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What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 6:08 pm

I know this is the generation for twin jets, but I been wondering for year what type of airliner would need three GE 90-115 or even just three RR Trident 800? Would you say a super jumbo or a jet that travel at a higher cruising speed,?
 
2H4
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Tue Mar 11, 2008 6:29 pm

Unless ETOPS was somehow stopped, I believe the only way a need for three would arise would be from the introduction of a completely new design, like a BWB.

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KELPkid
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 6:43 pm

To take the thread title at face value, a miracle  Wink

GE an Boeing have an exclusivity agreement that the GE90 belongs only to the 777 program  Sad
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avioniker
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 6:46 pm

Regardless of who loves whom; Who would need 300,000 pounds of thrust???
 Smile
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LMP737
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 8:58 pm

If a company wanted to lose billions of dollars.  Wink
Never take financial advice from co-workers.
 
KELPkid
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 9:43 pm



Quoting Avioniker (Reply 3):
Regardless of who loves whom; Who would need 300,000 pounds of thrust???

Think about it this way: With your engine selection, you would automatically have 1.5 times the fuel burn of a 777, one of the most fuel effecient airliners around. You'd better darn well be getting at least 150% of the 777 passenger and cargo load, as well just so that your machine would be competitive on the market. If it did, then I'd think Boeing and Airbus would have a new competitor in town  Wink
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thegeek
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 11, 2008 11:00 pm

What about a trijet powered A380-900? At least you'd reduce the engine maintenance penalty of the A380 (due to being a quad). Are trijets really that uneconomic that quads work out better above the 777 MTOW?
 
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Starlionblue
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 12:07 am



Quoting KELPkid (Reply 5):

Think about it this way: With your engine selection, you would automatically have 1.5 times the fuel burn of a 777, one of the most fuel effecient airliners around. You'd better darn well be getting at least 150% of the 777 passenger and cargo load, as well just so that your machine would be competitive on the market.

Actually it's probably not that bad since you could have much more than 150% of the payload. Assuming 100k/ngine, engine out thrust on our twin is 100k. Engine out thrust on our triplet is 200k.

Quoting Thegeek (Reply 6):
Are trijets really that uneconomic that quads work out better above the 777 MTOW?

Absolutely. The expense of designing, building and maintaining the center engine is staggering compared to a wing mounted engine. One reason McD went under was the expected expense of developing the engine mount for their next-gen trijet.
- Thorny airflow issues.
- Thorny engine and duct placement issues.
- Reinforcement (=more weight) of the tail area.
- Fast moving bits of engine very close to control runs in the tail (=more weight due to protection).
- Maintenance expense due to inaccessible engine location.

Ask MD11Engineer what he thinks of maintaining the center engine.  Wink
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dl767captain
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 12:25 am

A trijet the size of a 747 would be interesting, if you have engines powerful enough that can fly the plane on three engines instead of four but still need more than two then a trijet would be great, the only problem i could see would be weight distribution. I guess it could put too much weight in the back. I know everyone is into the twin engine idea but if you can't get a plane like the 747 up with two engines and can with three then it could still be more efficient than four.
 
tdscanuck
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 12:50 am



Quoting KELPkid (Reply 2):
GE an Boeing have an exclusivity agreement that the GE90 belongs only to the 777 program

I think it's just an exclusivity agreement that the 777-300ER will only use GE90...if Boeing wanted to put it another airplane I don't see why GE would care.

Tom.
 
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Starlionblue
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Wed Mar 12, 2008 3:04 am

Quoting DL767captain (Reply 8):
A trijet the size of a 747 would be interesting, if you have engines powerful enough that can fly the plane on three engines instead of four but still need more than two then a trijet would be great, the only problem i could see would be weight distribution. I guess it could put too much weight in the back. I know everyone is into the twin engine idea but if you can't get a plane like the 747 up with two engines and can with three then it could still be more efficient than four.

Weight distribution isn't really an issue for a clean sheet design. You'd "just" have to move the wing further back.

But the efficiency problems are numerous and complex, as I listed in reply 7.

Boeing did think of this concept way back: http://rosboch.net/aviationmedia/B747-300_Concept_with_three_engines.jpg

[Edited 2008-03-11 20:05:09]
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thegeek
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 8:46 am



Quoting Starlionblue (Reply 7):
Quoting Thegeek (Reply 6):
Are trijets really that uneconomic that quads work out better above the 777 MTOW?

Absolutely.

