Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Boeing 3Q deliveries up despite strike October 8, 2024
- Strike slows Boeing’s march toward improving safety culture October 7, 2024
- Aerospace supply chain still ailing; Sustainable Aviation Fuel isn’t the answer to go green October 4, 2024
- Bjorn’s Corner: New engine development. Part 27. Long developments October 4, 2024
- Longshoreman strike adds to Airbus, Boeing woes October 1, 2024
Bjorn’s Corner: New engine development. Part 6. Open Rotor
By Bjorn Fehrm
May 3, 2024, ©. Leeham News: We do an article series about engine development. The aim is to understand why engine development now has longer timelines than airframe development and carries larger risks of product maturity problems.
To understand why engine development has become a challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals.
We have in previous Corners discussed geared versus direct-drive turbofans. Now the time has come to discuss Open Rotor engines.
Figure 1. The GE 36 Open Rotor engine, the father to today’s CFM RISE. Source: GE Aviation.
Bjorn’s Corner: New engine development. Part 5. Turbofan design problems
By Bjorn Fehrm
April 26, 2024, ©. Leeham News: We do an article series about engine development. The aim is to understand why engine development now dominates new airliner development when it comes to the needed calendar time and risks.
To understand why engine development has become a challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals.
We discussed geared versus direct-drive turbofans last week. Now, we’ll examine some design problems for these engines.
Figure 1. The Pratt & Whitney PW1100G geared turbofan, with its unique aluminum fan. Source: Pratt & Whitney.
Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency
By Bjorn Fehrm
April 12, 2024, ©. Leeham News: We have started an article series about engine development. The aim is to understand why engine development now dominates the new airliner development calendar time and the risks involved.
To understand why engine development has become a challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals. We started last week with thrust generation, now we develop this to propulsive efficiency.
Figure 1. The base engine in our propulsive efficiency discussion, the CFM56-7 for the Boeing 737ng. Source: CFM.
Bjorn’ s Corner: New engine development. Part 2. Thrust generation
By Bjorn Fehrm
April 5, 2024, ©. Leeham News: We started an article series about engine development last week. The aim is to understand why engine development nowadays dominates the needed time and the risks involved in new aircraft development.
To understand why engine development has become perhaps the most challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals. We start this week with thrust generation.
Figure 1. The principle for thrust generation using air as medium. Source: NASA.
Bjorn’ s Corner: Engine development. Part 1. Introduction
March 29, 2024, ©. Leeham News: We finished our article series about New Aircraft Technologies last week. It dealt with the different new technologies that a next-generation airliner could use to increase efficiency and by it environmental emissions.
An area that we touched upon but didn’t dig deeper into was engine development. When airframe development historically decided how long a new generation of aircraft took to develop, it gradually changed to engine development being the more calendar-time-consuming and riskier development for the last generations. This article series will discuss why and what can be done about it.
Figure 1. CFM RISE, a new engine development for the next generation of airliners. Source: CFM.
Bjorn’s Corner: New aircraft technologies. Part 51. Wrap up
By Bjorn Fehrm
March 22, 2024, ©. Leeham News: Last week we did the first part of the Wrap-up of our 50 article series about the New Aircraft Technologies that can be used when replacing our present single-aisle airliners.
Now, we summarize the last 25 articles in the series, which covered how to develop, produce, and support a new airliner.
Figure 1. The Program Plan for a new airliner. Source: Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 50. Wrap up.
By Bjorn Fehrm
March 15, 2024, ©. Leeham News: We started the series a year ago about the New Aircraft Technologies that can be used when replacing our present single-aisle airliners.
We have covered a lot, including the typical development phases, from initial studies to preparing for the aircraft’s in-service phase.
Let’s make a resume of what we have discussed.
Figure 1. Boeing’s Truss Braced Wing X-66A demonstrator based on the MD-90. Source: Boeing.
Bjorn’ s Corner: New aircraft technologies. Part 49. Engine Maintenance
By Bjorn Fehrm
March 8, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.
For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We discussed airframe maintenance in the last article. Now, we look at engine maintenance.
Figure 1. The CFM56-7 engine for the Boeing 737NG. Source: CFM.
Bjorn’ s Corner: New aircraft technologies. Part 48. Maintenance Program for the A320/A321
By Bjorn Fehrm
March 1, 2024, ©. Leeham News: We are discussing the Operational phase of a new airliner family. For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We discussed the modern MSG-3 maintenance program for an airliner last week, why it was created, and its main analysis principles.
Now we look at maintenance data designed to the MSG-3 standard, the Maintenance Planning Document (MPD) for the Airbus A318/A319/A320/A321.
Figure 1. The front page of the A318/A319/A320/A321 MPD no 45. Source: Airbus.
Bjorn’ s Corner: New aircraft technologies. Part 47. MSG-3 Maintenance
By Bjorn Fehrm
February 2, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.
For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We started last week with how maintenance went from ad-hoc to a Hard Timed maintenance program in the late 1950s and early 1960s.
Figure 1. The maintenance manual for the Boeing 747. Source: Boeing.