PW Media Day 1: next gen GTF to cut fuel costs 10%-15% over today’s GTF

We’re at the Pratt & Whitney media days today and tomorrow. This is the Technology at PW panel. Participants are:

Alan Epstein, engineer and moderator. (AE)

Michael Winter, chief technologists (MW)

Graham Webb, MRJ, CSeries and EJet engines. (GW)

Jimmy Kenyon, advanced military programs. (JK)

All information is paraphrased.

GW: At $4/gal, over 60% of cost to an airline is for fuel. Engines must cut these costs. A380 and 787 consume less than 3 liters per passenger, about that of a compact car.

GTF is certified [on CSeries]. GTF now on five airframes with 12 sub-types. The engine reduces fuel and maintenance costs, reduced emissions. Fuel savings now demonstrated at 16% less than today’s engines.

Next generation of GTF will further reduce fuel burn by 10%-15%.

MW: The noise footprint will stay predominately within the airport boundaries, using 2,000 fewer foils, about half of our competitor’s engine. Emissions are about 50% below current regulations and working with NASA toward 88% below current levels.

Current bypass ratio about 13:1 and currently testing with NASA 15:1 and 18:1.

375% improvement in efficiency since the days of the Whittle jet engine.

We have the most advanced cooling system in the industry and we are exploring inserting advanced materials into the engines when there is real benefit to the customer.

JK: We’re seen similar trends to improve efficiency in military as with commercial. The Department of Defense is the biggest user of energy in the country, with about 80% in engines.

The military has seen really tight budgets in recent years. There is more than just a cost issue, it’s also an energy security issue (Iraq, Afghanistan challenges). There is a real interest in cutting energy usage and aviation being such a large part, it is a natural place to look.

The strategy considers places where you have to fly farther and/or stay on station longer. We’re working on technology to provide fuel management and efficiency to reduce costs, fly father and stay on station longer.

We’re working with USAF to obtain 25% improvement in fuel efficiency on next engines, and with Navy to also improve efficiency, and leveraging work in the commercial arena to improve thermal efficiency.

AE: Are you a one-trick pony? What have you got besides the gear?

GW: We have advanced fan module, bringing forward light weight fan cases, the next generation combustor, advanced core, state-of-the-art high pressure turbine and high speed low pressure turbine, all of which designed for the very high speeds. There are control system enhancements, working on next gen of the fan-drive gear system, short inlets for enhanced efficiency.

MW: We don’t see tremendous value in unducted engines right now due to weight penalties and other issues, and challenges for noise. But if the day comes when it does, PW is well-positioned if the market chooses to go there.

AE: PW does thinks larger turbo-props will be built and PW Canada is researching, but there would have to be another spike in fuel prices.

JK: PW going into service now is essentially a new engine [for KC-46A] vs original EIS. Right now the engine is meeting the needs that are there and should have some runway well ahead of it.

AE: Battery powered airplanes: Batteries have 1/100th the energy intensity of jet fuel. If you want to go 1/100th of the distance, you could use batteries. MIT told us you could have the electric motors but you have to eliminate the shield to save weight and the emissions would kill the people sitting nearby. Of course, the airlines could charge a premium fee to sit away from the motors.

Editor’s Note: Epstein has a good, dry sense of humor. Describes a photo on his wall of a hydrogen engine: It was a super-secret military project, so all its details are on the Web–Project Sun Tan.

GW: Our focus is on the five applications for the GTF and we have the technology to scale up to the wide-body. We can do it, it’s just a matter of when. [Did not answer question, however, if GTF could be developed on Airbus timeline for A330neo.]

MW: When you look at entire parameter space, an open rotor won’t be able to compete with the next generation GTF nor even maybe the third generation GTF.

AE: If you mean by Open Rotor a countra-rotating propeller, there have been 28 in service since 1928. This allows you to reduce the size of the propeller. If your idea is a pusher at the back, there are FOD and icing issues. If you put it on the front as a tractor, you have size issues. The GTFs will raise the bar at airports [for  noise]. The prop fan had objectionably high noise on the ground and can’t match GTF.

AE: We’re looking at new technologies that we can’t tell you about. We are looking at new manufacturing technologies.

