Leeham News and Comment
Intelligence for the Aviation Industry: Value*Performance*Reliability
Leeham News and Comment
- Air Berlin files for bankruptcy August 16, 2017
- Small airlines face replacement challenges August 15, 2017
- Boeing’s tactical option for MOM sector August 14, 2017
- Pontifications: Avolon sees strong sales for Boeing 737-10 August 14, 2017
- Bjorn’s Corner: Electric aircraft, Part 7 August 11, 2017
Bjorn’s Corner: Electric aircraft, Part 7
By Bjorn Fehrm
August 11, 2017, ©. Leeham Co: In this Corner, we will design the hybrid propulsion system for our 50-seat regional turboprop. We could see in previous Corners that we can’t use batteries as a backup for our gas turbine core and main generator.
The battery gets too heavy as the specific power weight of a battery is simply too low. We will now design a hybrid power chain with a different redundancy concept.
Figure 1. ATR 42-600 serves as a template for our 50-seat regional turboprop. Source: ATR.
Bjorn’s Corner: Electric aircraft, Part 6
By Bjorn Fehrm
August 03, 2017, ©. Leeham Co: In our search for an electric regional aircraft configuration, we found that a jet aircraft requires too high power levels. The higher speeds of a jet aircraft take the power levels beyond what we can handle with an electric hybrid propulsion system.
Our ambition is to transport 50 passengers on a regional network. For networks which have sectors around 200-300nm, the turboprop is the preferred regional aircraft. We will now re-direct our hybrid regional aircraft project to this market segment.
Figure 1. An ATR 42-600 48 seat regional turboprop. Source: Wikipedia.
Bjorn’s Corner: Electric aircraft, Part 5
By Bjorn Fehrm
July 28, 2017, ©. Leeham Co: In the last Corner, we looked at the mass of the propulsion components for a regional airliner.
Now we complete the mass estimations for the complete hybrid electric system.
We do that for our aircraft project, which is a regional jet airliner with 50 seats. It’s using a hybrid propulsion system with four electric propulsors fed by a Gas turbine driven generator. The system uses a battery as a redundant energy source.
Figure 1. Zunum aero regional airliners and a NASA boundary layer ingestion airliner. Source: Zunum aero.
Bjorn’s Corner: Electric aircraft, Part 4
By Bjorn Fehrm
July 21, 2017, ©. Leeham Co: In this Corner, we will start looking at the mass of the different components in a hybrid electric propulsion system compared with a classical turbofan propulsion.
Our propulsion project is for a regional airliner with 50 seats. The segment marked the start of the regional airliner with Bombardier’s CRJ-200 and Embraer’s ERJ-145. Today, the segment is more and more flown with Turboprops like ATR42-500.
Figure 1. Zunum aero regional airliners and a NASA boundary layer ingestion airliner. Source: Zunum aero.
Bjorn’s Corner: Electric aircraft, Part 3
By Bjorn Fehrm
July 14, 2017, ©. Leeham Co: In the last Corner, we developed a hybrid aircraft propulsion system and looked at system efficiencies. Today, we look a bit deeper at how hybrid propulsion can be implemented on an aircraft.
What are the advantages on an aircraft level, that such a chain can have? Can aircraft level efficiencies compensate for more parts and lower propulsion efficiency of a hybrid systems?
Figure 1. Zunum aero regional airliner. Source: Zunum aero.
Bjorn’s Corner: Electric aircraft, Part 2
By Bjorn Fehrm
July 07, 2017, ©. Leeham Co: In last Corner we could see that battery driven electric aircraft will be for the extreme short-haul.
The stored energy per kg battery is 70 times lower than for fuel. In addition the weight is constant. Fuel gets burned off during the flight.
A more useful configuration is the hybrid, which adds a combustion driven generator as energy source.
Figure 1. The Siemens electrically engined Extra 330LE aircraft. Source: Siemens.
Bjorn’s Corner: Electric aircraft
By Bjorn Fehrm
June 30, 2017, ©. Leeham Co: One of the areas I explored while at Paris Air Show last week was electric aircraft technology. With electric aircraft, we mean an aircraft where the propeller/fan is driven my an electrical motor.
We don’t talk about “more electrical aircraft systems” like for the Boeing 787.
One of the companies investing in technology for electric aircraft is Siemens. A Siemens-engined aerobatic aircraft, the Extra 330LE, made daily flight displays during the show.
Figure 1. The Siemens engined Extra 330LE aerobatic aircraft. Source: Siemens.
Bjorn’s Corner: Interesting aircraft at the sides of Paris Air Show 2017
By Bjorn Fehrm
June 22, 2017. ©. Leeham Co: When visiting the Paris Air Show this week, we strolled several times into the Aeronautical museum which is placed at the Le Bourget airfield. It has a fine collection of historical aircraft, helicopters, missiles and space rockets/capsules.
One of the most interesting eras in French aeronautical history, captured in the museum, is the period directly after the second World War. The French industry, destroyed by the war, started its way back. Part of the way was to learn about jet propulsion for military and civil aircraft and how to design a practical supersonic fighter aircraft for the French Air Force.
Experiments with high subsonic ramjet aircraft, the Leduc 21 in 1953. Source; Google images.
From a multitude of experiments with different aircraft types and propulsion systems, came finally the successful Dassault Mirage jets, the Caravelle jet airliner and the only Supersonic passenger jet, the Concorde. Here a video and some pictures from these exhibitions.
Bjorn’s Corner: Keeping airliners operational. Part 9.
Bjorn Fehrm
June 16, 2017, ©. Leeham Co: This week we finish our analysis how an operator would keep our tentative airline operational. By now we know the maintenance of the fleet is a critical part of running an airline.
If we miss a beat from our approved operator’s maintenance plan, our airworthiness authority can ground us.
We now finish the series with looking at how some cost-heavy parts are kept fit. We then summarize our costs for keeping our Airbus A320s flying.
Figure 1. The first modern maintenance program was formed around the Boeing 747. Source: Wikipedia.
Bjorn’s Corner: Keeping airliners operational. Part 8
By Bjorn Fehrm
June 09, 2017, ©. Leeham Co: This week we continue our analysis of the operator’s maintenance plan we made last week for our tentative airline.
Our airline is using Airbus A320s as our operational airplane. For these aircraft we have completed a maintenance plan based on the aircraft OEM’s Maintenance Planning Document (MPD) as well as other regulatory requirements.
Figure 1. The first modern maintenance program was formed around the Boeing 747. Source: Wikipedia.