# HoverCars are here! Don't crash! **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2005, 5:27pm UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091 "2005-04-19T17:27:08Z")\ **Posts on this page:** 10\ **Page:** 4
**Author:** ![drewbert](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drewbert/32/15890_2.png) [@drewbert](https://boards.straightdope.com/u/drewbert)\ **Post date:** [April 21, 2005, 2:41am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/61 "2005-04-21T02:41:26Z")
Yeah, bring on the flying cars! 'Cause, y’know, I never really liked observational astronomy anyway. [sub]Oh, wait, I do. Drat.[/sub] ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [April 21, 2005, 3:37am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/62 "2005-04-21T03:37:44Z")
> [@Broomstick](#): > > …Multiple engines theoretically offer more safety, but it’s offset by a greater complexity that can and does kill people in some circumstances. Bingo The Skycar has 8 friggin´ engines; at first it may seem like a very reliable system, lots of backup if something goes wrong, but… 8 engines fail 8 times more frequently than a single one; that´s one of the reasons why the Harrier (Jump Jet) has just one engine; the pilot knows that if it fails he pulls the black and yellow handle and gets a nice Martin Baker tie. With 8 engines you´re complicating decitions that must be taken on a split second, for example if a left engine fails, you just lost not 1/8 of the power (assuming hovering) but 1/4th of it because you have to shut down an opposite engine immediately or else you´ll be upside down in no time. I don´t think that thing would take 1/4 thrust reduction kindly. So what do you do?, you have to think, and in this case, if you think you loose, a loss of an engine while hovering is not the same as in normal flight where the plane has forward momentum to buy time before it slows down, here you just fall or tumble. Pull the lever and get the hell out of the plane or deploy a parachute, no second thoughts. So multiple engines are not worth it, a single engine can be mantained easier so it yields a better reliability. ---
**Author:** ![Muad\_Dib](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@Muad\_Dib](https://boards.straightdope.com/u/Muad_Dib)\ **Post date:** [April 21, 2005, 4:02am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/63 "2005-04-21T04:02:44Z")
God Damn it! THESE ARE NOT FLYING CARS!!! These are ugly airplanes! You want to know what a flying car looks like, go watch _Back To The Future Part 2_. No moving parts = flying car. ---
**Author:** ![antechinus](https://avatars.discourse-cdn.com/v4/letter/a/fbc32d/32.png) [@antechinus](https://boards.straightdope.com/u/antechinus)\ **Post date:** [April 21, 2005, 4:13am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/64 "2005-04-21T04:13:51Z")
OMG… think of the uses The Terrorists could make of these. :eek: ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [April 21, 2005, 4:30am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/65 "2005-04-21T04:30:38Z")
> [@antechinus](#): > > OMG… think of the uses The Terrorists could make of these. :eek: Ooohmmm… kill themselves? ---
**Author:** ![Scarface\_Z](https://avatars.discourse-cdn.com/v4/letter/s/50afbb/32.png) [@Scarface\_Z](https://boards.straightdope.com/u/Scarface_Z)\ **Post date:** [April 21, 2005, 4:58am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/66 "2005-04-21T04:58:51Z")
> [@mike1dog](#): > > Let’s see, the prototype goes fifty miles an hour, uses four rotary engines (not noted for their fuel efficiency), and can fly for two hours. Color me underwhelmed. Actually, the fifty mph one has just one engine I believe. Check out the link I posted back at post# 35, it has a picture. But it’s still stupid. ---
**Author:** ![caligynephobia](https://avatars.discourse-cdn.com/v4/letter/c/7feea3/32.png) [@caligynephobia](https://boards.straightdope.com/u/caligynephobia)\ **Post date:** [April 21, 2005, 5:46am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/67 "2005-04-21T05:46:35Z")
I suspect that if the Moller contraption (I swear I read about this 20 years ago in Popular Mechanics) ever approaches FAA certification, it would actually fall under the newer “Powered Lift” category and not “Airplane” or “Helicopter.” Seems to have the same kind of limitations that the V-22 and BA609 do/will; For instance, cannot takeoff or land like an airplane (as I understand, a Harrier can), and cannot autorotate. What struck me about the CBS bit on Sunday was how the 60 Minutes folks tried to tie HITS to a handful of fringe aircraft. CarterCopter is definitely the least marginal of those shown, and still is going to be a tough sell because it doesn’t look conventional, or even cool. Who will probably make good use of HITS? Plain old airplanes with fancy new instrument panels. The only remarkable new aircraft we’ll see with this capability in the very near-future are the so-called microjets: Eclipse, Javelin, Safire, Mustang, etc. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 21, 2005, 9:58am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/68 "2005-04-21T09:58:23Z")
