Owly
Newbie
I'm new here, and I assume the topic of jump takeoff has been discussed extensively, and probably dismissed as impractical. But I believe that within limits it can work. In my case what I am talking about is jumping perhaps 5' off the ground and accelerating to flying speed. The purpose is to be able to operate out of hostile terrain where a roll is not practical. Here's the idea. The pre-rotation goes to well above operating RPM.... perhaps 25-30% with the blades in normal flight pitch. A collective designed to operated only during takeoff is linked to the pre-rotator linkage, and when the pitch is snapped in, the pre-rotator kicks out. At this point you are at full power with a fairly powerful machine, it leaps and begins to accelerate as the blade speed decays toward normal flight RPM or thereabouts, and hopefully the airspeed increases rapidly enough to drive the blades fairly quickly and little altitude is lost. The airspeed as it increases pulls off the jump takeoff pitch gradually until the blades are in normal flight pitch at which point there is NO PRESSURE on the collective mechanism. That mechanism might be a flex cable like the Scorpion II used such that it would not be bothered by rotor head tilt. A simple vane mechanism that reacted to airspeed would be the device that would pull off the pitch. The idea is that once the takeoff sequence reached the "leap point" the pilot would ONLY fly the aircraft and not worry about an extra function that he had to control. This could be a locked wheel takeoff, or even be done with skids, and the only object would to be to get into ground effect rapidly and clear of low ground obstacles such as sagebrush and rocks. It would NOT offer true vertical takeoff or give the ability to climb tall buildings or clear tall trees. It would offer access in and out of places such as sand bars in the Yukon River where willows are an obstacle or the desert country of the west where sage and lava rock make getting in the air with a ground run problematic at best. As I mentioned....I am well aware that there have been many experiments with jump gyros, and probably much discussion of them here in the past. I am not familiar with the methods used, but I have concluded that simplicity is critical, both in design and in pilot work load. It is also obvious that you cannot power the rotors after takeoff without ending up with a very complex machine, so stored energy in the form of rotor inertia is about the only practical option. It's also very obvious that lots of horsepower is critical if something like this is to work. The whole thing is contingent on the the stored energy in the rotor and rapid acceleration to flying speed. I personally think it could work. But what do I know