UWE Bristol Engineering showcase 2015

Jens Rucker
MEng Aerospace Engineering (Systems Engineering)
Project Supervisor:
Dr. Pritesh Narayan
Assessment of the Me 262’s performance during one engine operation
Introduction
The shown Me 262 is a replica from the
Messerschmitt Foundation in Germany.
In cooperation with them, this project is simulating
the behaviour of the first axial flow engine
powered aircraft of that times. It was faster than
every existing aeroplane but had a lot of problems
regarding the reliability of the engines (Jumo 004).
As a replica it has to be certified as well and this
project supports the process of conforming the
regulations of the one engine operation with the
help of engineering simulations and calculations
based on the theory of the equations of motion of
an aircraft.
Research and concept
The part B was based on the results from part A,
where the dynamic model in MATLAB revealed
some issues with the controllability. Therefore, the
development was pushed into a realtime
simulation model with Simulink. Based on the
equations of motion and new estimated moments
of inertia as essential inputs to the model.
Consequently, the research focused initially on a
method to estimate accurate moments of inertia
(these have been the major uncertainty in part A)
and later on the program Simulink to understand
the software principles and the design steps.
Changes to part A
Initially, new findings concerning the MOI´s have
been implemented to the models of part A.
Additionally, the three models have been
integrated to one comprehensive model with an
extracted m-file for aircraft and condition
parameters. This way it is possible to implement
another model easily.
Simulink Model Development
The development was created step by step, where
initially linear forces along the x-axis such as thrust
and drag have been considered. Later the forces
along the z-axis and the moments have been
added and the equations of motion have been
updated to consider more factors and to improve
consistency.
Throughout the development a variety of
modifications and additional effects have been
implemented. One example is the additional
rolling moment due to the sideforce of the vertical
tail (see next figure) and with specific calculations
it was possible to visualise the movements with a
simplified aircraft by Simulink.
Results
From the developed model it is possible to extract a
variety of results such as angular rates, moments,
forces or speeds and accelerations. The following
figure shows the resulting moments after an engine
failure with the initial oscillation in yaw:
For the assessment of the one engine performance
it is important to have a look at the angular rates as
direct outcome as response to the moments.
Here it can be seen that the Me262 oscillates in yaw
and then changes the yaw angle (blue line) and the
roll angle changes significantly (yellow line).
Verifications have been performed with the
engineering simulator at UWE and the software X-
Plane. Overall many results can be reviewed with
uncertainties in mind due to simplifications and
missing effects.
Project summary
This project dealt with the assessment of
performance in the case of an engine failure
of the German WWII aircraft Me262 by
Messerschmitt. This was done with the help
of Simulink realtime simulations based on the
theoretical equations of motion and the
different moments acting during the
asymmetric thrust situation
Project Objectives
The deeper understanding of the flight
mechanics and the performance as well as
the simulations of the aircraft should reveal
dynamic results which enables the evaluation
of the behaviour qualitatively and
quantitavely with specific values such as
minimum control speeds during one engine
operation.
Project Conclusion
The development of the Simulink model
offered some challenges and a significant
amount of time was spent on debugging the
model. After all there are uncertainties due to
missing effects or simplifications. However, it
is possible to assess the tendencies of the
aircraft. The current model shows an initial
oscillation in yaw and over the time it enters
the spiral dive, which is a logic outcome and
all values such as roll and yaw rates can be
evaluated separately and in the big picture.