> [@caligynephobia](#): > > I suspect that if the Moller contraption (I swear I read about this 20 years ago in Popular Mechanics) ever approaches FAA certification, it would actually fall under the newer “Powered Lift” category and not “Airplane” or “Helicopter.” I take back what I said before - I think you’re right, it would fit under powered lift better than airplane. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 21, 2005, 10:51am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/69 "2005-04-21T10:51:14Z")
> [@av8rmike](#): > > Honestly, **Broomstick** , I wouldn’t waste your time doing a line-by-line dissection of the article or anything. You and I have been around here long enough to know how many times this topic has come up that you could probably just link to one of the earlier threads. Waste my time? Nonsense - it’s my new hobby. Besides, since the wind has been blowing 30 knots everytime I’ve planned to fly in the past week I find myself with unanticipated free time. Here’s the first part: > [@](#): > > Have you ever dreamt about the day you can buzz around in your very own flying machine? Yeah, I _used to_ dream about it… then I went out and got my pilot’s license. > [@](#): > > Well, that day may be sooner than you think. For me, it happened in May, 1995. > [@](#): > > The folks at NASA have built something called “The Highway in the Sky.” Nuh-uh - they are _developing_ this system, which is not yet ready for prime time. > [@](#): > > It’s a computer system designed to let millions of people fly whenever they please, and take off and land from wherever they please, in their very own vehicles. Aside from the problem that your neighbors and local zoning board may not condone the “take off and land anywhere” side of this, computerized systems are only as good as the hardware and software employed. Hardware can break down. Software can be buggy. Yes, we can build robust and reliable systems and thoroughly test them, but in the real world it will fail from time to time - what then? Shrug your shoulders and say “oh, well”, call your significant other on the cellphone and say “Buh-bye”? Currently, those that fly deal with the inevitable breakdowns through a combination of back systems and training. What about these flying cars? What back up systems do they have? > [@](#): > > And here’s the good news – a lot of people are building machines you’ll be > able to buy. If you can afford a regular ol’ SUV, you can afford to buy an airplane _right now_ > [@](#): > > Norris, 66, asked one of his test pilots to demonstrate the AirScooter for 60 Minutes on a hilltop outside San Diego, Calif. It can fly for 2 hours at 55 mph, and go up to 10,000 feet above sea level. Somehow I have a hard time imaging the road bullies who insist on driving 60 through a school zone will settle for a mere 55 in the sky. > [@](#): > > Everything is controlled from the motorcycle-like handle bar. Push it forward and the two counter-rotating blades pivot forward. Push it back and it goes back. This isn’t a flying car. It’s a helicopter. Comments on its safety and engineering I will leave to those who know more about such things. > [@](#): > > Norris says you won’t need a pilot’s license if you fly it under 400 feet in non-restricted air space. Norris needs to re-read his regulations. Even allowing for filtering this through reporters. IF it qualifies as an ultralight (and I have my doubts about that - on their website they don’t give a weight, they say “qualifies for FAR Part 103”) you are NOT restricted to “under 400 feet”, in Class G (i.e. “uncontrolled”) and most Class E airspace you can fly considerably higher. However, you would not be able fly it from cities or suburbs. And while it’s true, ultralights require neither training nor licensing, I humbly submit that anyone attempting to fly one _without_ training is a fool and an idiot. Sure, the Wright brothers taught themselves to fly - and they took something like 20 years to go about it. Very, very few people have that kind of patience and caution. After a program was set up to provide ultralight training the accident, maiming, and death rates went down remarkably. This was generally seen as a Good Thing. If it’s not an ultralight then you _will_ need a license of some sort. And why would that be shocking? We require licensing for cars and motorcycles, does anyone honestly think “flying cars for the masses” wouldn’t require _something?_ You won’t necessarially need a private license - there are now two licenses that require less training, Recreational and Sport Pilot. It’s a little less time and money. You’ll still have ground school and a checkride, though. > [@](#): > > Molt Taylor’s Aerocar. You could detach the wings and haul them behind you. But they failed to catch on because they were too expensive and hard to fly in bad weather. You know what? The Air Scooter is going to be hard to fly in bad weather, too. It’s the nature of flying machines - the smaller and lighter they are the less bad weather, or even mediocre weather, they can handle. > [@](#): > > More important, there was no way to really manage all the potential traffic from millions of them buzzing around You know, this is somewhat vaguely insulting to those of us who currently fly and manage to do so without slamming into things. > [@](#): > > Bruce Holmes is one of NASA’s chief strategists You