计算机代考 MECH5740 Rotary Wing Aircraft

MECH5740 Rotary Wing Aircraft

MECH5740M Rotary Wing Aircraft

MECH5740M Assignment

Due Thursday 1st December 2022 at 12:00 (noon)

 ALL WORKING MUST be shown to obtain ALL of the marks in each

 All drawings, sketches, graphs, plots, figures must be drawn by YOU ONLY
and cannot come from lecture notes or any other sources.

 Drawings and sketches may be hand drawn but clarity will be considered for

 Always specify unit of measures

 When solutions use spreadsheets, sample calculations MUST be provided.

 You MUST include any Matlab or Excel files used to complete the
assignment.

 There are a total of 50 marks available for this assignment.

 Submit your report electronically as a single PDF file through Minerva.

 Include on the first page your name, SID number, module number, and
programme of study.

 The report must be a maximum of 8 pages in total with a minimum font size

of 11. No work presented in appendices will be assessed.

You are required to design a single main rotor for a Skycrane helicopter. Each student
is assigned a unique Maximum Take-Off Weight (MTOW) given in Table 1. Therefore
your design will be different to that of all of the other rotary wing designers !You are
required to;

1. Perform a preliminary sizing of the rotor using the technical data given in
Table 2, and assuming that the blades are ideally twisted and have a uniform
induced velocity distribution. The helicopter must be able to hover at sea level
(out of ground effect) at its maximum take-off weight, and have sufficient
excess power to be able to sustain a minimum steady vertical climb rate of 2.5
m/s from sea level. Use the supplied paper “Comparison of Helicopter
Turboshaft Engines” by J. Schenderlein and T. Clayton from the University of
Colorado, to identify a suitable engine for your design. Your submission must

a. Justification for your chosen sizing, including a discussion of the trade-

offs that you have considered

b. A fully worked calculation of the total power to hover at sea level,
including any assumptions made

c. A fully worked calculation of the climb rate at sea level, including any

assumptions made
[15 Marks]

MECH5740M Rotary Wing Aircraft

2. Starting with your preliminary design from Q1, perform a more detailed design
of the rotor blades using the Blade Element and Momentum (BEM) theory. For
Q2 you should assume;

 a linearly twisted blade

 a constant chord

 a root cut-out ratio, x0 =0.15

 a NACA 0012 blade aerofoil (lift and drag coefficients should be predicted
using the equations provided in section 2.14.8 of the lecture notes,
including compressibility and stall effects).

You should develop a computer program using Matlab to predict the
characteristics of the isolated rotor in hover at sea level (out of ground effect) at
its maximum take-off weight using the BEM method. Students that have not
taken the MECH1010 module may use a MS Excel spreadsheet instead. Use
the Matlab/Excel program to explore the design space and determine the effect
of collective pitch angle and blade solidity on hover performance. Choose a
suitable range of collective pitch angles (θ0) and consider blade solidities in the
range σ = 0.05 to 0.2.

Your submission must include;

a. A hover performance chart for your rotor, presented as a single fully
annotated graph of CT / σ vs CQ / σ with curves representing constant
solidity (σ) and collective pitch angle (θ0). See Figure 2.55 in the lecture

notes for an example of what is expected. Note that since you have been
assigned a unique aircraft configuration these performance curves will

be different for all students.

b. From your hover performance chart determine a suitable rotor solidity and
collective pitch angle. Specify and justify your chosen design parameters
including number of blades, blade washout and chord, as well as the total
power required to hover.

c. For your chosen rotor design at the sea level hover condition, include

plots of the blade spanwise distribution of Mach number, blade angle of
attack (in degrees), induced velocity (in m/s), thrust coefficient, profile
and induced torque coefficients.

d. A working copy of the program file (“.m” for Matlab, “.xls” for Excel),

including:
i. Full set of comments in the program file to show which sections

carry out which calculations as well as the meaning of the variable
names used.

ii. A brief user guide (in the program file) to explain to a peer how to
change the rotor parameters and run the code.

[35 Marks]

MECH5740M Rotary Wing Aircraft

Table 2: Technical data for the Skycrane helicopter

Main Rotor

Blade lift curve

Blade section

coefficient

4.00216.00087.0  

Helicopter

Vertical flight
installed power

vertical flight

equivalent flat
plate drag

Table 1: Individual Maximum Take-Off Weight (MTOW)

First Name Last Name

(Kg) First Name Last Name

Piyush . 22,549 16,760

Sarmd Al-Sudany 5,786 9,380

24,895 13,656

9,479 18,263

23,062 23,575

24,998 Connell 5,896

13,792 20,970

24,594 24,896

8,623 18,080

11,426 Declan Robinson 7,037

22,610 8,327

18,575 14,795

23,160 9,130

18,653 14,771

22,069 8,649

de dos Santos19,146 Ninad Singh 7,498

Si Goh 9,166 8,298

Gonzalez 22,750 24,747

-Oldroyd 23,065 6,818

16,155 10,064

21,040 6,196

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