
MIT’s gas-powered drone is able to stay in the air for five days at a time - janober
https://techcrunch.com/2017/06/27/mits-gas-powered-drone-is-able-to-stay-in-the-air-for-five-days-at-a-time
======
projectramo
At first I thought the kicker was going to be: the gas is helium, it just
floats.

And then I thought: why is that a joke? Could you save fuel keeping it aloft
with a lighter than air gas and just use the fuel to move it around?

~~~
PatentTroll
I think you just invented the dirigible?

~~~
projectramo
Ha, yes.

I guess another way to phrase the question would be: why don't they use
dirigibles to solve extended air time problems?

~~~
mikeash
Dirigibles require huge volumes, because the lifting power of gas is small.
Those huge volumes make for a relatively weak, slow, and difficult-to-maneuver
craft. A big reason why airships disappeared in favor of airplanes was that
airships had a really tough time handling or avoiding bad weather because of
these limitations.

~~~
jp555
I have a blurry recollection of seeing an aircraft design that was a
combination of an airplane and a dirigible. It looked like a poofy manta ray,
an inflated rigid lifting body or flying wing. It wasn't quite VTOL & needed a
very short runway, but it also gained more maneuverability in flight. Maybe it
was too much of a compromise though.

~~~
astebbin
Could it be this one [0], or its predecessor [1]?

[0] [http://www.latimes.com/business/la-fi-lockheed-martin-
aircra...](http://www.latimes.com/business/la-fi-lockheed-martin-
aircraft-20160308-story.html) [1]
[https://en.wikipedia.org/wiki/Lockheed_Martin_P-791](https://en.wikipedia.org/wiki/Lockheed_Martin_P-791)

------
emmelaich
Just goes to show there's nothing remotely like fossil fuels for energy
density.

~~~
schiffern
> Just goes to show there's nothing remotely like _organic molecules_ for
> energy density.

GTFY (generalized that for you). ;)

It's all about the energy in that carbon-hydrogen bond. Lipids have a similar
energy density, which is why migrating birds have a similar nonstop range as
fossil fueled airplanes (11,000 km vs 14,000 km for the 747 long range
variant).

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864269/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864269/)

~~~
traviscj
Reminds me of Fight Club's premise, but with a different output.

Not sure a tiny biodiesel internal combustion engine is a very suitable power
source for laptops, though. :-)

~~~
honestoHeminway
[https://www.toshiba.co.jp/about/press/2009_10/pr2201.htm](https://www.toshiba.co.jp/about/press/2009_10/pr2201.htm)

Exists. Stop disguising your nostalgia as future entusiasm :D

~~~
traviscj
Really cool, thank you for sharing! Would totally be interested in buying one,
if you happen to have a stockpile :-)

------
jobu
That's neat, but not very revolutionary. The Rutan Voyager flew for 9 days
(around the world) without refueling back in the 80s -
[https://en.wikipedia.org/wiki/Rutan_Voyager](https://en.wikipedia.org/wiki/Rutan_Voyager)

~~~
wyldfire
That craft had two pilots onboard, this one had a single remote pilot. It's a
real challenge to design a small craft that maximizes payload and minimizes
fuel consumption along with scores of other constraints.

Voyager also needed a long runway for launch and probably costs vastly more
than this drone. Its use case as an emergency communication device is
revolutionary.

~~~
Camillo
It seems that not having to have pilots onboard would make things easier,
though.

~~~
nols
This is meant to be portable, weighing only 150 with fuel and payload.

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Abishek_Muthian
To be frank, for the non-Americans who read the article; the first thought
would be that the drone is actually using some form of 'gas' and not liquid
petroleum. I presume 'gas' in this context means gasoline and not LPG.

~~~
chenster
It definitely perplexed me until the word "gasoline".

------
rdiddly
Well they inadvertently proved once again just how energy-dense and how
incredibly ridiculously efficient liquid petroleum fuels are and what a boon
and a curse they've been to humanity during this brief one-or-two-century
blip, and how difficult it will be to replace them with anything that could
even come close to current levels of energy output/consumption.

(That's a problem statement, not an ad.)

~~~
walrus01
If you have a truly ridiculous amount of electricity, such as from a multi-
megawatt scale photovoltaic system that was almost free to install, or from a
theoretical very high power/low cost nuclear reactor... You could electrolyze
seawater into hydrogen and store it in tanks. Doesn't necessarily have to be
fossil fuel.

