Hurricane Mk IIC cannon:drum-magazine or belt-fed?

[Bill Walker]

P is rate of roll. Say degrees per second. Anything "dot" to an engineer is rate of change with time. So, P dot (usually written as the letter P with a dot over it, but I can't figure out how to do that here) is degrees per second, per second. If you start with a roll rate of zero, and one second later your roll rate is 90 degrees per second, your average P dot over that one second was 90 degrees per second, per second.

In most aircraft, a roll input (aileron deflection) induces mostly a P dot. I'm using a lot of weasel words here, like "mostly", because I'm over simplifiying. Partly because it's hard to put equations in words, and partly because I've forgotten a lot of stuff. So, with cannon in the wings, P dot initially may be slow to build (because of roll inertia) but it will build. It then becomes hard to stop, again because of inertia. Moving the stick the other way introduces a P dot of a different sign (roll rate starts to decrease, but is still positive for some time). It takes you longer to reduce and then reverse P dot, so P continues to build. That's why you see modern aircraft with restrictions on roll inputs with wing stores or tip tanks. It will get away from you. You will reach a dangerous value of P even after you have reversed the stick.

The short term response to a throttle increase may include a speed increase, but the long term response will always be an increase in climb rate. Modern aircraft have to be designed to minimize the short term response. It's built into the regs a designer has to meet today, but this has not always been the case. But the long term response is built into the laws of physics. Different aircraft may have different short term responses, but the long term response will ALWAYS be the same. This is all complicated when the power change changes the aircraft trim state (due to thrust vector not being aligned with the drag vector). This will be more noticeable in a higher powered aircraft. Then, a throttle input is also partly a longitudinal trim input, and longitudinal trim "mostly" controls speed. But still, the throttle "mostly" controls rate of climb. Notice the weasel word again? What this means is that it is not a case of the pilot "can maintain speed by loosing altitude". The aircraft WILL maintain speed by loosing altitude, unless the pilot does something in the pitch plane.