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Sailplane Center of Gravity (CG) Calculator PDF Print E-mail
Written by Henryk Kobylanski   
Monday, 28 August 2006
Click to enlarge

Enter the variables at left using the same units for all entries (eg: mm OR cm - not both).

For an aircraft to be stable in pitch, its CG must be forward of the Neutral Point NP by a safety factor called the Static Margin, which is a percentage of the MAC (Mean Aerodynamic Chord).

Static Margin should be between 5% and 15% for a good stability. Low Static Margin gives less static stability but greater elevator authority (more sentitive), whereas a higher Static Margin gives a more static stability but reduces elevator authority (less sensitive). Too much Static Margin makes the aircraft nose-heavy, which may result in elevator stall at take-off and/or landing. A tail-heavy aircraft will also be more unstable and susceptible to stall at low speed, e. g. during the landing approach.

Click here to calculate multi-pannel wings

Model Name : 
Wing Root Chord (A):
Wing Tip Chord (B): 
Wing Sweep Distance (S): 
Wing Half Span (Y): 
Stabiliser Root Chord (AA): 
Stabiliser Tip Chord (BB): 
Stabiliser Sweep Distance (SS): 
Stabiliser Half Span (YY): 
Distance between both LE's (D): 
Type of Stabiliser: 
Enter your desired Static Margin:
 %

 

Results for:
AC - Distance from Wing Root LE to AC = 
NP - Distance from Wing Root LE to NP = 
CG - Distance from Wing Root LE to CG = 
   
Wing Area = 
Wing Aspect Ratio = 
Wing Taper = 
Wing Sweep Distance at MAC (C) = 
Wing Mean Aerodynamic Chord MAC = 
Wing - distance From Root Chord to MAC (d) = 
   
Stabiliser Area = 
Stabiliser Aspec Ratiot = 
Stabiliser Taper = 
Stabiliser Sweep Distance at MAC (CC) = 
Stabiliser Mean Aerodynamic Chord MAC = 
Stabiliser - distance From Root Chord to MAC = 
Tail Arm (distance btwn Wing AC and Stabiliser AC) = 
Stabiliser Volume Ratio - Vbar = 

  
Last Updated ( Wednesday, 13 December 2006 )
 
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