
Human-Powered Helicopter Wins the $250,000 Sikorsky Prize - comatose_kid
http://www.popularmechanics.com/technology/aviation/diy-flying/finally-a-human-powered-helicopter-wins-the-250000-sikorsky-prize-15682369
======
iandanforth
For much more detail on the design I recommend the Draft FAI World Record
Claim they are submitting.
([https://dl.dropboxusercontent.com/u/5093348/Draft%20Atlas%20...](https://dl.dropboxusercontent.com/u/5093348/Draft%20Atlas%20World%20Record%20Claim.zip))

Interesting tidbit:

"The pedaling of the pilot pulls on and reels in four Vectran cords, which are
pre-spooled onto each of the four rotor hubs. The action of unspooling the
cord and pulling on the rotor hub drives each rotor to overcome the drag
force."

~~~
curveship
Thanks for the link! Lots of interesting info:

Empty Weight: 55.1 kg All-Up Weight: 130.1 kg Flight Power (0.5 m): 450 W
Flight Power (3 m): 750 W

I wonder if those wattage numbers are estimates or measurements.

~~~
curveship
Replying to self, as I just noticed (awesome!) they included a power chart for
the record flight.

About 1kw for the first 12 secs, then settling down to 600w for most of
remainder. That's a boss ride, especially for a 70kg rider. Dude's a monster.

~~~
davidjohnstone
That's very impressive.

To put that into perspective, that's a chart[1] that some exercise scientists
have put together that shows what power cyclists of varying levels tend to be
able to produce. The data in the spreadsheet gives an average power of 708W
for a minute, which equates to 10.1W/kg at 70kg, which puts him at the level
of a category 1 racer or domestic pro.

Keep in mind that the ~1000W spike for 10s at the start of the ride probably
harms the overall average, as a more constant power output generally leads to
a higher overall average (or, higher power outputs are disproportionally
harder).

Edit: according to the photo gallery in the article, Reichert is a nationally
ranked speed skater in Canada, which is another one of the "big quads" sports.

1\. [https://s3.amazonaws.com/cyclinganalytics/static/cycling-
pow...](https://s3.amazonaws.com/cyclinganalytics/static/cycling-power-
table.png)

~~~
spullara
I think that he had to spike at the beginning to get up to the 3m mark and
then could "coast" at the lower value to stay level.

Edit: spelling

~~~
davidjohnstone
Yes, there's a chart that shows power and height vs. time, and it certainly
looks like that was the case. I bet it didn't feel like coasting though :-)

------
ChuckMcM
The shape of things to come I suspect. While folks talk about blimps and what
not there is value to having "permanent" points of presence in the air above,
be it a communications node, surveillance node, or early warning theatre
defence. 'Human powered' is a good predictor of 'solar powered' since the
total energy extractable from humans per pound payload is lower than solar.
Thus if you're doing the calculus for keeping something up 24x7, this is a
good indication you are close.

~~~
scoot
>the total energy extractable from humans per pound load is lower than solar

Whilst that may be true, don't forget that the energy output is in kinetic
form, so for comparison you'd need to factor in the weight of motors, and for
a "permanent" presence, some form of energy storage for night time use (and
batteries are far from light!)

~~~
ChuckMcM
Yup, now do the math.

1 sq meter of monocrystalline cells (approximately 2kg) deriving about 166W/hr
over a 6 hr solar "day" (1000 W.hrs) stored in LiFePo batteries (about 1kG/100
W.hrs) so 10kg of betteries, with .5 kg of electronics (battery charger) and
wires, delivered over 24hrs or 12.5kg/41watts continuous. Human athelete lets
call it 165 lbs, so 75kg, or 6 * 12.5 or 246 continuous watts over a 24hr
period, or a total of just over 5.9Kwh per 24hr period.

So basically anything a human can power, an equivalent mass of solar power
infrastructure can power. The interesting bit is of course that you can use it
all at once (like a human sprint) or spread it out over time. It will have
more surface area however which often limits the ability to just swap solar
cells for other forms of power.

~~~
scoot
I did:

Your batteries have to provide 600W continuous for 18 hours (actually more as
that was the power needed for a controlled decent), and your solar panels have
to provide that same energy in your 6 hour 'solar day'. In addition, the solar
panels would need to provide another 600W for 6 hours in order to run the
motors whilst charging the batteries.

So that's 10.8KWhrs of batteries, and 2400W/hr or 14.5sq m of solar panels.

That translates to 108KG of batteries and 29KG of solar panels using your
weight to power ratios - 137KG in total, compared to the rider at 75KW, so
your 24 hour solar bird is a sadly flightless before even adding motors,
gearboxes electronics and cabling.

~~~
ChuckMcM
Can you say more about how you got the 600W number?

~~~
scoot
There's a power / height chart in the world record claim form (as well:

[https://dl.dropboxusercontent.com/u/5093348/Draft%20Atlas%20...](https://dl.dropboxusercontent.com/u/5093348/Draft%20Atlas%20World%20Record%20Claim.zip)

More considerations are the additional power needed for control inputs and to
resist wind, and to compensate for thinner air at altitude, and the weight of
a craft strong anough to operate outdoors.

