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Hybrid Dual Envelope Airship Biplane Flying Boat
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Take the fuel efficiency of an airship, the land anywhere body of a flying boat, the lifting properties of a biplane (coupled with the lifting properties of dual helium filled semi-rigid envelopes), space the envelopes on opposite ends of the biplanes wings (angled so that they do not contact the water when the hull lands), and only enough helium to lift when aerodynamic principles and the propeller are employed...and what do you have?

Other than an entirely too long run on sentence?

The Zephyr-by James Harkness :)

What I am hoping for is an entirely new incredibly fuel efficient hybrid aircraft that will reignite the spark of global travel through personal aircraft. Is helium so elusive an element that it would need to be refilled constantly making long distance travel/cost efficiency an impossibility and would the speed generated by the wings/propeller and the drag produced by the dual envelopes be inefficient for flight?

James Harkness, Dec 27 2010

NC 4 Flying Boat http://upload.wikim...guration-detail.jpg
This is what the main idea would be but with two semi rigid envelopes on each side and scaled down a lot more. 1 engine, smaller hull, more streamlined, and aerodynamic, etc, etc.. [James Harkness, Dec 27 2010]

Lockheed P-971 http://en.wikipedia...wiki/Lockheed_P-791
not Boeing [BunsenHoneydew, Dec 27 2010]

Hybrid airships http://en.wikipedia...wiki/Hybrid_airship
combine features of lighter than air and heavier than air craft [BunsenHoneydew, Dec 27 2010]

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       I think whenever you design something you need to be clear about what present method of getting the job done you're trying to improve on.   

       It sounds like you're proposing putting a couple of blimps on the tips of a biplane's wings. Before getting into the advantages, if any, you've got a structural consideration of having two big gas envelopes that are going to need to be secured together via the aircraft in the middle without tearing the whole thing apart when the wind hits them. That will require a pretty strong structure in the middle, so why not get rid of it and just have one big airbag instead of two? Then you've got a biplane that's supposed to do what? Supply lift? You've already got the gas bag(s) doing that so not much point there, might as well get rid of that too.   

       So next thing you know, you've lost the dual gas envelopes and the biplane in the middle and you've just got a blimp.   

       Unless your design has some improvement over present methods that I'm not seeing.
doctorremulac3, Dec 27 2010

       Not related to the substance of your post, James, but welcome to the HB!   

       I see you joined a couple of days ago - did someone give you the HalfBakery for Christmas? If so, I have to warn you - batteries are never included, and there's usually some assembly required...
lostdog, Dec 27 2010

       Yea, forgot about that part. Welcome.   

       And don't feel bad, I got smacked around pretty hard my first post but frankly I had it coming. ;)
doctorremulac3, Dec 27 2010

       .... and often still do ....   

       Anyway, to the idea. It kind of falls into a hole between two design concepts; the airfoil-supported high speed heavier-than-air machine, and the low speed, buoyant-flight airship.   

       Airships are slow because they have huge drag coefficients, even if well streamlined. Because of square law, to get an airship from 80 knots to 100 knots requires stupendous amounts of additional power.   

       Aircraft fly fast because their drag profiles are optimised to convert thrust into lift with minimum drag loss; hence gliders have very long, thin smooth wings.   

       Placing the gas bags at the outer ends of the wings will generate large yawing moments when turning, and the wings themselves will need to be very stiff (although carbon fibre composites would be up to the job). Ideally, the lift should be applied in the centre of the wing.   

       Modern blimp designs like the Skyship use vectored thrust to acheive a simiar result, rather than aerodynamic forces from forward motion.
8th of 7, Dec 27 2010

       Having two envelopes rather than one halves your lifting efficiency. Volume (thus, lifting gas contained) increases as the cube of linear size, while surface area (thus, structural dead weight to contain the gas) only as the square. So the larger the envelope the better, and a single large gas bag will always be more efficient than two smaller ones. It also simplifies structure and lessens the stresses involved, as others have pointed out above.   

       But yours does sound delightfully baroque and kooky.   

       There is a design - and I believe a prototype - out there from one of the larger aerospace concerns (Boeing?) which achieves your ends by a somewhat different design - a single, rigid, envelope shaped as a lifting body, neutral buoyancy and powered forward flight with aerodynamic lift.   

       /goes away/comes back/ adds [link]s
BunsenHoneydew, Dec 27 2010

       // Boeing //   

       And they'll be right back on it, soon as they've bottomed all the problems with the 787 .....   

8th of 7, Dec 28 2010


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