X-66 Concept

[MolaKule]

I don't think this topic has been discussed before but this is an interesting concept.

https://simpleflying.com/nasa-boeing-sustainable-flight-demonstrator-project/

They will be taking a DC-90 fuselage and moving the wings to the top of the fuselage with underwing mounted engines.

Since the wings will be long and thin 'glider-type' wings, a strut will support the wing.

Due to the length of the wings, they will have to be segmented fold-up types in order to dock at conventional gates.

I haven't seen any X-66 wing profiles in the public domain but I suspect it will be a modified version of the NACA 661212-il profile or something similar.

One thing for sure, lift is a very strong function of the airfoil camber:

https://en.wikipedia.org/wiki/Camber_(aerodynamics)

FWIW, here's how we learned to analyze wings at Embry-Riddle:

https://eaglepubs.erau.edu/introduc...icles/chapter/worked-examples-airfoils-wings/

 

[fdcg27]

I'm not sure how much space the carry-through structure will take at the top of the fuselage, although with the wing being strut braced it might not be too bad, kind of like a strut braced Cessna on a much larger scale.
It is nice to see movement toward a new configuration, although the 30% fuel efficiency gain seems unlikely.
Still, even 20% could make this the next gen configuration for single aisle aircraft.
B797 anyone?

 

[MolaKule]

I'm not sure how much space the carry-through structure will take at the top of the fuselage, although with the wing being strut braced it might not be too bad, kind of like a strut braced Cessna on a much larger scale.
It is nice to see movement toward a new configuration, although the 30% fuel efficiency gain seems unlikely.
Still, even 20% could make this the next gen configuration for single aisle aircraft.
B797 anyone?

Yes, the structural design of this craft will be interesting.

When earlier announcements said, "ultrathin wings braced by struts with larger spans and higher-aspect ratios"

https://aerotoolbox.com/intro-wing-design/

I was imagining almost straight, sailplane like wings, but later artist renditions are showing a thin, sweptback wing supported by struts.

Those struts will have to be low-drag designs and some lit says these airfoils will also provide some lift.

I don't think Boeing has ever had a B790 designation so is this also a possibility?

 

[BusyLittleShop]

We were taught in the USAF that the red-line on the engine indicated where not to be while the engine was running because parts of the turbine could slice clean through you during an uncontained failure...

 

[MolaKule]

We were taught in the USAF that the red-line on the engine indicated where not to be while the engine was running because parts of the turbine could slice clean through you during an uncontained failure...

I was on the engine containment design and analysis team (three of us) analyzing fan and turbine blade containment on the 777 for all three engines.

We settled on a layered, repeating titanium-carbon fiber composite structure. It passed all engine cell, blade-out tests.

 

[burbguy82]

So is this a new plane or an old plane outfitted with new stuff?

 

[MolaKule]

So is this a new plane or an old plane outfitted with new stuff?

It is an older DC-9/MD-90 airframe that is being fitted with a special wing, strut, and underwing engines.

"The MD-90, the stretched derivative of the MD-80 and thus the third generation of the DC-9 family,[citation needed] was launched on November 14, 1989 when Delta Air Lines placed an order for 50 MD-90s, with options to purchase a further 110 aircraft.[8][9] The type was 57-inch-longer (1.4 m) longer than MD-80 and featured a glass cockpit (electronic instrumentation) and more powerful, quieter, fuel-efficient IAE V2525-D5 engines, with the option of upgrading to an IAE V2528 engine.[10]"

https://en.wikipedia.org/wiki/McDonnell_Douglas_MD-90

It will be a technology "demonstrator" to prove certain design concepts.

 

[burbguy82]

In my limited experience with airplanes:

It is an ugly airplane.

 

[JimPghPA]

Given Boeing's track record over the last several years, if this is ever built in my lifetime, I'm not getting on one until it has at least 3 years of safe flights.

 

[4WD]

Hope they rethink the mid - and the B797 nameplate is used for a carbon fiber single aisle with NEO and stretch capability …
(Replace B737) …