Graviman,
To address your question:"Slowrotor, i'm still trying to figure out what the typical mission profile of your machine is? Are you trying to achieve fixed wing efficiency/range but with limited endurance VTOL landing? Even with a turbo-piston engine you will struggle to get much speed."
I think the bird flight discussion here is a good start.
Consider the hummingbird to be the natural world equivalent of the helicopter. The hummingbird burns more fuel than a seagull because it stays in rotary wing mode. The seagull can maintain forward flight with occasional power strokes between energy saving glides and is more efficient. The seagull cannot hover for more than a second, I think, but this brief hover ability is all the seagull really needs to land on a rock perch.
A brief hover is all that is needed for a fixed wing. And if a hover is not possible in the first edition, direct lift is still useful in that the landing run could be as short as a few feet. In fact, it might be better to forgo attempts at hover as this requires additional complex control ability.
I was in a Pilatus Porter turboprop fixed wing that landed on the muddy tundra of Alaska in an area about the size of a tennis court. The pilot locked the wheels to eliminate mud flinging and applied full reverse and we stopped in about 50 feet it seemed.
The seagull lands in a similar manner, gliding in with a burst of reverse thrust just before touchdown the same as the STOL airplane. But the seagull also has brief LIFT added with reverse thrust and is therefor capable of a shorter landing. This extra lift, directed up and rearward is what I seek to provide, only needed for a few seconds. Turned forward and upward these lift fans would provide a quick launch.
Does this make sense?
slowrotor