If it's that bad, why did McD persist with trijets for so long? Were they crazy? The 727 must have shown the way.
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 11:41 am



Quoting KELPkid (Reply 2):
GE an Boeing have an exclusivity agreement that the GE90 belongs only to the 777 program Sad

I do not know of any exclusionary agreement forbidding GE to provide those same GE90 engines for other aircraft.
GE has exclusive right to supply GE90 engines for the 777-200LR and 777-300ER aircraft. Is that what you're trying to say?
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 12:22 pm



Quoting Thegeek (Reply 11):
If it's that bad, why did McD persist with trijets for so long? Were they crazy? The 727 must have shown the way.

Not crazy. More like stuck in a corner. McD had a lot of R&D already sunk into trijets. A lot of the development work was already done, if you will. However when the MD-XX was thought up they pretty soon figured out that developing the tail section for an even larger turbofan was not financially practicable. So they could build a quad or a twin but that would face stiff competition from the financially stronger Boeing and Airbus.

http://rosboch.net/aviationmedia/Proposed_MD-XX_MD-12_trijet.jpg

The 727 is a much smaller aircraft with much smaller engines. It was also developed in an era when two engines were not powerful enough, and long before ETOPS.
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KELPkid
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Wed Mar 12, 2008 5:45 pm



Quoting F14D4ever (Reply 12):
I do not know of any exclusionary agreement forbidding GE to provide those same GE90 engines for other aircraft.
GE has exclusive right to supply GE90 engines for the 777-200LR and 777-300ER aircraft. Is that what you're trying to say?

Nope, GE Cannot offer the GE90 on anything other than the 777. Why do you think that GE didn't offer an updated GE90 to Airbus when the A350XWB became the bloated plane it is now (more specifically, the -1000 series)? The reason that they don't offer the GeNX is that Airbus grew the plane too large, clear out of the upper end of the thrust targets for the GeNX series. A GeNX might work on the -800 or the -900, but the engine family wasn't designed to grow in thrust into what is today the GE90's territory. I wish lightsaber was around in this discussion...  Wink
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu Mar 13, 2008 2:10 am



Quoting KELPkid (Reply 14):
Nope, GE Cannot offer the GE90 on anything other than the 777. Why do you think that GE didn't offer an updated GE90 to Airbus when the A350XWB became the bloated plane it is now (more specifically, the -1000 series)?

GE cannot offer the GE90 on a non-Boeing aircraft...that's why they didn't offer it on the A350XWB (besides Airbus wouldn't have bought it anyway). That still doesn't explain why Boeing couldn't use the GE90 on some other Boeing aircraft.

Tom.
 
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Mon Mar 17, 2008 3:31 pm



Quoting Tdscanuck (Reply 15):
GE cannot offer the GE90 on a non-Boeing aircraft



Quoting KELPkid (Reply 14):
GE Cannot offer the GE90 on anything other than the 777

Don't be misled by circumstances.

My contacts within GEAE are not aware of any exclusivity agreement binding on GE. Such an agreement has not been acknowledged publicly by GE. Has Boeing publicly claimed it exists? If there were such an agreement, it would be near-impossible to conceal.

Let's think about these questions:

1) Who is bigger, GE or Boeing? Answer: GE, by a healthy margin.

2) Who helped whom; did GE financially assist with the 777, or did Boeing assist with the GE90? Answer, GE offered up money for 777 development; they own a piece of the pie. Not the converse. GE developed the GE90 with their own money (with minority partners Fiat, IHI, and Snecma), and are therefore entitled to sell it anywhere they choose.

I think the more obvious and compelling reasons we don't see the GE90 on any other aircraft are a) the GE90 core was sized for the larger -110/-115 size fan, so the smaller GE90 variants don't compete as well against the similar-sized Trent, and b) the bigger GE90 variants are just too big for anything out there yet.

Am I missing something?
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 18, 2008 3:29 am



Quoting F14D4ever (Reply 16):

1) Who is bigger, GE or Boeing? Answer: GE, by a healthy margin.

GE as a whole, yes. GEAE, no.

Quoting F14D4ever (Reply 16):
Am I missing something?

The question would then become, why doesn't Boeing offer any other engines on the 777-300ER? GE must have been willing to give up something in order to get exclusivity on the 777-300ER...tribal wisdom is that the trade was that they wouldn't give the engine to Airbus, although I've never actually seen that said by either company. The alternative is that both RR and PW just decided they didn't want in on that market, and I find that a little unlikely.

