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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

#51

Post by pc86 »

pdelbarba wrote: post #39
neurotech1 wrote: post #30

Earlier quoted context omitted.

Small "personal" helicopters like the Robinson R22 are quite difficult to autorotate safely in a real emergency, due to low rotor inertia. [0] For the SureFly, Hypothetically if loss of several motors caused the aircraft to be unable to maintain altitude, the aircraft would not suddenly drop like a brick, but drift down to a controlled landing. [0] http://philip.greenspun.com/flying/robinson-r22

No, worse. That thing would turn into the tumble dryer from hell with partial power. It has no blade pitch control (like a helicopter does), requiring power on the motors in all four corners to maintain stability. The real emergency situation to worry about would be a total power failure. Failure of the individual electric motors will likely be extremely rare but a battery fire or controller failure could send this t…

BRS parachutes have been tested as low as 260' AGL at 187 knots (several times faster than this craft would ever go) and individuals have reported successful deployments below 100' AGL[0] The question of course is how quickly it can be deployed in this craft as the vertical speed will likely be much faster than a Cessna or Cirrus in the event of total power failure.

[0] https://www.flyingmag.com/g00/how-it-works-brs-aircraft-para...

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

#52

Post by cryptoz »

throwawayjava wrote: post #29
Amorymeltzer wrote: post #12

Earlier quoted context omitted.

Average weights (no median, sorry) from the CDC ( https://www.cdc.gov/nchs/fastats/body-measurements.htm ): >Men: 195.7 pounds >Women: 168.5 pounds So this could carry an average man, average woman, and under 36 pounds. At that point, the weight of your clothing or a bottle of wine becomes very important.

Yes, I did say healthy , which a good half of the USA isn't. but that still implies a 100m person market, just in the USA, and people in other developed countries tend to be closer to the "healthy" range. There are lots of healthy people out there. In short, I don't think this will be the make-or-break for flying cars...

> a 100m person market

No, not really. Only extremely wealthy people can buy this. It's more like a 10,000 to 100,000 person market in the US I would guess.

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

#53

Post by Hasz »

hangonhn wrote: post #45

Can anyone verify if this thing is actually built and not just some rendering? The shallows in some of their pictures don't seem right so I was wondering if those are pictures of an actual craft or just a Photoshop.

There is a video of it at a trade show on YouTube. The craft definitely exists, whether or not it flies is a different question.

https://www.youtube.com/watch?v=Ll-3jDTibSQ

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

#54

Post by Shivetya »

dumb question, but why would it not be a good idea to enclose the blades so anyone walking up to it won't be hurt? (just a simply loop / bumper arrangement?

on a side note, I hope to be around where a Blade Runner like Spinner is a thing or at least a possibility

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

#55

Post by FabHK »

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…

Electric motors are less complicated and more reliable than piston engines (as in small helicopters), I'd say (not sure about turbines). And then there's the ballistic parachute rescue system, though of course there's a minimum altitude you need for that.

The Volocopter (a competing concept that actually exists and has had manned flights since 2016) has 18 rotors (six arms with 3 rotors each in a single plane), opposite rotors driven by the same battery/drivetrain ensemble, from what I gather, and remains controllable with up to 3 rotors (at least) faulty.

I'd hope well engineered aircraft of this sort will surpass safety of traditional helicopters, but let's see.

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

#56

Post by FabHK »

zellyn wrote: post #32
mrfusion wrote: post #25

Earlier quoted context omitted.

Should be four or less considering each arm has two props. (Unless the motors aren’t powerful enough)

If all four on one side went out, I assume you'd be in big trouble.

I'd imagine if two stacked ones go out, you'd be in trouble (as the centre of gravity will not be exactly in the intersection of the two diagonals).

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

#57

Post by Zak »

bergesenha wrote: post #15
dzhiurgis wrote: post #4

I thought gasoline turbine generators are sort of here (used in hybrid buses), womder why they stuck with piston generator. Also, any ideas what battery pack you’d need to do the same 70miles?

My best guess is fuel efficiency at small size scales and is probably the same reason that make them economical in large buses, but not small cars. The usual intuition is explained using the Reynolds number, a dimensionless quantity that can help to predict the possibility of maintaining laminar flow or wether the flow breaks down into turbulence in the generator, drastically reducing efficiency in the compression-co…

It's my understanding that most gas turbine engines can be convinced to run on a wide range of flammable liquids, with some impact to performance and longevity. That the AS350 is actually designed to do so is interesting.

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

#58

Post by pdelbarba »

pc86 wrote: post #51
pdelbarba wrote: post #39

Earlier quoted context omitted.

No, worse. That thing would turn into the tumble dryer from hell with partial power. It has no blade pitch control (like a helicopter does), requiring power on the motors in all four corners to maintain stability. The real emergency situation to worry about would be a total power failure. Failure of the individual electric motors will likely be extremely rare but a battery fire or controller failure could send this t…

BRS parachutes have been tested as low as 260' AGL at 187 knots (several times faster than this craft would ever go) and individuals have reported successful deployments below 100' AGL[0] The question of course is how quickly it can be deployed in this craft as the vertical speed will likely be much faster than a Cessna or Cirrus in the event of total power failure. [0] https://www.flyingmag.com/g00/how-it-works-brs-…

I can't imagine an inverted deployment at 100' would end well...

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

#59

Post by iamleppert »

I'm skeptical of a company that is doing so many different projects, and none of them seem particularly well developed, far along, or consistent within the framework of some core vision.

That being said, I'm jealous. Where do people actually get money to finance these pet projects?

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

#60

Post by danaliv »

dmitrygr wrote: post #33

> 1 hour of fuel > 70 mph speed This means that the maximum legal range with FAA-mandated fuel reserves is 46 miles (assuming no wind). Also despite shots of it on a driveway, it would most likely be impossible to actually take off or land on your driveway due to local ordinances in most cities. Oh and it doesn't appear to be properly equipped for IFR, so clear weather operation only.

Rotorcraft fuel requirements are different from airplanes. Under VFR it's first intended point plus 20 minutes, day or night.
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