CFI oral questions

[Kaman]

Hi Guys and Gals,
Perhaps some of you that are more learned than myself might have the answers to these questions:

1. What is a "Centroid"
2. What does "Zero Wing Fuel Weight" mean?
3. Under the Technical knowledge for Aeromedical the acronym (at least I think it's an acronym???) "SODA" mean?

Thanks!

ex-Navy rotorhead

 

[Wiggums]

1. In what context? Centroid is a brand of fuel gagues, but I don't think they are used in airplanes.

2. Zero Wing Fuel Weight - the maximum weight of the aircraft before loading fuel. Here is an example, lets say that an airplane has a max gross of 3800lbs, an empty weight of 2500lbs, and a zero fuel weight of 3500lbs. Your useful load would be 1300lbs, however, you could only load 1000lbs in the cabin. The last 300lbs would have to be fuel.

3. Statement of Demonstrated Ability

 

[ch47fe]

Centroid

Dude,
If you crewed military aircraft you should know this one....

A centroid is an indicator locating the center of a specific cargo compartment for determining weight and balance for internal loads. You can figure out the exact weight and balance using the water lines in the Operators Manual.

This is very helpful with internal loads. Palletized loads or Robinson tanks could be easily loaded using these marks painted on the sound proofing on the aircraft.

Is this a civilian question?

Later

 

[Kaman]

re: "Centroid"

Hello,
I crewed on the SH-2F and SH-60F/HH-60H. Neither of those aircraft were weight and balance critical. We basically loaded what internal cargo we might be carrying within the stations that were right about on the C.G. We primarily flew ASW, SAR and other missions and weight and balance was not a big issue and we had "canned" W&B sheets for various mission configs, so as long as we were under gross we just tossed it in.
As for the centroid "thingy", it apparently refers to the fuel cells. However, I think that what you suggested is also true, so I'll just go with both Thanks for your help!

Ex-Navy rotorhead

 

[NParker]

Centroid

When you say "Centroid", you have to say "Centroid of <something>", such as area, volume, mass, etc.

The Centroid of area is essentially the center, but on irregular figures, it might be hard to calculate. But the Centroid of a circle is the center; if the circle is made of some uniform substance, then the Centroid of area is the same as the Centroid of mass.

The Centroid of mass for an airplane is it's CG, but it probably doesn't coincide with the centroid of volume.