Bjorn’s Corner: Boeing’s 787 and Airbus’ 350 programs, a snapshot

 

By Bjorn Fehrm

By Bjorn Fehrm

Introduction

23 April 2015, C. Leeham Co: It has been an eventful week for Boeing with Q1 results reported and with that an update on the 787 program. At the same time we ran into Qatar Airways CEO Akbar al Baker, while visiting Airbus the other day and could exchange a few words with him and his team re the A350. I therefore decided that this week’s Corner should provide a snapshot on where these two new aircraft projects stand right now.

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A321neo configurations and A320 production

By Bjorn Fehrm

18 Jan 2015: As part of the preparations for the Airbus A321LR article 15 Jan. we saw a need to clarify with Airbus the production configurations for A321neo. There had been several iterations of what will be produced come mid-2018 when the A321neo variant is scheduled to roll off the FALs at Airbus in an enhanced Airbus Cabin-Flex (ACF) variant.

This variant features a three-door pairs layout that allows a raised max passenger limit by virtue of displaced door three and an addition of a second overwing exit. Recent media articles have suggested that both the initial four-door variant as well as the three-door variant would be available.

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Airbus formally launches A321LR; we look behind the “LR” to see what’s there

15 Jan 2015: Airbus officially launched what to date has been called A321neoLR as the A321LR at their annual press conference Tuesday. The former A321neoLR name was formed by Leeham News on 21 Ocober 2014 when we could reveal the existence of a A321neo variant which Airbus hadLeeham logo with Copyright message compact started to present to airlines at the time. The final name kept the LR attribute used in the article to distinguish the longer range variant from the standard A321neo.

The A319 has used the LR designation but its use has been limited. The suffix is more commonly identified with Boeing, used as it is with the 777-200LR. Boeing has also commonly used the ER for extended range like 777-200ER, 737-900ER and 777-300ER.

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Airbus reveals record orders at annual press conference

By Bjorn Fehrm

Toulouse 13 Jan 2015: Airbus today held their annual press conference where they among other things revealed their final numbers for orders and deliveries. The press conference was hosted by Airbus CEO Fabrice Bregier accompanied by COO Customers John Leahy, new COO Tom Williams and new Head of Programs Didier Evrard.

Airbus in 2014

Bregier started with pointing out that 2014 was a very eventful year for Airbus. Airbus did their customary end of year sprint and passed Boeing for net orders with 24 aircraft netting 1456 commands, Figure 1.

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Figure 1. Airbus orders for 2014. Source: Airbus.

On the delivery side Boeing is ahead with 723 deliveries versus Airbus 629, Figure 2.

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Figure 2. Airbus deliveries for 2014. Source: Airbus.

Further Airbus certified the A350 and delivered the first aircraft to its launch customer, Qatar Airways. It also launched the A330neo and got 120 orders during the year. Finally they flew the A320neo first prototype.

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A380neo decision likely this year, triggering the next widebody engine project

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By Bjorn Fehrm

Introduction

Jan. 12, 2015: One of the subjects which is sure to come up on Airbus annual press conference on Tuesday the 13th in Toulouse will be when and how Airbus will re-engine the A380.

Airbus Commercial CEO Fabrice Bregier vowed during the Airbus Group Global Investors Day last month that an A380neo is coming.

There is much speculation around this subject as the business case of re-engineering an aircraft that is selling at such low numbers is difficult to get to close. The business case is difficult to make work for Airbus Leeham logo with Copyright message compact(such a project will cost in the order of $2 billion) but it will be equally hard for the engine manufacturers to offer engines that have enough efficiency gain to make the overall project feasible from an efficiency improvement perspective.

Summary

  • A380 Classic equals Boeing 777-300ER seat fuel costs.
  • Boeing 777-9 beats A380 on CASM, an A380neo regains the advantage.
  • Engine makers face hard choices to retain dominance or to broaden market penetration.

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Merry Christmas

We’ll be back next week on our reduced Holiday schedule. Merry Christmas.

