An examination of the turbofans powering today’s production business jets, including the latest Passport and PW800 engines
The quest for reduced emissions, increased fuel efficiency and lower noise and vibration levels drives business aircraft turbofan development. The majority of engines equipping new aircraft types are derivatives of ‘fans’ decades old in their original design, yet transformed in capability by the latest technologies. Although there are notable exceptions.
General Electric is looking towards seeing its all-new Passport enter service on the Global 7000, while the service debut of Pratt &Whitney Canada’s PurePower PW800 on the G500 is imminent. Meanwhile, Dassault is looking forward to Safran’s Silvercrest working as advertised, so that it can return in earnest to its delayed Falcon 5X programme.
General Electric’s flagship business jet engine, the Passport turbofan is powering Bombardier’s ultra-long range Global 7000 through its flight test programme, with first deliveries scheduled for next year. The engine is installed as an ‘integrated propulsion system’ within a Nexelle nacelle, employing technologies derived from GE’s development work on the GE90, GEnx and GP7000 engines to reduce emissions and fuel burn compared to other motors in its class.
The manufacturer claims an 8% fuel burn advantage over existing engines of similar thrust, as well as emissions so carefully controlled that Global 7000 operators may benefit from reduced landing fees, or even no landing fees at all in some regions. The Passport has so far only been selected for the Global 7000 and 8000, but efforts to find other platforms continue.
According to GE, the combined Passport and Global 7000 test programmes will accumulate in excess of 4,000 hours of engine flying in more than 8,000 cycles, equivalent to a decade of operations. Among other features, the high-tech Passport includes a front fan blisk with integrated blades for lower cabin noise and vibration, and software modulated turbine clearance. Reducing weight, while improving heat resistance and acoustic performance, the Passport employs ceramic matrix composites in their first non-military application to a GE engine.
Meanwhile, the CF34 remains in widespread use, particularly on Bombardier Challenger variants and the Canadian OEM’s CRJ regional airliners. It remains as the production standard powerplant on the Challenger 650, albeit in its latest CF34-3B MTO form, considerably enhanced through years of development compared to the CF34 that powered the first CRJ100 airliners in 1992. The CF34 also power Embraer’s Lineage 1000E, in its rather more powerful CF34-10E7-B variant.
General Electric partners Safran in the CFM International joint venture, responsible for the CFM56 that optionally powers the ACJ319, 320 and 321, and 737-based BBJ. Designed to replace the CFM56, the next-generation LEAP is being built for the A320neo and 737 MAX airliners and will subsequently appear on their new-build ACJ and BBJ derivatives.
Delivering around 2,000lb thrust, the HF120 has been designed as a next-generation light jet engine. Created by General Electric and Honda joint venture GE Honda Aero Engines, the HF120 is currently unique to the unusually configured HondaJet.
According to GE Honda information, the HF120 is the most advanced engine in its class, thanks to features including a titanium blisk fan and composite fan outer guide vanes. It’s also the quietest and toughest, with super alloys used in its hot section for higher operating temperatures and extended parts life.
Updated versions of Honeywell’s classic TFE731 power the Learjet 70 and 75, and Dassault’s Falcon 900LX trijet. The model was certificated in 1972, since when Garrett, and subsequently Honeywell, have delivered more than 13,000 engines. Constant product improvement has enhanced reliability and efficiency, to the point where the latest TFE731-50R offers as much as an 8% improvement in fuel burn compared to its immediate predecessor.
Honeywell also produces the HTF7000 line, delivering more thrust than the TFE731 and specifically for business jet applications. The HTF7000 base engine powers the Challenger 300, subsequent developments including the HTF7350B (Challenger 350), HTF7350G (G280), HTF7500E (Legacy 450/500) and HTF7700L (Longitude).
Pratt & Whitney
Pratt & Whitney partners MTU Aero Engines and Japanese Aero Engine Corporation in producing the V2500 turbofan optionally available on ACJ319/320/321 aircraft.
In its quest for an engine to replace the V2500 and compete with CFM’s LEAP on the next generation of short/medium-range airliners, Pratt & Whitney worked alone to produce the PurePower PW1100G geared turbofan. Already in service on the A320neo, it will ultimately be an ACJ320neo option, while the PW1900G’s Embraer E2 application will presumably lead to the engine powering future Lineage versions.
Pratt & Whitney Canada
Pratt & Whitney Canada complements Pratt & Whitney’s engine output with a huge range of small turbofans, turboprops and turbofans. Delivering between 4,700 and 8,000lb thrust, its PW300 series is well established in service, specific models including the PW306D1 (powering the Citation Sovereign+ and Latitude), PW307A (Falcon 7X), PW308C (Falcon 2000LXS and 2000S) and PW307D (Falcon 8X).
The 2,900 to 4,500lb thrust PW500 series includes the PW545C (Citation XLS+) and PW535-E (Phenom 300), while among the 900 to 3,000lb thrust PW600s, the PW615F powers the Citation Mustang and the PW617F1-E equips the Phenom 100.
Largest of Pratt & Whitney Canada’s dedicated business jet engines, the PurePower PW800 powers the G500 in its PW814GA form and the G600 as the PW815GA. The PW814GA enters service on the G500 later this year, Pratt & Whitney Canada promising a 40% reduction in scheduled maintenance compared to comparable legacy powerplants. The engine also benefits from lightweight advanced materials, high efficiency and reduced emissions.
During the 1990s, Rolls-Royce joined BMW in a joint venture that developed the BR700 turbofan. Bombardier subsequently chose the BR710 derivative for the Global Express, while Gulfstream applied it to the GV. Now the responsibility of Rolls-Royce Deutschland after BMW withdrew, the latest BR710A2-20 powers the Global 5000 and 6000, the BR710C4-11 equips the G550, and the G650ER and G650 employ the BR725A1-12.
The result of an entirely separate product line, Allison developed the AE3007 before its acquisition by Rolls-Royce in the mid-1990s. Built to power the Citation X, it remains in service on the latest X+ variant as the AE3007C2 and also powers the Legacy 650 as the AE3007A2.
Chosen for the Dassault Falcon 5X and Citation Hemisphere, Safran’s Silvercrest has met a number of issues, delaying certification until early 2018 and the Falcon 5X’s service debut until 2020. Performance, vibration and other problems led to an engine redesign, but Safran believes the Silvercrest’s woes are behind it. In March 2017, Dassault was awaiting a set of new engines in order to resume the Falcon 5X test programme, having begun discussions with Safran over compensation for the programme delays.
Although it has found a market in a variety of small-jet applications, the Williams International FJ44 is most readily associated with light business jets, today including the Citation M2 (FJ44-1AP-21), CJ3+ (FJ44-3A) and CJ4 (FJ44-4A); Nextant 400XTi (FJ44-3AP); and PC-24 (FJ44-4A-QPM).
The FJ33 is a smaller engine in the 1,000 to 1,900lb thrust class, developed by leveraging advanced technologies from the FJ44 programme. In its FJ33-5 form it powers the Cirrus SF50 Vision.
By April 2017, more than 5,000 FJ44s were in service, accumulating between them in excess of 11 million hours.