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Purpose-designed jet MRP engine layout?

Tony Williams

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Jan 10, 2013
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Some idle thoughts to kick around:

Maritime recce/antisub planes spend much of their time cruising fairly slowly at lowish altitudes, for which high power is not needed but good economy is. They do need higher power for limited periods, for take-off and closing with a target.

So... the optimum main engine for continuous use would be the biggest, most fuel-efficient high-bypass turbofan for the cruising power required, which could be fitted into the tail of the aircraft. Just one of them, for maximum economy.

For meeting burst-power needs (and in case something happens to the main engine) small turbojets would be optimal; fuel consumption would not really be an issue, so it would be better to keep the diameter of the engines as small as possible, to minimise drag when cruising. One or two would be needed, ideally at the tail end of the plane to keep the thrust symmetrical. Depending on the layout, the possibility of a retractable fairing over the jet engine intake(s) to minimise drag might be worth considering.

I don't know if any designers have ever considered something like this.



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Nov 25, 2020
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The idea of mixing powerplants (for maritime patrol aircrafts included, the P2 Neptune illustrated for example) is not a novelty.

The only modern purposed built maritime patrol aircraft I can think of is the Japanese Kawasaki P-1. It is motorised by four high bypass turbofans especially developed for it.

Talking about your solution and from my humble point of view, a single engine for cruising low and slow would be unsafe in case of engine problem, giving only a short amount of time before going feet wet.
High bypass turbofans seem to give enough power and economy to avoid the complexity of two types of powerplants. But someone with real knowledge of motorisation may have a better answer.


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Aug 18, 2020
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Many eons ago, when I worked for the since-reorganized and renamed Hamilton Standard, we did props for the P-3. The advantages of turbofans is that they get MPA to their patrol areas far more quickly and permit them to cover much larger areas of surface, since their role includes tracking surface ships.