Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Does an A220-500 need a new wing and engines? Part 2. May 8, 2025
- Embraer downplays tariff impact on 2025 results May 6, 2025
- JetZero readies effort for private equity fund raising May 5, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 20. May 2, 2025
- Supplier Howmet exceeds expectations despite tariffs May 1, 2025
Bjorn’s corner; Turbofan engine challenges; Part 2
By Bjorn Fehrm
November 04, 2016, ©. Leeham Co: We will now start to go through a modern turbofan airliner engine and look at the technologies which are used and what are their technical challenges. We will start today with the engine intake and the fan.
To make things concrete, we will use a GasTurb simulation of a Rolls-Royce Trent XWB 84k engine. This will provide us with realistic example data for the different parts of the engine. I want to stress that all values are assumed as typical for such an engine. I have no specific knowledge of the Trent XWB and will not use any data outside what is public information.
Figure 1. Stilistic cross section of a three-shaft turbofan with section numbers. Source: GasTurb.
The GasTurb cross section of a three-shaft turbofan is shown in Figure 1. We will use the station numbers in the figure to navigate the engine and the data from the simulation to understand modern airline engines and their typical data. Read more
Bjorn’s Corner: Turbofan engine challenges, Part 1
By Bjorn Fehrm
October 28, 2016, ©. Leeham Co: Before we go into the details on the innards of airliner turbofans, we will look at some basics. We do that so that everyone is on the same page.
A turbofan engine generates thrust by pumping air out the back of the engine. This air has a higher speed than surrounding air. Air is actually quite heavy: it weighs 1.2kg per m3 at sea level. By kicking out air at an overspeed in relation to the aircraft, thrust is generated.
In a modern turbofan, the kicking gets done by the fan to 80-90% in the modern By Pass Ratio (BPR) 8-10 engines. A single aisle engine generating 10 tonnes of thrust throws around 350kg of air per second backwards at close to sound speed in a take-off situation. To drive the fan to do that, there is a lot of shaft horse-power needed, around 30,000hp.
Figure 1. Work cycle for jet engine/turbofan core compared to car engine. Source: Rolls-Royce book “The Jet Engine.”
These hp are generated by the core. The thermodynamic cycle to generate all these hp in a jet engine or turbofan core (we call both a gas turbine) is like the one in a normal car engine, Figure 1, with the difference that it is a continuous cycle.
We will now go through this cycle in steps. Read more
Engine industry clamoring for road back
By Bjorn Fehrm
Subscription required.
Introduction
October 13, 2016, ©. Leeham Co: The airline engine industry is like a ticking bomb. Over the years, a business practice of selling the engines under manufacturing cost and planning to recover costs and make a profit on the aftermarket developed. This goes back decades.
The practice was fostered by fierce competition over the engine contracts for aircraft which offered alternative engines. The losses of the engine sales could be made up later by selling spare parts and services at high margins.
Figure 1. Trent 7000 from Rolls-Royce. Source: Rolls-Royce.
These “jam tomorrow” practices have several implications. The engine industry is now confronted with these and wonder how it could put itself in such a bind. How to handle these and what is the way back?
Summary:
- High competition in engine sales forced ultra high discounts for the up-front engine sale.
- Aftermarket schemes was created that should recover profits over spare parts and services.
- But these maintenance practices create all sorts of problems in the used engine market.
- The engine industry now wants to return to more normal business practices. But how do they find the way back?
Russian-Chinese wide-body: Program responsibilities
By Bjorn Fehrm
Subscription required.
Introduction
September 29, 2016, ©. Leeham Co: We will now finish our series about the Russian-Chinese wide-body with looking at who will have what role in the program.
Figure 1. Concept for new wide-body airliner. Source: United Aircraft.
As we described in the initial article, “Background and outlook,” Russia and China have vastly different competencies when it comes to making a state of the art wide-body aircraft.
Russia has made airliners since the 1930s, including wide-body jets. China did not design its own jet aircraft (military or civil) until the mid-1980s. Most of the aircraft produced still today in China have their origin in Russian designs.
At the same time, we saw in the article about the market demand for the aircraft that the Chinese market is 90% of the home market. This makes for China demanding important parts of the aircraft’s production, and China has the money to invest in production facilities.
All this will influence how different parts of the project will be shared between Russia’s United Aircraft Corporation (UAC) and Commercial Aircraft Corporation of China (COMAC).
Summary:
- Russia and China enter the wide-body project with widely different knowledge bases.
- Russia has long time knowledge on how to develop and produce aircraft and their engines.
- China on the other hand has the market for the aircraft.
- China also know a lot about serial production and have money to invest. Read more
No sanctions will be levied on Airbus and Boeing in WTO dispute
Subscription Required
Now open to all readers.