Tom.
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 18, 2008 6:45 am



Quoting Tdscanuck (Reply 17):
The question would then become, why doesn't Boeing offer any other engines on the 777-300ER? GE must have been willing to give up something in order to get exclusivity on the 777-300ER..

Well, AFAIK there is no other engine even close to that thrust level. More like Boeing gave up something (offering more than one engine) so that GE would be convinced to cough up the R&D dollars.
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Tue Mar 18, 2008 9:29 pm



Quoting Tdscanuck (Reply 17):
The question would then become, why doesn't Boeing offer any other engines on the 777-300ER? GE must have been willing to give up something in order to get exclusivity on the 777-300ER...

Yes, GE lent money to an - at that time - pretty cash strapped Boeing to pay for 777-300ER development. In addition to paying all own expenses on developing the GE90-110/-115.

Since GE paid a lot of the 777-300ER R&D costs, then they naturally didn't want to see that plane fly with engines from a competitor. And Boeing needed that money from GE, therefore accepted to limit the 777-300ER to that one engine type.

GE also didn't want Boeing to break their neck on 777-300ER R&D since without that plane they might have to wait fifty years for another customer for an engine on which they were going to spend billions in R&D.

So Boeing can according to the risk sharing contract not put anything but GE90 under the wings of the 777-300ER.

But GE can sell the GE90 to anybody who wants it. There just are no other customers.

It has a price for Boeing: GE can in principle ask whatever price they want for GE90 engines. If they think that Boeing earns too much on selling 777-300ER, then they can just increase the GE90 price until Boeing's profit margin is too small to accept plane orders. But in the real world GE is of course interested in selling as many GE90 engines as possible, and not to hurt Boeing. It also reduces GE's incentive to spend money on further improvements on the GE90. It doesn't eliminate the incentive because airlines can still get all the RR engines they want, if only they sit on an Airbus, or some other Boeing plane type.

Boeing's advantage is that without that risk sharing contract they wouldn't have been able to design the plane. Or they would have had to delay it several years, making room for much more A330/340 sales.

That's how business is. If you are a money tank (like GE), then you play the game your own way. If you are cash strapped, then you play the game of those you are willing to finance your game.

When Boeing launched the 787, then they were in a much healthier financial situation. The A320 chock had been overcome. At record speed they had updated their "bread and butter plane" into the 737NG, which was able to compete against its rival. They could suddenly play their own game. They did that wisely. They told two engine manufacturers (GE and RR) to do their very best to come up with some world beater engines. And they told them that the airlines would choose among them based on their own judgements of performance, MX costs and price. That created two new engine families, GEnx and Trent 1000, on which the manufacturers will have to fight on quality and price for every single order, and which are scheduled to wipe everything else off the market in the 60 to 90klbs class. And if both turn out successful, then it is guarantied that they will be constantly improved by whatever possible means during the coming decades. In five years time they will sit on every new A350, A380, B747 and B787.
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri Mar 21, 2008 11:57 pm



Quoting Prebennorholm (Reply 19):
GE can in principle ask whatever price they want for GE90 engines.

Is this really how it works? That only makes sense to me if GE profit share on the 77W/77L planes. The I have read the RB211/L1011 had a fixed price that RR could charge for each engine, and that makes sense to me.
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Sat Mar 22, 2008 3:36 pm



Quoting Tdscanuck (Reply 17):
GE must have been willing to give up something in order to get exclusivity on the 777-300ER...

Your logic is the wrong way round there. GE paid to be on the 772LR and 773ER. In return they got exclusivity on those planes. Since they paid, why would they agree to restrict any other potential application for the GE90?

Quoting Tdscanuck (Reply 17):
The alternative is that both RR and PW just decided they didn't want in on that market, and I find that a little unlikely.

IIRC, RR was very interested, but wasn't prepared to pay the level of investment Boeing were looking for. I'm sure PM will be along shortly to correct me.  wink 
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litz
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Mon Mar 24, 2008 8:35 pm

Setting aside all the GE/Boeing arguments ... consider this - by the time you built a strong enough tail to actually mount and support a GE90 (they ARE fairly huge!) ... would you have anything near a viable airframe?

Can you imagine the CG on that thing? It would just about be under the rear galley!

