[dusan]

I'm posting here to find some answers to some specific riding questions, I've ridden motorcycles in my youth, but definitely I'm not an expert.

I'm part of a team that is designing a personal aircraft, capable of vertical take-off and landing (VTOL), the pilot having a prone position, as riding a bike. I've attached images so you can have an idea of how it looks like. More details here: aliptera.com/#ADR-1

My first question is about the airspeed. How uncomfortable is to resist the air pressure of the wind blowing into your face at high speed, as our speed estimates for the aircraft is at about 120 kts (140 mph)

My second question and I guess is the most important one is: how likely is for you to ride one. I would like your detailed opinion either pro or cons, even if you do not know anything about flying an aircraft. Let's suppose the aircraft is easy to fly, with minimal training. We all know that riding a bike is not the safest thing out there; how do you compare riding your bike to flying an rid-able personal aircraft, from the perceived safety point of view.

Thank you!

 

[Eye_m_no_angel]

School project?

 

[WintrSol]

Traveling at more than 100mph on a bike, even with a windshield, can be very tiring. The turbulence of that big prop behind one's feet would add to that. But, I suppose, if the craft has auto stabilization, the workload could be a lot less, but that prop could still be a problem. I also fly model aircraft, and know the landings are the hardest part, so it would have to have emergency features, like a parachute or airbags, or both. For short rides, it could be real fun, though; I might try one.

 

[Zebraranger]

Flying meat grinder, no cage separating the rider from the prop? Looks crazy to me.

 

[SemiFast]

:surprise: Now that right there is funny :grin: I don't care who you are :wink2:
:
lain:

 

[Dodsfall]

My guess is there will have to be a lot more propeller for VTOL and a lot more wing for level flight.

 

[dusan]

@Eye_m_no_angel: No this is not for a school project; it is a real project.
@WintrSol: Thank you for the comments, they are really helpful. The craft is planned to have augmented stabilization, especially for the VTOL flight. You are right, the landings and take-offs are the hardest part of any aircraft; flying at 3000 ft, there are no many things to bump on. The pilot will be strapped on, no chance of falling into the rotor. A ballistic parachute for the whole aircraft is provided. Airbags are considered, as well as retro-fuses for low speed and altitude safety.
@Zebraranger: as I mentioned, there will be no chance for the pilot falling from the aircraft, he/she will not come off the aircraft except when on the ground, rotor stopped.
@Dodsfall: the rotor is big enough for VTOL flight, the ADR-1 VTOL characteristics are similar to the Hiller VZ-1 The rotor lift is augmented, as the wing provides lift even in hover mode.
The wing span is about 12 ft, double than the "world's smallest" Stits SA-2A, DS-1, and Starr's Bumble Bee. It's a bit smaller than the Colomban_Cri-cri and Beecraft Wee Bee. We're estimating the lift per drag ratio to be between 8 to 10.

 

[Eye_m_no_angel]

What's going to power this craft?

 

[WintrSol]

Thank you for the comments, they are really helpful. The craft is planned to have augmented stabilization, especially for the VTOL flight. You are right, the landings and take-offs are the hardest part of any aircraft; flying at 3000 ft, there are no many things to bump on. The pilot will be strapped on, no chance of falling into the rotor. A ballistic parachute for the whole aircraft is provided. Airbags are considered, as well as retro-fuses for low speed and altitude safety.

I assume you mean 3000 ft AGL. Not a problem for most areas, as 3000 ft AGL is less than 5000 ft ASL. Above 5000 ft ASL, fatigue can set it fairly rapidly for one not acclimated. Riding on the Blue Ridge Parkway, a friend and I realized we needed to rest, after riding in the 6000 ft and above portions, even though it was early in the day. I'd say. unless you provide some oxygen assist, you would need an altitude limiter. Flights from Denver could be a problem, unless really short.

 

[dusan]

@Eye_m_no_angel: The first prototype will be electric as it provides a lot of control advantages. It needs about 40KW for hovering and 12KW for level flight. The electric propulsion have the extra advantage of having high efficiency at lower power setting as for level flight. A final version could be electric if designed for fun flying, or could be internal combustion powered for longer trips, marketing will decide that. My goal right now is to determine if there is any perceived value in riding such an aircraft; if I build it and perfect it, will be there enough potential users/ buyers to be a viable product, or it will be perceived as a "flying meat grinder" and nobody would want to ride one. This is basically why I'm here on this forum.
@WintrSol: I do mean 3000 ft AGL. I guess oxygen could be provided as an aftermarket add-on for advanced users, or for flying in places that requires it.

 

[SemiFast]

It would take a unique individual that would want to ride / fly that!
Not me.
And that's coming from a guy that regularly FLIES a motorcycle....




I'm not riding to fast, I'm flying to low. :smile_big:

 

[dusan]

@SemiFast: Could you provide a reason?

 

[SemiFast]

The force that attracts a body toward the center of the earth.
Gravity... lain:

 

[DGS65]

My daughter just graduated from Penn State as mechanical engineer and they had a similar school project that lets just say never got off the ground.
Best of luck with your project I think it is a cool concept not sure I have to balls to fly one but would love to watch you test it out!

 

[Offcenter]

Let me say that I just LOVE flying!
But laying on my chest like that???....with my neck bent back to see
where I'm going????
I wouldn't last five minutes in that position. I wouldn't last five minutes on
today's sport bikes either, where the rider is leaned forward with all his weight on his wrists, for the same reason. No thanks.
If it works, flying it would appeal to me....except for laying down like that.

 

[Eye_m_no_angel]

So you're hoping for a hover time of, maybe 15 minutes and a level flight time of an hour or so?

 

[Eye_m_no_angel]

It would take a unique individual that would want to ride / fly that!
Not me.

Me either.

It's interesting, but if I'm going to be flying something I want at least the hope that it can glide if something goes wrong.

 

[dusan]

@Eye_m_no_angel: It can glide alright; the estimated stall speed it's a bit under 40 kts, so it can land as a regular airplane if the electrics malfunctions.
It cannot do full auto-rotation, but it can recover energy by windmilling to recharge batteries, and do an emergency VTOL landing in case batteries are drained.

 

[dusan]

So you're hoping for a hover time of, maybe 15 minutes and a level flight time of an hour or so?

This is correct. As the hovering is so energy intensive, the idea is to limit hover time as much as possible, take-off, accelerate and transition to level flight as soon as possible. Arriving at destination, slow down and transition to hover and land without loosing too much time. Probable the whole time spent in hover and transition is only few minutes.

At any speed under 40 kts (46 mph) the rotor needs to provide direct lift, as the wing is unable to provide full lift anymore. The rotor needs also to provide enough thrust to counterbalance drag, which is also high at slow speed, as the wing has a high angle of attack. The rotor angle, wing position and other parameters are optimally set continuously by a flight controller based on measured flight data, so the pilot doesn't need to trouble himself with such details, piloting is transparent, seamless and intuitive.

 

[WintrSol]

What I'm hearing is it will be an expensive toy for someone who has, or can get, a pilot's license, and fly around his/her neighborhood for a while.