effort and costs have been taken into account.