mean, “NASA - our spaceships blow up on slightly frosty mornings” NASA? The same NASA where a bit of fuel tank insulation lead to wreckage strewn from the Pacific to Louisiana? The same NASA that still hasn’t developed a bail-out system, or really anything the pilot can do when the crap hits the fan except shrug and say “oh, well?” OK, NASA _has_ done some good things over the past 40-50 years. But lets recognize that they are also capable of craptacular failures. > [@](#): > > He showed Simon a flight simulator, a new computer system that can be put into any new airborne vehicle. And how much does it cost? How much does it weigh? What kind of power does it draw? **Cost:** the Garmin 400 in a Mooney a couple of friends of mine own - which is already far past state-of-the-art these days - cost close to $10,000 dollars. That’s a noticable chunk of change. How much will a HITS unit cost? Would you put a $60,000 navigation sytem into an aircraft only worth $50,000? And if it’s factory installed, that aircraft _will_ cost more than $50,000. **Weight:** If you’re trying to bring one of these flying cars into being under the Part 103 ultralight weight limit this is going to be a huge factor. It’s hard enough to build an ultralight that meets weight requirement if you leave flight instruments off entirely… even a five pound HITS unit is going to be hard to fit into the weight limit. **Power:** computers don’t run on pixie dust. Where does the power for this thing come from? A battery? The engine? They stated you can mount this on “any” aircraft? Oh, _really?_ If I have an Aeronca Champ - a line of airplanes that never had electrical systems from the factory - what do I do? Install an alternator? A large battery? How much will _those_ cost? How much will _those_ weigh? Well, maybe that was unreasonable, Champs are sooooo old… let’s talk about the old reliable Cessna 150, an airplane already considered underpowered. Let’s assume you shoehorn a HITS unit onto the rather small panel. OK - where’s the power going to come from? The battery? It’s miniscule. On a cold Chicago morning you got just enough power to attempt two or three starts… IF you’re careful of the power. You’re going to run a whiz-bang graphics program off _that?_. Better wait until the engine is running to turn it on. I dunno… at night, the cockpit lights tend to dim when the engine is at idle, it’s a little disconcerting. You’re going to add _another_ piece of electronics to it? > [@](#): > > He says it will make flying easy, and will manage all the new traffic up there. I’d like to point out that flying IS easy - it’s knowing what to do when things abruptly _stop_ flying when you don’t want them to that’s the hard part. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 23, 2005, 11:37am UTC](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091/70 "2005-04-23T11:37:36Z")
> [@](#): > > It’s called “The Highway in the Sky,” and here’s how it works: In a NASA animation, pilots focus on one main screen. And run smack into a bird! Sorry - but, folks, you really _do_ need to look outside the cockpit, too. Especially when low to the ground because there IS stuff out there. Sure, you can program buildings and towers into a database, but flocks of birds move around. Hitting a flock of birds ranks as one of the Bad Things of aviation. > [@](#): > > It’s very much like a videogame. Except there’s no “reset” button, good play does not earn you extra lives. there are no cheat codes, and no godmode. > [@](#): > > It’s a $130-million program that can also help pilots fly in bad weather. But if you’re talking about a lightweight aircraft maybe they _shouldn’t_ fly in bad weather. Are they flying cars going to have anti-ice equipment? How well do they hold up to lightning strikes? > [@](#): > > The Skycar is the latest attempt to build a real flying car. It’s been described as a cross between a Ferrari and a Batmobile. Its inventor is Paul Moller, of Davis, Calif. I am _not_ spending my time on Moeller. There are other threads where we beat that dead horse. Except for this bit: > [@](#): > > For instance, Moller thinks it will be able to save people from burning buildings – as demonstrated in his promotional video, which shows the Skycar bypassing traffic jams, extending a built-in catwalk, and ultimately saving the day. Let’s see, he’s going to extend a catwalk from this flying machine while it’s in the air… consider catwalk as big lever… put human on end of lever… how do you keep the skycar from flipping over? > [@](#): > > It’s called the CarterCopter, and it has a large top rotor and small wings which double as fuel tanks. Propulsion is generated from the tiny secondary propeller at the rear of the plane. It can take off and land vertically like a helicopter, but can fly as fast as an airplane. THIS one actually looks plausible, not the least because _it actually flies_. > [@](#): > > “Even though this is a propeller driver aircraft, and we can only probably fly maybe 400 miles an hour, we can beat a jet if you talk about from point to point,” says Carter. “Even if you go all the way across the United States, we can beat a jet. And when you’re starting to talk about from point to point, small town to small town, and you don’t have to worry about the