Airbus Propfan Concepts from the 80's

[Antonio]

Found this drawings on a Spanish "popular science" magazine from 1985

 

[agricola64]

why does the spb-11 concept have the engines in different positions on every side of the a/c?

 

[AeroFranz]

it probably shows two different possible configurations.

 

[hole in the ground]

Are there any details to go with it or just this tantalising graphic?

 

[Antonio]

No details from my source, only the drawings

 

[Vahe Demirjian]

I'm curious, what do the acronyms SBP and WBP in the designations for the 1980s Airbus propfan airliner projects stand for?

 

[dan_inbox]

SBP shielded bypass ?

 

[TomS]

Probably single-aisle and widebody, since that seems to be the main difference between the two fuselages.

 

[overscan (PaulMM)]

slim body propfan and wide body propfan.

 

[JohnR]

What happened to propfans, in the late 80's through to the early 90's, all sorts of proposals were being made for them, but nothing seems to have appeared.

 

[overscan (PaulMM)]

1) Fuel costs went down
2) Noise was an issue
3) Reliability similar to turbofans would take a while to achieve
4) It didn't suit underwing mounting on existing designs which meant unique airframes needed designing
5) More efficient turbofans made enough improvement at lower risk.

Modern geared high bypass turbofans are getting closer to propfan territory.

 

[taildragger]

1) Fuel costs went down
2) Noise was an issue
3) Reliability similar to turbofans would take a while to achieve
4) It didn't suit underwing mounting on existing designs which meant unique airframes needed designing
5) More efficient turbofans made enough improvement at lower risk.

Modern geared high bypass turbofans are getting closer to propfan territory.

Passenger preference probably also played a role. Airlines discovered that many passengers will select flights to avoid anything with propellers when regional jets were introduced. I'd guess that vibration was also an issue.

 

[coanda]

Potentially, the offset propfans were to try to avoid sound wave interactions from the tips of the fans - even through the tailplane. Possible that it could reduce the noise (a noted issue with open rotors) but also manage fatigue stresses in the tailplane.

 

[1635yankee]

What happened to propfans, in the late 80's through to the early 90's, all sorts of proposals were being made for them, but nothing seems to have appeared.

When I worked with propfans, fuel costs were about 10% of an airline's operating costs.

 

[uk 75]

The two podded engine airliner has established itself as the best solution to the exclusion of all the paper and prototype designs that have been put up against it.
If some kind of energy renewable alternative is developed we may see this change, but I am not holding my breath.

 

[coanda]

The podded engine approach is useful for offsetting wing bending moment, however its a more complicated engineering task for the wing team. I think, overall, podded engines aren't going anywhere with the conventional tube and wing layout. What will be of interest is what's in those pods. I am an advocate of a central power generation system with electric fans, and I'd like to see where that could go. That might not necessarily preclude open rotor fans, since, they're potentially lighter than a nacelle/fan. Again, the problem is more about the acoustics than anything else as far as I'm aware.