AE: The gear goes well on any engine. It scales up better than it scales down. When PW decided not to bid on the 787, we decided the sweet spot is [the single-aisle] airplane. There are now 6,000 engines on order representing $10bn in fuel savings. Lots more orders will be announced at Farnborough. We have put the gear on A380-size engines [testing]. We learned a lot of things on the GTF that we didn’t appreciate how good it was. Look at the A320, a plane highly optimized for the 63 inch fan, we’re putting an 81 inch fan on it.

We’re 700-800 pounds lighter than the competitor on the A320neo, who has a smaller fan.

MW: An engine fan is better the slower it goes and the spool is better the faster it goes.

AE: I expect in the next decade everybody will be building geared turbo fan; Rolls-Royce is going there. Snecma says it will look at this.

AE: The real advantage of an open rotor is take off and descent, not at cruise. At 300 miles, you want a propeller airplane.

16 Comments on “PW Media Day 1: next gen GTF to cut fuel costs 10%-15% over today’s GTF

  1. Scott, did PW mention any time frame for possible availability of 2nd gen GTFs?

    • Not yet, not here, but in the public domain elsewhere it’s been suggested around 2020. MTU sort of spilled the beans on its last earnings call.

  2. Regarding PW not bidding for the 787 is a load of cr*p.

    The company I used to work for did work on the concept together with PW. Work stopped when PW was not down-selected (by Boeing) in competition wit RR and GE, not when PW voluntarily pulled out. The disappointment was large on the PW side I recall.

    I was not personally involved, working at the time on an aero-derivative gas turbine, but the gal next door was so I had some second hand insights. What I can remember was that the engine was fairly conventional in architecture, like the GEnx, but perhaps a little less tech on the component side (not GE’s rag-and-glue fan, nor GE’s high temp alloys, which at the time were leading the pack). If I am not mistaken, the working name was PW-7E7…?

    We did (as a company) eventuallt and later become involved in the GEnx, so we did ok (apart from the hideous, cash-draining delay…).

      • …having said that: P&W sort of did pull out later, as they didn’t want to sign up to some of the financial risks of the overall 787 programme (as opposed to just the risks of the engine development).
        They probably knew they were slimming their chances by not agreeing to this requirement, which amounted to a kind of passive withdrawal. They submitted a bid, but were aware their chances were slim.
        However, they’ve since been trying to paint themselves in a more active role in all this – see the “P&W decided not to bid on the 787” quote above. In 2005, they even said they had been “selected technically”, but then withdrew. Which is probably stretching things a little.

        There’s some detail in this thread from 2005:

      • Ah, PW-EXX it was! I knew there was an “E” in there somewhere, but did not remember much more. Thanks!

    • My reading is that they didn’t bid a GTF for the 787. One could obviously infer from that statement that they didn’t bid at all.

    • P&W developed a proposal but required a sole source contract. When Boeing nixed any chance of sole source on the 787 (for any OEM) they effectively dropped the bid.

    • Or the A350, or A380? Looks like the A330 and 777 missed the boat.

    • No GTF exists larger then PW1100G of about 33klbs. Nobody missed it.

  3. The way they are talking, things are going to change dramatically in the engine market over the next 10 years. How much is hype and how much is cold, hard facts?

    I guess the issue is still going to be reliability and maintainability which is going to take a few years of in service experience to prove those aspects.

  4. Is this a good moment to ask what the difference between ta GTF and a three spool design is? I have always understood that the point of the three spool design was to allow the different sections of the engine to rotate at their optimum speeds.

    • The 3 spools of a 3 spool engine still have the fan/compressor stage(s) and turbine stage running at the same rpm. A gear can change that.

  5. This is what Wiki says:

    The advantage three spools gives is that the front-most fan (driven by the third, rearmost turbine) can be tuned to rotate at its optimal (fairly low) speed; the two compressors are driven by the two other turbines via their spools.

    Is this wrong then? If its correct, can I re-ask my original question? Or am I just being slow on the uptake!?

    • The fan is still directly driven by the low pressure part of the turbine. Just the segments in-between can run at more optimal higher speeds. The optimal speed for the low pressure turbine is still much higher than the optimal speed for the fan. The gearbox is the solution to let run both at their optimal speed.

      On this page the is a schematic illustrating the 3 shafts of an RB211:

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