Design your flight 2013 guru gobind singh indraprastha university-team leo (2)

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RC PLANE DESIGN REPORT

RC PLANE DESIGN REPORT

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  • 1. Development Phase In the preliminary design stages, various designs were studied and analysed for their performance in accordance with the problem statement. Design aspects which were beneficial for one aspect of flight but harmful for some other were weighted for pros and cons and an ultimate decision was made in order to come up with the best possible design for the required problem statement. The monoplane was selected even though the biplane design offers greater strength. This was because, strength was not the paramount concern as the plane was supposed to be light and the preliminary designs which were tested using ANSYS software confirmed that the structure was strong enough for the purpose. Further biplanes have inherently more drag for a given amount of lift than monoplanes. Monoplanes are capable of higher speeds and lower energy consumption. Markets were surveyed for the availability of construction material as well as the auxiliary items required to build the plane under a decent budget and of the desired quality. Out of the various types of batteries available, the Lithium Polymer (Li-Po) battery was chosen even though it is more expensive. Li-Po batteries offer the advantages of lower weight and increased capacity and power delivery.
  • 2. Management Phase Organization of the team Figure1. Various team members were given the responsibility of various aspects of the project. They were given these responsibilities along with the authority necessary to carry out their responsibilities. The person best suited for the department was chosen democratically and according to their abilities. The members in each department were also chosen according to their abilities and keeping in mind their personal choice. Figure1 is a diagrammatic representation of the team’s organization. The network analysis diagram in figure 2 clearly shows the time taken in days in order to complete a specific task. Division of work enabled the work to be completed quickly as members of each department were able to complete their own tasks in a short period of time as not much man power was required for any aspect of the project
  • 3. Conceptual Design The problem statement requires us to carry the greatest payload possible over a specified course. There are various regulations on take-off and flight and some restrictions on the weight. Therefore, it is imperative to design the aircraft under such strict conditions. The greater the payload, the more power the airplane requires which increases the size of the batteries and the motors ultimately increasing the size of the plane and its weight as well. Therefore, by restricting the total weight of the airplane there is also an implied restriction on the payload that can be carried. Better design and manufacture will help us achieve a result as close to the maximum as possible. The NACA four-digit wing sections define the profile by 1. First digit describing maximum camber as percentage of the chord. 2. Second digit describing the distance of maximum camber from the airfoil leading edge in tens of percents of the chord. 3. Last two digits describing maximum thickness of the airfoil as percent of the chord. This formula is for the shape of a NACA 00xx foil, with "xx" being replaced by the percentage of thickness to chord. where:  c is the chord length,  x is the position along the chord from 0 to c,  y is the half thickness at a given value of x (centerline to surface), and  t is the maximum thickness as a fraction of the chord (so 100 t gives the last two digits in the NACA 4-digit denomination).
  • 4. Figure (A) Various aspects like chord, camber etc. are illustrated in figure (A). Equation 2 where:  m is the maximum camber (100 m is the first of the four digits),  p is the location of maximum camber (10 p is the second digit in the NACA xxxx description). Equation 2 was used as the cambered airfoil offers a number of advantages over the symmetrical one. Considered formulas: 1. Ar = Wing span/Chord length Ar is aspect ratio 2. Wing loading= weight in oz / area in ftsq. 3. Lift=1/2 .rho. v sq.. wing area.coff. of lift 4. Wing planform area= chord length . wingspan( both for upper and lower wings added)
  • 5. Preliminary Design • Various components like wings, fuselage etc. were designed using PTC wildfire 5.0 (Pro/E). • The design is according to the norms given in the rulebook. • The initial design was tested for operational validity using ANSYS. • Calculations for specifications of the driving and control motors were done using MotoCalc 8. The usage of software to design and test a prototype eliminates the need to construct and test the component time and again thus saving a lot of time and money both of which can be put to better use. But, the usage of the software does not completely eliminate the need for models. Several 1:1 scale models were made for solving the following problems. • Check the availability of space for components like motor, controls etc. • Check the dimensions achieved in actual practice.
