How Rolls-Royce Engines Differ From General Electric Engines

GE Aerospace and Rolls-Royce (RR) currently dominate the large widebody engine market[1], although RR also wants to challenge GE once again in the massive narrowbody engine market. These are two of the largest Original Engine Manufacturer (OEM) giants in the commercial sector, along with Pratt & Whitney (P&W) and Safran. GE Aerospace[2] and Rolls-Royce[3] offer competitive engines that have different underlying design philosophies.

These design philosophies produce engines with different strengths and weaknesses, though none has a decisive advantage. Unbeknownst to many, GE and RR also compete with maritime variants of their airliner engines to power the Western and Western-aligned world's naval ships. One area where RR does dominate is with high-end flagship business jet engines.

Here are some things to know about the differences between GE and RR engines.

The Airline Industry's Widebody Engine Duopoly

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Apart from a few remaining Boeing 767s modified as KC-46A Pegasus tankers, Pratt & Whitney has exited the widebody engine market. In the past, the widebody engine market was mostly a three-way race between Rolls-Royce, Pratt & Whitney, and General Electric. However, P&W exited the race by de-prioritizing large widebody engines.

Widebody engines are extremely expensive and risky to develop, a problem exacerbated by Boeing's very deep relationship with GE. P&W has prioritized other engines, like the PW1000G[4], which is an option for the A320neo and is the engine for Embraer E-Jets and the Airbus A220. This left RR and GE as the two widebody engine manufacturers.

Of these, GE has been the largest with the higher profitability margin, although RR does come in a respectable second. GE Aerospace's engines have become the primary engine of Boeing's widebody aircraft. Its engines exclusively power remaining orders for legacy Boeing 767s (apart from military tankers) and Boeing 777s.

It is the exclusive OEM for the upcoming Boeing 777X and is now by far the most popular engine option for the Boeing 787 Dreamliner. RR is 'the' widebody OEM for Airbus widebody aircraft in production. Its engines power only the A330neo and A350, and are also the least popular option for the Dreamliner.

RR & GE Different Design Philosophies

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RR and GE follow different design philosophies, and these are reflected in their engines. RR focuses on refined mechanical harmony and long-term fuel efficiency through its three-spool core architecture[5] in its Trent series of engines.

The three-spools are Low-Pressure, Intermediate-Pressure, and High-Pressure. This offers benefits like long-term efficiency, lower NOx emissions, lower noise, and more. Meanwhile, GE Aerospace has a two-spool core architecture in its GEnx, GE9X, and other engines (Low-Pressure and High-Pressure).

This achieves power through simplicity, reducing the engine's complexity. GE's engines have fewer moving parts, are 10-15% lighter, deliver higher peak thrust, and are easier to maintain overall. In other words, RR engines are designed for optimized efficiency, while GE engines emphasize raw thrust and reliability.

Rolls-Royce (Trent series)

GE Aerospace (GEnx & GE9X)

Spools	3-Spool (Low-Pressure, Intermediate Pressure, High Pressure)	2-Spool (Low-Pressure, High-Pressure)
Key benefits	Overall better efficiency, lower NOx emissions	Simplicity, increased reliability, raw thrust, lower maintenance
Fan blades	Greater use of carbon-fiber composite blades	Greater use of ceramic matrix composites (CMCs)

Both families of engines have similar bypass ratios (9-10:1) and similar overall pressure ratios (50:1 for modern Trents and 47:1 on the GEnx).

As a simpler design, GE's engines are generally easier to disassemble. Another area where the engines differ is the materials used for fan blades and hotter cores.

GE Vs. RR Thrust By Engine

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When it comes to the engines with the most thrust, GE Aerospace leads with its GE9X.

The GE9X has a record-breaking test thrust of 134,300 lbf, although its typical commercial takeoff thrust rating is 105,000 lbf. The GE9X is part of a family of engines with thrust ratings ranging from 81,000 lbf to 115,000 lbf. Variants include the GEnx (found on the Boeing 787), the Engine Alliance GP7000 (found on the A380), the CFM International LEAP, and the GE9X (found on the Boeing 777X).

After this family, the next-highest-rated is Pratt & Whitney's PW4000 series, which reaches a maximum of 99,040 lbf. The highest-rated Rolls-Royce engine in production is the Trent XWB-97, which has 97,000 lbf. The -97 powers the Airbus A350-1000 variant, while the XWB-84 variant powers the smaller A350-900 variant[6].

While many enthusiasts may be keen to compare thrust ratings to see which is the "biggest and best", engines are designed with different thrusts to serve different aircraft types. Instead of thrust, the Trent 1000 blade crackings were much more consequential in airlines turning against the engine. The Boeing 787 Dreamliner is the only widebody aircraft currently in production produced with two aircraft options (apart from legacy 767s).

Its RR Trent 1000 variants offer 62,264 to 78,129 lbf, while the GEnx engines provide 69,800 lbf for the 787-8, 74,100 lbf for the 787-9, and 76,100 lbf for the 787-10.

GE Aerospace's Open Fan Vs. Rolls-Royce's UltraFan

Credit: Rolls-Royce

Looking forward, both GE Aerospace and Rolls-Royce are working to develop the next generation of engines for the 2030s. This includes making the engines bigger.

