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SureFly – a personal helicopter designed for safe and easy flight

workhorse.com

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Re: SureFly – a personal helicopter designed for safe and easy flight

#141

Post by mveety »

jimbob21 wrote: post #140
Balgair wrote: post #137

Earlier quoted context omitted.

As any pilot knows, the stomach unfriendly words from Tower are: "Caution, Wake Turbulence". The air, being a sparse fluid, can change fast. Especially so if another aircraft has flown through it recently. It's not that there isn't anyone there, it's the air they left behind is all non-laminar now. Doubly being suddenly downwind of stationary objects like towers, wind farms, and mountains. Also, quick point of cautio…

It comes with a parachute

Which doesn't help at all when you hit wake on final. Chutes take a surprisingly long time to grab the air and slow you down.

Re: SureFly – a personal helicopter designed for safe and easy flight

#142

Post by rotten »

oliv__ wrote: post #19

A part of me thinks this is really cool tech and it would be amazing for anyone to be able to just hop aboard their personal helicopter and fly wherever they want, but then another part of me thinks of the future this would create, skies no longer clear, filled with objects buzzing around and what hell that would be, on top of the already stressful and crazy life we have now. It's the kind of situation where I think…

I wouldn't worry. Most people can't afford $200K cars that burn an entire tank of gas an hour.

Re: SureFly – a personal helicopter designed for safe and easy flight

#143

Post by nradov »

markbnj wrote: post #42
oliv__ wrote: post #19

A part of me thinks this is really cool tech and it would be amazing for anyone to be able to just hop aboard their personal helicopter and fly wherever they want, but then another part of me thinks of the future this would create, skies no longer clear, filled with objects buzzing around and what hell that would be, on top of the already stressful and crazy life we have now. It's the kind of situation where I think…

On the other hand think about the positives: all the terrestrial traffic and distributed refueling and service infrastructure that might no longer be needed; it would revolutionize everything from personal transportation to shipping and logistics. And yeah it would require a vastly enhanced and much more autonomous traffic control system.

These helicopters still require refueling. In fact they're generally going to be less fuel efficient than passenger cars, even after accounting for traffic delays and routing.

Re: SureFly – a personal helicopter designed for safe and easy flight

#144

Post by nradov »

zaroth wrote: post #133
Animats wrote: post #122

Yet another really big personal quadrotor-type drone. Its a lot like the eHang 184, from 2016.[1] That flies, but they don't trust it with a live passenger yet. Here's one with a passenger, but they don't want to get any altitude.[2] There are five or six projects like this. Few have flown with a human on board yet. [1] https://www.youtube.com/watch?v=qPARvS31Oq0 [2] https://www.youtube.com/watch?v=V3pi4HfQ0Gc

If they wanted to prove the design, why can't they offer package delivery services with the drones and ramp up volume to at least 100 flights a day until it's proven?! If they've proven it works, they should get the money necessary to test it and deploy it. They need to get to market and see if it sells. I think the problem is crashing over populated areas, even if it's not occupied? Hard to make deliveries if you ca…

It would be difficult to get FAA approval to offer cargo delivery services with a large drone due to the risk it would pose to manned light aircraft flying under VFR. They would have to carve out controlled airspace in a specific area and temporarily ban VFR flights there.

Re: SureFly – a personal helicopter designed for safe and easy flight

#145

Post by nradov »

throwawayjava wrote: post #9
wanderfowl wrote: post #5

Wait: - Curb Weight: 1100lbs - Max Takeoff Weight: 1500lbs So... you, your passenger, and any cargo combined can't weigh more than 400 pounds? That's a pretty serious limit for people hoping to transport multiple adults. And "precision agriculture" or the sorts of practical uses they discuss all go right out the window.

The BMI chart maxes out healthy weights at 192. So unless you have two NBA players or something, it should work well for most but perhaps not all healthy people.

What chart are you looking at? BMI is based on height, so someone 6'4" tall has a normal healthy weight range up to 205lbs.

Re: SureFly – a personal helicopter designed for safe and easy flight

#146

Post by dragonwriter »

calchris42 wrote: post #36
wanderfowl wrote: post #5

Wait: - Curb Weight: 1100lbs - Max Takeoff Weight: 1500lbs So... you, your passenger, and any cargo combined can't weigh more than 400 pounds? That's a pretty serious limit for people hoping to transport multiple adults. And "precision agriculture" or the sorts of practical uses they discuss all go right out the window.

400 lbs capacity for passengers / cargo is in line with an R22, a common 2 seater helicopter (389 lbs for Pilot, Passenger and Baggage). However the SureFly situation is likely worse than that. Typically the empty weight does not include fuel weight, which might be another 100 lbs. It seems that SureFly has designed an aircraft with less than half the range of an R22, that can't autorotate, and costs roughly the same…

> However the SureFly situation is likely worse than that. Typically the empty weight does not include fuel weight

Empty weight does not typically include usable fuel, but curb weight, which is what is cited here, generally does (though it's not a figure usually, IME, specified for aircraft).

Re: SureFly – a personal helicopter designed for safe and easy flight

#147

Post by nradov »

foxyv wrote: post #82
euyyn wrote: post #44

How am I supposed to "store it inside a standard garage" if it doesn't have wheels to move it in?

A lot of light helicopters are transported on dollies or trailers.

Robinson light helicopters have mounting points on the skids where you can temporarily attach small wheels to move them around on the ground.

Re: SureFly – a personal helicopter designed for safe and easy flight

#148

Post by asterius »

JasonFruit wrote: post #22
advisedwang wrote: post #11

I'm very skeptical of their claims of "unparalleled safety". Thanks to "autorotation"[1] regular helicopters can safely land in most situations even with complete power failure. The claims of safety of this craft seems to derive from N+1 battery redundancy which isn't that impressive. They say they have 8 independent motors, but don't say how many are needed to stay aloft. [1] https://en.wikipedia.org/wiki/Autorotati…

Could it be because autorotation requires a skillful, vigilant pilot, and the redundant systems of this machine help avoid urgent need for it?

Autorotation is often taught after only 8 hours of training. It is very feasible to have an AFCS that will do an autorotation, but it is harder to find a place to land.

Re: SureFly – a personal helicopter designed for safe and easy flight

#150

Post by asterius »

SideburnsOfDoom wrote: post #2

What is the benefit of more, smaller rotor blades over fewer, larger ones? I thought that the area of air that the blades worked on scaled with pi-r-squared, which favours fewer larger rotor blades, as seen on most helicopters?

You are correct, much better lift, speed, economy from a single large slower moving rotor (or a pair of counter-rotating blades, cost/benefits described in other posts).

The reason all the cheap drones use 4 or more engines is that they can individually be very simple, with the motor directly driving a rotor. With no swashplate to alter blade pitch the mechanism is very simple. Short blades are easy to make for a required strength and stiffness, and the torque of electric motors is sufficient to rapidly change rotor speed to change lift for steering. The control system is simple. However efficiency is terrible, both in terms of lift, and maneuvering.

The energy to change blade speeds constantly to maintain attitude is a significant cost. But having low rotational inertia, frequent changes are required, especially in windy conditions. As blade diameter increases (and hence inertia) the resulting energy costs to change speed increase too, as does the size/power/weight of the motor.

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