This page contains a very long flat list of aircraft types, roughly categorised. As it grows, it will become a less than useful index, and if it isn't complete, that's also less than useful... so, in an attempt to provide some better indexing, try one of these alternatives:
... 2, the element 2a is zero and it is impossible to divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in the formula should be understood as ...