  • 6. Figure 3 Figure 3 shows the first prototype which was constructed out of thermocol and glue. As can be seen, it employed a biplane design which was later discarded in favour of a monoplane design as the monoplane gave a more satisfactory result in analysis.
  • 7. Figure 4. Figure 4 shows the final model that was constructed which more closely resembles the final design of the plane It was constructed after the monoplane was found out to be more advantageous as compared to the biplane design as per our requirements.
  • 8. Detail design After a number of designs on computer softwares and the construction of models, a design was approved; which was deemed to be the final design. Manufacturing and fabrication of the design was approved by the team with valid proof that the design in robust and fit to carry out its function. WINGS Figure 5 Figure 5 shows the final design of the wings.
  • 9. The final wing design has the following specifications; • Design : NACA 2417 profile • Material Used: Balsa Wood • Strength (kPa): 18100 for compression parallel to grain, 4600 for shear parallel to grain, 1200 or tension perpendicular to grain. • Justification for selection: Balsa is an ideal material for constructing an RC plane. This is due to the fact that not only is it light but also has high strength for its weight. Also, it does not fail easily in bending which is the type of stress which the wings need to withstand. Figure 6 CFD analysis of airfoil Figure 6 shows the successful CFD analysis of the airfoil carried out on ANSYS.
  • 10. Figure 7 Modal analysis Figure7 shows the modal analysis of the wing span on ANSYS. Modal analysis uses the overall mass and stiffness of a structure to find the various periods at which it will naturally resonate. These periods of vibration are very important to note in dynamic systems, as it is imperative that the natural frequency does not match the frequency of expected vibrations. If a structure's natural frequency matches the frequency of vibration, the structure may continue to resonate and experience structural damage. ```````` Figure 8.
  • 11. The analysis of the landing gear is important as the landing gear must be able to withstand the entire weight of the plane while landing. Analysis of the landing gear in ANSYS reveals that the design is well within the safety required for operation. PLANE DESIGN Figure 9 shows the isometric view of the assembled plane on PRO/E. Figures 10 and 11 show front view and top view respectively
  • 12. DIMENSIONS • Wing Span: 100 cm • Length: 75cm • Chord Length: 14.5 • Propeller: 9’’. ELECTRICALS
  • 13. Figure 12 Motor Specifications Figure 12 shows the result for the motors to be used as indicated by the design software MotoCalc. Using this information the driving and control motors were selected from the ones available in the market. Motor: 1800rpm/V; 0.2A no-load; 0.056 Ohms. Battery: 1800mAh @ 3 cell 11.1V; 0.0257 Ohms/cell. Speed Control: Generic Brushless ESC; 4 controls (separate); 0.006 Ohms; High rate.
  • 14. Figure 13 Figure 13 shows the controller used for flying the plane. It is a 4 channel controller. The receiver that is used along with this controller is shown in figure 14.
  • 15. Figure 14 The Lithium Polymer battery used is shown in figure 15. Figure 15
  • 16. Figure 16 Figure 16 shows a micro servo motor. Servo motors are used for control mechanisms. Their capacities in accordance with the values calculated for a satisfactory performance.
  • 17. Manufacturing Process Once the design was complete and the models were analysed and the team members were satisfied that the design is up to the mark, the manufacturing process was started. The wing airfoil was made of balsa and bonded together in pairs in order to give greater strength. The manufactured wing is shown in figure 17. Figure 17 Such intermittent construction allows us to reduce the weight of the wings and still maintain the shape and strength required for flight. A single airfoil is of the shape shown in figure 18.
  • 18. Figure 18 Figure 19
  • 19. Figure 19 shows the fuselage of the plane. It has been constructed out of chloroplast and has been bonded using super glue. Super glue was selected after carefully analyzing the pros and cons of several bonding materials available. The pros and cons are listed in table 1. Super glue was selected as it was easily available and was the best option for bonding several components as the entire airplane is not made of a single substance but is a composite of several components. Table 1
  • 20. Figure 20 Figure 21 Figure 20 illustrates the push rod mechanism employed to control the motion of the airplane. Figure 21 shows specifically the aileron control. The links are fixed in such a way that they coincide with the zero position of the motor when in the neutral position. This enables the controller to move the controls in either direction easily and bringing it back to the mean position is a fairly simple task.
  • 21. CONCLUSION A safe and reliable design approach was adapted. Extensive testing has been done including the gliding capabilities of the models constructed and static analysis of the model we are ready with the final design and the airplane is approaching completion. All is left to do is the flight analysis and test the limits of the airplane so that the plane which we put forth to compete is capable of competing with the other teams.