6 ms·

They're turbojet engines, not the turbofans that you see today. Turbojets have a smaller intake and the entire thing produces thrust. Unlike today's much more

They're turbojet engines, not the turbofans that you see today. Turbojets have a smaller intake and the entire thing produces thrust. Unlike today's much more efficient turbofans, where a small turbojet turns the larger fans to produce most of the thrust.

mirimir 10y ago
OK, I get it. Thanks :) They are very cool looking.
- int_19h 10y ago
  FWIW, other turbojet airliners had larger intakes. E.g Tu-104 (which, coincidentally, was propped by Comet's fall, becoming the only jet airliner in service for a couple of years): http://i.imgur.com/L4KLas2.jpg http://i.imgur.com/L4KLas2.jpg
cstross 10y ago
The Nimrod maritime patrol aircraft was a modified Comet airframe: https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod In the early 2000s, BAe Systems had a project in train to upgrade them to the MRA4 spec, essentially remanufacturing the existing MRA2/MRA3 Nimrods around a new wing structure that could accommodate RR BR700 turbofans, doubling the aircraft's range: https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 (Go look at the photos on the respective wikipedia pages and examine the engine inlets at the wing roots: the MRA4's air intakes are much larger.) The MRA4 upgrade was at least as radical as the proposal to re-engine USAF B-52 bombers with four GE high-bypass turbofans (as seen in the photograph on the web page below, showing a B-52 flying with the new engine in the inboard starboard pod): http://aviationweek.com/defense/ge-rolls-pratt-vie-b-52-engine-upgrade http://aviationweek.com/defense/ge-rolls-pratt-vie-b-52-engi... ... Which also got cancelled; in the case of the B-52 the USAF had so many old engines in mothballs that re-engining the B-52 would cost more than just swapping out old units, and in the case of the Nimrod MRA4 the program ran into nightmarish cost-overruns when it became apparent that the aircraft they were trying to remanufacture were all different — the RAF's Nimrod fleet had been hand-built then patched for half a century and simply couldn't be consistently upgrades. (Moral of story: upgrading a 50+ year old design is harder than it looks.)
- mirimir 10y ago
  Doh, I never really noticed how small those B-52 engines are. It makes the plane so elegant and insectile.
- gaius 10y ago
  Following the cancellation, the Defence Secretary Liam Fox used the Nimrod MRA4 procurement as an example of the worst of MOD procurement performance Ah those innocent days, before the QE carriers and the F35 made that look like mere pocket change.
  - rjsw 10y ago
    I thought the consensus was that the construction of the carriers had gone really well.
    - gaius 10y ago
      They were supposed to have finished their sea trials by now. Also they were supposed to be convertible to cats & traps at the drop of a hat, which would have allowed the UK to procure a non-BAe fighter to fly off them, couldn't have that...

mirimir 10y ago

OK, I get it. Thanks :) They are very cool looking.

int_19h 10y ago
FWIW, other turbojet airliners had larger intakes. E.g Tu-104 (which, coincidentally, was propped by Comet's fall, becoming the only jet airliner in service for a couple of years): http://i.imgur.com/L4KLas2.jpg http://i.imgur.com/L4KLas2.jpg

cstross 10y ago

The Nimrod maritime patrol aircraft was a modified Comet airframe: https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod In the early 2000s, BAe Systems had a project in train to upgrade them to the MRA4 spec, essentially remanufacturing the existing MRA2/MRA3 Nimrods around a new wing structure that could accommodate RR BR700 turbofans, doubling the aircraft's range: https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 (Go look at the photos on the respective wikipedia pages and examine the engine inlets at the wing roots: the MRA4's air intakes are much larger.) The MRA4 upgrade was at least as radical as the proposal to re-engine USAF B-52 bombers with four GE high-bypass turbofans (as seen in the photograph on the web page below, showing a B-52 flying with the new engine in the inboard starboard pod): http://aviationweek.com/defense/ge-rolls-pratt-vie-b-52-engine-upgrade http://aviationweek.com/defense/ge-rolls-pratt-vie-b-52-engi... ... Which also got cancelled; in the case of the B-52 the USAF had so many old engines in mothballs that re-engining the B-52 would cost more than just swapping out old units, and in the case of the Nimrod MRA4 the program ran into nightmarish cost-overruns when it became apparent that the aircraft they were trying to remanufacture were all different — the RAF's Nimrod fleet had been hand-built then patched for half a century and simply couldn't be consistently upgrades. (Moral of story: upgrading a 50+ year old design is harder than it looks.)

mirimir 10y ago
Doh, I never really noticed how small those B-52 engines are. It makes the plane so elegant and insectile.
gaius 10y ago
Following the cancellation, the Defence Secretary Liam Fox used the Nimrod MRA4 procurement as an example of the worst of MOD procurement performance Ah those innocent days, before the QE carriers and the F35 made that look like mere pocket change.
- rjsw 10y ago
  I thought the consensus was that the construction of the carriers had gone really well.
  - gaius 10y ago
    They were supposed to have finished their sea trials by now. Also they were supposed to be convertible to cats & traps at the drop of a hat, which would have allowed the UK to procure a non-BAe fighter to fly off them, couldn't have that...