Huge Flying-Boat BWB Idea

[KJ_Lesnick]

I remember seeing a picture of these gigantic flying wing designs in the game "Ace Combat 6".  I'm wondering how big could you actually make a flying-boat BWB design?

KJ Lesnick

[Captain Canada]

That's easy : As big as you want !

Now get building !

[jcf]

Not exactly a BWB...

http://home.att.net/~dannysoar/BelGeddes.htm



http://www.fantastic-plastic.com/BelGeddesAirliner4CataloguePage.htm



eV1N3 of Scott Lowther's electronic Aerospace Projects Review (eAPR) has an extensive article on BWB
designs, and while none are 'aquatic' it easy to see how some may be adaptable.
http://www.up-ship.com/eAPR/ev1n3.htm

Jon

[Daryl J.]

Let's see the materials list:

Two 1/48 P-47N drop tanks
One 1/72 Revell Horton Go-229
Evergreen sheet and tubing for "fuselage" buildup
A Bazillion 1/350 scale window decals  (?1/288?)
Epoxy putty
Hobby knife
Send spouse, kids on a spring clothes shopping trip........

Daryl J.

[KJ_Lesnick]

Out of curiousity, not to sound retarded:  Could the BelGeddes design have actually flown?  Would there have been any pressurization issues (as it could fly as high as 45,000 feet)  Additionally, what lead to it's cancellation?


KJ Lesnick

[jcf]

Out of curiousity, not to sound retarded:  Could the BelGeddes design have actually flown?  Would there have been any pressurization issues (as it could fly as high as 45,000 feet)  Additionally, what lead to it's cancellation?

KJ Lesnick

Hi Kendra,
the 45,000 ft figure is for a 747, and there never was a project to 'cancel'.
Airplane #4 was just one of Bel Geddes many design exercises, and if the
power was sufficient it could possibly have flown. However, in reality it was
more an attempt to see how far they could push the available technology and
aerodynamic knowledge.

http://www.hrc.utexas.edu/research/fa/belgeddes.bio.html

Do a search on Norman Bel Geddes and you'll get a slew of results.

Track down a copy of his 1932 book Horizons if design from the period is of interest.

Jon

[Mossie]

The Beriev Be-2500P would fit the bill Kendra.  There are several designs on similar lines, this is probably the most blended.



Todd's made a good point. You can go huge, even with current powerplants & materials, that CL-1201 that Jon posted might just possibly fly.  Practicality is the main deciding factor real world, how much will it cost, where can it operate & just how big will modern powerplants let you build?  There are engines in development that will put out well over 100,000lb thrust.  I'm no engineer & can't give you figures, but couple several of those those to an aircraft with a very high lift/drag ratio & I reckon you could build something a sight bigger than an An-225.

[B777LR]

Here's what Lesnick is refering to:

http://www.youtube.com/watch?v=HIACx8q7t7Y

[KJ_Lesnick]

Well, my inspiration actually does come from that game.  However, what I'm actually wondering is how far could one take a flying-boat BWB in real life.

KJ Lesnick

[KJ_Lesnick]

Personally I'd be thinking of a design that was more like the McDonnell Douglas BWB design...

Or like this concept here...



Scaled up if possible with modifications to allow it to operate off water...


Not that I'd be totally opposed to a design that was somewhat B-2 or Manta-Ray esque...

[KJ_Lesnick]

Could a retractable hydro-ski system like the Saro P.121 work even on the scale of the B-2, or even larger designs such as the X-48 or McDonnell Douglas twin-deck BWB (or even larger) providing multiple retractible skis were used?

KJ Lesnick

[Mossie]

I think hydroskis come into problems with larger aircraft, for similar reasons to hydrofoils.  The amount of hydrodynamic lift generated by a ski does not rise proportionally with the weight of an aircraft so the area of ski you need for a large aircraft becomes a problem.

There's more reading on Global Security, it's specific to hydrofoil limitations but some of the principals remain the same:
http://www.globalsecurity.org/military/systems/ship/hydrofoil-limits.htm

[KJ_Lesnick]

Mossie,

From what I read the limit is 400 tons.  For a ship that isn't all that extreme, but for an aircraft 400 tons is absolutely gigantic.  Truthfully though I'm trying to see for this hypothetical how extreme in size one could go.  Does this work regardless of the amount of hydrofoils used (I was thinking of having one foil under the nose gears, two pairs of foils under the mid-section and another smaller set outboard about 40% of the span)?

I'm also wondering about some other things

1.)  Is it possible to design some kind of telescoping hydrofoil in which essentially three panels can retract out of one and could substantially increase lift. 
2.)  To exploit super-cavitation is it possible to use some kind of mechanism to blow exhaust or some kind of air over the hydrofoil to help improve acceleration?  I remember there was a Russian torpedo design which used super-cavitation, was rocket powered and used some of the exhaust from the rocket and directed it over the skin of the torpedo to help get it up to supercavitation speed (where it could do it on it's own).


KJ Lesnick 

[jcf]

Mossie,

From what I read the limit is 400 tons.  That maybe small for a ship but for a plane that's gigantic!

Hi Kendra,
the 747-400ER has an MTOW of 910,000 lbs (455 tons).

The A380-800 MTOW is 1,200,000 lbs (600 tons).

The MTOW of a big BWB would be easily in the A380 range and greater.

Anyhow as to getting a BWB off of the water I think you'd be relying more on aerodynamic forces than hydrodynamic,
with all that wing area I don't see any need to have the 'hull' plane in the conventional sense, instead you'd probably
literally fly it off the water.

Jon

[KJ_Lesnick]

JonCarrFarrelly

Hi Kendra,
the 747-400ER has an MTOW of 910,000 lbs (455 tons).

The A380-800 MTOW is 1,200,000 lbs (600 tons).

The MTOW of a big BWB would be easily in the A380 range and greater.

Well, the point I was trying to make was that 400 tons for an aircraft is actually quite massive.  Most aircraft are less than 800,000 lbs...

Though you are correct that the B-747, A-380, and such are larger.  If I recall correctly though the B-747-400ER was 925,000 lbs (at least there was a proposed variant of that weight)

Anyhow as to getting a BWB off of the water I think you'd be relying more on aerodynamic forces than hydrodynamic,
with all that wing area I don't see any need to have the 'hull' plane in the conventional sense, instead you'd probably
literally fly it off the water.

Yeah but the centerbody of the plane would be sitting flat in the water which would be a lot of surface area that would be in the water, though not too deeply below the waterline truthfully...

Honestly I don't know how the drag dynamics of all this would work out.