Submitted on 3/10/2021
Team 7
DBF 2021
Final Report
Team
Members
Mohamed Ghanem
Mohamed Salah
Yousef Salah
Mazen Hossam
Moaaz Zaki
Team 7 DBF 2021
Page 1
Table of Contents
Introduction 2
Preliminary Design 2
Weight estimation ....................................................................................................... 2
Constraint graphs ........................................................................................................ 3
Airfoil Selection ............................................................................................................4
Configuration selection .............................................................................................. 5
Detailed Design 9
Overview ........................................................................................................................9
Weight Balance Table................................................................................................. 11
Wing.............................................................................................................................. 12
Tail Assembly...............................................................................................................13
Mission Mechanisms..................................................................................................13
Manufacturing 15
Materials ...................................................................................................................... 15
Machines Used............................................................................................................ 15
Process ......................................................................................................................... 15
Management Summary 17
Team 7 DBF 2021
Page 2
Introduction
Our plane is called DBF-7. A UAV airplane designed for a banner mission
consisting of 3 stages: the first one is performing one lap with the banner on board,
the second one is deploying the banner and completing two additional laps, and
the third one is releasing the banner and doing a final lap before landing.
The plane has a conventional configuration which is a high wing with a
conventional tail assembly, it best meets the requirements of the mission because
it has better aerodynamics data, saves room for the banner, and also well
distribution of weight.
Preliminary Design
Weight estimation
The first stage of preliminary design was estimating the weight of the aircraft
using statistical data that was supplied by the UDC staff. A graphical model of
useful weight against the maximum takeoff weight was built from the data and
then used to estimate the maximum takeoff weight of our own aircraft.
ℎ = ℎ + ℎ
= 0.180 + 0.250 = 0.43
Fitted curve from weight estimation data
Team 7 DBF 2021
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Using the model, we have estimated our MTOW (maximum takeoff weight) to
be 0.814 kg, however, that was not the weight we used in the latter calculations
as it was soon apparent that the data was inconsistent after review by the UDC
staff, and the MTOW was later increased to 1.5 kg as advised by said staff.
Constraint graphs
A number of design constraints related to the mission requirements had to be
made and used to calculate important parameters of the aircraft. The variables
used to model the constraints were either assumed or given by the mission
requirements. The following is a list of the variables used in the model.
• Stall speed = 7 m/s • Cd
0
= 0.02 • Throwing speed = 5 m/s
• Cruise speed = 20 m/s • AR = 7 • Cd
T/O
= 0.03
• CL
max
= 1.4 • T/O speed = 7.7 m/s • T/O distance = 2 m
• Weight = 1.5 kg • Thrust = 13.23 N
Constraint Graphs
Team 7 DBF 2021
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A point chosen on the graph was used to choose the airfoil and calculate a
number of crucial parameters as follows.
Airfoil Selection
Using the data retrieved from the constraint graphs we have narrowed down
the search for a fitting airfoil to 3, namely the Clark Y, N-81, and NACA 2412.
After tedious research and consideration, our team settled on the N-81 airfoil
owing to its high lift and superior stability.
N-81 Airfoil Specs:
• Maximum thickness = 12.99%
• Maximum thickness position = 22.52%
• Maximum camber = 3.52%
• Maximum camber position = 22.52%
• Weight = 1.529 kg • AR =5.5 • CL
2D
= 1.34
• Stall speed = 7 m/s • Wing span = 1.485 m • CL
3D
= 1.244
• Wing area = 0.401 m
2
• Mean chord = 0.27 m • Cd
0
= 0.02
N-81 airfoil XFLR5 analysis
