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Had The Convair 880/990 Been A Twin?  
User currently offlinezippyjet From United States of America, joined Sep 2001, 5488 posts, RR: 13
Posted (2 years 10 months 1 week 6 days 16 hours ago) and read 2888 times:

Though billed as the fastest jet in the world back in the day, the Convair 880/990 never really took off sales wise. Another what if thread; What if these 2 Convair Jets were twins instead of 4 holers? Same performance, same size, same capacity etc. Could it have given the 707/720 and DC-8's some formidable competition? How would this have impacted the 727 and 737 programs?


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15 replies: All unread, jump to last
 
User currently offlinepolot From United States of America, joined Jul 2011, 2261 posts, RR: 1
Reply 1, posted (2 years 10 months 1 week 6 days 15 hours ago) and read 2840 times:

Quoting zippyjet (Thread starter):
Same performance, same size, same capacity etc. Could it have given the 707/720 and DC-8's some formidable competition? How would this have impacted the 727 and 737 programs?

How would it have the same performance (I assume you mean in range/speed and not fuel burn), same size, and same capacity etc while being a twin? The technology just wasn't there. If it existed it probably would give the 707/DC-8 formidable competition...it would be incredibly advanced compared to them.


User currently offlinezippyjet From United States of America, joined Sep 2001, 5488 posts, RR: 13
Reply 2, posted (2 years 10 months 1 week 6 days 15 hours ago) and read 2787 times:

Quoting polot (Reply 1):
How would it have the same performance (I assume you mean in range/speed and not fuel burn), same size, and same capacity etc while being a twin?

Maybe more along the size of a 737-100 or 200.



I'm Zippyjet & I approve of this message!
User currently offlineFlaps From United States of America, joined Feb 2000, 1286 posts, RR: 4
Reply 3, posted (2 years 10 months 1 week 6 days 15 hours ago) and read 2766 times:

Given the available engines of the day a twin engine 880/990 would have needed about a 25,000' runway to get off the ground. If it could get off the ground at all.

User currently offlineYXwatcherMKE From United States of America, joined May 2007, 1014 posts, RR: 2
Reply 4, posted (2 years 10 months 1 week 6 days 14 hours ago) and read 2741 times:

There is one big problem with you idea! The technology of the day just was not there yet for an aircraft of it's size and performance to produce an engine strong enough to fly the a/c with only two engines. Had there been such an engine back then, then yes, they would not been able to keep up with the demand for them.


I miss the 60's & 70's when you felt like a guest on the plane not cattle like today
User currently offlineBMI727 From United States of America, joined Feb 2009, 15781 posts, RR: 27
Reply 5, posted (2 years 10 months 1 week 6 days 14 hours ago) and read 2713 times:

Quoting zippyjet (Thread starter):
What if these 2 Convair Jets were twins instead of 4 holers? Same performance, same size, same capacity etc.

That simply was not possible at the time. Engines just did not have the power to achieve that.



Why do Aerospace Engineering students have to turn things in on time?
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 6, posted (2 years 10 months 1 week 6 days 14 hours ago) and read 2705 times:

Check this old forum!

Convair 880 / DC-8 Survivability/Longevity (by Blackbird Jul 21 2007 in Tech Ops)

It contains pictures of a Convair twin.


User currently offlinerikkus67 From Canada, joined Jun 2000, 1661 posts, RR: 1
Reply 7, posted (2 years 10 months 1 week 5 days 12 hours ago) and read 2278 times:

I vaguely remember there had been some talk of re-engining at least part of the remaining ex-TWA fleet with 2-CFM's. Did anything go farther forward than just on paper?


AC.WA.CP.DL.RW.CO.WG.WJ.WN.KI.FL.SK.ACL.UA.US.F9
User currently offlineNavigator From Sweden, joined Jul 2001, 1214 posts, RR: 14
Reply 8, posted (2 years 10 months 1 week 5 days 9 hours ago) and read 2170 times:

Quoting zippyjet (Thread starter):
Though billed as the fastest jet in the world back in the day, the Convair 880/990 never really took off sales wise. Another what if thread; What if these 2 Convair Jets were twins instead of 4 holers? Same performance, same size, same capacity etc

You did not have any engines to be able to do that in those times. You could never get that performance out of the engine technology available at that time. So you question is really not realistic.



747-400/747-200/L1011/DC-10/DC-9/DC-8/MD-80/MD90/A340/A330/A300/A310/A321/A320/A319/767/757/737/727/HS-121/CV990/CV440/S
User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1389 posts, RR: 3
Reply 9, posted (2 years 10 months 1 week 5 days 9 hours ago) and read 2141 times:

The APU on a 777F has more power (though none of it is used for thrust) than the first generation turbojets. When the CV came out, it was using generation 1.5 of turbojets, still offering less thrust than even the first generation CFM56-3 engines.

But, I suppose that in another 50 years someone born 30 years from now will ask "Why did they use turbofan engines back then, and not a Hyperdrive?"



From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlineebj1248650 From United States of America, joined Jun 2005, 1932 posts, RR: 1
Reply 10, posted (2 years 10 months 1 week 5 days 6 hours ago) and read 1993 times:

Quoting 474218 (Reply 6):
Check this old forum!

Convair 880 / DC-8 Survivability/Longevity (by Blackbird Jul 21 2007 in Tech Ops)

It contains pictures of a Convair twin.

Found that very interesting. The twin with the aft mounted engines was an especially interesting idea. I presume Convair determined there was too much competition to pursue the project?