Introduction
Sept. 26, 2016, © Leeham Co.: It’s hazardous to use the word “never,” but the US and European Union will never impose trade sanctions or tariffs on Airbus or Boeing airplanes.
No sane president would do so. (Cue Donald Trump.) It would start a devastating trade war and the collateral damage on innocents in the Airbus-Boeing illegal subsidies disputes would be severely harmed.
Summary
- US tariffs on Airbus aircraft and EU tariffs on Boeing aircraft would hurt engine makers, suppliers—innocents in the illegal subsidy disputes.
- Some key customers order from Airbus and Boeing. Tariffs on one or the other company risk alienating these customers.
- Sanctions/tariffs permitted on other companies, industries.
- Canada, Brazil never imposed sanctions in Bombard-Embraer violations.
Russian-Chinese wide-body: Aircraft performance
By Bjorn Fehrm
Subscription required.
Introduction
September 19, 2016, ©. Leeham Co: In Part 4 of the article series, we put together an assumed complete Chinese-Russian wide-body aircraft with fuselage, wing, engines, etc. It is now time to understand what kind of performance that can be expected, given the data we have from the wide-body partners, Russia’s United Aircraft Corporation (UAC) and the Commercial Aircraft Corporation of China (COMAC).
Figure 1. Concept for new widebody airliner. Source: United Aircraft.
We will combine these data with the ones we have deduced as plausible to fill the gaps, given the time frame and technology level that UAC and COMAC intend to use.
Out will come a first estimate of what kind of performance such an aircraft can have in terms of efficiency and payload versus range capability.
Summary:
- We can use all the data we have gathered to make a first estimate of the efficiency of the Russian-Chinese wide-body.
- We also have enough information to do a first payload-range diagram and to compare that with the diagram for Boeing’s 787-9.
Russian-Chinese wide-body: The aircraft, Part 4
By Bjorn Fehrm
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Introduction
September 15, 2016, ©. Leeham Co: In Part 3 of this series, we identified the type and size of wing we would have on a new Russian-Chinese wide-body. It’s now time to go through all the considerations around the engines for the aircraft.
Figure 1. Concept for new widebody airliner. Source: United Aircraft.
The aircraft would enter the market around 2025. We would have to decide on what size engine that would be needed, what engines would be available at the time and could this project motivate any new engine developments.
Summary:
- The Russian-Chinese wide-body as outlined would require engines in the size class of the Boeing 787-9/10.
- GE and Rolls-Royce have been mentioned as engine suppliers. The question would be: will they offer updated 787 engines or new designs and will Russia compete with its announced engine project for the aircraft?
Russian-Chinese wide-body; The aircraft Part 3
By Bjorn Fehrm
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Introduction
September 08, 2016, ©. Leeham Co: Having covered the possibilities of reusing parts of the Il-96 fuselage for a new Russian-Chinese wide-body, it’s now time to look at the existing IL-96 wing and how far this is from a modern design.
Figure 1. Concept for new wide-body airliner. Source: United Aircraft.
The intent is not to propose that the existing wing is reused but rather to check the technology level against western designs and how big a leap it will be for the partners to make a modern high performance wing for the aircraft.
Summary:
- The IL-96 wing is roughly on the technological level of the Airbus A340-300 wing with a bit lower aspect ratio.
- The dimensions are close to what is needed for the new wide-body but sweep and aspect ratio needs to be changed for a new wing.
- A wing for a 2025 long range wide-body also need a more modern construction technology than classical aluminum alloys.
Russian-Chinese wide-body: The aircraft, Part 2
By Bjorn Fehrm
Subscription required.
Introduction
September 01, 2016, ©. Leeham Co: In Part 1, we concluded that the existing Il-96 fuselage cross section would be suitable for a new Russian-Chinese wide-body. This means that a lot of experience and existing designs for fuselage sections can be re-used.
Figure 1. Concept for new wide-body airliner. Source: United Aircraft.
Most importantly, it means that mock-ups and cabin sections can be made early in the project to start work on new and better cabin equipment. This is an area where the partners really lag their western competitors.
We will now look at what aircraft capacities can be conceived with the existing Il-96-300 and -400 fuselages and what changes will be necessary to achieve the targeted sizes that Russia’s United Aircraft Corporation (UAC) and Commercial Aircraft Corporation of China (COMAC) have communicated.
Summary:
- The IL-96 fuselage can be re-used for a Russian-Chinese wide-body.
- The existing IL96-300 cabin is on the small side whereas the Il-96-400 cabin is a bit larger than needed.
- The project will likely choose an intermediate size fuselage to reach the targeted 250 to 280 passenger capacity.