Laser Propulsion - Scientific Discussion (Engine is real!) +New poll!

[RacingManiac]

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Incredibly silly concept... and pointless. You could have simply said the VGT was powered by jets, and you'd get the same effect. Never mind that "900 hp" of thrust going out into the air instead of to the ground isn't going to get you to 60 mph in 1.5 seconds.

Thats the thing though, Jet would make less sense than this, as far as a ground based, circuit driving thing on wheels and tires. You don't get enough modulation or reaction time using jet because of the ramp up/ramp down in thrust. This is possibly instantaneous on-off with possible different level of thrust in short amount of time. As far as a bat**** insane concept for a ground vehicle, this makes sense in their choice of madness. Also have seen the cyclist on rocket video that's going around recently? He got up to speed quite awfully fast...As far as outlandishness goes, its no more of fantasy than having a EV that can have enough power to run 24 hours race and still have the performance of a current car, since you have the exactl same challenges, whats the energy source and what are you using to store it. Until you have something good enough storage density its a fantasy, much like the compact laser and its energy store.

The "Air Generator", might be used to power auxiliaries? Granted there are other ways to do it, say driving an alternator off a wheel or something, but maybe they want to keep the wheels free of other drag, and run basically as said a windmill to piggy back on laser's propulsion.

Also unlike EV or something, this might make some interesting noise since its essentially external combustion....

Its a fantasy car for sure, but its an interesting one IMO...

 

[Exorcet]

I understand that but, so? Why care? Tell me, why do you care?

GT is supposed to be a simulator in some form.

This car is kind of what some people thought the Red Bull X1 was. The X1 is actually pretty believable. The 2X relies a bit too much on imagination. Its components can work, but the end result GM is presenting might not actually come out of the physics behind the concept.

If this was just a laser powered car, it would be easier to accept, and even if it only had 1/10 the performance, increased believability would have made it just as interesting.

 

[ManicDan]

a few quick questions i hope to see answered in game
if this thing draws 670KWs, then its battery pack must be huge and we would see a high car weight
if the pack is small and weight is down, then it should only do 1-2 laps on single charge

anyone care to do the math to find out how much the battery pack would weight for this thing to drive 10 minutes at 100% throttle?

 

[Aloha62_2]

A video which only shows the receiving plate not the actual laser emitter. For this car to work the laser either needs to be mounted to the car and have a power generator of unreal density or be powered by an external unit like some sort of giant magnifying glass positioned over the track pointing at the back of the car at all times. It isn't a concept car it's utter nonsense.

 

[vasiliflame]

A video which only shows the receiving plate not the actual laser emitter. For this car to work the laser either needs to be mounted to the car and have a power generator of unreal density or be powered by an external unit like some sort of giant magnifying glass positioned over the track pointing at the back of the car at all times. It isn't a concept car it's utter nonsense.

thats the guy who done that test i was on about but he did it in a field in England somewhere

 

[Griffith500]

... be powered by an external unit like some sort of giant magnifying glass positioned over the track pointing at the back of the car at all times. It isn't a concept car it's utter nonsense.

Is exactly how it would work.

Target tracking and beam manipulation is already working. High power lasers already exist at the megawatt level. Check out the Boeing FEL.

All this car needs is a special prism to receive the laser energy. Imagine a large Pylon in the centre of the track with beams tracing each car. Obviously line of sight is an issue, but not insurmountable.

Power regulation is already achieved with pulse width modulation, clever manipulation of which can give you sounds we're all familiar with with existing racing cars, with a twist. The trouble will be any lag between driver input and laser output.

 

[vasiliflame]

Is exactly how it would work.

Target tracking and beam manipulation is already working. High power lasers already exist at the megawatt level. Check out the Boeing FEL.

All this car needs is a special prism to receive the laser energy. Imagine a large Pylon in the centre of the track with beams tracing each car. Obviously line of sight is an issue, but not insurmountable.

Power regulation is already achieved with pulse width modulation, clever manipulation of which can give you sounds we're all familiar with with existing racing cars, with a twist. The trouble will be any lag between driver input and laser output.

i expect it to sound similar to this

 

[Beat the Beat]

I'm not a rocket scientist... but having the laser mounted on the car itself, instead of beamed from external sources, seems to defeat the whole concept of that curved mirror. If you have an on-board laser, why do you need a giant mirror to aim the light in the right places? Why isn't the laser just designed to focus where it needs to focus?
It IS a great concept if the lasers were shot at it remotely from stationary places on the tracks, maybe for a land-speed record or a cool explanation for boost sections in a sci-fi racing game, but I don't think that will be a part of this.

