Suryaj C J

GLIDER WITH FOLDABLE WING MECHANISAM SURYAJ CJ AND AKSHAY BABU Department of aeronautical engineering, Mount Zion engineering collage, Kerala technological university, Pathanamthitta, Kerala Abstract: The purpose of this paper is to create a glider with folding wings so that the transportation storage and protection of the glider will be more efficient. We aim to create a folding wing mechanism for a glider, where the wings can be opened remotely. The foldable wing glider can be a major improvement in the unmanned glider section because it can lessen the space normally fixed-wing gliders occupy, as a result, it can be much more efficient for transportation. Other than these the wings will be better protected when folded. For scientific purposes like collecting atmospheric data, for knowing the geography of an area for a military operation. by using this design more than one folded glider can be sent using the same aircraft or rocket because of the less occupying space and each of them can carry the collected data to the destined location. Commercially the glider can be used for surveillance of an area, and obviously in the entertainment section, maybe for taking a video or to follow you when you are paragliding or skiing down a mountain. What we have done in this project is simply a prototype of the first step towards a better glider. We used balsa wood for the wings and tail as it was comparatively light and easy to work with. A carbon tube as the fuselage and a 3D printed head. The wings were hinged to the head such that when folded the wings are under the fuselage. The wings are opened using a spring arrangement connected to one end of each wing and both the other end screwed inside the head. Neodymium magnets are provided on each end of the wing edges and the head with opposite polarity so that the wings will stay in place when opened. The wings are closed and locked using a servo, which can be remotely opened. The finished glider had a total weight of 380g with a wingspan of 160.40cm. The glider has a light and compact design and because it is not equipped with an engine for propulsion it is launched using a slingshot. The glider is capable of silent flight with minimal power consumption Keywords: folding wing, minimal power consumption 1. Introduction In the past years unmanned aerial vehicles have been gaining popularity among the public and science sector. Scientist have been trying to create a better design to increase the efficiency and to minimize the noise produced. Gliders can be considered the best choice when it comes to efficiency and stealth movement. A glider is simply a fixed wing aircraft that is supported in fight by the dynamic reactions of the air against its lifting surfaces and does not depend on an engine for free flight. for field surveys there are specialized systems in aviation that can carry multiple air vehicles such as rockets and dropping them on the targeted locations. For such air vehicles reducing the weight, size and spacing they occupy are very crucial for the transportation of maximum payload. And by selecting the suitable materials that are most compatible and making a better design can allow multiple vehicles to be transported efficiently. One of the best ways we can apply in the better designing of these vehicles is by making the wings foldable and such designs have been successfully applied to reduce the volume of mini air vehicles. Gliders have been around even before the 17th century and gaining more popularity every day. They are ideal for noise less flight and because most of the time they are gliding they comparatively consume only low amount of energy. But because gliders are fixed wing aircrafts, they occupy a large amount of space for storage and transportation, also some gliders without any engine to create the initial lift can only be flown by throwing it up or throwing it from a high building or mountain. To minimize this difficulty, we have come up with a design, that is the foldable wing glider with a sling shot launching system. When it comes to the structure of airfoil NACA (National Advisory Committee for Aeronautics) type is more commonly used and we are using The Eppler-793 type because it is better for mini gliders and speedcritical applications, where thickness, camber, and efficiency ratio are crucial. The glider does not have a motor for production of lift, so for proper function, the glider should be glided from a certain initial height for it to perform well. The glider components are well packed so that it will be light weight and small size. The glider, when the wing is folded can be placed in a sling shot shaped like a cross bow to lunch the glider to the desired height. The sling shot is designed with a wooden base with long steel rods used as the bows and rubber strings attached to them. Steel rods have more elastic property and are strong, so it is better to be used. A hook is attached under the glider so the rubber string can be attached under it. The wing opening mechanism is based on springs attached to both sides of the wings and locked in place using a servo. The wings will automatically be in place when the servo is opened and wing can only be closed manually. Other control surfaces are elevator and rudder are also controlled by two servo motors placed in the head and connected to the control surfaces using small fiber rods. The whole operations on the glider is remote based and the folded wing is opened by remote control after it reaches maximum height by launching using the sling shot. 2. MODEL DESIGN WING DESIGN Wing Design While considering the suitable material for the glider, the material should obviously be light weighted, strong and easy to work with. Balsa wood is easily available, strong, light weighted and easy to work with so the wing of the glider is made of balsa wood with an EPPLER 793 airfoil. The wing span is 160.40 cm. The wing and airfoil shape was developed by hand using sand paper. A mathematical model of the glider has been created considering the wing dimensions. Fig 1 model design WINGS Wings of the glider are created using balsa wood with an EPPLER 793 airfoil (e793-il) with 160.40 wing span. Balsa wood was chosen because of its low weight to strength ratio and high workability. The balsa wood can be sanded to the required shape and size with little effort. Each wing was sanded so that they only occupy the least possible weight with the best possible strength. The finished wings weighted 72g each. Fig 2 Right wing section Dimensions are: WING AC = 2.68Cm WING MAC = 9.6Cm WING SPAN = 160.40Cm WING AREA = 1524.00Cm WING ASPECT RATIO = 16.88 ELEVATOR