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De Havilland Comet  
User currently offlinePMN1 From United Kingdom, joined Jun 2007, 78 posts, RR: 0
Posted (5 years 1 month 2 weeks 2 days 12 hours ago) and read 3788 times:

Did de Havilland ever look at the possibility of 6 Ghost engines for the Comet?

What would the extra power enable de Havilland to have done?

6 replies: All unread, jump to last
 
User currently offlineMetroliner From United Kingdom, joined Jan 2007, 1067 posts, RR: 1
Reply 1, posted (5 years 1 month 2 weeks 2 days 6 hours ago) and read 3720 times:



Quoting PMN1 (Thread starter):
What would the extra power enable de Havilland to have done?

Consume 50% more fuel?  Smile

The earlier Comets were no hotrods, by all accounts, and the four Ghosts were about adequate for the early, short-fuselage Comets.

The beefed-up Comet 4 introduced Avon engines with a whole lot more thrust. I read an article in Flight Illustrated YEARS ago on the last flying Comet in the RAF - 'Canopus' - which had a fantastic pull-out poster with the bird sustaining a 45-degree climb. Lightly loaded, and even not, the Comet 4s were powerful airliners even by modern standards.

The bigger question is why DH chose to go against the Boeing ethos of podded engines - the Comet 5 was to have possed engines - but it was already too late by then. Traditional story of British aviation!  Sad



Set the controls for the heart of the Sun
User currently offlineVirginFlyer From New Zealand, joined Sep 2000, 4537 posts, RR: 41
Reply 2, posted (5 years 1 month 2 weeks 2 days 2 hours ago) and read 3687 times:



Quoting Metroliner (Reply 1):
The beefed-up Comet 4 introduced Avon engines with a whole lot more thrust.

In fact the Comet 2 was the first to use the Avon. If I recall correctly, the intention had always been that the Comet would eventually be powered by the Avon, but the Ghost allowed them to have an aircraft in operation sooner.

Quoting Metroliner (Reply 1):
The bigger question is why DH chose to go against the Boeing ethos of podded engines - the Comet 5 was to have possed engines - but it was already too late by then. Traditional story of British aviation!

I believe arguments in favour of the buried engines included allowing them to be placed closer to the centreline, which allowed a smaller fin and rudder, and keeping them further away from the ground, which reduced the risk of FOD. Obviously in the scheme of things the disadvantages of the buried engines outweighed these advantages.

As for the traditional story of British aviation, I recall reading a comment by the great man himself that even if his Comet had not suffered from the fatigue cracks, and had had have been technically equivalent to the 707 or the DC-8, manufacturing of aircraft in the UK was a cottage industry compared to the USA, and it was always destined to be eclipsed by the Americans. I think rather than bemoaning the passing of the British airliner (and trust me I've done my fair share of moaning about it!), we should be thankful that, in spite of the hindrances, they achieved as much as they did...

V/F



"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh
User currently offlineLongHauler From Canada, joined Mar 2004, 4915 posts, RR: 43
Reply 3, posted (5 years 1 month 2 weeks 2 days 1 hour ago) and read 3676 times:



Quoting Metroliner (Reply 1):
The bigger question is why DH chose to go against the Boeing ethos of podded engines - the Comet 5 was to have possed engines - but it was already too late by then. Traditional story of British aviation!

The pictures (drawings) I have of the Comet 5 have the four RR Conways in the wing root like all the other Comets. The wing sweep does appear to be greater, and the tail is swept as well. The same lean elegant look of the earlier Comets, with a more modern twist.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlineMetroliner From United Kingdom, joined Jan 2007, 1067 posts, RR: 1
Reply 4, posted (5 years 1 month 2 weeks 1 day 17 hours ago) and read 3609 times:



Quoting LongHauler (Reply 3):
The pictures (drawings) I have of the Comet 5 have the four RR Conways in the wing root like all the other Comets. The wing sweep does appear to be greater, and the tail is swept as well.

Any chance we could get a look at those?  Smile

Quoting VirginFlyer (Reply 2):
we should be thankful that, in spite of the hindrances, they achieved as much as they did...

Not disagreeing with you at all there.  Smile

(Though I do reserve the right to be forever grumpy about the ending of the Avro RJ programme.)



Set the controls for the heart of the Sun
User currently offlinePMN1 From United Kingdom, joined Jun 2007, 78 posts, RR: 0
Reply 5, posted (5 years 1 month 2 weeks 1 day 16 hours ago) and read 3595 times:



Quoting Metroliner (Reply 1):
The bigger question is why DH chose to go against the Boeing ethos of podded engines

Interesting section from Tony Buttler’s 'British Secret Projects: Jet Bombers since 1949' reagarding engine installations.

The Short SA4 was a 1945 bomber design with either 4 or 6 buried engines.

'Agreement for ordering two S.A.4’s was reached in late February 1947 at which point it was planned to house the four AJ65’s side by side in two underwing nacelles. However, in mid-February 1949, after tunnel tests at RAE Farnborough. Keith-Lucas confirmed that two engines in a single vertical nacelle above and below each wing had been adopted instead of the previous arrangement or an alternative four single underwing nacelles. Rolls experience on a design with twin engines mounted side by s side had indicated that the aerodynamic forces on the cowl were very large and needed a heavy structure. Engines arranged horizontally in a nacelle suspended below the wing by a slim faired strut were also suggested (and favoured at RAE), but Shorts rejected this because it presented several structural problems and would be difficult to accommodate without extensive redesign of the wing. Prototype construction had just begun.'


User currently onlineViscount724 From Switzerland, joined Oct 2006, 24889 posts, RR: 22
Reply 6, posted (5 years 1 month 2 weeks 1 day 8 hours ago) and read 3510 times:



Quoting Metroliner (Reply 1):
The bigger question is why DH chose to go against the Boeing ethos of podded engines

As did the first two Russian commercial jets, the Tu-104 (based on the Tu-16 bomber), and smaller Tu-124.


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