The watthours per amount of hydrogen stored are ridiculous, but as giant scale
photovoltaic becomes commonplace, it might be possible.
[https://en.wikipedia.org/wiki/List_of_photovoltaic_power_sta...](https://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations)

Cover a 20 x 20 km section of Libyan desert with ground mount 360W PV panels,
there's your power source.

~~~
kogepathic
_> Cover a 20 x 20 km section of Libyan desert with ground mount 360W PV
panels, there's your power source._

Sure, but first you need to find a desert in a relatively stable country, and
then you have to account for the fact that the panels will need to be cleaned.

UAE is building lots of solar, if you've been through DXB or AUH you've
probably seen the Total [0] ads for solar. However I know from personal
experience that even in the desert you need to have methods to clean the
panels or they will be covered in dust/sand after some time, and this
significantly reduces their output. [1]

[0] [http://www.total.com/en](http://www.total.com/en)

[1]
[https://en.wikipedia.org/wiki/Cleaning_event](https://en.wikipedia.org/wiki/Cleaning_event)

------
pj_mukh
Confused. There seem to be plenty of drones that can stay up there for 120
hours or so [1]. Presumably, their solar additions should be able to do even
more?

[1]: [http://www.airforce-technology.com/features/featurethe-
top-1...](http://www.airforce-technology.com/features/featurethe-
top-10-longest-range-unmanned-aerial-vehicles-uavs/)

~~~
pdelbarba
Precisely. This is an incredibly easy problem to solve. See all the Rutan
projects, the model plane that crossed the atlantic, etc; most from over a
decade or more ago.

They claim that solar efficiency is not there yet, but look at the NASA
Helios. Yes, it's large, but such is life if you want solar. The math behind
it is incredibly simple.

Yet, as usual, HN is foaming at the mouth because it has the word drone in the
title.

Edit: this is just another MIT fluff piece. Watch the video, it's a carbon
fiber tube filled with random COTS hobby grade components. With a hot wire and
some composites knowledge you could make this in your garage.

~~~
lochieferrier
NASA Helios was quite expensive and tricky to build, with not a lot of margin
left for useful payload.

There's a weight runaway that occurs with solar powered aircraft, look at Fig
12 in this report:
[http://hoburg.mit.edu/publications/gassolar.pdf](http://hoburg.mit.edu/publications/gassolar.pdf)

Disclaimer: I worked on this project, so am super biased.

~~~
throwawaycrank2
Please read the next four paragraphs.

Could you kindly reply with your email, as I would like to email you. I am a
crank inventor (no but keep reading, just three and a half more paragraphs!)
who has invented something similar to a free-energy machine, except in the
field of aviation and specifically renewable energy flight, where free power
is in the skies for anyone so it's not totally cranky. After all you just
wrote a 27-page draft about it. (By the way your paper is very solid and
prominently describes in detail several trade-offs that I address specifically
through a different mechanism; you are the real deal.)

I would like to work with a collaborator (such as yourself) and then patent
and license the technology. Specialist patent offices I contacted said that
they would have a conflict with their existing large clients Boeing etc, and
for this reason cannot work with me.

On the other hand if they do not have this experience it is kind of a
catch-22. Your personal resources and if appropriate (if it works) your
resources at MIT would alleviate this issue.

We can discuss the rest by email. I look forward to your reply. It will not
take much of your time to make a determination. I promise it will be
interesting and well-specified (usually crank inventors misuse common
terminology, don't correctly understand the principles they use, and are vague
and underspecified, committing logical errors and non-sequiturs to arrive at
their mechanism - this isn't like that.) Thank you!

~~~
toss1
OK, two obvious questions.

What is the general range of weight vs power levels are you producing with
your device (that wouldn't reveal anything about the tech, only what sort of
craft it might suit)?

What is the range of scales at which this device will work (what is the
smallest, largest, optimum range for the device)?

------
arikr
Does anyone know where the US Airforce posted the challenge?

Is there a good repo for all of the US Govts challenges/requests (e.g. DARPA
ones + others like USAF?)

------
flyGuyOnTheSly
Very impressive.

I was quick to look up how long The Spirit Of Butts' Farm [0] was in the sky
for, only 36 hours.

In 5 days, assuming MIT's model held a similar speed, it could probably
circumnavigate the globe.

[0]
[http://news.nationalgeographic.com/news/2002/08/0805_020805_...](http://news.nationalgeographic.com/news/2002/08/0805_020805_transatlantic_2.html)

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dougmany
Curious how they used gpkit for the design, I found this:
[http://gpkit.readthedocs.io/en/latest/examples.html#simple-w...](http://gpkit.readthedocs.io/en/latest/examples.html#simple-
wing)

~~~
lochieferrier
Code is here: [https://github.com/hoburg/jho](https://github.com/hoburg/jho)

------
jacquesm
There is no way a gas powered drone will help bring internet access to some
remote area.

