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Post by George Carty - HJG on Jul 13, 2006 11:29:46 GMT
Why didn't more airlines buy 707-420s rather than 707-320s, given that the Rolls-Royce Conway was more pilot-friendly and had a lower SFC than the Pratt & Whitney JT4A? Was there a strong "buy American" preference?
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Post by garryrussell on Jul 13, 2006 12:44:03 GMT
The 420 according to a friend who was a navagator on them before becomming a VC 10 pilot had a better range than the 320..but the 320B had a much better range than the 420.
The 320 was turbojet and the 420 and 320B turbofan. BOAC bought 320B/C's once they were availiable in place of 420's. Really the 420 should be compared to the 320B rather than the straight 320.
Having said that the reason why BOAC ordered Conway version was balance of payment offset by using the Rolls-Royce engine. The better range was because it was a turbo fan....so it was more of a lucky bonus in BOAC's case.
Garry
Garry
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Post by George Carty - HJG on Jul 13, 2006 13:08:39 GMT
I thought that the -420 had range very little longer than the -320. More efficient engines, but also a smaller central fuel tank.
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Post by garryrussell on Jul 13, 2006 13:36:26 GMT
Maybe, I only know what my ex crew mate said in that it had a better range, he never said how much better, just better. Certainly they were over the moon about the 336B's a vast improvement over the 420.
Garry
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Post by jimhalinda on Jul 13, 2006 14:40:15 GMT
I would guess the same reasoning would apply to the DC-8-40, as compared to the P&W equipped -30 and -50 series?
George, what was it about the RR Conway that made it more pilot friendly?
I'm partial to the RR-equipped 707s and DC-8s, partly because Air Canada's first DC-8s were -40s. And two of my favorite 707 operators are BOAC and Air India. Guess I'm a British Commonwealth kind of guy, and what's more British than a Rolls-Royce engine?
Regards,
Jim
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Post by aerofoto - HJG Admin on Jul 13, 2006 14:41:35 GMT
Range is a "very grey area".
It really depends on so many other perameters/factors.
However .... the range of the a fully laden fanjet powered -420 was in fact only a little more than that of a turbojet powered -320.
As powerful, fuel efficient, and more environmentally friendly as the -420's RR CONWAY fanjet engines were in comparason to the P&W JT4 series turobjet engines, they were just as quickly followed in to service by the even more powerful, fuel efficient, and environmentally friendly (for the times) P&W JT3D series fanjet engines .... and these quickly outclassed the RR powerplants to the extent of becomming a B707 standard.
At least that's my understanding of things.
Mark C AKL/NZ
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Post by George Carty - HJG on Jul 13, 2006 15:02:34 GMT
George, what was it about the RR Conway that made it more pilot friendly? Faster acceleration, plus an automatic speed limiter which meant that the pilot could simply apply full throttle for takeoff, rather than having to carefully set the correct EPR rating as on a P&W aircraft.
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Post by George Carty - HJG on Jul 13, 2006 15:04:02 GMT
However .... the range of the a fully laden fanjet powered -420 was in fact only a little more than that of a turbojet powered -320. Due to the -420's smaller centre tank. As powerful, fuel efficient, and more environmentally friendly as the -420's RR CONWAY fanjet engines were in comparason to the P&W JT4 series turobjet engines, they were just as quickly followed in to service by the even more powerful, fuel efficient, and environmentally friendly (for the times) P&W JT3D series fanjet engines .... and these quickly outclassed the RR powerplants to the extent of becomming a B707 standard. So the RR Conway's real problem was that it was too late, and was soon superseded by the JT3D?
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Post by christrott on Jul 13, 2006 16:16:19 GMT
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Post by piedmont700 on Jul 13, 2006 20:58:53 GMT
Also, you may want to read the book "Comets and Concordes (and those I flew before)" by Peter Duffey. He flew the -320 and -420 series' that BOAC operated, and he preferred their version of the -320. For one, he mentions that, and I don't remember how, but the -420 was apparently very easy to strike the bottom of the nacelles on landing, while the -320 was not. Also, the systems were different enough to potentially cause problems, and the performance of the -320 was preferred by the pilots over the -420
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Post by aerofoto - HJG Admin on Jul 13, 2006 20:58:55 GMT
Probably not no so much that it was too late .... but rather .... development of the P&W powerplant was only some 2 years behind RR anyway and was ultimately a better and more economical performer .... despite RR powerplant still being a very good engine. I don't now it it's true, but, I recall someone telling me the fan on RR CONWAY engines actually rotated in the opposite direction from that of P&W and other powerplants Looking at success of B707-420. With the exception of Germany's LUFTHANSA, it really only sold within regions of significant British influence. Despite this they were a very good aircraft .... and I think AIRTOURS operated some of the ex BRITISH AIRWAYS aircraft into the early l980's. Mark C AKL/NZ
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Post by garryrussell on Jul 13, 2006 21:15:04 GMT
Hi Mark
BEA Airtours did indeed run the 420's for many years running them into the ground (not literally).
VARIG was another 420 customer.
Garry
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Post by jimhalinda on Jul 13, 2006 21:45:50 GMT
I seem to recall reading somewhere that Trans Canada Airlines (which became Air Canada in 1964) bought RR-equipped DC-8s for similar reasons - Canada being a former British dominion, I think it was simply an automatic pro-British decision.
Of course, it didn't stop them from buying P&W equipped models later on...
Regards,
Jim
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luke
CV-990
Posts: 36
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Post by luke on Jul 13, 2006 22:38:14 GMT
I seem to recall reading somewhere that Trans Canada Airlines (which became Air Canada in 1964) bought RR-equipped DC-8s for similar reasons - Canada being a former British dominion, I think it was simply an automatic pro-British decision. Canadian Pacific also purchased Series 40 DC-8s. Cheers! Luke
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Post by jimhalinda on Jul 13, 2006 23:40:35 GMT
Of course, forgot about them! One of my favorite colour schemes too!
Like Air Canada, they later purchased P&W equipped models. As is mentioned in this thread, I'm sure they just couldn't argue with improved power and fuel efficiency.
But those RR engines sure have a nice deep growl to them!
Regards,
Jim
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