TRENT ENGINES

[ALV2500]

Does anyone know the reasons behind the newer trent engines not having the integrated exhaust nozzle like the 700 or RB211 535 ?
Also what kind of gas is in the wide chord fan blades ?

Thanks , AL

[Fargoo]

They're inflated with an inert gas during construction to take their shape. Don't know what gas is used though.
Might say in the new Rolls book - i'll have a look for you tomorrow.

Don't know about the first Q though.

[ALV2500]

Fargoo,

Thanks for reply. If you have the new " Jet engine book " by Rolls please let me know what you think of it. I am thinking about ordering it.

Regards, AL

[belowMDA]

I have the new version. It is very nice, but I feel a little less technical than in the past. The illustrations I don't think are quite as detailed as before, though it is a while since I last read one of the older ones. This is just a first impression because I haven't had a chance to have a thorough read yet. It arrived very quickly which was a very pleasant surprise.

[Fargoo]

ALV2500, I had a look in the new Rolls book but there's not really much in the way of info on the fan blade construction.
As belowMDA mentioned the new book is fantastic but it's not that in depth. Makes a nice read and has some great illustrations and photos but not much use as a reference book.

[Sootikin]

I'm not sure which gas is used on manufacture, but I believe that there's a vacuum inside the finished fan blades. There's a piece of GSE called a Tap Tester which is used in checking for cracks in the blade, and it works on the principal (IIRC) that any cracks would allow some air to seep in, affecting the acoustic properties of the blade.

On the first question...I believe the issue is weight. As engine diameters go up, the associated weight of a full length cowl increases. At some point, the benefits from a noise / efficiency viewpoint are outweighed by the increased engine weight / drag. It gets evaluated seperately on each new aircraft + engine type.

Hope this helps, but you could drop a line to RR for a definitive answer.

[ALV2500]

I was pretty sure it was down to weight althought wasn't sure how other factors were considered. It's been proven that the RB211 (with the IEN) on over 80% of the worlds 757s is more fuel efficient than the PW 2037.
I understand that the IEN gives increased thrust and better fuel efficiency as well as reduced noise but curiously this is not a feature of the Trent 800 while it is on the 700. Apparently a Rolls powered 777 is 7500lbs lighter than one powered by PW.
Thanks for input.

AL

[Sootikin]

"RB211 ... of the worlds 757s is more fuel efficient than the PW 2037."

I had heard that the 2037 has a slightly better efficiency than the 535E4, but that its unpopularity stems from an awfully low on-wing life. What you gain on fuel costs, you more than lose on maintenance costs.

[ALV2500]

UPS based nearby in Kentucky had been a big PW user but recently made the switch to RR. I'm told the PW engines were not making TBO and were less fuel efficient than the RR.
American Airlines added 26 757s from TWA with the PWs to their fleet of 136 RR powered 757s. I hear they will sell the 26 soon due to the high price of oil and their high consumption. That's just the word.

Regards, AL

[Sootikin]

Well, I sit corrected ! Thank you.

I guess this is why RR's share price keeps rising, and PW seem to be disappearing and a Civil Engine producer.

[ALV2500]

Yeah,
might be a good idea to buy some RR shares. I think IAE also looks very good which of course benefits RRs bottom line. PW have said publicly that they will be more focused in the defense markets since they were left out of the 787 deal.

AL