what is a 100mph ring or 2rad ring?
Allied Aircraft gunnery unit of measurement for hold off or lead by the radius of the ring sight.
1 rad = 35Mil ring and the lead amount is the radius or 17.5.
2 rad = 70Mil ring and the lead amount is the radius or 35.
3 rad = 105Mil ring and the lead amount is the radius or 52.5.
The British 100mph ring concept is a 2rad ring. As fighters got faster and cannon rounds were slower the British changed to the 3 rad ring. Bullet time of travel to 200-300 yards (600-900 feet) in relation to the con's time of travel.
The Germans used a 100Mil ring and their units of lead were based on radii fractions of the 100Mil ring. The tick marks were there to help with visual fractions. They divided the 100Mil ring into 6ths.
With all of this the best shots were naturals or got so close you didn't need a slide rule. The rest did their best. Overall, anything more than a ring and dot was wasted on air to air fighter gunnery. That was the reason behind the K14. But you still needed some reference marks to fire rockets. That was the K14A. Even the B25H got an update to the manual ranging on its N-3C gunsight A1 sight head visa radar because most 75mm rounds were a miss. That's when the Falcon radar (and the C-1 sight head) came in making the B25H very accurate with the 75mm.
Very few of us are very good at shooting moving objects from a moving object.