hub, now it gets to be major!” See, this guy is making sense. Yes, it’s slower than a jet, but because you don’t spend hours driving to a big hub, and you bypass a lot of the stuff required by airlines and big airports. door-to-door it’s actually faster. > [@](#): > > Carter says he will initially sell the vehicle for about $300,000. This is another reason I think this guy is on the level - the price. It’s in the ballpark for new 4-seat aircraft these days. Yes, that price is steep. Sorry. This is why there’s such a market for used aircraft. I’m not sure how the “Carter Copter” fits into the regs. I could make an argument that having both a fixed wing and a rotor license would be a good thing for the pilot. The FAA will, if necessary, happily write rules for a new category of aircraft if that’s deemed a good idea. They just added “weight shift” and “powered parachute” last year, as two examples. They’re still working on “spacecraft”. So if it’s really viable that’s not an insurmountable obstacle. > [@](#): > > A bizarre looking contraption called the Springtail is the jetpack for the 21st century. It’s a million-dollar prototype that flies using two large ducted fans. Um… that’s a bit pricey for Everyman, don’t you think? OK, OK, it’s a prototype. > [@](#): > > Harry Falk and his team at Trek Aerospace are still testing its vertical abilities. And to protect their investment, they’ve also tethered it to a crane. When it takes off, it’s loud and generates a lot of wind, but the team says it’s designed to fly for two hours, at 90 mph, at an altitude of 400 feet. If they tether it for test flights it gets me to thinking there are stability issues. Not that those can’t be overcome - Sikorsky tethered his prototype helicopter for a number of test flights. Unlike Moeller, though, he progressed to untethered flight. Not sure how the Trek boys are doing. Fixed wing aircraft have the stability built in (with a few exceptions, such as certain fighter planes). It’s a feature of aerodynamics of the hull itself, and thus is not dependent on computers or power to remain stable. Helicopters are inherently _un_stable, in which case it’s the _pilot_ who keeps things stable. However, it is important to design such aircraft so that it is humanly possible to maintain stability. Jet packs and personal ducted fans motors do not have the stability of an airplane’s hull. Neither do human bodies, for that matter. So how do you stay upright? Extensive training? Gyros? But wait -! Gyros can and do fail…and how will you power those gyros? What’s your backup. These are not insurmountable problems, but, you know, if your Segway craps out you just step off it onto the ground. With a Trek machine “stepping off” is a long way down. What you gonna do? The 400 foot altitude is low for a rip-cord deployed chute, it’s really the bare minimum. Oh, OK, base jumpers launch from lower - does that mean you need to develop base-jumping skills to be safe here? Are you going to jettison the Trek first? How do you do that? How much time does it take? If you have a 'chute big enough to support both you and your flying machine (such 'chutes do exist) where do you mount it, how do you trigger it, and how reliable is it? You can, of course, use computer-controlled fly-by-wire stability… but then you’re back to the weight and expense and power problems. Even if you overcome that, what do you do when it fails? Because, inevitably, a system will fail at some point. If your computer crashes in, say, an F-16 you pull the magic ejection handle because if the computer crashes the plane will, too, in short order. And while ejection seats might sound attractive to the layperson, ejection can cause severe injuries or death under some circumstances. Flying machines ARE wonderful… but things _will_ go wrong and you need a gameplan to deal with them. > [@](#): > > “Clearly, we’ve caught a wave of the future,” says Falk. “NASA’s building the ‘Highway in the Sky’ program is really what develops the infrastructure for us to be able to put these things in the air and fly them safely.” Um… again, this is a little insulting to those of us who fly _now_ and manage to do so without smacking into things. Navigation alone does not make you safe. The vehicle you are in also has to be safe from an operational and mechanical standpoint. And the human has to refrain from doing stupid stuff, too. > [@](#): > > Although Falk was nervous, AirScooter inventor Woody Norris was eager for Simon to fly. Norris arranged for Simon to take his $50,000 invention out for a spin. First, his team tied the machine down to the ground. They didn’t want Simon flying away forever, until he felt comfortable taking off evenly…_snip_…On Simon’s first try, he lifted off, but couldn’t hold it even. So he tried again, and again. On his tenth attempt, he finally did it. So… training is required, yes? Perhaps a certification and licensing program of some sort? How is that different from the pilot training we have right now? I’ll say it again - if you want to learn to fly _do it now_, don’t wait for some hypothetical wonder machine. We already have “flying cars”, but we call them airplanes and helicoptors. [Previous page](https://boards.straightdope.com/t/hovercars-are-here-dont-crash/300091.md?page=3)