The back of a clock is decorated with 6 congruent ellipses and 7 congruent circles, as shown. Every circle is tangent to adjacent ellipses, and every ellipse is tangent to adjacent circles and ellipses.

The large, outer circle—the circumference of the clock's face—is tangent to the 6 ellipses and 6 circles with the numbers 1, 2, 3, .. 13

If the 7 congruent circles all have a radius of 1 inch, what is the diameter of the large circle in inches?