- litz
 
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SEPilot
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Mon Mar 24, 2008 9:23 pm



Quoting Starlionblue (Reply 7):
Absolutely. The expense of designing, building and maintaining the center engine is staggering compared to a wing mounted engine. One reason McD went under was the expected expense of developing the engine mount for their next-gen trijet.

 checkmark 
I would suspect that the difficulty of a center engine increases as the square or the cube of the diameter. I would not expect to ever see another tube with wings trijet; if we ever see another one it will be something radically different, like a BWB.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
jetlife2
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Mon Mar 24, 2008 9:50 pm

The following is all public domain info: GE paid part of the development costs for the 777-300ER. (This is normal by the way, for the engine company to pay the airframer, it happens all the time both Boeing and Airbus). In this case due to the size of the payment, Boeing agreed to exclusivity for GE for this airframe family.

There is nothing to prevent GE offering the GE90 on other applications. But to do that would require another payment to another airframer to partially fund that aircraft, and more development and certification costs for GE to design and certify the installation. If after all that, the resulting combination ends up competing with the 777, then it is not good business for GE.

Regards

GHR
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Stitch
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Mon Mar 24, 2008 11:52 pm

When Boeing was developing the 777X (what would become the 777-200LR and 777-300ER), all three existing 777 engine partners were invited to pitch an engine.

Pratt and GE both felt the market for such a plane would be quite small (they blew that one), so both demanded exclusivity to justify the expense of the program. Rolls, whom had default exclusivity on the A340-500 and A340-600, was willing to have either GE or Pratt as a second supplier.

Pratt never had a real chance (the PW4098 was a failure and the PW409x series had it's own issue), so that left RR and GE as the only two real contenders. GE agreed to fund some of the development cost of the 777X program if they received exclusivity whereas Rolls did not wish (or could not) provide said funds. So GE won the contract.

To my knowledge, the cut-off is for planes with an MTOW greater then 700,000 or 750,000lbs. So in theory the GE90 could be used on the A350XWB, but Airbus won't take it - they want something at least a generation or two newer.
 
mandargb
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu May 01, 2008 6:10 am

When you have 2 engines with 90 KLB thrust under wing, you call it B777.
When you have 3 engines of that size, you make it 2 story and call it MD12. And say that design is shelved.
But when you add one more engine and then move it under wing, you call it A380.
Smile
 
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Starlionblue
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu May 01, 2008 6:58 am



Quoting Mandargb (Reply 26):
When you have 2 engines with 90 KLB thrust under wing, you call it B777.
When you have 3 engines of that size, you make it 2 story and call it MD12. And say that design is shelved.
But when you add one more engine and then move it under wing, you call it A380.

Good one, except that the 380 engines are nowhere near as powerful as the upper band GE90s.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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SEPilot
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu May 01, 2008 5:00 pm



Quoting Mandargb (Reply 26):
When you have 3 engines of that size, you make it 2 story and call it MD12. And say that design is shelved.

What engines was the MD-12 designed around? The GE-90-11x did not exist (and was not even in the talking stage) when the MD-12 was proposed.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
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SEPilot
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu May 01, 2008 5:07 pm



Quoting SEPilot (Reply 28):
What engines was the MD-12 designed around? The GE-90-11x did not exist (and was not even in the talking stage) when the MD-12 was proposed.

Well, I did a little research and answered my own question. The MD-12 would have been a quad with 65K engines. The MD-XX was the trijet which would not have been as large, and would have used the same engines as the MD-12. MD never looked at a 110-115K engine because it did not exist when they did, and was not even being talked about. The 777 was 85-90K when it first came out, and that was at that time considered the practical limit.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
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Starlionblue
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Thu May 01, 2008 11:53 pm



Quoting SEPilot (Reply 28):
What engines was the MD-12 designed around? The GE-90-11x did not exist (and was not even in the talking stage) when the MD-12 was proposed.

Indeed, they would have been 380 class. For the MD-XX triplet I guess 80+ as you say. Incidentally designing the nacelle and such for the center engine was so expensive they had to abandon any thoughts of the program. It could be said that the center engine killed MD.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 2:08 pm



Quoting Starlionblue (Reply 30):
It could be said that the center engine killed MD.

I believe that what killed MD was the bad rep that the DC-10 acquired after AA191 and UA232 plus their unwillingness to commit to the necessary development for a completely new plane in the 80's. What tied them to the center engine was their unwillingness to start with blank paper, which is why both the MD-11 and MD-90 were disappointments.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
astuteman
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 2:48 pm



Quoting KELPkid (Reply 5):
Quoting Avioniker (Reply 3):
Regardless of who loves whom; Who would need 300,000 pounds of thrust???


