Full-on Hover Mode Time Machine

[aotmfilms]

The minimum height for a ballistic airframe parachute to work is 250 feet. This will not help you for any of the most dangerous stages of flight, where you are most likely to lose control, have a mechanical failure or enter vortex ring state. Honestly ejector seats would work better.



Building a VTOL that is merely shaped like a DeLorean is slightly easier than trying to convert one, but this is still much harder than a properly shaped airframe which is itself a task so hard that no one has been able to build one yet (Moller demonstrating how much investment and engineering talent you can burn up trying).



Then the weight distribution would be completely off.



What do you think you need to make fans spin? Moving air takes horsepower. Thrust engines get less efficient the smaller the nozzle is, because it forces you to use more exhaust velocity to make up the necessary force, and due to k = mv^2 that means you use more power to generate the same thrust. This is why helicopters use big rotors not tiny fans; it is much more energy efficient, and they still have engines rated >500 hp. The only reason light aircraft can fly with relatively low powered engines is that the wing acts as a huge thrust multiplier, causing a large amount of air to experience a small downward velocity change. Aircraft that can hover on their propellors (e.g. a few stunt aircraft) need an order of magnitude better power-to-weight ratio than typical light aircraft because direct thrust is so much less power efficient.

The Moller M400 needs 700 hp just to hover in ground effect, and that is a 1000kg vehicle with twice the intake area you are proposing.



That will not 'clean up the air flow' (which is not necessary at these pressure ratios), rather it will add lots of parasitic drag and increase the power requirements even more. The 1957 Hiller flying platform needed 80 HP to hover for a 250kg vehicle, but that was a direct fan with again more than twice the intake and exhaust area you are proposing, and no power-sapping ducting.



You think that because you are hopelessly optimistic and haven't done any actual calculations. The fact that many many really talented aerospace engineers have failed to make a 'flying car' type vehicle for the last sixty years despite huge funding and not having the major restriction of making it look like a DeLorean should be telling.

You cannot tell me with GM's or Ford's resources that a "Flying Car" couldn't atleast get made. Now, it seeing mass production is another thing but IMO the big 3 have the tech to make a "Flying D" a reality.

[Timebender]

I would think that it would need an additional engine and go old school, aka Harrier technology that the Brits used. or put a bigger engine in place of the Corvette. The issue would be to have the tires become the nozzles as well. If I had a cool million available I would research it. Parts for what you are asking wouldn't be hard to come by for aging equipment such as the US or British versions of the harrier design.

That's basically the idea I had, aside from it having two engines, which is a good idea like you said for redundancy, but then where would engine 2 go, being the whole back engine bay would be filled with the F35 style turbines (vs. harrier design)?

[aotmfilms]

That's basically the idea I had, aside from it having two engines, which is a good idea like you said for redundancy, but then where would engine 2 go, being the whole back engine bay would be filled with the F35 style turbines (vs. harrier design)?

Engine would have to be where the luggage is at unfortunately. Now where we would put the fuel is anybody's guess. I could mock something up in 3d. I don't know how it would get more than 5 or 10 feet off of the ground due to the power/fuel requirements but if you could get the frame light enough....

Atleast I could visualize it for us. Concept-wise but like the other guy said, the power/fuel requirements, not to mention safety, would only allow this "car/D/whatever" to get about 5 to 10 feet in the air safely, at least initially.

Transistioning to ground vehicle would be something else though....I'd have it land on its nozzles or have retractable landing gear, then transistion the tires to "road mode".

--Doug

[Timebender]

Engine would have to be where the luggage is at unfortunately. Now where we would put the fuel is anybody's guess. I could mock something up in 3d. I don't know how it would get more than 5 or 10 feet off of the ground due to the power/fuel requirements but if you could get the frame light enough....

Atleast I could visualize it for us. Concept-wise but like the other guy said, the power/fuel requirements, not to mention safety, would only allow this "car/D/whatever" to get about 5 to 10 feet in the air safely, at least initially.

Transistioning to ground vehicle would be something else though....I'd have it land on its nozzles or have retractable landing gear, then transistion the tires to "road mode".

--Doug

That was my idea (I think I had that in my first post), with the engine in front. It's been done before on a dual engine DeLorean. The question was where would you put the second engine, as the engine bay in the back would be taken up by the fans.
As I went out to lunch it occurred to me that you might be able to put two 4 cylinder, turbo-charged engines in front side by side (running lengthwise), hooked up to the one transmission. If one fails, you might have just enough power for a safe landing, as well as be able to drive away.

Fuel tank could be moved under the body around where the bell-housing currently is on both sides so it goes under the parcel shelf. Someone figured it out for the two-engine DeLorean. If you make the frame a composite (carbon fiber for strength) and the skins out of aircraft aluminum, then you could shed quite a bit of weight.

http://jalopnik.com/5515205/dual-eng...le-engine-sale

[Timebender]

Another idea for the engines would be two Honda 1835cc modified Valkyrie/Goldwing engines side by side. I have this on my Honda Rune, a 900 pound bike on it's own, and even at 70mph, with a 240 pound rider (me), can take off like a shot in 5th gear.