Why do these press releases always include the most farfetched goals?

~~~
jandrese
It will bring internet, but only to the US Army as it trundles across the area
and needs an over the horizon repeater to get the signal back to the uplink
station.

A 5 day duration manually operated drone is clearly not going to provide long
term service.

~~~
Gravityloss
Why not? They've done television broadcasts from circling B-29's ffs. This is
quite a bit more efficient, to say the least.

~~~
jandrese
Your example is from 70 years ago, and it proved to be impractical.

------
rebootthesystem
I'm sorry to have to be negative on this. I look at a bunch of this stuff that
is DOD/Armed Forces funded and all I have seen for decades are nothing less
than what I would call scams. Total waste of taxpayer money. And this isn't
universities only, it's companies that win stupid-as-fuck "research" grants
and produce crap in return.

There are a few companies out there playing with what are nothing more than
ridiculously expensive toy RC planes (< 6 ft wingspan) that almost anyone
could build out of parts available in the open market.

This MIT thing is nothing less than an overgrown model airplane. It uses what
looks like a stock 4 stroke model airplane engine with a stock model airplane
propeller. It probably uses stock model airplane servos, electronics and 2.4
GHz TX/RX.

Oh, wait, advanced materials. Nope. I have been designing and building RC
airplanes as a hobby for three decades. I was vacuum-bagging large (12 foot
wingspan) glider wings from fiberglass, carbon fiber and also Kevlar twenty
years ago. I still have and use my vacuum bagging setup to build planes today.
I have also made custom carbon fiber propellers by CNC machining aluminum
molds and stuffing them with epoxy impregnated carbon fiber rovings.

So, this is what I would call "advanced hobby" stuff.

Special airfoils? Nah. Any serious RC glider pilot who has built planes knows
what airfoils to use. Not a secret. These guys didn't do anything special on
that front.

Oh, but it can be taken apart and stuffed into a box for FedEx shipping. Guess
what, so can any large scale RC glider. Nothing new there. Make the wing in
six foot sections and you are golden.

Yeah but...

Yeah but nothing.

Here's a guy flying an OFF THE SHELF 6 meter wingspan RC glider. What do you
think the wings are made from?

[https://www.youtube.com/watch?v=k3xxjqpIRNg](https://www.youtube.com/watch?v=k3xxjqpIRNg)

That's nearly 20 feet. The MIT "drone" has a 24 foot wingspan.

Here's another guy flying a 6.5 m, 21 ft motorized glider:

[https://www.youtube.com/watch?v=r_U_e_EEduo](https://www.youtube.com/watch?v=r_U_e_EEduo)

Replace the electric motor with an internal combustion engine and a fuel tank
and bingo. Again, off the shelf.

And here are a BUNCH of guys with huge gliders, powered and not, including one
that has a 51 FOOT wingspan. And, look, no truck for launch, they use another
large scale RC airplane to tow it up to altitude.

Here's a list of a bunch of large scale RC sailplanes you can buy off the
shelf today.

[https://www.scalesoaring.com/scale-
sailplanes](https://www.scalesoaring.com/scale-sailplanes)

Here's an 8 to 8.8 meter (~26 to 27 ft) DG 1000 S you can buy and build for
about $5,000 Euro:

[https://www.paritech.de/content/modelle/dg1000.php](https://www.paritech.de/content/modelle/dg1000.php)

Shame on MIT for being a part of a scam. It's embarrassing.

~~~
The_Double
Calm down, this was just a fun practical experience course for students, that
is being oversold by the news article:

From the original press-release:

>Hansman and Hoburg worked with MIT students to design a long-duration UAV as
part of a Beaver Works capstone project — typically a two- or three-semester
course that allows MIT students to design a vehicle that meets certain mission
specifications, and to build and test their design.

Obviously a bunch of undergrads aren't going to design a revolutionary new
airplane.

~~~
rebootthesystem
You missed my point.

No problem with any of this except their use of tax money to fund it.

If they need a capstone project they can pay for it themselves. Don't create a
bullshit grant for something that will not be delivered. I mean, a five minute
napkin calculation would quickly reveal the solar-whatever idea was nonsense.
They still took the money and built exactly what the Air Force did not ask
for. That's wrong in more ways than one.

------
PatentTroll
I remember when we used to call them model airplanes.