Think about it this way: With your engine selection, you would automatically have 1.5 times the fuel burn of a 777, one of the most fuel effecient airliners around. You'd better darn well be getting at least 150% of the 777 passenger and cargo load, as well just so that your machine would be competitive on the market. If it did, then I'd think Boeing and Airbus would have a new competitor in town

Mmmm  scratchchin 

You could actually have up to 345 000lb..  Wow!

Around 330 000 lb should be about right for a 625t A380-900.
I'm pretty sure such a plane will carry dramatically more than 150% of the payload of a 777, possibly even double.
This trijet wouldn't be much of a competitor, methinks  no 
Which sort of answers the question really..  scratchchin   Smile

Quoting Starlionblue (Reply 27):
Good one, except that the 380 engines are nowhere near as powerful as the upper band GE90s.

Gods - imagine if they were... 460 000lb thrust - some 40% more than even the 625 tonner will need  faint 

Rgds
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 6:10 pm



Quoting Astuteman (Reply 32):
Quoting Starlionblue (Reply 27):
Good one, except that the 380 engines are nowhere near as powerful as the upper band GE90s.

Gods - imagine if they were... 460 000lb thrust - some 40% more than even the 625 tonner will need

Rgds

And I don't think the operators of them would like to see their fuel bill at that point, either...  Wink That might make an A380 a hot rod, but it would probably loose it's CASM advantage rather quickly.
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astuteman
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 7:21 pm



Quoting KELPkid (Reply 33):
That might make an A380 a hot rod

Once it had finished dragging the nacelles along the ground......  Smile

Rgds
 
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 7:24 pm



Quoting Astuteman (Reply 34):
Once it had finished dragging the nacelles along the ground......

You put casters on them, of course!
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The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
KELPkid
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Fri May 02, 2008 7:24 pm



Quoting Astuteman (Reply 34):
Once it had finished dragging the nacelles along the ground......

Rgds

The secret is taller landing gear  shhh 
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Devilfish
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Mon May 05, 2008 1:47 am

One then wonders why Airbus bothers filing a patent application for a trijet if its power requirement would be less than or just slightly above what two GE90-115s or even RR Trent-800s could economically provide, and if none (trijet) was under consideration or would be built?.....

http://www.flightglobal.com/articles...-patent-for-new-trijet-design.html

[Edited 2008-05-04 18:51:05]
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Mon May 05, 2008 2:16 am



Quoting DEVILFISH (Reply 37):
One then wonders why Airbus bothers filing a patent application for a trijet if its power requirement would be less than or just slightly above what two GE90-115s or even RR Trent-800s could economically provide, and if none (trijet) was under consideration or would be built?.....

Bragging rights?
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
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RE: What Who It Take To Build An Ge 90 Powrered Tr

Mon May 05, 2008 3:41 am

Quoting DEVILFISH (Reply 37):
One then wonders why Airbus bothers filing a patent application for a trijet if its power requirement would be less than or just slightly above what two GE90-115s or even RR Trent-800s could economically provide, and if none (trijet) was under consideration or would be built?.....

Airbus and Boeing, just like Microsoft, Intel and IBM, file patents for all sorts of things they will never use. Just in case...

It even says so right in the article:
But Airbus's North American division has downplayed the design's relevance to the airframer's future plans: "Airbus is regularly filing patent applications and this is normal business for a company that is a leader in innovation and technology," the company says. "That's not to say this is 'the' design we're looking at in the future - just one of a very many possibilities."

They do have a point about the ever growing turbofans. At a certain weight the engines on a twin just become too expensive (to develop, produce and mount) with current technology. The current solution is to go quad. I guess Airbus is just hedging bets with this one.



BTW that is one fugly aircraft.

[Edited 2008-05-04 20:42:37]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
TrijetsRMissed
Posts: 1981
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RE: What Who It Take To Build An Ge 90 Powrered Trijet

Mon May 05, 2008 3:57 am



Quoting Mandargb (Reply 26):
When you have 2 engines with 90 KLB thrust under wing, you call it B777.
When you have 3 engines of that size, you make it 2 story and call it MD12. And say that design is shelved.
But when you add one more engine and then move it under wing, you call it A380.

Except the MD-12 was designed as a quad as well, very similar to what the A380 would become.
There's nothing quite like a trijet.

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