For the flying bike dreamer that should live in all of us, and the lunatic element that actually made a prototype. He has my total respect in that regards. The spec page fails a little bit, seems a tad optimistic.
Working prototype, maybe not yet. I don’t see how any lateral stability is achieved and have serious doubts that it would fly untethered. Forward speed also seems doubtful.
The hovering prototype is completely tied to the ground, which means all hes doing is sitting on a big fan that’s pushing up and that’s it.
The issue is what happens when you tilt and now that thrust wants to spin you upside down. It looks like he’s going for a good old fashioned 2 fin thrust vectoring system but I don’t see that working for more than 5 seconds before you fly out of control and kill yourself.
Something like this could potentially work if it had a LOT of technology involved. This is effectively what made the Segway and Stealth bomber work. Both are inherently unstable designs, but work by taking simple controls and connecting them to a very fast computer system with lots of redundancy. The computer detects the 100 times you are about to crash every second and makes small and invisible adjustments to the pilot/driver to keep them from dying.
It certainly works - and I’ve seen people trying to achieve very similar things with rocket ships, but it’s a massively complex investment. This right now looks to be more of a sweet science project, but the whole “not dying” thing is tough.
Remember the Icon plane? Sweet design, but that thing is still vaporware and it has had a lot of big backers and is a much simpler design (they’ve been making hydroplanes for nearly 100 years).
Martin Aviation has similar power/thrust size envelope to the hoverbike model. The magic of the jetpack design (or a helicopter for that matter) is that the weight is suspended below the force, acting as a pendulum and stabilizing everything. If the thrust center was horizontally inline with the center of gravity, nothing will stop it from rolling over. The hoverbike will tip over sideways in a body twitch or a microgust.
The carbon fiber vanes under the Martin Jetpack are key to everything. No need for tilting rotors.
Here is my illustration on a configuration that might work. The higher the rotors the better, but too high gets the pilot into the vectored airflow.
With less weight, less thrust would be required, and depending on prop/fan design you can find 2 small fans that are capable enough to lift a person and small machine (like the jetpack that was posted).
But that still doesn’t explain how to make it stable or forgiving enough to ride without killing you. I also am not sure how he got his figures on range and speed…seems “optimistic” at best.
I understand the appeal of a simple design that resembles a motorcycle, but a redesign that puts the rider 90 degrees from where he sits now and dropping him below the fans like nxact’s sketch could still result in a cool design that works better. It could look like a combination motorcycle, ultra light and helicopter.
I’m wondering what’s going to happen if his “prime mover” conks out at, say… 600 feet altitude. Unlike a helicopter, this thing isn’t going to be able to auto-rotate to save it’s arse. And at 600 feet even a helicopter would have a hard time pulling it off.
Auto-rotation is how a helicopter is able to land when power is lost. As soon as the engine quits, and the aircraft starts to drop, the pilot pitches the rotor blades into a negative configuration so that the up-rushing air keeps the main rotor spinning. At the appropriate moment before impact/landing the pilot returns the positive pitch to the rotor blades and the inertia of the spinning rotor assembly supplies enough torque to provide lift and prevent the inevitable what-goes-up-must-come-down scenario from occurring.
It’s a one-shot deal.
Note: In this practice auto rotation approach the engine is still running, at idle.
I like the “self leveling” cockpit module… but you have to ask, where is the engine and how is/are the fan(s) driven?
Perhaps a bevel gear on the end of the drive shaft at each side of the cockpit module (doubling as the cockpit pivot) commonly driving a very large diameter bevel gear on the inside diameter of the fan ring? Just looking at the image the diameter of a drive shaft compared to the inside diameter of the fan ring is at least 100:1. Whatever is driving that thing would be putting out some pretty healthy rpm.
So the problem is … even if they were counter rotating fans, all that counter-torque has to go somewhere and it would more than likely just spin the cockpit module around inside the fans.