AVIATION

DESIGN OF AIRCRAFT

 


 


  1. Designing an aircraft is a major task. World wide in big companies employs 100s of engineers to design aircraft and its components. Nevertheless with so many years in aircraft designing, the industry has a road map of how to go about designing an aircraft.

 
2.   A typical design of aircraft goes through following steps :-
-Studying user requirements
-Literature and historical survey of available aircrafts of the class and available technology
-Feasibility and constraints
-Preliminary Design
-Weight calculations
-Drag Polar Calculations
-Weight estimations
-Selection of optimum wing loading
-CG Calculations
-AC Stability Calculations
 
 
  1. Let us take a small exercise of designing a 40, 000 Kg Freighter which can take upto around 400 passengers. Its range should be around 6500 – 7000 Km and endurance to be about 8 hrs. Mach no to be at 0.8 – 0.8.
 
  1. A Survey of following aircrafts was undertaken.
 
-       Mc Donnell Douglas DC – 10 Transport.
-       Aribus A 320.
-       Ilyushin 76.
-       Lockheed L- 100 Series.
-       Ilyushin 86II.
-       Boeing 707.



  1. As an example the survey of Mc Donnell DC 10 is given here, then when all the aircrafts of the same class were studied, ‘Ratios were obtained from the collected data’ so that general indications of fuel weight, basic empty weight, wing loading, powerplant could be arrived at.
 

 
    The ratios of various parameters such as fuel weight, basic empty weight, wing loading, power plant is given here.
    RATIOS OBTAINED FROM COLLECTED DATA
     
     

     

Fuel Estimation – Fuel estimation is carried out depending upon the stated mission  which is stated along with the calculations – read for yourself



 
 
Preliminary Design Dimensions - Based on the historical survey of different aircrafts in the class, dimensions for preliminary drawings are drawn and preliminary design drawings are sketched.



 
 
 
DRAG POLAR CALCULATIONS - Various Drag Polar Calculations are carried out for wing which include interference and induced drag.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


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