Leveling 1

[Equestion]

Good day all

I am struggling to get my head around this one
The situation is as follow;

If an aircraft is being weighed with 3 scales ( one at Each main Landing gear and one at the nose Landing gear) at a given and known angle for eg 4 degrees, is it possible to predict the GC at 0 Degrees?

I would like to know is there a way of applying maths as an iterative method to solve it?

A bit of background to why the question arose, I weighed an A/C getting the following readings:
In Situation A I got 3131 KG on the Main LG and 275Kg on the Nose LG, the angle was measured at 4.8 Degrees.

In Situation B I got 3035 KG on the Main LG and 363 Kg on the Nose LG, the angle was measured at 2 Degrees. Situation B was created by deflating the Nose LG strut slightly. See pics below to illustrate situation A and B better.

 

[Equestion]

The CG height is based on the CAD models CG height.
I used it as it doesn't seem to change too much when the CG shifts to its extremities.

Any advice on further reading on M&B? especially regarding Leveling?

Life is a DIY project

 

[rb1957]

if you trust CAD for the CG height, why not the CG location ?

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

Equestion...

One of the reasons real-world testing [such as W&B determination] is used to validate CAD models is for the intangibles. A few examples...

What is the effect of paint finishes and other variable coatings... such as fuel tank sealant, rain-erosion coatings, etc... on the real acft CG?

What is the effect of individual balancing/ballasting of each flight control surface [unique for each surface] on the real acft CG?

What is the effect of assembly shimming [solid or liquid], liaison repairs, overhauls and modifications on the real acft CG?

IF CG/weight is remarkably off-expectations [or previous measurements], then 'WHY'?

What is the affect of material and manufacturing variations, such as: raw material thickness variations, machining tolerances, etc.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]