AND RUDDER The elevator and rudder are also designed using balsa wood with a symmetric air foil. They are made as thin as possible with consideration to its strength. The elevator has a span of 24cm with a maximum breadth of 7cm and a thickness of 5mm. The rudder was designed in a similar manner with half the area of the elevator with the same thickness. Fig 3 Elevator Fig 4 Rudder Dimension are: TAIL AC = 2.04 Cm TAIL MAC = 6.62Cm TAIL SPAN = 24.00C TAIL AREA = 156.00 Cm TAIL ASPECT RATIO = 3.69 STABILIZER VOIUME =0.68 HEAD The head of the glider has to hold the essential electronic components such as the battery, servo motors, etc., plus it has to hold fuselage, and the wings in place. For the fordable wing to be possible a spring arrangement also need to be included in the head. It should be such that the spring will automatically open the wings in place after the lock is opened. When the head is in folded position and launching up using a sling shot or by other means the wing edge of the joint section of the wing produce a disturbance in the movement of the glider. The drag produced can cause the glider to slow down and thereby it won't reach the maximum height possible. So, in order to minimize this effect a fin section is provided on both sides of the head Fig 5 Head ELECTRONIC COMPONENTS USED 1. LM2596 DC-DC BUCK CONVERTER The Dc-Dc Buck converter is a type of power converter which steps down voltage while stepping up current from its input supply to its output load. We have used the LM2596 model for our glider. Fig 6 LM2596 DC-DC BUCK CONVERTER 2. REMOTE AND RECEIVER The receiver is an electronic device that uses built-in antennas to receive radio signals from the remotecontrol unit. But the receiver doesn’t just receive signals from the glider controller, it also interprets the signals and converts them into alternating current pulses .This information is then sent to the flight control board, or flight controller, which puts the information into action by controlling the drone as indicated by the original radio signals. 3. Li po battery A lithium polymer battery, is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. The most important property of Li po battery is its high energy storing capacity compared to its low weight, which makes it an ideal choice for aircrafts. We are using a 3.7V and 150mAh battery. 4. SERVO MOTOR A servomotor is a rotary actuator or linear actuator that allows for precise control of angular or linear position. It consists of a suitable motor coupled to a sensor for position feedback. It also requires a relatively sophisticated controller, often a dedicated module designed specifically for use with servomotors. In this glider three servo motors are used one each for controlling the elevator and rudder and one for locking and releasing the folded wing SPRING USED The fordable wing glider opens its wings using the potential energy stored in springs when the wings are closed. Two small springs are used for the glider and both are selected by evaluating them manually. One end of both the springs are attached to the head of the glider and the other end is attached to each of the wings. Two neodymium magnets attached to the wing end and head to keep the opened wings in place FUSELAGE A carbon fiber tube is used for the fuselage because of its lite weight and high strength. AIRFOIL when considering the airfoil for the wings, the design should be easily folding and freely opening. So, the better design was found to be EPPLER 793 design. Eppler wing structure allows easy assembly and easy folding by virtue of not being excessively cambered Fig 7 Eppler 793 airfoil 3. ASSEMBLY For the final assembly of the fordable wing glider, all the electronic components are connected as in the fig 13. On the front of the head the battery is attached connected to the buck converter. The buck converter steps down the voltage and the output are connected to the 2.4GHz 6 channel receiver. From the receiver the servos receive the necessary commands for their function. Fig 8 Electric Circuit The completed circuit is then placed inside the head and fixed in place. After the carbon tube was attached to the head and the necessary strings to control the tail section was passed through it and a pair of thin wires ware also provided for the wing locking and opening servo which was placed at the tail section. The tail section is attached to the carbon tube and the threads are connected to the control surfaces. They were then checked to be fully functional. The wings ware attached to the other half of the head section provided with a hinged movement. The springs ware attached to the same section and connected to the wing. A pair of magnets ware glued to the wing ends and, on the head, section following a 90° with the same position as the wing. So, when wings are open, they will be connected. The wing attached head section is attached to the other half of the head. They are attached in such a way that the wings will be closed below the fuselage and tail section when closed. Both the head sections ware then screwed together and by that the assembly of the fordable wing glider was completed. 4. CONCLUSION The foldable wing glider was completely assembled and is fully functional. The finished product weighted 380 grams. The glider was launched using a sling shot and when the maximum height was reached the servo locking the wings ware released and the wings opened instantaneously. The opened wings ware set in place by the magnets attached. The control surfaces ware working perfectly. The finished glider was working well as expected. The project objective was to create a glider with wing folding mechanism so that it will be easy to transport in a comparatively small space. The result of the project was satisfactory. The foldable wing mechanism work perfectly and the wings can be opened instantaneously. The glider was low in weight and occupied small amount of space to store and was efficiently transported. 5. REFERENCE 1.Mini Glider Design and Implementation with Wing-Folding Mechanism, Ali Anil Demircali and Huseyin Uve 2. Long Distance/Duration Trajectory Optimization for Small UAVs, Jack W. Langelaan 3. A STUDY OF UNMANNED GLIDER DESIGN, SIMULATION, AND MANUFACTURING Anil Demircali, Huseyin Uvet 4. Long Distance/Duration Trajectory Optimization for Small UAVs, Jack W. Langelaan 5. Aerodynamics characteristics of glider GL-1 based on computational fluid dynamics, E Amalia, M A Moelyadi, R Julistina, C A Putra 6. EPPLER 793 AIRFOIL (e793-il) (airfoiltools.com) 7. LOW-REYNOLDS-NUMBER AIRFOILS, P. B. S. Lissaman 8. Balsa DLG Build Tutorial - Episode 1 | WINGS - YouTube