One notable project GE is working on through CFM International is the CFM International RISE open fan engine. Superficially, this new generation of narrowbody engines looks like a turboprop engine. RISE is being developed for Airbus' narrowbody cleansheet A320-family replacement expected in the 2030s.

RISE promises to deliver engines that are 20% more fuel efficient in the 2030s. Key to CFM RISE's fuel efficiency is doing away with the cowling, allowing the fan blades to be larger. Meanwhile, RR is working on the UltraFan to develop an engine able to deliver 25% fuel improvements[7] compared with the first generation of Trent engines.

Many of the improvements to the UltraFan are achieved by making the engine larger. The massive 140-inch engine is using scalable technologies that can be applied to engines in the 25,000 lbf to 110,000 lbf range. RR has stated it wants to reenter the narrowbody engine market[8], and it believes technologies from the UtraFan will enable it to get back in the competitive game. It is unclear what narrowbody aircraft RR would like to target.

Both Airbus and Boeing are expected to replace their respective A320 and 737 aircraft in the 2030s.

GE Dominates Narrowbody Aircraft, RR Bigger With Business Aircraft

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When it comes to smaller aircraft, GE Aerospace dominates the narrowbody aircraft engine market through its CFM International 50/50 joint venture with France's Safran. The CFM International Leap turbofan exclusively powers the Boeing 737 MAX, the COMAC C919, and is the most popular option for the A320neo. Pratt & Whitney's PW1000G dominates the rest of the market.

But RR does make engines for business jets and is a major player in the market. P&W and P&WC (P&W Canada) together constitute the most significant player in the regional aircraft market and lower-end business jets. The main RR business jet engine is Rolls-Royce's Pearl family (BR700).

The Pearl 15 powers the Bombardier Global 6500/7500, the Pearl 700 powers the Gulfstream G700/G800, and the Pearl 10X powers the Dassault Falcon 10X. These engines focus on ultra-long-range and low-noise.

Select OEMs

Engines

Select business jets powered

PW/PW Canada	PW300, PW500, PW600, PW800	Falcon 6X, Gulfstream G280, Gulfstream G400/G500/G600
Rolls-Royce	Pearl Series (BR700)	Gulfstream G650/G700/G800, Bombardier Global 5500/6500/8000, Dassault Falcon 10X, Bombardier Global Express
GE Aerospace	GF34, GE Passport	Bombardier Challenger 650, Bombardier Global 7500/8000
Honeywell	HTF7000	Bombardier Challenger 3500, Gulfstream G280, Embraer Legacy 500/450, Cessna Citation Longitude

When it comes to military aircraft, both GE and RR make engines for high-performance fighter jets. However, GE is dominant, providing the engines for numerous US and partner fighter jets.

RR's engines for in-production frontline fighter jets are limited to the Eurofighter Typhoon, which uses the Eurojet EJ200 engine. Notably, RR is also providing RR F130 engines (Pearl series) as the re-engining upgrade for the Air Force's fleet of B-52 Superfortress strategic bombers[9].

GE Dominates With Warship Gas Turbines

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Both GE and RR have naval variants of aero engines initially designed for widebody airliners to power NATO and allied warships. Here, GE Aerospace dominates with the General Electric LM2500 marine gas turbine developed from the General Electric CF6, the most successful widebody engine in history[10].

In the air, the CF6 is still produced for the remaining Boeing 767 freighters. The LM2500 is found in warships of 39 navies around the world. In the US Navy, notable ship classes powered by the LM2500 include the America-class amphibious assault ship, the Ticonderoga-class cruiser, the Arleigh Burke-class destroyer, the Constellation-class frigate, and many others.

The engine powers frigates, destroyers, and other classes of warships produced for many European, Indian, Japanese, Australian, and other navies. A distant second, RR's MT30 Marine Gas Turbine is the main alternative to the GE LM2500[11]. It is derived from the Trent 800 developed for the Boeing 777.

It powers the Royal Navy's aircraft carriers, upcoming Type 26 frigates (including Australian and Canadian variants), and other warships, including the US Zumwalt class.

The RR WR-21 gas turbine draws from the RB211 and Trent families and powers the Royal Navy's Type 45 class destroyers.

References

1. ^ GE Aerospace and Rolls-Royce (RR) currently dominate the large widebody engine market (simpleflying.com)
2. ^ GE Aerospace (simpleflying.com)
3. ^ Rolls-Royce (simpleflying.com)
4. ^ P&W has prioritized other engines, like the PW1000G (simpleflying.com)
5. ^ RR focuses on refined mechanical harmony and long-term fuel efficiency through its three-spool core architecture (simpleflying.com)
6. ^ the XWB-84 variant powers the smaller A350-900 variant (simpleflying.com)
7. ^ RR is working on the UltraFan to develop an engine able to deliver 25% fuel improvements (simpleflying.com)
8. ^ RR has stated it wants to reenter the narrowbody engine market (simpleflying.com)
9. ^ the re-engining upgrade for the Air Force's fleet of B-52 Superfortress strategic bombers (simpleflying.com)
10. ^ the General Electric CF6, the most successful widebody engine in history (simpleflying.com)
11. ^ MT30 Marine Gas Turbine is the main alternative to the GE LM2500 (www.rolls-royce.com)