Leeham News and Analysis
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Leeham News and Analysis
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PW mum about reported thrust bump on GTF
Sylvain Faust, who follows the Bombardier CSeries more closely than anyone else we know except the program participants, last night posted a piece that says the Pratt & Whitney Geared Turbo Fan engine now in testing with the CSeries is up to 25,000 lbs of thrust–a 9.3% increase. The thrust bump is more geared toward take-off performance than economy, Faust reports. The CS100 is a short-field, hot-and-high airplane, among its other attributes.
Pratt & Whitney declined to comment directly on Faust’s report.
“Pratt & Whitney is on track to meet the PW1500G engine commitments made to customers on entry into service. Our focus remains on successfully supporting Bombardier in the completion of aircraft certification testing and meeting all of our performance commitments on schedule,” a spokeswoman said.
Meanwhile, Bombardier posted a short video update on the program.
I suspect P&W can get a lot more thrust from the GTF design than that.
Toronto’s Billy Bishop airport’s longest runway is 3,988 ft. Porter has asked to extend the runway by 551 ft at each end bringing it to a total of 5,090 ft but there is opposition which may delay the approval.
CS100/CS300 landing field length at max landing weight is 4,449/4,902 ft
CS100/CS300 take off run at Max take off weight is 4,800/6,200 ft
So a CS100 would have no problems. A CS300 could land fully loaded but could not take off fully loaded from the extended runway.
I am not an expert but it seems that with the extra thrust a CS100 might be able to take off and land from the current runway with a reduced payload.
9.3% increase? I seem to recall the design thrust was 24 klbf, which makes for 4.1% increase, not 9.3%… at least the engine designation was PW1524G, implying 24 klbf.
Anyhow, there might have been some margin in that… as rumored here and there about several aspects of the PW1000G specs.
Original design thrust for the PW1524G was 23,300 lbs although that is still only a 7.3% increase to 25,000.
http://www.purepowerengine.com/technology.html
Thrust increases tend to compensate something unforeseen, meeting contracted performance guarantees.
More available thrust from the engines also opens the possibility of an extented fuselage version of the CSeries. Could a CS400 be launched as a quick replacement for the CS300?
However, the current CSeries wing is optimized for the CS100, the CS300 already being a stretch with the same wing.
I can see a CS500 as soon as the CS300 has enetered service. The CSeries Wing seems optimized for the CS300. The wingspan is the same as an A321..
http://i191.photobucket.com/albums/z160/keesje_pics/CSeries100300500FakeAirlinerscom.jpg
This looks like a new takeoff rating, [not a bump], that Pratt is proposing to 25K SLST. The flight and thrust management computers and flight manual would have complete performance data for that rating usable anywhere. If 25K is not needed then takeoff power could be derated using an alternate rating or by assuming a higher-than-actual temperature.
A “bump” is a unique power setting, meant for occasional use at a specific airport. The flight manual would only have data for that airport. It is actually a permissible overboost. After takeoff, power settings would revert to the previous climb ratings. Examples would be HGW hot day operations specifically for Mexico City or Nairobi.
I don’t want to appear a messenger with the bad message (so don’t chop off my head) but the silence of BBD in the matter leads me to infer a possible short-fall in the wing’s high lift devices’ aerodynamic performance, BBD presently assessing if/the extent to which calling upon P&W to reset the GTF normal thrust rating could tentatively assist with delivering guaranteed CSeries TO performance ? P&W co-operate willingly, as is expected, being in the same boat as BBD, keeping a tight line of concerted communications with the airframer, both jointly flagging up hints at “the Porter challenge” to momentarily defuse intrigued observers’ close-nosed queries ?
“Air Canada said Thursday it decided to keep 25 Embraer SA jets instead of replacing them with new narrow-body aircraft, dealing a blow to Bombardier Inc.’s CSeries.
Canada’s biggest airline said it will continue to operate 25 of Embraer’s E190 jets, “given their young age, productivity and high customer acceptance on existing routes and to avoid additional capital expenditures and debt.”
Montreal-based Air Canada had been evaluating the CSeries as a replacement for its Embraer jets since announcing in December an order to buy Boeing Co. 737 Max planes valued at $6.5 billion.”
http://business.financialpost.com/2014/05/15/air-canada-loss-widens-on-weak-canadian-dollar-rough-winter/
Ouch.
If Air Canada had not lost $341m in the last quarter I would have thought their decision had something to do with Bombardier. I think they will buy CSeries at some point but for now they have to preserve capital and reduce debt.
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