Dare to dream; dream big!
User currently offlinemilesrich From United States of America, joined Jul 2003, 2006 posts, RR: 6
Reply 11, posted (2 years 10 months 1 week 4 days 21 hours ago) and read 1781 times:

Quoting BMI727 (Reply 5):
That simply was not possible at the time. Engines just did not have the power to achieve that.

The development of airframes depended on the development of engines. This was true in the piston era and in the jet age. If you read this board, you would know that the jet engines that powered the first airliners, the DC-8 and 707, as well as the CV-880, came from military applications. The J-57, 75, and 79 were military designations for the P&W JT-3, JT-4 and the GE CJ-805. The first JT-3's only developed 10,000 of thrust. The JT-8D, which powered the DC-9 and 727, produced was the military J-52. The development of this engine enabled Boeing and Douglas to build twin and tri-jets that could carry economical payloads. Hi Bypass engines came along with the development of the C-5A and 747, and of course, rest is history, but the basic premise of this thread is nonsensical. Not only that, there was a preference for four engine airplanes by the public and the airlines. Look how many airlines replaced Convairs with DC-6's to carry another 10-20 passengers when payloads averaged less than 50%. The business has changed. The economics have changed, . . . . . Perhaps if Convair had designed their aircraft to accept P&W or RR engines as alternatives, or designed a fuselage that could have been stretched, they could have sold the airlines on the comfort quality of 2-3 versus 3-3 seating, but American nixed that idea in 1955 when they told Boeing, widen your airplane or we are going with Douglas. The whole idea of three American manufacturers developing aircraft that were so close in application just made no sense. Convair originally thought that targeting the medium range market would give them a niche, but then Boeing, at United's request produced a lighter weight, less expensive, medium range 707, the 720, and instead of ordering Convair, ordered the 720. Remember that the non fan jet 720 sold the exact same number of airframes as the 880. The fact is that once the 727 was put into production, the market for the 720/880 was very limited, and at the time these aircraft were first sold, there was no fan jet other than the after fan RR Conway, and the GE CJ805 that powered the 990, and neither of those were a match for the JT-3D. Convair was successful building smaller twin propeller airplanes, plus they were also fortunate to have the Glenn Martin Company as their competitor, a firm that knew nothing of about building transports and proved it. The same might be said about Consolidated Vultee but they got their act together and improved the originally 240, and they also benefited from large DOD contracts. The beginning of jet age was an exciting time to live through, but at the beginning everything was speed, and a sort of bubble attitude on the part of the airlines that if their competitor had a new plane, they needed one too. And this really was the environment until deregulation. Hence, Eastern, Delta, Continental, National ordered 747's. There was a time 35 years ago that you could not compete in the Mainland - Hawaiian market or the Trans Atlantic market without wide bodied airplanes. If United or American were able to buy 757's in 1975 and fly them on the Hawaii routes against competitors 747's, and DC-10's, they would gone broke. Western tried it and was not very successful. TWA operated that round the world service for a short period of time with the 707, and if they had had good loads at least on the LAX-HNL leg, perhaps they would have hung on longer with it, but as I said, no one wanted to fly in a 707 when they could take a 747 or DC-10.

[Edited 2011-12-18 13:52:21]

User currently offlineaviatorcraig From United Kingdom, joined Mar 2010, 232 posts, RR: 0
Reply 12, posted (2 years 10 months 1 week 4 days 21 hours ago) and read 1735 times:

Also bear in mind that ETOPS did not exist back then. ALL aircraft that were going to spend several hours over water were 4-holers. It was only many years later that the three-engined L-1011 and DC-10 broke that mould before they too were surpassed by the newly approved ETOPS ops of the 767, A300 etc.
To have fitted the 880/990 with just two engines back then (even if such powerplants existed) would have restricted its possible missions against the competitors 707/DC-8/VC-10/IL-62



707 727 Caravelle Comet Concorde Dash-7 DC-9 DC-10 One-Eleven Trident Tristar Tu-134 VC-10 Viscount plus boring stuff!
User currently offlinemilesrich From United States of America, joined Jul 2003, 2006 posts, RR: 6
Reply 13, posted (2 years 10 months 1 week 4 days 20 hours ago) and read 1683 times:

Quoting ebj1248650 (Reply 10):
Found that very interesting. The twin with the aft mounted engines was an especially interesting idea. I presume Convair determined there was too much competition to pursue the project?

Once Convair (General Dynamics) took the hit on the 880/990 project, taking a writeoff of an unheard of at the time $475 Million, they got out of the large airframe/airliner business. Those drawings must have been done before the decision was made to "shut it down". I don't remember if taking the loss required them to scrap the tooling or not.


User currently offlineprebennorholm From Denmark, joined Mar 2000, 6485 posts, RR: 54
Reply 14, posted (2 years 10 months 1 week 4 days 18 hours ago) and read 1566 times:

Quoting zippyjet (Thread starter):
Had The Convair 880/990 Been A Twin?

Then it would have used the same engines as the B757.

For engine availability the first prototype would have been ready for its maiden flight at roughly the same time as when the last 880/990 was scrapped.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently offlineBurkhard From Germany, joined Nov 2006, 4401 posts, RR: 2
Reply 15, posted (2 years 10 months 1 week 4 days 11 hours ago) and read 1387 times:

Quoting BMI727 (Reply 5):
That simply was not possible at the time. Engines just did not have the power to achieve that.

... nor did they have the reliability for long range flying...


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