------
msandford
It was only a matter of time until the materials got good enough for this to
happen.

I'm always surprised that these teams never seemed to try and recruit pro
athletes for this kind of thing. I've got a friend who's a professional
cyclist and his 30 second power rating is something like 1100 watts and I'm
sure at a minute it's only degraded by 50-100 watts.

~~~
fuzionmonkey
From what I remember, pro cyclists are simply too expensive.

It's better to have an amateur who is 80-90% as good as a real pro, but is
genuinely interested in the project and would be more dedicated than a hired
pro.

~~~
jlgreco
Genuine question: what are pro-cyclists generally spending their time doing?
Are they in races or ramping up / recovering from races all year?

If they have downtime I don't see why you couldn't find a pro that is
genuinely interested in what you're doing.

~~~
JackGibbs
Most top tier pro cyclists clock 25000-35000 miles a year on their bikes, and
race 80-140 days a year. Other than that, the job is mainly sitting around
recovering. Although cycling is an incredibly complex sport, on the level of
gridiron football or basketball in terms of the number of calculations that
have to be made as part of tactical decisions, the longer-term playout of
actions (at least in long road races) means that riders and their sporting
directors (think coaches) have time to think about their decisions, and that
combined with how much of racing is done on feel means there isn't the same
need for things like film study and in-depth tactical coaching on a daily
basis.

------
rdl
Is there a good overview of materials improvements over, say, the past 150
years? It seems like one of the areas, along with IT and biotech, which has
had huge gains even in the past 20 years, contrary to the "end of innovation"
thesis of Thiel et al. You can get carbon fiber in _everything_ now, ceramics
are more used in things other than pottery, and companies like Crucible made a
lot of awesome steels (including...cast stainless steels!) from the 1970s to
now. Sure, the properties don't get 10x better, but a 1% improvement in
strength-at-2000C for the blades makes a jet turbine a lot more efficient.

~~~
durkie
(i'm a material scientist by training and by trade (up till a month ago))

to me, the history of materials improvements is the history of materials
characterization techniques.

so much of materials science is just trying to figure out the right lever to
pull to control some property, and modern tools like electron microscopy,
tga/dsc, xps, afm, bet, etc. all provide amazing insight that was simply
unavailable 150 years ago.

but also, 150 years is a really long time frame. people were only just
beginning to study material fatigue in the mid 1800s.

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makmanalp
Wow, I love that the blades seem to be spinning so slow, yet it all works.

Exciting times to be a human.

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thetwiceler
This is really cool!

On a similar note, for those of you who may not be aware, there has also been
a human-powered airplane:
[http://en.wikipedia.org/wiki/Gossamer_Albatross](http://en.wikipedia.org/wiki/Gossamer_Albatross)

I am totally amazed by the Gossamer Albatross. It was made in 1979. And here's
the most awesome part - a cyclist flew it across the English Channel!

------
incision
Interesting that Aerovelo won this. As I recall, they were the only contender
_not_ using electronic assists which were set to become invalid this month:

 _' With the pilot using both hands and feet to power the aircraft, UMD faced
a challenge developing a control system for the Gamera II. But an attempt to
clarify the rule prohibiting energy-storage devices inadvertently opened the
door to electronic controls being used on both the Gamera II and Upturn II.

AHS has closed the loophole, but both teams have until July to attempt winning
the prize under previous rules._[0]

0:
[http://www.aviationweek.com/Article/PrintArticle.aspx?id=/ar...](http://www.aviationweek.com/Article/PrintArticle.aspx?id=/article-
xml/AW_03_04_2013_p68-553183.xml&p=1&printView=true)

------
michael_miller
To me, this is really cool, since presumably it means the materials have
gotten light enough for an electric helicopter to become a reality (beyond the
crappy Firefly project). Imagine what it would be like if you could commute
from the suburbs of NY to the downtown heliport without paying for fuel or
expensive maintenance. It could transform the way people commute to work,
eliminating traffic and the effect of accidents.

~~~
pavel_lishin
> It could transform the way people commute to work, eliminating traffic and
> the effect of accidents.

Hopefully, the same people who are causing the accidents in cars won't be able
to directly control the helicopter.

A car wreck slowing traffic down to 10% on a freeway is preferable to death
looming from the sky because someone really needs to check twitter right now.

