747-600X
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The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 3:51 am

If an aircraft developer were to develop an aircraft of substantial size, perhaps akin to a 747, and give it design very similar to the MD-11 or L-1011 but far larger, perhaps there would be something to be said for having 'just' three engines, when an overseas, esp. Pacific flight would count this as 'especially' three engines. On very large aircraft, three engines would prove more economic than 4, such as on something between the size of a 747 and A3XX with 777-size engines. The efficiency and range of these aircraft, and the safety, especially of mind just knowing you've got the extra engine, would - I would think - propell a New Large Trijet into the viable market.
Opinions?
 
Guest

RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 4:04 am

I like tri-jets alot, but maybe overall it is just too expensive to create jet´s with a third engine in the tail.
 
Guest

RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 4:07 am

That leads to the Question, are the 4 engines on Quad`s similar to each other ?
 
747-600X
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Ab.400

Sat May 06, 2000 4:16 am

All aircraft use the same engines, no matter where they are. I don't know if that's what you were asking, but even on L-1011s and MD-11s the engines are all the same make. I would prefer the L-1011 design for a variety of reasons, but I don't think it's too much more expensive, also, by having it closer to the ground maintence could be easier.
 
D L X
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Hold The Phone!

Sat May 06, 2000 4:21 am

Not so fast 747-600X,

There are 727s where the outer two engines are a different, less powerful make than the internal engine. I think UPS flies these.

Also, one of the ideas for a stretched 747 would have had two 777 class engines near the fuselage, and regular 747/767 engines on the outboard.

As long as it is symmetric, it will fly.  
And actually, even then that's not entirely true. There was an experiment for a new bizjet with one jet engine. The intake was on one side, and the outflow was on the other. However, it was DAMN ugly, so I doubt it would sell.
 
747-600X
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D L X

Sat May 06, 2000 4:25 am

I'd thought of that in the past, however I was informed by a UA pilot that all aircraft's engines are the same (DC-10 pilot). It makes sense, but I didn't know they did it (I mean, use different strengths). If that's the case, then it doesn't change my original suggestion at all.
 
ual757
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RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 4:40 am

2 on the side and 2 outboard? in a way, i think it'd look pretty cool..

i'm not sure the 777's have enough push for a loaded 747, but considering some of the things i've seen those engines do, i wouldn't be suprised..

as to the A3XX, what is the average expected MTOW? and the speed? i'm sure 3 RR's ain't gonna happen, the engine design's already done, and there's no way they're going to throw in a 7 foot hole near the tail!  

although it would be quite a sight!  
 
747-600X
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The '7-foot-hole' Problem Fixed Easily

Sat May 06, 2000 4:42 am

Imagine this: Three air intakes, not 1, so that the end looks like a 727. An L-1011's in-fuselage engine, with two side air intakes and one on top, each would be relatively small, so that the engine could get it's air and the tail wouldn't be too displaced. I have the A3XX spec.s at home (I'm at school right now) so I'll post them later. (I'm supposed to be working on designing houses, but...)
 
747-600X
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RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 4:44 am

As far as the A3XX comparison, I'm talking about something a bit smaller, maybe a bit more feasible as a new large airplane, bigger than a 747, as an alternative to redesigning it into the -6 or -7 00.
 
Guest

RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 9:28 am

The MD-11 should be looked at more closely by Boeing.
The Tri-jet format is ideal to forget about the ETOPS rule.
It may have burn more fuel than expected, but it had
enough range, more than the 777-200, and the A330. And
with Boeing's knowlege put together, they can make the
range even further than the the near 9000NM. it has. With
the stretch version should be also be consider cause of its
range. the 777-300. But know, their is the 777-300ER in the make.
The regular 777-300 has a much less range than trying to
replace the 747-100 and -200. The MD-11 stretch
(maybe formaly called the MD-12X in the past, or the
MD-XX STRETCH) and with better aerodynamic and
more effeicent engines, the range will rival their own 747-400ER and
the A340-600 with the capcity of the 747 Classic, the A330,
and the 777-200. I think the wings are the ones that are
killing it in the drag. they should maybe replace it with
777's type-wings, and add wing-outlet. But It might be
because that the MD-11 had more powerful engines that
was really needed to carry passangers. That would have
mean for not comsuming more fuel. As i sayed in the begining,
the tri-jet format is better in range than a twin jet and near
the same range than a 4 engine jet and much less operating
cost as well, I just hope Boeing is considering this in the
future. And the frighter is far much better than the 747 in
cost wise, and i dont think a twin can carry lost of cargo in
long-haul flights. Also the MD-11 has more payload and more cargo
area then the 747-400F? Cheers to the MD-11 and hope to have a nice
future on a geart wide-body tri-jet airliner!


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FDXmech
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RE:Hold The Phone II

Sat May 06, 2000 11:15 am

UPS 727-100Q models have all 3 identical engines. Rolls Royce Tays.

Fedex 727-200RE have JT8D-200 engines #1 & #3 and JT8D-17 without thrust reversers on #2.
You're only as good as your last departure.
 
747-600X
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767-400ER And FDXmech

Sat May 06, 2000 12:47 pm

767: Yeah, but I would prefer an in-built L-1011 type engine to the outside MD-11 format, which would also make maintence easier. All of your points are valid. An MD-11ER would, in my opinion, have had a heck of a possibility on the market even though I dislike MD products.


FDX: Thanks for the info! I don't really know what the difference is between those two engines on your -200RE's, and I didn't even know there were jets of any kind still operating without thrust reversers (to DC-8s have reversers?)
 
penguinflies
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RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 1:59 pm

777 engines are also derated in terms of power. Some think that if the engine developed as much power as it can, it could break off the wing. (heard that rumor).
 
Spacepope
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RE: The MD-XX And The Potent New Trijet Market:

Sat May 06, 2000 4:50 pm

The MD-12X was a quadjet, not an extended MD-11. I remember all the hoopla because kansas city was supposedly a finalist for the factory (back to the glory days of Noth American and their B-25/P-51/F-82 factory in KCK) but i think shreveport LA won it. From what i remember, it was suposed to look like a whole hell of a lot like the A350.

The last of the famous international playboys
 
FDXmech
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RE: 747-600X

Sun May 07, 2000 11:21 am

The Fedex 727-200RE #1 & #3 engines are JT8D-217 engines, the same as on the MD80. They even have hydraulically operated thrust reversers like the MD80.

The #2 engine is a conventional JT8D-17 engine historically used on the 727. The thrust reverser mechanism was removed on this mixed engine type.

T/O Thrust
JT8D-217.....21,000 lb thrust
JT8D-17.......16,000 lb thrust
You're only as good as your last departure.
 
747-600X
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RE: The MD-XX And The Potent New Trijet Market:

Sun May 07, 2000 1:06 pm

Thanks FDXMech! That's an interesting little thing to add to my 'trivia' category since I doubt it'll ever be particularly useful!

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