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The content of this chapter is taken from the EUROPA CODE SPECIFICATIONS, see [6].
The European Rotorcraft Performance Analysis (EUROPA) was developed by the BRITE- EURAM Rotorcraft Efficient and Safe Procedures for Critical Trajectories (RESPECT) consortium as a helicopter performance prediction tool. The software is able to investigate the performance aspects of novel takeoff and landing techniques. The EUROPA code essentially consists of the following two elements:
1. Helicopter performance simulation, including the control logic required to run multiple performance-simulations.
2. Manoeuvre optimisation, research, and the calculation of performance data for the generation of aircraft performance charts.
The EUROPA code was used in the BRITE EURAM "RESPECT" project, as a research tool for predicting the take-off and landing performance of helicopters operating in a variety of complex situations. The code must be capable of accurate performance prediction and it must be suitable for the task of finding the optimum piloting strategy for each manoeuvre.
Once fully developed, the code may be used by members of the consortium (and possibly by other parties) for the estimation of helicopter performance for research, and the calculation of performance for certification and flight manual chart production. In this role
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• To define the safety criteria (necessary performance margins) for existing and future procedures.
• Analysis of manoeuvres and modelling of flight test events for parameter identification.
The validation of the model for each task will always be the responsibility of the user.
The work required to create a useful tool falls into two categories:
• Creation and validation of an accurate vehicle performance-simulation.
• Development of an easy to use performance prediction tool, which uses the vehicle simulation as a "performance calculation engine".
The initial development version of the EUROPA programme is known as EUROPA 98.
When the code was developed to release standard and was validated against flight test data, it was given a first release name of EUROPA 2000. EUROPA 98 is written in the FORTRAN programming language. The coding standard is contained in ’The BRITE- EURAM ’RESPECT’ Project FORTRAN Coding Standard’. The software is written in FORTRAN 77, but in a manner which is compatible with FORTRAN 90.
The EUROPA software and documentation is jointly owned by the European Commission and the Consortium partners, in accordance with the BRITE-EURAM ’RESPECT’
consortium agreement.
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The EUROPA vehicle simulation is capable of predicting both the steady-state (trim) and dynamic (manoeuvre) performance of helicopters. Performance data will be recorded for each simulation run (or trim condition) and will be replayed for post run analysis output.
The data may be plotted to produce performance charts (H/V diagram, takeoff and landing charts (WAT) etc.).
To speed up the production of performance data, the simulation is able to reiterate several manoeuvres (e.g. critical engine failure point) and also able to cycle through multiple cases (i.e. run a series of cases automatically, varying the aircraft mass, pressure altitude, OAT, wind speed, etc.).
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The EUROPA programme is modular. The calling sequence is as follows:
NO
YES NO START
MAINEUROPA EUROPA
FIRST
PASS? INIT RINPT RTITLE
RLOGIC
RFLT
STITLE
RVDAT
RCONF
RRMAIN
RRTAIL
RFUSAIR
RFIN
RTPLANE
RENG
RLGEAR
MTITLE SCALCS
ATMOS
ISA YES
DYNSIM CFORCE CROTOR MRCONT
EOM
ENGDYN
TRANSMIS
AFCS
FUSAIR
FIN
TPLANE
LGEAR
CRMAIN
TRCONT
CRTAIL
MODFLAP
RDFM
LAMSUB
GRNDEF IN TRIM ?
TRIM
LEVEL TURN SIMPLE
HTAXI CAT A MANOV PILOT
TEST FOR END
FINISH WVER STOP
NO
YES
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Where the functions of the subroutines are:
MAINEUROPA Main program unit EUROPA Core subroutine
INIT Initialisation and data input
RINPT Read input data and write input data to main output file RLOGIC Read simulation logic data
RFLT Read flight condition and case data RCONF Read in the aircraft configuration data RVDAT Read in the aircraft input data
RRMAIN Read in the main rotor input data RRTAIL Read in the tail rotor input data
RFUSAIR Read in the fuselage airloads input data RFIN Read in the fin airloads input data RTPLANE Read in the tailplane airloads input data RENG Read in the engine model input data
RLGEAR Read in the landing gear terrain feedback input data SCALCS Subsidiary calculations
ATMOS Atmosphere model
DYNSIM Dynamic simulation core subroutine
CFORCE Calculate forces and moments acting on the aircraft CROTOR Calculate the rotor forces
MRCONT Main rotor control logic (interlinks etc.) CRMAIN* Main rotor calculations
TRCONT Tail rotor control logic (interlinks) CRTAIL Tail rotor calculations
FUSAIR Calculation of fuselage airloads
11 TRANSMIS Calculation of transmission (summation of power, rotor speed variation) TRIM Iteration to find initial trim
PILOT* Simulation of the helicopter pilot (manoeuvre simulation) PRINT Print results
FINISH Close down simulation
WVERS Write out version details of all subroutines visited during execution
The (*) subroutines call:
CRMAIN Main rotor calculations -MODFLAP Main rotor flapping equations -RDFM Main rotor forces and moments -LAMSUB Main rotor inflow
-GRNDEF Ground effect
PILOT Simulation of the helicopter pilot (manoeuvre control) -MANOV Manoeuvre selection
-LEVEL Top level manoeuvre logic - Level flight -TURN Top level manoeuvre logic - Turn
-SIMPLE Top level manoeuvre logic – Simple manoeuvre -HTAXI Top level manoeuvre logic - Hover taxi
-CATA Top level manoeuvre logic - Cat A takeoff -FLYSPOT Complex handling logic - Hover over a spot -FLYTRK Complex handling logic - Follow a ground track
-DEMZ Basic handling logic - Adjust collective to attain and hold height -DEMZ1 Basic handling logic - Collective to attain and hold
vertical speed
-SETTQ Basic handling logic - Collective to set and hold a specified torque
-FLYUGS Basic handling logic - Adjust pitch attitude to hold ground speed -FLYEAS Basic handling logic - Adjust pitch attitude to hold EAS
-FLYVGS Basic handling logic - Adjust roll attitude to hold lateral speed -PEDALS Basic handling logic - Adjust yaw pedals to hold heading
-PEDBAL Basic handling logic - Adjust pedals to centre slip-ball
