A class of mechanics expresses my whole.

[5]

I am composed of seven letters.

My 6, 7, 4, was used in war.

My 6, 4, 5, 2, 3, 1, is a seat of war.

My 2, 7, 4, 3, is a useful animal.

My whole is loved by every true-hearted American.

[6]

My 4, 2, 7, 10, is a planet, a chemical combination, and a town.