~~~
lmm
It's a lot easier to avoid hitting anything in the air, because there's a lot
more space up there, and a lot more directions in which to dodge. During the
war we sent teenagers with <20 hours of training to fly in combat (and while
many of them died it wasn't because they were crashing into each other or the
ground).

~~~
nknighthb
It's not so simple. A worst-case scenario for a flying car might be nose-down
terminal velocity into a crowded building. Or even faster, if the driver were
deliberately accelerating into the building, trying to use the car as a
kinetic weapon.

Scheduled commercial airline flights are quite safe, which makes people think
"flying is safe", but general aviation, which lacks many of the strong
controls that scheduled airlines have, is much worse[1]. I would expect flying
cars under manual control of typical drivers over a crowded city to be much,
much worse still.

[1]
[http://www.ntsb.gov/news/2012/120427.html](http://www.ntsb.gov/news/2012/120427.html)

------
psb
Is cycling the most efficient way to extract power from human muscles? I would
guess something like deadlift/rowing motion to be better

~~~
pge
for sustained power output of any duration, pedaling a fixed gear crank is
about as good as it gets for getting power out of a human body. See Bicycling
Science by David Wilson, MIT Press, for some interesting quantitative
analysis. As an example to address your specific suggestion of rowing, compare
a rowing scull with the Decavitator (MIT built pedal powered boat).

Edit: Corrected typo noted below - "skull" to "scull" \- oops.

~~~
Someone
The huge speed difference with a single scull probably has more to do with
inefficiencies in 'the drive train' (moving your weight around in a rowing
shell introduces dipping, which loses energy; using oars is less efficient
than using a propeller) than with inefficiencies of the rowing motion vs a
cycling motion.

[http://rowingbike.com/site/EN/](http://rowingbike.com/site/EN/) shows a bike
operated using a rowing motion. That machine is competitive with 'normal'
recumbent bikes, except in climbs. The main parts also could be fitted on that
Decavitator. I would expect similar speeds.

~~~
pge
Interesting point - it may be that rowing is comparable to biking in power,
but the ease of building a cycling drivetrain generally wins out for projects
like this, because the parts are readily available in any bike store (the
cockpit of the copter here is an off-the-shelf bike frame and crankset
attached to the spools).

------
WestCoastJustin
Here is the official release [1], their homepage also have a great video of
what looks like the successful run [2].

As one of the people that donated to the Kickstarter this make me very happy!

[1] [http://www.aerovelo.com/2013/07/11/aerovelo-officially-
award...](http://www.aerovelo.com/2013/07/11/aerovelo-officially-awarded-ahs-
sikorsky-prize/)

[2] [http://www.aerovelo.com/](http://www.aerovelo.com/)

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oh_teh_meows
It is possible, perhaps through a clever arrangement of gears and what not, to
create a human powered copter that can create sufficient lift with just one
rotor?

~~~
b_emery
Interesting question. Seems like they have a lot of weight in the
superstructure that would be removed with a single blade (and tail rotor).

~~~
starpilot
You lose weight in the external structure, but you'd gain some back in
stiffening the blades to prevent excessive blade deflection (you'd have one
big rotor instead of four small ones). You could also stiffen with external
tension cables, but these rotate with the blades and would incur drag
(streamlined wires were invented for this reason, also bicycle wheel disk
covers) and disturb the axial flow. It's all about tradeoffs.

\- former HPH member

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peteretep
I wonder if this will be like the four minute mile ... now it's been achieved
a little, people will smash it, and my helicopter is on its way soon...

~~~
marvin
I would be willing to bet that this will never make its way into a consumer
product or even a hardcore hobbyist product. Even human-powered winged flight
is on the borders of what is anatomically and physically possible, and
helicopters are even farther out on the feasibility scale. It's cool for a
proof of concept, but you won't be able to improve this design by an order of
magnitude even with weightless materials.

~~~
bigiain
True, but my ~$120 quadcopter has about 80% of the power this thing needs to
climb to 3m. There are people out there building human carrying scaled-up
hobby quadcopters (well, hexa or duodec or hexadec copters).

I suspect there are (other) people out there now thinking things along the
lines on "Hmmm, made from balsa and foam covered in poly film, prepreg carbon
tube, kevlar tow, epoxy and cyano. All pretty common high-end but regularly
homebuilt model plane techniques. 10m long rotor blades are big - but only 2
or 3 times longer than pretty common competition rc glider wings. There's a
very reasonable chance that the right group of comp rc glider builders and
quad rotor hobbyists could build something that weighs maybe only twice what
this does, and has 5 or 10 times as much power available - probably for a
budget of not much more that $10k."

I don't think "hardcore hobbyists" will be pedaling one of these anytime soon,
but flying something similar electrically is certainly not an impossibility.

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sadfaceunread
Pretty cool result. I'd wonder what the performance would be with ~150 lb of
batteries, motors and electronic sensors/controllers instead of a human. I
wonder if given the same mechanics of this system a human is the optimal motor
just because of the built-in automation and control system (probably not).

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jtchang
Nothing short of astounding. Some people didn't think it could be done. And
now we have something that truly proves it.

What's next? Lighter materials? I'd love to play around with something like
this and not have to be a world class cyclist.

~~~
jrblast
For "What's next?" I would hope for something smaller. Impressive as this is,
it's way to big to be practical. I suppose lighter materials could help reduce
the size though.

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methehack
Awesome! It's inspirational to see people attempt something they're not sure
they can do, work hard for a good while, and finally do it. Just what I needed
to start the afternoon!

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farinasa
This doesn't actually seem to be a helicopter. It looks like a multicopter.
There is a significant function and theoretical difference.

