Bjorn’s Corner: Airbus A330neo flight test starts

By Bjorn Fehrm

October 20, 2017, © Leeham Co, Toulouse: The Airbus A330neo flew its first flight yesterday. The aircraft lifted off from Toulouse Blagnac Airport in front of invited airline customers, suppliers and media. It landed after a successful four-hour mission.

We’ll take the opportunity to look at the A330neo changes and its flight test program. We also look at the drag reducing changes from A330ceo to A330neo.
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Bjorn’s Corner: Aircraft drag reduction

By Bjorn Fehrm

October 06, 2017, ©. Leeham Co: In the last several Corners, we wrote about research around laminar flow for aircraft. It’s research to lower the aircraft’s drag. Why is this important? How large are the different drag types and what can be done about them?

To find out, we will spend some Corners looking into the drag of an aircraft and what is done to optimize the drag for different aircraft types.

Figure 1. The “Blade” equipped A340-300, researching into lower drag for an airliner. Source: Airbus.

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Bjorn’s Corner: Laminar flow aircraft, Part 2.

October 06, 2017, ©. Leeham Co: We introduced the Airbus “Blade” laminar flow research program in the last Corner. Now we continue to look into what this research is all about.

We will explain the difference between laminar and turbulent flow (really, laminar and turbulent “boundary layer” flow) and discuss some of the work that has been done with laminar flow structures.

Figure 1. The “Blade” equipped A340-300. Source: Airbus.

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Bjorn’s Corner: Laminar flow aircraft

By Bjorn Fehrm

September 29, 2017, ©. Leeham Co: Airbus flew its “Blade” laminar flow research aircraft for the first time this week. It’s a project in the European Clean Sky research program.

The “Blade” aircraft is a modified Airbus A340-300, where the outer wings have been replaced with special laminar flow wing sections. We will spend a couple of Corners to understand why this research is done and why it’s important.

Figure 1. The “Blade” equipped A340-300. Source: Airbus.

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Bjorn’s Corner: Electric aircraft, Part 13

By Bjorn Fehrm

September 22, 2017, ©. Leeham Co: After 12 articles about electric aircraft, it’s time to wrap up. We will go through what we have learned and discuss future developments.

Our designs were aimed for the next decade and the result was sobering. Electric aircraft have important challenges to traverse. As had electric cars, and they have turned the corner.

Figure 1. Idea for future aircraft that could use electric propulsors. Source: NASA.

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Bjorn’s Corner: Electric aircraft, Part 12

By Bjorn Fehrm

September 15, 2017, ©. Leeham Co: Last week we compared the energy economics of our 10-seater electric commuter to an equivalent commuter with gas turbine power.

Now we dig a bit deeper in the operational costs of the two aircraft. Is the electric commuter cheaper to operate over short sectors than a gas turbine driven variant? For the energy costs, it could be the fact. What about other operational costs?

The commuter designs we discuss would be similar to the Zunum Aero 10-seater commuter in Figure 1.

Figure 1. Zunum Aero’s short-haul turbofan commuter. Source: Zunum Aero.

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Bjorn’s Corner: Electric aircraft, Part 11

By Bjorn Fehrm

September 8, 2017, ©. Leeham Co: After our definition of an-all electric 10-seater for Ultra short-haul flying in last Corner, we now compare its economics to a gas turbine propelled design.

Our designs have the Zunum Aero 10-seater commuter in Figure 1 as reference.

Figure 1. Zunum Aero’s short-haul turbofan commuter. Source: Zunum Aero.

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Bjorn’s Corner: Electric aircraft, Part 10

By Bjorn Fehrm

September 1, 2017, ©. Leeham Co: in the nine previous Corners, we looked at 50-seat regional jets and turboprops with hybrid electric propulsion systems.

We have seen that at the state of technology until the mid-next decade, such aircraft have dubious efficiency. The hybrid propulsion chain weighs too much, and can at best match the propulsion efficiency of gas turbine based aircraft when one includes any airframe gains that can be made.

We will now finish the series by looking at a pure electric concept, designed for extremely short-haul routes. The Zunum Aero 10-seat commuter in Figure 1 will be our reference for such a design.

Figure 1. Zunum Aero’s short-haul turbofan commuter. Source: Zunum Aero.

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Bjorn’s Corner: Electric aircraft, Part 9

By Bjorn Fehrm

August 25, 2017, ©. Leeham Co: We finished the weight sizing of the hybrid propulsion system for our 50-seat regional turboprop in the last Corner. Now we go a bit more into detail. There are additional parts needed in the system that we skipped over last time.

We discuss the impact of these additional components and any gains we can make with the aircraft configuration.

Figure 1. ATR42-600 serves as a template for our 50-seat regional turboprop. Source: ATR.


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Bjorn’s Corner: Electric aircraft, Part 8

By Bjorn Fehrm

August 18, 2017, ©. Leeham Co: In this Corner, we will finish the design of the hybrid propulsion system for our 50-seat regional turboprop. We use the ATR42-600 as a reference, as before (Figure 1).

We found an acceptable redundancy concept in the previous Corner, with an APU+generator+battery as backup power source. Now we will finish the design of the hybrid propulsion chain and compare with the original turboprop propulsion.

Figure 1. ATR42-600 serves as a template for our 50-seat regional turboprop. Source: ATR.

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