Burnelli's "lifting body" designs: road not taken or dead end?

[Default Setting]

Throughout his career, Vincent Burnelli remained committed to the idea of lifting body, as a transitional stage to full-flegded flying wings. But none of his designs met commercial success. I'm looking in particular at the CB-16, which flew in 1929 and of which only one was built.

So did the concept have potential, or was it doomed to failure no matter what?

[scooter]

IMHO, its probably not dead, but is part of a continual development as aerospace engineers look into improving fuel efficiency, range, and load capacity of future airliners.  It has had fairly extensive military application, with the F-14, the F-15 series, Fulcrum, and the Flanker family.  Besides, if it weren't for Burnelli's lifting body concept, the Israeli F-15 below, would have become a 30 million dollar crater instead of being able to return to base, be rebuilt and returned to service.

[Weaver]

I suspect that what killed it off for airliners was pressurization. The need for that plus minimal weight effectively forced designers to make cabins that were tin tubes with hemispherical end-caps. You  might see it come back with carbon-fibre composites though. It really depends what the priority is: structural efficiency or aerodynamic efficiency.

[Dizzyfugu]

Second that. AFAIK there are some research projects for BWB airliners which have become feasible through new materials like carbon fibres. They will be much more fuel-efficient than current designs, but the material technology is not ready yet for full-scale application in serial production. The Boeing 787 and the Airbus 350 are just as good as it currently gets, but I am certain that the BWB/Lifting Body design will be the next major step forward.

[Old Wombat]

Yep, multiple tubes, joined by cross-tubes occupying a lifting-body airframe. Not necessarily super-fast but able to move large numbers of people cheaply. Only the outer tubes would have windows & would be reserved for 1st-Class passengers.

... Could be a military use there!

[Weaver]

Doesn't need to be multi-tube with modern design techniques and materials: you can make a complex-shaped pressure vessel with walls that vary in strength locally depending on how much help or hinderance the shape is. Also, remember that it's not a submarine: the pressure differential it's trying to contain is less than 1 atmosphere, i.e. about 14 psi. The real challenge is not 'doing a Comet' and having it crack after x-hundred pressurization cycles.

[Rheged]

If anyone fancies a scratch built lifting body, the Cunliffe Owen OA-1  (data below) might fox the odd JMN or two.  Actually flown by the RAF and Free French air forces the Clyde Clipper, as it was known, ended up as part of a bonfire on VJ night.  Slip it into a selection of whiffs and see if it's identified as real world.


https://en.wikipedia.org/wiki/Cunliffe-Owen_Aircraft

[jcf]

CC&F built the CBY-3 in 1944:
https://en.wikipedia.org/wiki/Burnelli_CBY-3

It's being restored at NEAM:
http://warbirdsnews.com/aviation-museum-news/neam-burnelli-cby-3-loadmaster-restoration-update.html

Of course the ultimate source of Burnell info, a combo hagiography and breathless conspiracy theory mutterings,
is this site:
http://www.aircrash.org/burnelli/sitemap.htm

[Old Wombat]

One of the problems I can see with lifting bodies is that the fuselage has to be built to give maximum lift & minimum drag within a certain speed range.

If I remember rightly, the pilot of the F-15 had to keep a lot of power onto stay airborne. Yes, he'd lost a wing, but the fuselage was optimised to provide lift at high speeds.

A heavy freighter/airliner needs that lift on take-off, which means that at higher speeds the fuselage begins to become inefficient & draggy.

However, before someone jumps down my throat, I'm sure that modern engineering could overcome this through various means or a combination thereof.

[Weaver]

The reason why the F-15 pilot had to keep his speed up was that his aircraft was trying very hard to roll to the right, and he needed enough airflow over his one remaining aileron and the tailplanes to fight it. Every time he slowed down, the aileron & tailplanes began losing and the remaining wing (bigger than the aileron) began winning.

[Default Setting]

Doesn't need to be multi-tube with modern design techniques and materials: you can make a complex-shaped pressure vessel with walls that vary in strength locally depending on how much help or hinderance the shape is. Also, remember that it's not a submarine: the pressure differential it's trying to contain is less than 1 atmosphere, i.e. about 14 psi. The real challenge is not 'doing a Comet' and having it crack after x-hundred pressurization cycles.

So, pressurization wouldn't be too much of a technical challenge despite the unusual shape of the fuselage?

[Weaver]

Doesn't need to be multi-tube with modern design techniques and materials: you can make a complex-shaped pressure vessel with walls that vary in strength locally depending on how much help or hinderance the shape is. Also, remember that it's not a submarine: the pressure differential it's trying to contain is less than 1 atmosphere, i.e. about 14 psi. The real challenge is not 'doing a Comet' and having it crack after x-hundred pressurization cycles.

So, pressurization wouldn't be too much of a technical challenge despite the unusual shape of the fuselage?

I'd be amazed if you couldn't get a pressurizable shape, the issue would be whether it was worth the inevitable weight penalty or not. If your fuselage is generating lift that benefits you more than the weight penalty costs you, then you're in business.