~~~
csours
Yea, but this model airplane is bigger than a car (looks like 3x wider at
least)

~~~
jaclaz
Yep, we used to call them LARGE model airplanes.

Now, seriously, allow me to doubt that flying some 2 minutes a plane (model or
not) that has (or has the possibility to carry) on board five days worth of
fuel actually means that the engine is capable of reliably running 5 days no-
stop.

------
averagewall
So many fascinating inventions seem to be supposed to be used for search and
rescue. We've had jetpacks, robot drones, this drone, robot walkers, crashable
drones, even the Boston Dynamics Atlas walking robot is for search and rescue.

Is there actually a need for so many robots? Even if there is, is the market
big enough to make economical sense? It seems like it's just an easy thing to
imagine when you can't think of a real purpose for your robot.

~~~
cma
The Defense Department used to just be more honestly called the War
Department. Search and Rescue is how lots of inventions are sold to
newspapers, Search and Destroy is probably how they get sold at military trade
shows :P.

~~~
dragonwriter
> The Defense Department used to just be more honestly called the War
> Department.

Not exactly; the (now subcabinet) Department of the Army used to be called the
(cabinet level) War Department. The Department of the Navy used to be its own
cabinet-level Department. Then a new cabinet level Defense Department was
formed, the Air Force split out of the Army and made co-equal, and each of the
three (two before the split) service departments made subordinate to the new
Defense Department.

------
mmmrtl
Too bad the project is (presumably) slowing down now that Warren Hoburg has
been selected as an astronaut.

------
jmelloy
So when asked to build a solar-powered airplane, they ... built a gas-powered
one?

~~~
techonup
This was actually modeled! See here:
[https://github.com/hoburg/gas_solar_trade](https://github.com/hoburg/gas_solar_trade)

------
HockeyPlayer
SkyFront ([https://skyfront.com/](https://skyfront.com/)) builds hybrid drones
than fly 10 times as long as battery only drones.

------
faragon
The future: ultra-light drones with 90% of its weight being batteries of
charging during day time, so they can be operative at night. Flying 24/7,
forever (e.g. zeppelin-like).

~~~
motoboi
If they need batteries, this cannot be forever. Not even close. Even less if
they let the batteries deep-discharge, which dramatically decreases their
lifespan.

------
jhallenworld
We need an efficient way to use solar to create gasoline.

------
balozi
I guess that when the vehicle isn't helping deliver communications to areas
impacted by natural disasters or other emergencies, the Air Force will strap
an AGM-114 Hellfire package on it and have it linger over combat zones for
days.

I hope these college kids are bright enough to recognize that they are
building killing machines unlike anything warfare has seen before.

~~~
pulse7
The one who will build high-capacity, low-weight batteries will also build
"super" killing and "super" spying machines...

~~~
anotheryou
You could rule out things by licensing.

~~~
dragonwriter
No, you can't. You might get paid what the courts find is fair value for use
of your IP, but IP rights are not an effective to prevent government use of
your work.

See 28 USC Sec. 1498(a) regarding patents, and Sec. 1498(b) regarding
copyrights.

~~~
TheAceOfHearts
Source
[https://www.law.cornell.edu/uscode/text/28/1498](https://www.law.cornell.edu/uscode/text/28/1498)

It looks like you would need to have a patent. If you manage to create a magic
battery and you keep the manufacturing process a trade secret, then you could
disallow government use of your work. Is that correct? They'd obviously be
able to attempt to reverse-engineer your product, of course.

This got me wondering. Could they force someone to provide them with a license
due to extreme circumstances? e.g. Time of war, magic battery can help us win.

~~~
toss1
Yes, they can force you to provide your goods to them in any situation they
declare urgent/emergency, and at priority over all other customers, even
prepaid ones.

You will get paid, it's not confiscation, but it is an offer you cannot
refuse.

I'd be surprised if the situation isn't the same in every other country --
national security/defense takes a very high priority. Moreover, any truly
revolutionary technology that could create a significant military advantage
will be almost required to be controlled by the mil, lest the adversaries get
it.

If you don't want to ever be in a situation where you could help the military
of your country, you probably need to move to a country without a military.
Then worry about other countries deciding to invade for your revolutionary
technology.

------
andybak
Gas in the American colloquial sense? Or actual gas?

~~~
randyrand
It's in the article!

------
penetrarthur
The less fuel is left, the lighter the drone.

------
ge96
Damn that's like a DLG on steroids

------
honestoHeminway
They used a refill service drone?

------
wentoodeep
Equip it with Neural Net ML and it will find it's way to reach ground in no
time for at least 10,000 times.

