RC Retract

FOLDABLE WING –RC PLANE AEROMODELLING CLUB IITK

PROJECT MEMBERS

ANKITA MITTAL [email protected]

JEETESH AGRAWAL [email protected]

KRATIKA AGRAWAL [email protected]

PRATEEK SAZAWAL [email protected]

RAVINDRA DHAMA [email protected]

VIKAS RANA [email protected]

INTRODUCTION

FOLDABLE WING IS A SIMPLE WING WITH

ITS OUTER PARTS FOLDING.IT REQUIRES

SOME SPECIFIC MECHANISM TO FOLD THE

WINGS.IT IS MADE OF BALSA WOOD AND

BALSA PLY AND USED TO GIVE THE PLANE

ITS REQUIRED LIFT.

AIM AND OBJECTIVE

This report is about a remote controlled plane

(RC plane) with foldable wings and this action of

folding will also be remote controlled.

The basic aim behind folding the wings is that it

can be used both as a car and an airplane.

The most important aspect of this kind of plane

is that this can serve as a cheaper version of a

Plane Car.

AIM AND OBJECTIVE

The basic plan would be to make first a simple

RC plane at first with partitions in each wing

then we make use of hinges and springs to make

the wings fold.

DIFFICULTIES FACED

FINDING A SUITABLE PROBLEM

STATEMENT

First of all the problem must be feasible.

Secondly it must give you the maximum chance

to learn.

Keeping these two points in mind we decided to

go for this model.

HOW TO FOLD THE WING

The most challenging aspect of the project is to

find a suitable mechanism to fold the wing.

For this several methods were first tried on the

previous years models available with the club.

Stability of the wing in air was a very critical

issue.

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DIFFERENT MECHANISMS TRIED

To fold the wing using a servo alone.

This was not possible since the servo could not

take this much of load.

Then we tried it with a hinge.

The problem here was that of the fact that the

servo might loose control at any time and one can

not be very sure.


Then keeping these things in mind we decided to

use a rod in combination with the hinge.

In this case we will have to synchronize the

movement of the hinge and the rod.

The rod will provide stability and will give proper

strength.

But, it was a very difficult task to synchronize

the movement of the hinge and the rod.


So, we finally tried to modify the servo in such a

way that with a small movement of the servo we

could achieve a greater change in the angle by

which the wing moves.

For this we used a piece of ply to make the

Even, fiber glass would have worked well for this

purpose, but due to lack of availability we

couldn’t use it.

MAKING WING

Along with that we were working on the wing.

We needed to use a software DESIGNFOIL to

decide upon the airfoil shape and size.

Once this was done we had to make the wing.

Since our project was a folding wing we had to be

extremely careful while assembling and joining

the different airfoils.

MAKING WING

Thick balsa had to be used at the end of every

segment.

A lot of support was provided to the wing using

stringers.

Keeping in mind the complexities of the wing, we

decided to keep it simple and hence we did not

provided any dihedral angle.

AIRFOIL SPECIFICATIONS

Airfoil name NACA-2515-63

Chord length 26 cm

Angle of attack 3 degrees

Lift 0.667

Drag 0.0079

Lift to drag ratio 84.4

Coefficient of lift 0.667

POSITION OF AILERONS

Generally, in a wing on the trailing edge we

provide with flaps and ailerons.

The flaps are near to the fuselage and the

ailerons are near the wing tips.

This is done so that the ailerons work effectively.

Since the ailerons work on the principle of

torque.

POSITION OF AILERONS

However in our project since the wing is a folding

one so we can not have either flap or aileron on

the part near the wing tip.

Since ailerons are vital to an aircraft’s movement

we placed only ailerons on the wing.

We kept the aileron a bit bigger in our case

keeping in mind that it is placed near the

fuselage ( generally ailerons are kept far from

fuselage so as to produce large torque )

WING SPECIFICATIONS

Wing span = 182 cm

Chord Length = 26 cm

Dihedral angle = 0 degrees

Area of wing = 182*26 cm2 = 4732 cm2

Aspect ratio = 7

Length of part 2= Length of part 3 = 45.5 cm

Length of part 1 = Length of part 4 = 45.5 cm

AILERON SPECIFICATIONS

Length of aileron = 40 cm.

