From: Near Portland, OR
And I thought its U=RI Where [U]=V, [R]=capital omega and [I]=A?
No Omega on keyboards helped to change that usage I guess, but yes I remember that. I don't recall "U" for voltage, though.
Maybe it's different customs in different countries/languages? In the US, I've always seen the equation as V = IR and the power equation as P = VI. I should have said I^2R losses in my earlier post. Not enough tea that day...
If you substitute IR for V in the power equation, you get another way to calculate power which is (IR)*I, which is I^2R. What it means is that if you have high current, your transmission losses are going to be the square of the current. Even if the resistance is low, the power lost in transmission can be big. By raising the voltage and lowering the current, the transmission losses are reduced.
There is a difference between the unit designation and the letter used in calculations. In calculations, V=Voltage, I=Current, and R=resistance. When showing a value, Volts=V, Amps=A, and Ohms=Ω (omega).
And IFF was used extensively in the Pacific. In the Aleutians ground controlled approach was also used to allow landing in zero visibility conditions. This required the plane to have extra equipment on board. My father was a photographer attached to different units at different times. He flew with B-29s at Saipan, B-25s in New Guinea and the Philippines. At the end of the war he was flying in B-25s out of Attu. He said the Aleutian B-25s were loaded down with a lot of extra electronics that wasn't on the 5th AF B-25s. The planes were very cramped inside.
Sometimes aircraft also had more than one radio and radios were large power hungry beasts back then.
WitP AE - Test team lead, programmer