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Plectron
14th Apr 2010, 02:29
Just curious, perhaps the wiser crowd could enlighten me. Why hasn't the MD-11 and DC-10-30 been re-engined with twins? Many such in the past - radial gas to turbines; Convairs, Fokker F27, High-Bypass-KC-135, etc.

Just looking at the very un-natural center engine yesterday made me wonder why it is still there. Certainly it would have been designed as a twin if the technology was there. Or not?

Thanks.

411A
14th Apr 2010, 03:04
Certainly it would have been designed as a twin if the technology was there. Or not?

Not likely, ETOPS regulations being what they were...at the time.
The reason these airplanes have more than two engines is...they needed them, considering the engine thrust varients available at the time...long ago.
Redesign now?
Sorry, not cost effective.

rottenlungs
14th Apr 2010, 05:48
Hi

As far as I recall, the DC10 was initially designed as a twin, but a specific requirement to be able to operate from La Guardia was not achievable with the powerplants available at the time. Hence the centre engine.

As 411A quite rightly states, the cost of certification would not be viable.

Cheers

James

Chris Scott
14th Apr 2010, 11:53
Plectron,

I agree with 411A and rottenlungs.

But also: if you remove that heavy centre engine and its mounting structure, you push the C of G way forward. So you either have to move the wings forward (impracticable), or extend the rear fuselage. The larger-diameter engines would probably necessitate lengthening of the landing gear.

There are already two formidable big-twins on the market.

Chris

Plectron
14th Apr 2010, 13:47
Thanks guys - I figured it was impractical yet the airframe for the MD-11 sure must have years left on it to run and the fuel cost savings would be staggering. I am getting out of the biz anyway - just was curious - never got to fly either one of the beasts. Missed the 707 as well...sigh.

Chris Scott
14th Apr 2010, 15:40
Plectron,

If it is age-related retirement from airliner cockpits, welcome to the club!

Personally, did less than 3 years on late-model Seven-oh (P2) and about 18 months P1 on the DC10-30. Both are superb aeroplanes, in terms of economy and basic concept. But both seemed a bit archaic, mainly in terms of systems (particularly failure-redundancy), by the time I got my hands on them.

Guess you could have mentioned 411A's Tristar, a more sophisticated aeroplane.

Plenty of scope for reading and discussion in the Aviation History and Nostalgia forum?

Chris

Plectron
14th Apr 2010, 20:06
Nah, the L-1011 looks beautiful. It isn't an airplane where you wonder why it was was built like that. It looks perfect.

And yes, age related retirement. Plus I sure don't fit in very well with some of the "new" crowd. 'Nuff said on that subject.

barit1
16th Apr 2010, 03:04
The real reason for the #2 (center) engine:
http://images.pictopia.com.edgesuite.net/perl/get_image?provider_id=425&md=2007-04-15%2016:02:44&ptp_photo_id=dc3:703597&size=175x175_mb

It was so McD could draw this picture!

Graybeard
16th Apr 2010, 04:06
After Eastern A/L bought their firs A300s, the possibility of a Twin Ten was studied seriously by McDouglas, but there was never enough customer interest.

The rightful semi-retirement for the DC10-30 and MD-11 is conversion to military refueling tankers, where fuel economy isn't such a big deal. The KC-10A has always been the most reliable plane in the USAF fleet.

Tankers get about a tenth the utilization of airliners, so it is extremely wasteful to buy new tankers such as the KC-767 or A330 equivalent, when half-life airliners are plentiful and cheap.

GB

DCDriver
17th Apr 2010, 12:16
Why hasn't the MD-11 and DC-10-30 been re-engined with twins?
What??? And ruin the two most beautiful airliners after the Constellation?

Barit - loved the Dakten! :ok:

DCD (already in semi-retirement!)