Weight and Balance

After the weight and balance workshop at the 2002 KR Gathering I decided to take a first stab at my weight and balance to see how things were developing.  My first cut showed that I was very nose heavy.  In this estimate I had guessed the weight and cg location of the engine.  My guess proved to be off significantly.  This is good news because I had figured 240 pounds for the engine based on the fact that I had a Type IV with turbo and intercooler.  In addition I had guessed the CG of the engine to be at the center of the four cylinders.  Both of these estimates were off in the nose heavy direction.  To eliminate my panic over this nose heavy estimate, I remounted the engine and then reweighed the airplane.  This gave me the exact cg and weight of the engine.  Here is the link to the engine weight and balance determination.

    Estimated       Measured  
  Weight Datum Moment   Weight Datum Moment
               
Vertical Stab         4 124.00 496.00
Rudder         5 133.25 666.25
Flaps         6 57.00 342.00
Elevator         7 133.25 932.75
cowl         8 -14.00 -112.00
turtle deck         12 76.00 912.00
header tank         20 11.00 220.00
Tail         23 133.25 3064.75
Instrument Panel         47 20.00 940.00
Left main         82 19.00 1558.00
Right main         83 19.00 1577.00
Engine         219 -10.96 -2400.25
Altermator         7 -5.68 -39.73
baggage compartment 10 70.00 700.00        
battery 15 -1.63 -24.38        
canopy 12 38.00 456.00        
interior 15 36.00 540.00        
Outboard wings 60 35.38 2122.50        
prop 8 -28.00 -224.00        
windshield 4 19.00 76.00        
               
               
               
               
subtotals 124   3646.125   523   8156.775
               
Note:  Datum zero is located at the firewall.          
          CG range = 20.4 to 28.4 inches aft of the firewall datum zero line      
          CG range = 8 to 16 inches aft of the wing leading edge        
          It is recommended to only use the forward half of the CG range.      
               
    Estimated          
  Weight Moment Datum        
Empty weight and balance 647 11802.90 18.24        
               
pilot 180 5254.20 29.19        
               
Zero Fuel weight and balance 827 17057.10 20.63        
               

Header tank fuel

 153 1683.00 11.00        
               
Full Header weight and balance 980 18740.10 19.12        
               

Wing fuel

 180 6367.50 35.38        
               
Max Fuel weight and balance 1160 25107.60 21.64        
               

baggage

 50 3500.00 70.00        
               
Gross Weight 1210 28607.60 23.64        

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