The DeLorean weighs 2800 pounds. Go to a composite frame, replace the SS with aircraft aluminum skins, and replace the glass (glass is very heavy btw) with aircraft Lexan windows. You'd probably be, as a guess, down to 1200 pounds, but that's a rough guess.

[Starglider]

You cannot tell me with GM's or Ford's resources that a "Flying Car" couldn't atleast get made. Now, it seeing mass production is another thing but IMO the big 3 have the tech to make a "Flying D" a reality.

This argument makes no sense. Physics does not care how much money you have. It does not care how much you believe. The aerodynamics of hovering vehicles is fairly well understood and comes down to thrust-to-weight, drag, rotor area, center of gravity, control torque, damping and so on. Even back-of-napkin engineering calculations on whether something will actually work are much more relevant than how well known the developer is or your level of personal faith. Aside from anything else it demonstrates that whoever wants to do the thing is an actual engineer with any chance of building something that works.

GM and Ford do not have aerospace talent so no they are not equipped to make a flying car. They could subcontract of course, if they were prepared to invest billions in an extremely risky R&D for a luxury product. The current state of the art in fast VTOLs is pretty much this Boeing project;

http://i.kinja-img.com/gawker-media/...vmu5djyn0b.jpg

So a flying car in the sense of a VTOL that looks roughly like that is almost certainly possible, although expensive. Note that it does not look anything like a DeLorean; the relatively large fan area and lack of power sapping ducting is absolutely critical for achieving useful thrust-to-weight.

[aotmfilms]

I hate to burst your bubble but this was just from TWO DAYS ago. So a flying D COULD be possible.

http://www.cnet.com/news/terrafugia-...ng-car-design/

tfx2.jpg

This was just from a Google search of "Flying Car", it took me approximately 10 secs to find. So now tell me it's going to take Billions and that the Big 3 couldn't do it?

Here is a video. It is purported that it is more like a plane than a car but their getting there: ]

IMO we are in the early days of the wright brothers here but give it time and about another 50 years. With the Big 3, we would be about 10 years off.

[Starglider]

It is purported that it is more like a plane than a car but their getting there:

It is a light aircraft with folding wings. You drive it to an airfield and take off like a normal plane. These things have been around since the 1950s, but they have never been very popular because they are awkward compromise that sucks as both a car and a plane. Regardless this is in no way relevant to anything with a 'hover mode'; this kind of design will always need a large wingspan, a relatively high stall speed and a runway. Similarly there have been attempts to make helicopters that can be used as cars; it's possible but very impractical. Neither of these designs is anything like the flying cars envisioned in Back to the Future. Those used antigravity for a good reason; jet thrust as the main lift source is completely implausible for something that closely resembles a road car. Unfortunately to date there has been no credible indication that antigravity is physically possible.

[DMC5180]

Neither of these designs is anything like the flying cars envisioned in Back to the Future. Those used antigravity for a good reason; jet thrust as the main lift source is completely implausible for something that closely resembles a road car. Unfortunately to date there has been no credible indication that antigravity is physically possible.

+1

But it's always fun to dream right :-)

You seem well versed in all things aeronautical. Fwiw I work in the aviation field myself, R&D at Cirrus Aircraft.

[aotmfilms]

It is a light aircraft with folding wings. You drive it to an airfield and take off like a normal plane. These things have been around since the 1950s, but they have never been very popular because they are awkward compromise that sucks as both a car and a plane. Regardless this is in no way relevant to anything with a 'hover mode'; this kind of design will always need a large wingspan, a relatively high stall speed and a runway. Similarly there have been attempts to make helicopters that can be used as cars; it's possible but very impractical. Neither of these designs is anything like the flying cars envisioned in Back to the Future. Those used antigravity for a good reason; jet thrust as the main lift source is completely implausible for something that closely resembles a road car. Unfortunately to date there has been no credible indication that antigravity is physically possible.

Well it seems that some progress has been made in that area as well....http://gizadeathstar.com/2014/01/fri...-gravity-work/

But the bottom line here is what Mr. Cook's article suggests, and that is, that Russia, despite all public denials about pseudo-science and so on connected with Kozyrev's and his followers' work, is still conducting secret research into it, and if Podkletnov's assertions as revealed in this article are true, doing so on a large scale and developing first generation(or later) practical devices.

And finally, and most obviously, I hope you caught the subtle and implied message in the article: Russia is doing practical anti-gravity research, and they are ahead of us and we need to catch up fast....


Like I said, I think we are 10 to 50 years off. 10 to build a prototype and 50 to put it into production. We may or may not see it but your kids will.

Back in the day "They" said that breaking the sound barrier was impossible and that the earth was flat...well we know what happened

--Doug