Mini UAV CONCEPTUAL and PRELIMINARY DESIGN "Weight Sizing"

Mini UAV CONCEPTUAL and PRELIMINARY  DESIGN "Weight Sizing"

in the last post we introduced a general view about conceptual and preliminary design, and as we discussed preliminary design divided into three different stages

1. Weight sizing.

2. Weight sensitivity analysis.   

 3. Performance sizing

in this post we will discuss how to make weight sizing 

 WEIGHT SIZING

The goal of the weight sizing stage is to quantify the weight   parameters
Ground launch weight, W_GL

 Empty weight, W_E

Mission fuel weight, W_F 

 based on the following steps as shown in the Figure below

Steps of weight Sizing

Step 1:  From mission specification, construct the mission profile

Step 2:  From mission specification and collected data on existing

               payloads, determine the maximum payload weight, W_PL

Step 3:  Based on steps (1) and (2) above, estimate a likely value of ground launch weight, W_GL

Step 4:    Based on mission profile, determine the fuel weight, W_F

Step 5: Calculate the value of the empty weight, W_E

 Step 6: Find the allowable value of the empty weight from the

  regression relation between the ground launch weight and the empty weight, given in the Introduction Section.

Step 7: 

Compare the value for the empty weight obtained from          steps (5) and (6). Next, make an adjustment to the value of   

   the ground launch weight and repeat steps (4) and (6).

 weight Estimation Process     

Continue this iteration process until the values of empty weights agree with each other to within a tolerance of 0.5%.

At the end of step (7), the following air vehicle design parameters are available:

  1. Ground launch weight, W_GL

  2. Empty weight, W_E

  3. Mission fuel weight, W_F

   4. Payload weight, W_PL