Secondly, and maybe there's a good explanation for this, but why use an onboard laser when you could just use the batteries to power a giant spark plug which has the same effect on the air? Wouldn't that be more efficient?

 

[Beat the Beat]

sorry for double post

Is exactly how it would work.
All this car needs is a special prism to receive the laser energy. Imagine a large Pylon in the centre of the track with beams tracing each car. Obviously line of sight is an issue, but not insurmountable.

But that is the point of the curved surface already, it works like a kind of inverted radar dish to bounce all the light towards the ring. As long as an external laser is firing at roughly the same angle as the car it should work, so you could have one positioned at the start of each straight.

 

[Imari]

I'm not a rocket scientist... but having the laser mounted on the car itself, instead of beamed from external sources, seems to defeat the whole concept of that curved mirror. If you have an on-board laser, why do you need a giant mirror to aim the light in the right places? Why isn't the laser just designed to focus where it needs to focus?

Because it's a weird shape that it focuses in, it's kind of a ring around the edge of that parabolic spike. It's not like Johnny with his magnifying glass burning ants. Presumably they make it that shape for stability.

Secondly, and maybe there's a good explanation for this, but why use an onboard laser when you could just use the batteries to power a giant spark plug which has the same effect on the air? Wouldn't that be more efficient?

Because a spark plug won't generate the same temperatures. A spark plug will ionise a train of air between the electrodes, and then there's very little energy going into heating the air after that. You simply couldn't put the electrodes far enough away from each other to get serious heating, and even if you did you have extremely limited control over exactly where the heating occurs. Electricity flows through the easiest path, which is rarely exactly where you want it to go.

A laser can be designed to operate at a wavelength that is strongly absorbed by some of the components of air, and thus put a lot more of it's power into heating it. And you can control fairly precisely exactly where and how much you want it to heat.

a few quick questions i hope to see answered in game
if this thing draws 670KWs, then its battery pack must be huge and we would see a high car weight
if the pack is small and weight is down, then it should only do 1-2 laps on single charge

anyone care to do the math to find out how much the battery pack would weight for this thing to drive 10 minutes at 100% throttle?

Let's use Tesla energy densities, because that's a standard thing.

http://www.teslamotors.com/roadster/technology/battery

The pack weighs 990 pounds, stores 56 kWh of electric energy, and delivers up to 215 kW of electric power. Tesla battery packs have the highest energy density in the industry.

For ten minutes of 670kW we need ~112kWh of energy. Lets just assume that they can somehow jigger it so that it can actually output the energy that quickly.

990 pounds per 56kWh means ~17.7 pounds per kWh. For 112kWh that's then about 1980 pounds. About 900kg. Which isn't as bad as I thought, actually. But then, that's just in battery weight. You could assume that the laser assembly weighs about what a F1 engine/gearbox does, and that they chassis would be a similar weight to an F1 car and all up it's probably about another 600-650kg of gubbins.

So call the car 1600kg all up, and it only goes for ten minutes or so before it's out of beans, depending on how helpful it's air generator is.

Realistically, it's probably more than that because that's assuming 100% efficiency. Probably much more. Electric motors can be pretty efficient these days, but I have serious doubts about how efficient something like this could be. It's running on explosions in the open air, so it seems to me that at least half the power is being wasted going in the wrong direction.

There are other options than batteries that they could use, but I know less about the weights of those. It would be possible to power this for a lap or two at least, assuming that the laser wasn't obscenely heavy. Which probably depends on what wavelength they want to use, some lasers are still monstrous but there are some that might be workable.

 

[Griffith500]

The energy for the air generator effectively comes from the electricity source.

The difficulty is getting the air into the cavity and directing the thrust in the right direction, at the same time.

Thermal losses are a drawback; I don't know what energy the exhaust has compared with internal combustion engines, and whether any of it could be recovered without unduly affecting thrust.

If the laser unit is onboard, the power source still needn't be. Microwave power transmission is one viable option, and doesn't need such coherent structures and accurate beaming as a laser.

 

[sk8er913]

I could build it .... do you want my bank details? but i could build one if i had a budget.. But yeah Gm are blowing bubbles from there hoop it reminds me of the nike car slightly. batteries alone be bigger than the car

Depends what kind of battery that use we currently use lithium ions that have a capacity to hold 260W/kg there a lithium oxygen "Lithium-Air" battery in research labs that's estimated to have 3200W/kg. That would vastly lower the amount of kg dedicated to the battery. I would guess that the engineers designed around these batteries @Imari

@Jordan I don't know if you have seen this thread or not yet, but we have discovered a real version of engine that the Chaparral uses, It uses a 1 MW laser to lift a small craft in those "Shock Waves" And I wouldn't be surprised if it sounded the same too. Thought you might be interested. Sorry if I'm bothering you, I've been tagging you a lot lately.

