A pre-whirl generating apparatus is provided that employs deformable air deflecting vanes adjacent the inlet of a radial air compressor, which vanes can be mechanically deformed to generate positive, neutral, or negative pre-whirl flow to the compressor. One example method includes calculating a resolved address for an unknown reverse path forwarding neighbor in an any-to-any multicasting route. The amount of hydrogen present in the hydrogen storage unit is monitored using an on-board hydrogen fuel measurement system utilizing a microcontroller and multiple sensors. The latch maintains the seal in engagement with the first and second nacelle flow structures in the latched position.