Weights and Balance for C 170 N4163V Serial # 18495
Modern Aero 11/23/98
Larry Brickey

Item                                                   Weight                         Arm                          Moment           

Previous Data                                       1336                         41.9                           55978.40

Aircraft as weighed                             1617                         39.14                         63289.38
Fuel Weight                                          -300                         45.00                         -13500.00
                                                               1317                         37.80                          49789.30
Useful Load 2200 - 1317 = 883

Equipment List

                                              Items                                                                                               Other Equipment include

1            Propeller(metal 1A170)

Turn and Bank indicator
101        Starter (Delco-Remy) Sensitive altimeter
102        Carb Air Filter Artificial Horizon
103        Carb Air Heater and Mufflers (Hanlon-Wilson) Recording Tach.
201a      Goodyear wheels and brakes

Rotating Beacon (Whelen)
202a      6.00 x 6 tires Navigation Lights
204b        Scott Tailwheel (3200) Directional Gyro
306        Generator (Delco-Remy 35 amp) Suction Guage
210        Wheel streamlines plates only AT 150 Transponder
302        Battery
303        Landing Light (Grimes) O-300-A with Fuel Pump
307        Voltage Regulator (Delco-Remy) 4th 12.5 gal. tank in left wing.
401        Cabin Heat Valve Engine Cowl - seaplane
402a      Airplane Flight Manual EGT replaces Clock
604        Venturi Installation 2 each  

Unusable fuel 19 lbs at +53 for 3 tanks (for std 170) and estimate of 5 gal. at 30 lbs at +53 must be included.

The Calculations

Include unusable fuel - How much 4 gal.? 5 gal?

Measurements recorded by Tom Arsenault at the weighing.

D = 20.75" - distance from Firewall datum to Main wheels axis.
(Note this may be wrong because the aircraft documents show wheels at 22")
L = 228.75" - distance from Main wheel axis to tail wheel.
Jig = 0 (no negative refernce datum)
Tare = 17 lbs. (Why? What is it that takes 17 lbs off the tail wheel weight?)

Weights - Full gas tanks, 6 qt oil.

Left Main        753  -  756
Right Main      731  -  731
Tail                 149  -  147 (Tare 17 lbs)
Totals            1633   1634
minus Tare                    17
                                 1617 lbs

Formula calculation

CG = D + ( (R x L) / W)
CG = 20.75 + (130 x 228.75) / 1617
CG = 39.14
CG = 40.39 if 22 used instead of 20.75

Weight Calculation

Right main =   731   at 22            16820
Left main  =   753    at 22            16566
Tail          =    130   at 249           32370
Total        =  1614   at 40.74        65756

So what is the CG? 37.80 or 39.14 or 40.39 or 40.74?

39.14 is at 1617 and 37.80 is with empty fuel.