ORIGINAL: Missileman
A thought based on past experience working with naval aircraft. (ie.. carrier take offs)
A catapult would most likely be out of the question not only due to logistics but stress on the airframe would be tremendous but a blast deflector at the beggining of the runway would give your prop wash something to push against and may help get you up to speed faster.
Just a thought, it would be interesting to see how much difference it would make?
We did consider rocket assisted take-off in our initial design, but determined that it would be too risky and that the engine would be able to provide enough thrust to meet the take-off requirement. That's why we decided not to go with that.