I envisage a large, flat symmetrical wing inflated with a lighter than air gas which is propelled as a conventional plane would be to generate lift, perhaps with an extra vertical wing of similar size analogous to a tailplane to provide extra buoyancy and stability.One advantage would be that less fuel would be needed, and it might even be possible to switch to burning the hydrogen in the wings directly towards the end of the flight. Another would be that gas only slightly less dense than air could be used rather than hydrogen or helium.-- nineteenthly, Jun 24 2005 similar but gasless shameless self promo. Solar_20hot_20air_20hang_20glider_2e [2 fries shy of a happy meal, Jun 24 2005] Gravity-powered airplane http://www.fuellessflight.com/Different shape, similar idea. [Freefall, Jun 24 2005] One could take a salvage airplane fuselage and attach balloons to it. Maybe several that move lengthwise around the craft or... no, that's just stupid.-- bristolz, Jun 24 2005 Yeah; what sort of nutter would think of that?-- angel, Jun 24 2005 I don't see the hydrogen/helium thing being a problem. Sure Hindenburg was an issue, but we've all gotten over that now. I'm sure hydrogen would be a perfectly reasonable gas to use these days.
However, to benefit from the lift-potential of lighter than air gasses, you need to enclose a large volume. This is why traditional airships are so huge and bulky.
Fashioning a wing/airofoil of that magnitude would be a gargantuan task, and I'm not sure it would generate lift in the same way a regular sized wing does, on account of its huge size.
I like the idea - i.e. balancing lighter-than-air bouyancy with bernoulli(?) generated lift - I'm just not sure it would be as practical or as usefull as your regular bog-standard zeppelin.-- zen_tom, Jun 24 2005 It would probably be quite big compared to a conventional plane capable of carrying the same weight, but the actual mass of materials used would surely not be that great, and would also fall if the hydrogen was burnt. It would also crash relatively gracefully. Yes, it might be huge but is that a bad thing? If it took off from and alighted on water or another uncluttered surface such as an ice field, moor or sandy desert, that wouldn't be a problem.I also like the idea of the solar heated hang glider - perhaps these could be combined, and (this is very optimistic) the thrust of expanding gas used to push the plane along.-- nineteenthly, Jun 24 2005 Well, one thing's for sure: the wing loading would be low.-- bristolz, Jun 24 2005 In a sense it would be negative, so maybe it would need ballast.-- nineteenthly, Jun 24 2005 random, halfbakery