Airliner ASW Idea

[Cobra]

Hey Guys, tell me what You think of this:What If a 747,A 380,Etc. were Converted into an ASW Platform to Back planes like the Nimrod,Orion,Etc.? just struck me when Remembered someone here making a Comment about using the B-52 as an ASW platform. that got me to wondering if an Airliner could also be used for that! i also remembered hearing and reading about the P-3 being a Converted Airliner as well that being the Case for the Nimrod. what say you? thanks for looking. Dan

[Hobbes]

Well, the 737 is being offered for just that (as the P-8 Poseidon). I've been planning to build an A319 in the same role. The 747 and A380 are rather larger than necessary for ASW. I could see e.g. Britain wanting a very long range platform (to do UK-Falklands roundtrips), maybe using an A330/340.

[Weaver]

Actually MOST land-based ASW/MPA types are converted airliners or bombers: AFAIK, only the Atlantique/Atlantic was specially designed for the job. The Nimrod is a converted Comet and the P-3 is a converted Electra.

One problem is that these aircraft spend a lot of time flying low and slow over the ocean in relatively turbulent air, which causes fatigue problems. Old generation airliners like the Comet and Electra were over-engineered and could take this, but later generations of airliners have been designed ever-closer around the efficient 30,000ft cruise condition and don't have the strength margins to adapt. I suspect this is the major reason why the P-8 Poseidon is based on the 737 airframe rather than the later 757.

The aircraft also need a certain degree of agility at low level, which I suspect rules out the real monsters like the 747 and the A380. In any case, if the equipment suite for the job fits into a Comet-sized aircraft, what are you going to do with all the extra space? The main advantage of a bigger aircraft would be more fuel, but having a bigger cabin is a very inefficient way to achieve that: better to keep the cabin just the right size, beef up the wings and engines and add external or conformal tanks.

I think it's a real shame that the UK government couldn't fund an all-new Nimrod replacement instead of the MRA.4. My idea was to use it to kick-start a new generation of propfan-powered airliners in the same way that the 707 piggy-backed off the KC-135 program. Propfans are ideal for MPAs because they have most of the speed of a turbofan, most of the fuel economy of a turboprop, and a wide efficient cruise range which means they can dash or loiter without burning too much fuel. The main attraction of the Nimrod is it's four engines which means that it has a fast transit speed, but can then shut down two for efficient loiter and still have twin-engined safety. With two propfans, you could achieve the same results in a much simpler aircraft.

[pyro-manic]

The amount of money they spent on the MRA.4, they probably could have had an all-new design!

[GTX]

The other modern ASW/MP aircraft designed specifically for its role is the Kawasaki P-1:

One problem is that these aircraft spend a lot of time flying low and slow over the ocean in relatively turbulent air, which causes fatigue problems. Old generation airliners like the Comet and Electra were over-engineered and could take this, but later generations of airliners have been designed ever-closer around the efficient 30,000ft cruise condition and don't have the strength margins to adapt. I suspect this is the major reason why the P-8 Poseidon is based on the 737 airframe rather than the later 757.

Re the P-8A - despite the artwork, most of the time it will fly around 20000ft.  This is why there have been specially developed torpedoes etc.

Regards,

Greg

[apophenia]

The other modern ASW/MP aircraft designed specifically for its role is the Kawasaki P-1

Yeah, Kawasaki has kind of reversed things. They plan to turn the 4-engined P-1 into the 2-engined YPX airliner. (In the late '50s, Avro had similar plans for turning licenced Breguet 1150s into airliners -- the proposed Avro 754.)

[Weaver]

The other modern ASW/MP aircraft designed specifically for its role is the Kawasaki P-1:

Quite right - my bad.

Re the P-8A - despite the artwork, most of the time it will fly around 20000ft.  This is why there have been specially developed torpedoes etc.

Regards,

Greg

How do they intend to use MAD then? Nimrods have to get down to 200ft to get a worthwhile (still very short) range from it....

EDIT: found the answer: they deleted MAD in 2008 to save weight for increased endurance, although the Indian P-8Is will still have it. That then begs the question, how will they refine nebulous sonobuoy contacts?