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# Part Figure A –Q1 Axes, shows Balance the body and Stability axes of an aircraft and the earth axes that these can be referenced to. xB y x oB yB zB z yE Figure Q1 xE oE zE 1) Explain in your own words why and what they are, we use the 10 marks 2) Define the wind axes and explain how they are related to the motion of the aircraft in the presence of a steady wind. How might these appear within a flight dynamics model? 10 marks and the relationship between them. body axes earth axes,

Part Figure A –Q1 Axes, shows Balance the body and Stability axes of an aircraft and the earth axes that these can be referenced to.

xB
y
x oB yB

zB

z

yE
Figure Q1 xE oE

zE

1) Explain in your own words why and what they are,
we use the

10 marks

2) Define the wind axes and explain how they are related to the motion of the aircraft in the presence of a steady wind. How might these appear within a flight dynamics model?

10 marks and the relationship between them. body axes earth axes,

1

Second Year Flight Dynamics Assignment

Figure Q3 below shows the CG limits for a commercial aircraft.

% MAC

Figure Q3

3) Explain the source of the different limits, the reason for the loops in the centre of the

diagram and the terms MZFW, MLW and MTOW.10 marks

4) Explain the link between Figure Q3 and longitudinal stability of the aircraft. How is this linked to the equation for elevator angle to trim. Use the terms static margin and

5) State what is meant by the manoeuvre margin and explain the difference between

the manoeuvre point and the neutral point.5 marks

2

DepartmentUniversityofofBristolAerospace Engineering

Second Year Flight Dynamics Assignment

Part B – Equations of Motion
6) Provide the key steps involved in the derivation of the equations of motion for a rigid body aircraft in your own words. Explain any underlying assumptions in your answer and discuss the role that the inertial terms play in the equations. You may choose to

include part or all of the equations in your description if you wish.30 marks

7) What do we mean by the terms ‘trimming’ and ‘linearisation’ with regard to the rigid
body equations of motion for an aircraft? 20 marks
Part C – Strip Theory

8) In your own words explain the term ‘strip theory’ and how we have applied it in our
course. Include in your answer a description of the associated limitations and
assumptions. 10 marks
Figure Q9 below shows the planform for the Albatross Uncrewed Air Vehicle (UAV).

Figure Q9 – www.robotshop.com

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DepartmentUniversityofofBristolAerospace Engineering

Second Year Flight Dynamics Assignment

9) Unfortunately, a PhD student has made a mistake when re-programming the autopilot. The inboard control surfaces on the wing have now been linked in as the ailerons and the outboard control surfaces as the flaps.
On the assumption that each control surface is independently driven and zeroed correctly, use strip theory to derive an expression for the reduction in roll authority due to this error. Include any assumptions you make in the derivation and comment

on the result.20 marks

Figure Q10 below is a photo of the same Albatross Uncrewed Air Vehicle (UAV).

Figure Q10 – www.appliedaeronautics.com

10) It turns out the PhD student has also failed to connect the left ruddervator control

surface ( ) to the autopilot which means that only the right ruddervatorSee FiguresisfunctionalQ9nd.DescribeQ10 the effect this will have on the flight of the
Albatross using diagrams and equations where appropriate.10 marks

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DepartmentUniversityofofBristolAerospace Engineering

Second Year Flight Dynamics Assignment

Part D – University of Bristol Glider Flight Testing

Figure Q11 below shows the University of Bristol Glider for which we have collected some flight data.

Figure Q11

Within the same folder as this assignment, you will find:
– The Flight Manual for the DG1000S glider – which is the UoB model
– Flight_Times.txt
This file contains marker times for the flight data and will help you identify the
o sections of the flight data that you will need to answer these questions.
– UoB_Flight_Data.csv out by Professor Lowenberg in
This file contains the data for a flight carriedth
o the University of Bristol Glider on Thursday 17 March 2022. It is also the flight
csv
o that is referenced in the Flight_Times.txt file.
11) You should be able to open this file with Microsoft Excel.
Identify the five sections in the flight where the aircraft is trimmed for a given speed.
From this data identify the minimum sink rate for this configuration of the glider. Note
this flight was with the and not the 20 metre as shown
in Figure Q11. Identify any assumptions and difficulties that you have had in finding
this value. 18 metre wingtip co figuration 20 marks
12)
Compare the value calculated in question 11 with the flight polar given in the
DG1000S flight manual. In addition, what effect do the airbrakes have on the sink rate?
How might these be used on the approach to landing? 10 marks
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DepartmentUniversityofofBristolAerospace Engineering

Second Year Flight Dynamics Assignment

13) Please provide a short description of the five modes of motion that are found in the analysis of a conventional aircraft configuration. These must be in your own words, and please provide a sketch showing where you would expect to find them on the
complex plane.10 marks

14) From the glider flight data, you should be able to identify the phugoid mode. Provide
any relevant parameters you can from the response given.20 marks

Note: the flight simulators are available for your use in Queens Building. Please do feel free to use these to compare your results to the glider simulation.
Hints & Tip :
• Useful sources for this assignment include your Lecture Notes; online sources such as the
ESDU data sheets; ‘Flight Dynamics Principles’ by M V Cook; ‘Aircraft Control &
Simulation’ by Stevens & Lewis & other Flight Dynamics books. Whilst it is possible to
complete this assignment using your notes alone, further reading will aid your
• understanding.
Please do use other references as well where appropriate; make sure you cite them
• properly.
The use of equations and figures is vital in order to allow you to fully explain the concepts
• within this assignment.