Full-on Hover Mode Time Machine

[davidc89]

Just as a thought, I was thinking hub less wheels. They are obviously driven by something, but it may be easier to disconnect them and go in to hover mode. I don't really know how they are driven, but just an idea.

[Timebender]

I was thinking the same thing this morning - they have electric motorized rims - though then you'd lose the DeLorean rims. You could probably adapt an electric hub motor to the middle in place of the brakes - it could both provide locomotion as well as brakes (and then no more needing to change brake pads - ever). Wonder if there's a motor you could attach to the brake rotors instead...

[Starglider]

I was thinking the same thing this morning - they have electric motorized rims - though then you'd lose the DeLorean rims. You could probably adapt an electric hub motor to the middle in place of the brakes - it could both provide locomotion as well as brakes (and then no more needing to change brake pads - ever). Wonder if there's a motor you could attach to the brake rotors instead...

Electric vehicles still have mechanical brakes. The rate at which you can extract kinetic energy via regenerative or dynamic braking (using the motor as a generator) is fairly limited. Trying to actively brake by running the motor 'in reverse' is a bad idea because it rapidly heats the motor coils. The service live of the brake pads on a Tesla is about 100K miles; much better than purely mechanical brakes, but not 'forever'.

[Starglider]

And that's pretty much it in a nutshell.

There are massive control challenges and the power output required for a ducted fan solution is on the order of 2000 HP, continuous: if it ever becomes non-continuous you crash. This is why the Moller SkyCar project has been going for 20 years with still no untethered flight demonstration, and that uses a custom lightweight airframe and redundant rotary engines.

[Timebender]

There are massive control challenges and the power output required for a ducted fan solution is on the order of 2000 HP, continuous: if it ever becomes non-continuous you crash. This is why the Moller SkyCar project has been going for 20 years with still no untethered flight demonstration, and that uses a custom lightweight airframe and redundant rotary engines.

Yes I know- my stuff is all theory. If the turbines don't provide continuous thrust, then we pop a parachute. Also, I'd switch out the frame for one made of carbon fiber, and skins for aircraft aluminum.

If geared right, let's say you're using a smaller turbo charged engine in front, to the drive shaft to the turbines then it's not so much a case of engine HP output, but more about getting the fans to spin fast enough, which could be done through a gearbox that essentially increases rpm's to the fans. Duct those to the rims (which act as vanes to clean up the air flow even more) and I think, in theory, you could make this work.

[Starglider]

Yes I know- my stuff is all theory. If the turbines don't provide continuous thrust, then we pop a parachute.

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.

Also, I'd switch out the frame for one made of carbon fiber, and skins for aircraft aluminum.

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).

If geared right, let's say you're using a smaller turbo charged engine in front

Then the weight distribution would be completely off.

to the drive shaft to the turbines then it's not so much a case of engine HP output, but more about getting the fans to spin fast enough, which could be done through a gearbox that essentially increases rpm's to the fans.

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.

Duct those to the rims (which act as vanes to clean up the air flow even more)

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.

I think, in theory, you could make this work.

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.

[Timebender]

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.

Optimistic, yes. Many many really talented aerospace engineers is great, yet not a single one has cracked it. Only takes one person who thinks completely differently to do so.

Hopelessly so, maybe. Maybe not. Some of the best ideas and solutions come from people who aren't "trained" or professionally educated in a certain area. Their are dreamers who somehow beat the "real world data" and make things come true. Some of the best discoveries are from non-engineers (or I should say people who didn't major in engineering) who aren't stuck in the data sets and "what works as far as we know" mentality. James Cameron has developed one of the best subs for going deeper than any other submarine before him along with a friend and "engineer" - who made most of the materials based on things he found at automotive stores and ideas from his garage before moving into a real facility alongside some special effects folks.

http://www.popsci.com/article/techno...ad-ron-allum-0

Of note:
Ron Allum, a 65-year-old Australian broadcast technician, co-designed and built the Deepsea Challenger despite having no background in mechanical engineering, no qualifications in oceanic science, and no education beyond a trade-school certificate.

Btw I have 6 patents in something I had no college education from (I was a film student who switched to industrial design and architecture, and didn't finish) and were discovered mainly by looking at something from a very non-traditional perspective, and are now in the hands of Intel.

I worked alongside some of the most amazingly bright people at an R&D think tank, comprised of people from the special effects industry taking their craft and applying it to real world problems. Almost all had no degrees in engineering. They were just good at figuring stuff out from a different perspective.


I believe it can be done. And that's good enough for me.


End of conversation.

[Kane]

End of conversation.

Exactly. I'll have to remind myself to ignore your posts after this.

[aotmfilms]

Aside from getting some form of thrust through the wheels in hover mode (easy), and the wheels going from road to hover mode (easy), it's getting the rear wheels to connect/disconnect from the axles and then be able to reconnect - which is probably easy as well, but I'm stuck at that point.

I did come up with a basic solution to a real-world flying DeLorean using state-of-the-art/current tech, which is similar to the F-35 Joint Strike Fighter design.

Any mechanical engineers with a degree or those who are "home schooled" - if you have thoughts on this as their are a couple places I'm stuck, one being the above mentioned axle issue - is the pass-through differential.

So, in this case the engine is in the front of the car (it's been done as we know). It's connected to a drive-shaft which goes into a special differential - in drive mode it turns the back axles. In fly mode, it drives another smaller drive-shaft in the back of it, which in turn drives two turbines in opposite directions. The back louvers rotate to a vertical position to allow maximum airflow as well as keep from getting sucked down.

For takeoff, compressed air from the turbines is passed through a channel and outlets along the bottom of the car, strategically placed mainly for lift and balance.
Once enough height is reached for hover conversion (wheels out), the wheels turn out, and then airflow is redirected to the wheels, which have rounded caps behind them, and are the same diameter as the DeLorean rims. The air from there is then "cleaned up" per se, due to the slotted design of the rims (think wind tunnel effect), thus providing more thrust with less energy. Motion and direction is then controlled by each individual valve closing and opening enough - similar to how quadcopters operate by slowing down or speeding up the propellers.

And that's pretty much it in a nutshell.
And now this is of public record - if anyone wants to add to it, improve upon it or figure out how to make this work, please feel free to comment and help make it better.

And I'm willing to donate my DeLorean to the cause, as it's already been modded with a Corvette 350 engine.

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.

[aotmfilms]

Yes I know- my stuff is all theory. If the turbines don't provide continuous thrust, then we pop a parachute. Also, I'd switch out the frame for one made of carbon fiber, and skins for aircraft aluminum.

If geared right, let's say you're using a smaller turbo charged engine in front, to the drive shaft to the turbines then it's not so much a case of engine HP output, but more about getting the fans to spin fast enough, which could be done through a gearbox that essentially increases rpm's to the fans. Duct those to the rims (which act as vanes to clean up the air flow even more) and I think, in theory, you could make this work.

I would want two engines, 1,000 hp each fore and aft to control the nozzles, and some sort of redundancy just incase one fails so that you could atleast power rotor down similar to that of a helicopter.