Breadth of aileron = 5 cm.

The edges of the aileron were rounded to

minimize the drag effect.

MAKING TAIL

Once different parts of the wing were made, we

moved on to the tail.

One point to be kept in mind while making the

elevator and rudder is that their area too is to be

included in the area of the tail and vertical

stabilizer respectively.

HORIZONTAL TAIL SPECIFICATIONS The maximum length between base and its topmost

portion is 14.5 cm.

The minimum distance is 8 cm.

The length of the base is 64.5 cm.

The tail was inclined at a negative angle of 3 degrees

with respect to the fuselage.

VERTICAL STABILIZER

It was made trapezium shaped with the following

specifications.

Height = 29.3cm

Length of two parallel sides were 2 cm and 23

cm.

RUDDER SPECIFICATIONS

Length = 78 cm

Breadth = 7 cm

Its cross section was airfoil shaped so as to minimize

the drag .

FUSELAGE

We went for an simple fuselage design.

Our project was meant to be a high wing plane

since we do not know flying ( high wing planes

have higher stability,so they are recommended

for beginners)

Generally length of a typical fuselage is 70-90%

of the wing span.

In this case it is 82.5%.

Length of fuselage being 150 cm.

FUSELAGE

After making it we made the base.

We used 3 mm ply to make this basic structure of

the fuselage.

Hence, we need to impart strength to the

fuselage at several places.

Depending on the strength needed at several

places we used single or multi layers of 6 mm

balsa wood or ply.

FUSELAGE

In an aircraft reliability is a very important

issue.

Hence the strength of the plane is a very critical

issue and needed to be handled carefully.

FUSELAGE

To maintain the proper aerodynamic shape of the

fuselage several scanners were set in the hind

section of the fuselage.

Between the scanners trusses were made.

Similarly on the base we made trusses.

At some places 6 mm balsa wood was also used to

give strength.

FUSELAGE

Proper strength must be there because it must

not break due to the vibrations of engine.

Also, the part where Landing Gear have to be

mounted must be very strong, so that it can take

up the vibrations at the time of landing.

These parts were made using double layers of 6

mm ply.

FUSELAGE

For the landing gear a similar piece of ply was

attached at the bottom of the fuselage so as to fix

it in its proper place.

And then we tightened it using nuts and bolts.

We used cycle spokes as wires to connect servos

to different parts of the plane like ailerons,

rudder, elevator.

To the rudder also a landing gear was attached to

ensure the proper landing and take off.

FUEL TANK

We used a mixture of methanol and castor oil.

Level of fuel tank must match the oil input valve.

FINDING THE POSITION OF WING

One of the most important thing is to find a

suitable position for the wing.

For if the centre of gravity of the entire system is

not in between the aerodynamic centre and the

tail then the plane will not be stable.

We did not have exact data required for the

calculations.


What we did then was to try to keep the position

of centre of gravity at a distance of 0.1c to 0.2c

from the aerodynamic centre.

Here c is the chord length.

The aerodynamic centre is located at a distance

of 0.25c (approximately) from the leading edge of

the wing for subsonic speeds.


The centre of pressure is the position where

actually the total force vector is located.

But in most of the practical cases aerodynamic

centre is used for calculation purposes.

FIXING WING

The wing is attached to the fuselage with the

help of thin rubber tubes.

With this we can separate the two parts and

change the position of the wing as per the

requirements.

Like we can use a engine of better capacity.

But with that the weight will increase and so the

position of centre of gravity will vary.

So, we will have to readjust the wings position.

FINALLY FLYING…..

We need to use a five channel transmitter as

against the normal four channel transmitter.

Since in our case we have used an additional

servo for folding the wing.

For more information visit our website

http://students.iitk.ac.in/aeromodelling

Contact Jeetesh Agrawal [email protected]

Kratika Agrawal [email protected]

Tushar Sikroria [email protected]

http://students.iitk.ac.in/aeromodelling

Documents

RC Retract