9.1 inches between tank ribs

[rulmen]

All;

I know this is a dumb question.... why did they space the tank ribs 9.1 inches apart? Why not use the metric system? I have prepunched skins so the ribs have to be hyper accurate.

 

[mcencula]

I suppose you'd have to ask the designer to get the real answer, but I can say that aircraft standards were developed before the metric system was in widespread use in the US, so with all that history, there's a lot of inertia to overcome in order to implement an industry-wide change.

Besides, once you get used to working in Imperial units, it's not really much harder than metric anyway (at least for simple stuff like distance measurements).

 

[rulmen]

Conversion

I suppose you'd have to ask the designer to get the real answer, but I can say that aircraft standards were developed before the metric system was in widespread use in the US, so with all that history, there's a lot of inertia to overcome in order to implement an industry-wide change.

Besides, once you get used to working in Imperial units, it's not really much harder than metric anyway (at least for simple stuff like distance measurements).

How would you convert 9.1 inches to something usable? I guess I could go to metric then back to imperial. What a pain that is. I guess I can match it with the tank skin.

 

[mcencula]

How would you convert 9.1 inches to something usable? I guess I could go to metric then back to imperial. What a pain that is. I guess I can match it with the tank skin.

My scale has four sets of increments on it:

1/32 and 1/64 inch on one side
1/10 and 1/100 inch on the other side

So, you should be able to read 9.1 inch directly off the scale...no conversion necessary.

Good luck,

 

[rulmen]

Thanks ALPHA!!