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Fundamentals of airliner performance, Part 5; Approach and landing

By Bjorn Fehrm

Dec. 2, 2015: The time has now come to cover descent and landing in our Leeham logo with Copyright message compactarticles around airliner performance. As many aspects of descent are similar to climb we will repeat a bit what we learned in Part 4:

  • For high speed operation the pilots fly on Mach as this gives him maximum information around possible effects on the aircraft when he is close to the high speed limit, the maximum Mach number. Beyond this the aircraft gets into supersonic effects like high speed buffeting or unsteady flight.
  • For operations under the cross over altitude for Mach 0.78 to 300 kts IAS the pilot flies on Indicated Air Speed (IAS) which gives him maximum information how the aircraft reacts should he go close to the aircraft’s lower speed limits.

Lets now start to go through the steps that our 737 MAX 8 performs after leaving its cruise altitude.

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Happy Thanksgiving, 2014

Today we’re watching the Seattle Seahawks…Go Hawks!

We’re off until Monday.

Fundamentals of airliner performance, Part 4

By Bjorn Fehrm

Nov. 25, 2014: In our article series around the performance of a modern airliner we have now come to the climb after takeoff. Leeham logo with Copyright message compactWe started with cruise as this was simplest because the aircraft is flying in steady state, then we looked at the modern turbofan and how this is affected by both altitude and speed. We then examined how this affects the takeoff and today we continue with the climb after takeoff.

Before we start, let’s sum up a few points we need for today:

  • Drag is the one thing we always need to be aware of as this regulates how much excess power we have in different flight situations and therefore if we can stay on our altitude or climb.
  • Drag diminishes with altitude as the airs density diminishes and thereby our dominant drag component, air friction against our aircraft’s skin. This is the major component of the aircraft’s dominant drag, parasitic drag.
  • Our lift force is generated by forcing air downwards and this causes induced drag as this downwash cost energy to generate and maintain. Induced drag is mitigated by a wing with a large span.

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Fundamentals of airliner performance, Part 3

By Bjorn Fehrm

In our first article about how to understand the performance of a modern airliner we defined the main forces that are acting on an aircraft flying in steady state cruise. In our clinic we use the ubiquitous Boeing 737 in its latest form, the 737 MAX 8, to illustrate our case. Leeham logo with Copyright message compactIn the second article we introduced the aircraft’s engines and understood how they function by pumping air backwards faster than the aircraft’s speed and therefore generating thrust as air is in fact quite heavy. We also looked at the influence of flight altitude on the performance of the aircraft.

In short we can conclude our findings so far:

  • For cruise lift is the same force size as weight, only opposite. To understand the cruise phase we can therefore focus on how much drag this lift force and the aircraft’s friction against the air create.
  • When we have this drag we also know the engine thrust and we can calculate the cruise fuel consumption from the engines fuel consumption per unit of thrust and hour.
  • We also found that it is beneficial to fly high as the airs density diminishes and with this the airs friction against our aircraft’s skin.
  • Our lift force is generated by forcing air downwards and this causes drag due to weight as this downwash cost energy to generate and maintain. The air resists being downwashed and slinks up on the side of the wing thus generating large vortice sheds which consumes energy. This drag we call induced drag or drag due to weight.
  • We diminish this re-circulation of the air by spreading our wings as wide as we can, in fact we get double reward for increases our span, it counts twice in induced drag reduction.
  • Our limit to fly high for our cruise is set by the increase in induced drag, we are seeking a flight level where we have a drag minimum when adding the diminishing friction drag and the increasing induced drag.
  • We also have a problem with climbing to a to high cruise flight level, our engines lose power both due to the thin air and due to the aircraft’s forward speed.
  • Finally there are supersonic phenomena which stop high cruise altitudes. As the air gets thinner the wings need to throw the air downwards with higher speed (increase wing canting or alfa angle). This means the air on the top side of the wing has to speed up and is therefore going deeper into supersonic flow on parts of the wings overside. This causes disturbances called buffeting when these supersonic areas grow to strong.

Having covered the most important aspects of cruise we will today look at takeoff, a subject with a lot of aspects. Read more