1PERSONAL GLIDER DESIGNBy Valery Botsko

Index

Airfoil design.....2Wing design.....3Fuselage design....4Elevator design....5-6Tail fin design.....7-8Overall view....9Performance check....10-14Conclusions....15

2Airfoil designIt was planned to use a typical NACA design, such as the one from NACA 0010-35,which was downloaded from the official website.

Some performance of the airfoil is shown below:

The Reynolds values were between 100,000 and 400,000.

3Wing design

The length of the foil and the chord length are shown in the table. For the winglets, anangle of 70 degrees above the horizontal has been used. These can help to lower thevortices.

4Fuselage design

Once again, the detailed values are shown in the screenshot. The design was made asstreamlined as possible to improve efficiency. The degree of BS lines was slightlymodified. 4 for the X and 2 for the Hoop.

5Elevator design

As you can see, the elevator was set above the fin, making modifications in the z-axis asshown in the screenshot. Here are the values for the design of the elevator itself:

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7Tail fin design

The same screenshot represents that the the tail fin is slightly tilted across the x-axis. Thevalues for the design will be shown in the following screenshot:

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9Overall view

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Performance check

The entire dsign was analyzed. The angles of attack went from 0 to 10 degrees. The massof the glider was given to 50kg and its airspeed at 60 ms-1. Here are the results, for eachconcept.

Coefficient of pressure

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Examining the pressure by looking at the colour scale we can see that it goes from about0.9 to -0.1. This is overall a normal result since you cannot have a coefficient greater than1, because it means it is the stagnation point. Having positive and negative pressuresaround the airfoil is normal.

Lift force

There is some discotinuity from the first picture since there are winglets that prevent asmuch vortices as possible, but overall we can see that the lift vector is quite big, both forthe elevator and the wing. The wing area is big, as well as its aspect ratio, giving a highlift value. The surface of the wing is one of the values that is in the lift formula and this iswhat makes it high. There is a possibility to check the graph of lift against the angle ofattack:

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We can see by the linear curve, that the airfoil is symmetrical. Up to 10 degrees thecoefficient of lift keeps increasing which means that more lift will be created up to thisrange. A comparison with the drag force will be made.

Induced drag force

Induced drag is the drag produced by the redirection of the airflow itself. The pressuredifference above and below the airfoil can generate vortices that may affect the velocityand direction of the incoming airflow, producing the drag. A graph will be shown now:

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Comparing with the lift, the drag is much less and therefore the lift/drag ratio is high upto this range. Since we are talking about the induced drag another important parameter tomention is the downwash force.

Some errors are in the program, but we can still see that at the end of the airfoil there is adownwash generated due to the induced drag.

Stream flow

Here is a general picture of the entire airflow:

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We can see some vortices generated due to the winglets which try to minimise it as muchas possible. Same effect can be observed in the elevator and the fin.

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ConclusionsThe design satisfies the majority of the criteria to be a decent glider in real life conditions.The analysis of XFLR5 has provided an in depth analysis of the design and hugevariations that could be made to every component of the glider. This software is one ofthe best for designing basic aircraft and the simulation it gives, can save a lot of money,time and even lives. If somebody has to test a glider with a person, there is a risk of crashwhich can be fatal.