7/26/2017

Engine choices for NMA

It looks increasingly likely that next Boeing will launch the NMA -  or MoM, or 797, or whatever you want to call it.
One of the most interesting questions is the engine choice(s) that Boeing will make:
First of all, will the customer have an engine choice? Here the questions are:

-   does Boeing want to give the customers a choice
     and
- how large the engine OEM think the market for the new aircraft will be

3/29/2017

CFM A321neo noise levels revised

Yesterday the EASA published new noise levels for the A321neo, which now include the "right" noise levels for the A321-251N and A321-253N, fitted with the CFM LEAP-1A engines. As for the A320neo, the A321neo with the LEAP-1A is a little bit better (read_less noisy) than the PW1100G. This is surprising, as P&W always claimed that the GTF concept has, beside better fuel burn, it's merits in extreme low noise because of the slower spinning fan and the better damping of the low pressure turbine noise due to better atmospheric dampening.
I would be interested to hear how P&W and CFM explain the difference...

3/02/2017

A320neo and A321neo noise levels

Yesterday the A321neo with the CFM LEAP-1A32 engine was certified by both the EASA and the FAA. The EASA certification document for the aircraft family can be accessed here, the noise certification document is here. The FAA documentation is not online yet.

What strikes me is the high noise level of the A321-251N. The LEAP-powered A321neo is not really less noisy than the CFM56 powered A321ceo, which itself was considerably louder than the V2500 powered A321ceo.

If you compare the highest MTOW version (93.5t) you get a cumulated noise level of 281.7dB for the A321-251N, the A321ceo with the  CFM56-5B4/3 is certified with a noise level of 280.1dB (there are also versions of the CFM56 which have higher noise levels than the LEAP1A though.

The PW1133G in comparison has a cumulated noise level of 268.5dB, more than 13dB less than the LEAP-1A32. Both at the lateral and flyover noise points the GTF is less noisy by about 6dB, the approach noise, where the aircraft itself is the main source, is almost the same for both versions.

I wonder if the values for the LEAP-1A32 are real – or somebody at EASA put some wrong numbers in the document.

The noise values for the A320neo are telling a complete different picture: here, the LEAP powered A320-251N is better than the PW1127G powered A320-271N by 1dB, mainly through lower levels at the lateral noise point.


I wait for some good explanations...

1/17/2017

The future is geared!(?)

The future in commercial aviation is geared, it seems:
Of course P&W and it's partners in the PWW1000G engine thought so when they started to develop their engines for the Mitsubishi MRJ, the Bombardier CSeries, the A320neo and the Irkut MS-21 and the Embraer E2-Jets.
But then, about three years ago, RR started developing their own engine with a geared architecture, calling their product (to be) the "Ultra Fan".
No I read in an article from Aviation Week that also Safran is working on a geared fan engine, under the umbrella of the european Clean Sky initiative, the equivalent  to NASA's CLEEN program.
A cross section of the engine concept can be seen on page 17 of this presentation.
My guess is, all engine concepts that CFM, RR and  P&W will eventually offer Boeing and Airbus for a replacement of today's A320 and B737 will have a gear between the LPT and the Fan!

10/28/2016

A320neo start-up times

The hype was huge when the problem around longer start-up times of the PW1100G-JM went public. Indigo stated that the ~2min. extra time that it took to start up the engines would threaten their Business model as a low cost carrier with high utilization and short turn around times between flights. As I showed in an earlier post this was not very plausible from the beginning. But at airports with tight infrastructure (Frankfurt comes to my mind) it could cause some headache - more for the airport than for the individual airline though - as, if one aircraft blocks the way to the gates as it has to wait until the engines are started, other aircraft have to wait.
Believing what Airbus, P&W and Lufthansa said recently the problem is largely gone now.
Now we can read in a report from airwaysmag about the first revenue flight onboard on the first Frontier A320neo that the that the competing LEAP-1A engine has a "noticeably long startup time". What that exactly means we don't know yet. There was nothing official about that yet, showing once again that the PR Folks at GE, CFM and Safran are doing a much better job than those at P&W.
But maybe someone should tell Qatar Airways CEO Al Akbar about it as the LEAP-1B should "suffer" the same problem before he confirms his order for the B737MAX. Or maybe he already counts on compensations...?