Bombardier CSeries, first flyby and landing in ZRH

[TobyV]

A bit of real aviation, I believe the nacelles at least are made by Shorts in NI, so at least some UK content. This will replace the Avro RJ (in my signature!) in the Swiss fleet. Some orders have apparently been converted to the larger CS300, which is almost A319 sized.

First fly past and then landing in Zürich. Swiss are the launch customer. Aircraft was greeted at Pier B with a water salute but I was standing beyond the Rwy 16 threshold.

[Motormouse]

Going to be at Paris air show too?

Nice to see one flying after the FTV engine hiccup a few months back.

C series business jet next.....

Ttfn

Pete

[TobyV]

It or me? I think it came from Paris but as I understand it flew back to Canada yesterday.

Looks pretty nice I think and it's very quiet. An Avro RJ landed some while later and it seemed a bit louder than this to be honest.

[Dev One]

Twice as many blow torches might be a reason?
Keith

[TobyV]

When the 146 as it was originally known came into service, one of the main sales pitches was how much quieter it was than twin jets and even turboprops of the time.

Excluding things like the screaming front centrifugal compressor in the RR Dart engine, the main sources of noise in a turbofan are the front fan (if it is transonic especially); the buzz-saw sound of the shocks being "chopped" by the next blade, the efflux from the fan, mostly coming from the shearing from the differential velocities between it and the surrounding airflow and of course the efflux from the core, which is hotter and most likely has a different viscosity and turbulence scales. Higher bypass engines achieve the same thrust by moving a larger mass of cold air slower, whereas the old low bypass or even pure turbojet engines move a much smaller quantity of air much faster resulting in a high "shearing" between the efflux and the surrounding free stream air. Nowadays though you have all sorts of other clever techniques like acoustic liners, nozzles like the saw-tooth ones on the 787 that promote mixing between the efflux and the free stream and tools that can model aero-acoustics and guide designers towards producing fan designs that produce less noise. The P&W 1500G series engines on the Bombardier are producing something in the order of 2.5-3x the thrust of the ALF502/LF507 on the 146/RJ!

[dfarrow]

Poor old 146 was launched in 1973 , postponed in 1974 ; then first flown in 1981 . So I guess those Avco Lycomings were designed 45 or so years ago .....
Toby , thanks for the great photos and a very lucid explanation . Wish we'd had you explaining power plant / noise attenuation theory in 1972 !
Mind you nothing much could have been done for the RR Spey .
rgds dave f .

[TobyV]

The ALF502 is the core from the engine in the Chinnok (T55) with a fan on the front. I think they chose it after RR stopped development of the RB.203 Trent (probably because they went bust!) so 45 years ago is probably about spot on! Noise attenuation isn't actually a concern in what I do (given what I design sits inside a thick housing in a building quite away from where most people live) and I've never had to do any design work for it, but I attended a course at Cambridge a few years ago which covered the topic. I found it rather interesting despite its being of no use to my job!

[Dev One]

Poor old 146 was launched in 1973 , postponed in 1974 ; then first flown in 1981 . So I guess those Avco Lycomings were designed 45 or so years ago ..... .

If my memory serves me correctly, when I worked on the C5A wing design in Southall in '66 to '68, we had a lot of DH designers & draughtsmen who came from the 146 design office as I think there was a halt in the design at that time. So it looks as if its quite a bit older than you think!
Keith

[TobyV]

Keith, are you sure they had really been working on the 146? I am pretty sure that was only from 1970 or so onwards. Prior to that there were a number of abortive feederliner projects at DH/ Hatfield culminating in the HS136 around the time frame you mention. Other projects were the HS134 which had something close to a 757 or A321 already by 1965, using a Trident fuselage and RB.178 engines and the HS141 VSTOL airliner, the nose of which bears some resemblance to the 146. All of these were cancelled, or even in the case of the Airbus, stuttered as first Breguet & Nord were replaced by Sud Aviation and then at some point, the government decided it would no longer provide funding and so HSA designed the wing as a private venture.

[Dev One]

Toby, it is possible it was the 136, as I say my memory ain't what it used to be, & I was ex Vickers at Weybridge at that time, cursing at the government for cancelling TSR2.
Keith