Medusa and Orion engine thrust animation suggestion

[GHrynk]

The current (NPE 0.3.9.0) Medusa and Orion engine thrust animations are a multiple shots per second machine gun spray of pulse/bomb units. I would suggest making the visual and audio animations more in line with their real world designs.

Per "Some New Ideas for Nuclear Explosive Spacecraft Propulsion" by Solem, the Medusa engine should have a pulse interval of ~2.5 seconds. Although this is tailored for a 1g thrust level and a 7.5km tether spacecraft, it does give time for the pulse units to travel the fairly long distance from ejection to detonation, and for the stroke of the spinnaker and tethers to complete their cycles. In the NPE animation, there appears to be a stream of a dozen bombs en route while thrusting. For the smaller, Kerbal scale engine, I'd still expect on the order of a second or so between pulses. I understand for the sake of actual acceleration simplicity if the forces model does not match the audio/visual phenomena. On a similar vein, the explosion animation seems to stay with the accelerating spacecraft; I'd suggest utilizing the trailing plasma cloud animation from the Orion engine.

The Orion engine appears to eject bombs and cycle the pusher plate much faster than the associated audio animation. The 1964 General Atomics/General Dynamics Nuclear Pulse Space Vehicle Study refers to a pulse rate of a little under 1 second for a 10m vehicle, so the audio isn't far off, but the visuals don't sync.