No Gas.
Might have an extra bucking bar in there! (just kidding Stephen)
My magnetometer is in the rt wingtip, along with the extra wire and OAT probe. Hardly think that would be more than a pound.
This is an interesting problem, and it made me curious. So I sketched out a lateral schematic and did a quickie moment balance analysis:
The following table shows an lateral moment equilibrium. The neat thing about working problems like this is that you can choose any reference point, and as you can see from the diagram I chose the left wheel.
Just as an example, I assumed that the magnetometer weighs 1/2 lb, and that the wire that serves it also weighs 1/2 lb. Of course, those weights are estimates open to debate, but let them serve for this example.
---------------mass-----arm-----moment
Wire-----------0.5------107-----53.5
Magnetometer---0.5------166-----83
Totals---------1---------------136.5
As you can see, the total moment of the magnetometer and wire, measured from the left wheel, is 136.5 in-lbs. To find the force required at the right wheel to keep the system in balance, we divide that moment by the arm of the right wheel, 74" (again, not exact, but it serves this example):
137.5 in-lbs / 74" = 1.84 lbs
To finish off, we assume that all the forces acting on the magnetometer and wire are in some sort of balance, that those items aren't rotating around their axes or levitating or sinking. Since the parts weigh 1 lb, and the force applied at the left wheel is 1.84 lbs, we know that the force at the right wheel must be 1 lb - 1.84 lb = -.84 lb, or else the parts would be accelerating upward and maybe end up going through the roof. The difference between the forces at the right and left wheels is 1.84 - -.84, which simplifies to 1.84 + .84 = 2.68 lbs.
This example shows that adding about 1 lb of stuff relatively far out in the right wing results in about a 2.7 lbs difference between the two scales. That doesn't account for all the difference measured in the case at hand, but it likely accounts for a lot of it.
(Note: No 0.8 correction factors were harmed in the production of this moment balance analysis.)
Thanks, Bob K.
You're still my hero. Bob.
