Fabrication and testing of light weight composites for UAV

Published on 14 Jun 2021. Written by Gurudutt

An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a pilot on board.

In this project, our main objective is to fabricate a composite material combining depron, glass fiber, and balsawood strips to form three different combinations of composite material.

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Material selection:

To fulfill the objective balsawood strips is selected as core material, depron sheet, and glass fiber as skin material to fabricate the sandwich composite.

• Thin balsawood sheets: It is used for fabrication of aircraft because of its high strength-to-weight compared to other materials.
• Woven glass fiber: Glass fiber has the same properties when compared to other fibers such as polymers and carbon fiber. Though it is not tough and flexible as composites it is much better and cheaper when compared to other materials.
• Depron sheet: Depron (foam sheets) have a property to bear the impact of aerodynamic forces.

Methodology:

Step 1: Modelling

3D modelling is done using CATIA V6 software by importing coordinates from airfoil tools. Four models are prepared to compare the downforce generated with different cavities.

1. Wing without cavity
2. Wing with one cavity
3. Wing with two cavity
4. Wing with three cavity

Step 2: The fabrication

1. The CATIA V5 is used to design the 3D wing model for the wind tunnel testing
2. The designed model is fed into a CNC machine for fabrication
3. 18mm thickness foam sheet is used for fabrication
4. Top and bottom parts are separately carved and then joined together.

Step 3: Wind tunnel testing

The wind tunnel is used to analyze static models for testing and implementation. In a wind tunnel, the model is kept in the test section and the air is blown to find the pressure distribution over the model.

Step 4: Experimental procedure         

A two-cavity airfoil of chord 210 mm and length of 290 mm is placed in the test-section such that axis of the airfoil is perpendicular to the direction of the flow. The airfoil is fitted in front where pressure tapping is the forward stagnation point that also gives the total head of a free stream

Future work:

• Good correlation between wind tunnel data and CFD simulations encourage that future modifications on airfoil design can be investigated in simulation software
• By increasing the number of cavities over different locations can be tested and analyzed
• Sliding panels methods can be analyzed for the same models

Kit required to develop Fabrication and testing of light weight composites for UAV:

• Testing apparatus
• Laboratory

Technologies you will learn by working on Fabrication and testing of light weight composites for UAV:

• Aerodynamics

Any Questions?