Cruiser/Feeder Concept
The cruiser/feeder concept refers to a complex of different
aircraft. The cruisers transport passengers over long
distances. Locally, fuel or (and) passengers are fed to the
cruiser by feeder aircraft. This concept is reported by the
authors of the out-of-the-box studies to have a benefit with
respect to fuel consumption.
The soundness of the cruiser/feeder concept to bring about
a step-change in air transport is based on information
available for air-to-air refuelling being the most obvious
example of cruiser/feeder operations. With cutting down
the so called effect of “burning fuel to transfer fuel”, a
comprehensive estimate of fuel burn reduction potential is
near 20% for a typical 5000 nautical miles flight with a
payload of 250 passengers. In this case, the feeder is
called “tanker”, as it only transfers fuel to the cruiser.
PhD Candidate: MO Li
Department: AWEP
Section: FPP
Supervisor: G. La Rocca
Promoter: M. van Tooren
Start date: 18-10-2010
Funding: CSC
Cooperations: NLR, DLR, NRG, TUM, RKN
In the design process, fast modeling using high-levelprimitives is applied, which enables modifications happen
very quickly, which becomes the base of fast CFD analysis.
Internal fuselage design of the air-to-air refueling cruiser is
generated automatically by DARfuse cabin configurator,
which is a KBE application. With such an approach, design
iterations become much quicker and are well supported by
physical based analysis, allowing designer to explore more
Demonstrated as One of the concepts
Cruiser design tools and workflow
Aerospace Engineering
The cruiser/feeder concept requires a system of system
level perspective from designers. The design objective of
aircraft should obey the overall efficiency of the whole
system. Aircraft operation is integrated in the design
process. So dose air-to-air refueling/docking configurations.
Demonstrated as One of the concepts
Fuel consumed by itself is less than 10% of fuel
delivered to the cruisers
R nm
20 min refueling
10 min loiter
R nm
Better aerodynamic & structure efficiency
Small wing box volume is no longer an issue in this case as
the design fuel capacity is much less than normal airliner
Direct force control & gust relieve guarantee better riding
refueling boom
Demonstrated as One of the concepts
30 min loiter
10% extra fuel
Design range: 5000 nm (refueling once)
Passengers: 250 PAX
30% fuel efficiency improvement compared
with current aircraft of similar payload and
design range
Prandtl wing configuration
Automatic cabin layout generation
Feeder (Tanker in this case)
The overall benefit of fuel reduction potential and refueling
formation configuration has been analyzed. Preliminary
design of conventional cruiser is finishing. Novel
configurations will become trustworthy design after
Aug,2013. The design of forward extending boom is also in
progress. Meanwhile, iterations between aircraft design
and operation arrangement is starting, which will ensure
the benefit will be optimized at the system of system level
rather than the aircraft itself.
The first nuclear cruiser concept is already designed,
though there is still a lot of arguable information at this
conceptual level. The coming iterations will make the
design more reliable.
Further exploration for the pioneering case is the nuclear
cruiser concept in which passengers are transferred by the
fossil fueled feeder. The whole complex will act as an
airborne metro system around the globe. The top level
objective is to demonstrate on a preliminary design level
that such cruiser/feeder operations can be realistic.
Progress and Objectives
Special layout helps to avoid
aerodynamic instability
A retractable boom on the cruiser
allows shorter forward extending
boom while still keep enough
separation between two aircraft
Pump fuel against weight is proved
to be of little weight & power
Typical mission profile of tanker
Different design requirements have been
considered as:
• (Refueling radius) R = 250 or 500 nm
• (Refueling capacity) n = 1, 2, 3
demonstrated picture is an example of R=250, n=2
Selection of refueling configuration
Flying wing configuration
Small wetted area improves L/D
Less requirement for internal volume as fuel is
very dense compared with normal cargo
All the fuel is contained in wings, which helps to
relieve wing loading, results in lighter structural
Canard provide direct force control & better
longitudinal control in close formation
Config. D was selected because:
no hazard of collision with parts and debris detaching from tanker
in case of emergency, tanker can immediately separate by decelerating and reducing altitude
tanker pilot has good visibility of passenger aircraft
Safety/pilot training: cruiser pilot not required to perform approach maneuver, neither to fly in the
wake of the tanker.
Pax comfort: passenger less exposed to flow perturbation and noise from tanker. Passengers not
subjected to maneuvering acceleration
Pax aircraft architecture: passenger aircraft architecture minimally affected by the presence of the
refueling system.
Only tanker aircraft to be provided with air-to-air radar
no extra thrust requirement for passenger aircraft during refueling
The Challenge is to develop forward-extending refueling boom
- Mo Li, P. van der Linden, G. La Rocca. Trade-off and selection of the most convenient Cruiser-feeder Approaching Configuration for In-flight Refueling. RECREATE project. 2012
- Mo Li. Benefit of Staging Airliner Operations. RECREATE project. 2012

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