Boeing working on BWB freighter, page 5

Dirigibles are too slow and are too big.

So long as the power to weight ratios of aircraft engines remained low and specific fuel consumption remained high, the airship had an edge for long range or duration operations. As those figures changed, the balance shifted rapidly in the airplane's favor. By mid-1917 the airship could no longer survive in a combat situation where the threat was airplanes. By the late 1930s, the airship barely had an advantage over the airplane on intercontinental over-water flights, and that advantage had vanished by the end of WW II. The blimp remained a viable military system only until the conventional submarine was replaced by the nuclear submarine. Today, airships are used primarily for advertising where their size and novelty have an advantage.

A large BWB can carry 68 freight containers at around Mach .85 (561 mhp)
La rge BWB Freighter Study

By the time you load and make a delievery across the ocean, a large BWB will have moved more cargo to the extent that the cost savings is not nearly as big as the profit of moving the payload. Sometime it is not a matter of how cheap you move it, but how much you move. FedEx is a great example of that.

The only one in development is the ML866.

It would only be good for slow luxury use.
The payload and speed will eliminate it as a good freighter. I have only seen a few article mention that it can carry up to 120,000 lbs. (60 tons)in payload, with a 3,000 range.

An Airbus A380 can carry twice that, and go almost twice the distance at Mach .85.

A large BWB will be able to as much as the A380 with less fuel giving it more range.

It will take the ML866 (going 136 MPH) about 22 hours to make a freight shipment. An aircraft going Mach .85 (561 MPH) can go 3,000 in about 5 1/2 hours with twice the cargo.

This means that the time it will take the ML866 to make one trip with one load an A380 or large BWB could haul twice the payload and make 4 trips. That is 8 times the cargo moved over the same period of time.

It will be a luxury toy for rich people and that is about it.

[edit on 14-11-2007 by MrKnight]

Will your next generation dirigibles be useing Helium? I hope not. If you think fuel cost is going to go up, be aware of the fact that Helium is in short supply.

Consumers feel helium squeeze

BWB News Update:

AvioNews from Farnborough - "Bigger BWB 'X-Plane' Planned"



Military Aviation
02:56 pm - Wednesday
AVIONEWS at the “Farnborough International Air Show 2008” (12): bigger BWB “X-plane” planned
Farnborough, United Kingdom - On the tracks of the X-48B
(WAPA) - Boeing and the US Air Force have begun talks over development of a larger, piloted, blended-wing body (BWB) demonstrator that would follow on from the current subscale X-48B Unmanned BWB now flying at Edwards Air Force Base, California.

Company officials say the single-pilot vehicle will have a pressurized cockpit and be multi-engined. Final configuration will depend on definitive research objectives and funding.

Boeing says a piloted BWB would enable more realistic noise and handling performance tests that are difficult, if not impossible, to achieve with the current 21-foot-span X-48B.
(Avionews)



[edit on 16-7-2008 by MrKnight]

Aerospace America article on the X-48B and BWBs in general here *warning pdf*


To summarise.

-No commercial BWB within 20 years at best, Boeing has nothing of the sort on its roadmap.
- For cargo, the BWB is forced to use smaller separate cargo compartments, meaning the large equipment carried in say a C-5 cannot be handled. A definite minus.
- Use of composite materials is best technique yet of combating pressure vessel stress concentrations.
- Boeing reckon they can make the BWB work at up to Mach 0.85 without picking up too much transonic drag.
- X-48B program set to conclude at end 2008... "what happens next is up to NASA and the Air Force".

This is the part I love:

"I told you so!"

Update for those who still think that a small blended wing is not possible.

Graham Warwick of Aviation Week - Who Wants to Build a Bigger BWB?




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