What Could Possibly Go Wrong: Flying Hummers

But they would be so cool

By Tom Vanderbilt Posted 02.07.2011 at 11:09 am 14 Comments

Suicide Ride A flying Hummer would be inherently unstable and vulnerable to small-arms fire. Jamie Sneddon

Last April, Darpa proposed a novel solution to the problem of IED-strewn roads and otherwise impassable landscapes in Afghanistan and elsewhere: fly over them.

The Pentagon agency’s $50-million-plus exploratory program for the Transformer (TX) calls for a “robust ground vehicle” that can quickly transform into a vertical-takeoff-and-landing (VTOL) aircraft with a 1,000-pound payload capacity and a flying range of nearly 300 miles. Darpa has a daunting list of specs for any would-be contractors: It must be able to take on small-arms fire and meet federal standards for safety and crash protection. It’s got to have four-wheel drive and be able to reach an altitude of 10,000 feet. Oh, and should the driver become incapacitated, it has to be able to fly itself.

It’s a lot to ask. The fundamental challenge of making cars fly is combining two distinct sets of optimal design characteristics into one package without sacrificing too much performance on either end. The very phrase “roadable air vehicle” sounds like a sigh of compromise. The military considered developing a hybrid in the 1950s with the ungainly Piasecki PA-59K, or “AirGeep,” but then abandoned it because of cutbacks in military research. Advances in materials science and propulsion technology have lessened the trade-offs, but many challenges remain.

First, weight. NASA engineer Mark Moore says that, as a rule, conventional aircraft grow roughly three pounds heavier for every extra pound of payload they’re supposed to carry, whereas, “VTOL aircraft grow about five to six pounds heavier for every extra pound of weight.” Now picture a VTOL aircraft that happens to be armored and packing four soldiers and their equipment. The required compact, rotorless propulsion system means, Moore says, a “hurricane-speed flow field” of rocks and debris upon takeoff. So much for stealth. And all of this likely would do little to increase security. Transformers may be able to leap over IEDs, but insurgents can simply aim RPGs at the wings, which on one proposed Transformer design are laden with fuel tanks.

Enemy combatants in Iraq have brought down Blackhawk helicopters, which are faster and more maneuverable, with small-arms fire. As for the autopilot function—nearly half of the finalists in Darpa’s 2007 Urban Challenge for autonomous ground vehicles were unable to execute elemental driving tasks. There is little reason to believe that autopiloting an inherently unstable vehicle through a battle space under hostile conditions will work better.

How We Can Do Better

Stay focused on making actual Hummers tougher and more versatile. “We still don’t have a fighting vehicle capable of negotiating rough terrain,” says retired Major General Robert Scales, a military analyst.

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14 Comments

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ghost

02/07/11 at 11:35 am

it also looks butt ugly but thats just my opinion, why not just make a hover craft that you'd see in a science fiction movie or something like that? not much to cause the bomb to trip if there's technically nothing over it.

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lanredneck

from Northfield, Vt

02/07/11 at 12:10 pm

because the most deadly and common attacks are remoted detonations

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MtnRyder001

02/07/11 at 7:48 pm

It's just too ambitious with current technology, I agree that they should spend their money on better land vehicles, or make a compromise for something like this ... http://www.parajetautomotive.com/ . Light, fast and versatile.

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iluvkikis

02/07/11 at 9:02 pm

This is insane. If you look back on scifi books and movies from the fiftie's, you can see how we are acctually drifting towards the 'future.' I read an article a while ago about how if you lose an arm, you can replace it with a robotic octopus tentacle. Now we are acctually considering making flying cars. I am officially scared. I'll bet you anything that when the nucular war we are all so afraid about happens, we'll have to follow FallOut Boy, or some book, movie, or video game.

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PhilInYork

02/07/11 at 11:13 pm

Wouldn't it be easier to make flying terminators? Instead of trying to transport live humans, have the solders remote control killer robots with rotors that would swoop in and...

Ah.. err.. Nevermind. Forget I said anything....

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racztomi

02/08/11 at 8:41 am

@lanredneck
I guess with this the nature of deadly and common attacks (as well as accidents) will change.
The nature of it.

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PhilInYork

02/08/11 at 11:25 pm

Mark Moore is exactly right; I have done these calculations many times. Rotor size, weight, and power are all connected by simple math. With a given weight, power requirements go up drastically as the rotor size shrinks. Helicopters have 30 food diameter rotors for a reason.

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atGunPoint

02/10/11 at 11:37 am

I can't see anyone winning this. Solve this and you've solved every traffic problem.

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woolsocks

02/10/11 at 1:18 pm

A flying hummer would have to overcome high mass while taking off in as short a distance as possible while having as small a footprint as possible. It doesn't seem like the flying speed is an issue, just so long as it can fly. The technology most worth investigating in this issue seems to me to me fanwing technology (fanwing.com). You could have a 3 ton Hummer with fold-out fanwings, powered by a 1000hp turbine. No VTOL, but take off and landing in less than 100 ft and high stability at low speeds.

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Boomshadow

02/10/11 at 9:21 pm

@atGunPoint: You want to put VTOL flying Hummers in traffic? Think about the last chucklehead who cut you off on the freeway--do you really want that individual at the controls of a flying Hummer? He/she would be a multi-ton ballstic liability.

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Snerdguy

02/11/11 at 1:51 am

This project has less to do with developing a flying vehicle and more to do with funneling money. DARPA, like so many federal agencies, has to find ways to get more operating funds and money to front to certain favorite contractors. Its hard to believe that the Pentagon doesn't know that it would be impossible to build a vehicle to their requirements within the foreseeable future.

Congress wants to cut money to important programs such as those to prevent birth defects. But, they waste $50 million dollars on crap like this. Its shameful.

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Wireless.Phil

02/11/11 at 2:03 am

What idiot thought this up?
The rotor motor would take up a lot of the inside of the vehicle and there is the heat to deal with.
No wonder the country is broke!

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drchuck1

02/11/11 at 2:44 pm

you think maybe the 50 mil actually went somewhere else?

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