DARPA's Vertical Take Off And Landing Combat Drone Could Revolutionize Naval Combat Image Unavailable, Please Login
What's old is new again https://en.m.wikipedia.org/wiki/Convair_XFY_Pogo Image Unavailable, Please Login
A "tail sitter" makes sense for a drone, no pilot issues like noted above.. The advantage is that the aircraft can be a very efficient platform (long time on station) and much faster (quicker to get on station) in the normal flight mode and you can still land it in a small area (like the helo platform on a ship). The key gain is that you don't have the complexity of tilting rotors. Recall that Bell was pushing their "Eagle Eye" tilt rotor UAV a one time. That UAV was intended for Naval applications and actually did some shipboard trials, but it was a pretty complex system and not inexpensive by any means. What is interesting is that a friend of mine was the lead engineer on the original XV-15 (when he retired from BHTI he was given a plaque that called him the "Father of the Tilt rotor).. Several years after retirement from Bell he was pitching, for UAV's.... A tail sitter... So even the guy who basically was the father of the tilt rotor felt that a tail sitter was the way to go for a VTOL UAV. There is one downside, that is that the engine oiling system has to be capable of scavenging the sumps even when the engine is in the vertical position. Not a problem if the engine is designed for it in the first place, but it could be a show stopper if it wasn't. Interestingly, the engine for the Comanche (LHTEC T800) was actually designed for operation in either mode. Before Sikorsky won the Comanche, the Army wasn't sure if the aircraft would be a helicopter or a tilt rotor. But the engine development had to precede that decision, so the engine was designed for an operational envelope that included tilting to more than 110 degrees from the horizontal and the sumps were tested in a rig to verify that they would scavenge properly over the entire flight envelope.
Anyone remember building one of these as a kid? The photo in the post above reminded me of one I had. Image Unavailable, Please Login