 

[UltimateBMWfan]

So if a 670+MW laser is shooting out the back of that thing, if that reciever breaks off for whatever reason, someone driving behind it is going to have a very, very bad day. Sounds quite dangerous actually.

 

[vasiliflame]

I voted other so i will show you my option the propulsion from Mr Garrison it bike .

Dont click if offended easily



wonder how PD would model that one

 

[ManicDan]

Let's use Tesla energy densities, because that's a standard thing.

http://www.teslamotors.com/roadster/technology/battery



For ten minutes of 670kW we need ~112kWh of energy. Lets just assume that they can somehow jigger it so that it can actually output the energy that quickly.

990 pounds per 56kWh means ~17.7 pounds per kWh. For 112kWh that's then about 1980 pounds. About 900kg. Which isn't as bad as I thought, actually. But then, that's just in battery weight. You could assume that the laser assembly weighs about what a F1 engine/gearbox does, and that they chassis would be a similar weight to an F1 car and all up it's probably about another 600-650kg of gubbins.

So call the car 1600kg all up, and it only goes for ten minutes or so before it's out of beans, depending on how helpful it's air generator is.

Thanks for the math.

So now that we know the energy is likely stored off the car, my ability to like it has gone way down

 

[sk8er913]

Thanks for the math.

So now that we know the energy is likely stored off the car, my ability to like it has gone way down

Idk if you saw the post I made but in a research lab there are some scientist attempting to create a battery capable of storing 3.2kw Per KG, Someone said it needed was only 70% efficient so the battery would need:

(10/7) * 671 = 959 KW(lets say 960)

So 960/3.2 = 300

It would weigh 300KG if it was using the theoretical Lithium-air batteries, and Sodium-air(also indev can hold 1.6 KW) which would make it weigh 600KG. And as Imari said current batteries would weigh a ton. (pun intended)

 

[djslofstra]

Should I say more? Well, I think this video pretty much covers it:

 

[IneedSchool]

I feel too stupid for this thread. lol

 

[ManicDan]

Idk if you saw the post I made but in a research lab there are some scientist attempting to create a battery capable of storing 3.2kw Per KG, Someone said it needed was only 70% efficient so the battery would need:

(10/7) * 671 = 959 KW(lets say 960)

So 960/3.2 = 300

It would weigh 300KG if it was using the theoretical Lithium-air batteries, and Sodium-air(also indev can hold 1.6 KW) which would make it weigh 600KG. And as Imari said current batteries would weigh a ton. (pun intended)

Redbull cars are already under 600KG, and output 1200+HP

i wouldnt mind if they somehow found a way to get a jet engine in there that did 1000+HP and weighed 300KG (no idea how close real life stuff is to that thought)

 

[Pseudopod]

Let's use Tesla energy densities, because that's a standard thing.

http://www.teslamotors.com/roadster/technology/battery



For ten minutes of 670kW we need ~112kWh of energy. Lets just assume that they can somehow jigger it so that it can actually output the energy that quickly.

990 pounds per 56kWh means ~17.7 pounds per kWh. For 112kWh that's then about 1980 pounds. About 900kg. Which isn't as bad as I thought, actually. But then, that's just in battery weight. You could assume that the laser assembly weighs about what a F1 engine/gearbox does, and that they chassis would be a similar weight to an F1 car and all up it's probably about another 600-650kg of gubbins.

Tesla cars have the highest density batteries out of all current cars, but not the highest possible you can get out of the lithium technology today. Additionally, batteries with 4x the energy density of what we have today are "on the horizon", and if this is a concept of what we might see in the future, it wouldn't be too unrealistic for it to have 10 times the energy density of today's batteries.

Of course, even with that, the propulsion system is still silly.

 

[Griffith500]

Just noticed the sound is pretty authentic in the video. I'll be very interested to hear how that works in the game. Since this is the first thrust-driven car, I wonder if it needed changes to the physics.

So if a 670+MW laser is shooting out the back of that thing, if that reciever breaks off for whatever reason, someone driving behind it is going to have a very, very bad day. Sounds quite dangerous actually.

It's the other way around; the bit on the back is the emitter, firing into the cone-shaped "mirror" which focuses the energy into an ever shrinking space Such constant exposure to the laser energy rapidly heats the air in that space.

The immense heat deposited into so small a volume causes rapid dissociation to an insanely hot plasma. That is, you get a bloody great explosion. The force of that is caught by the same structures used to catch the laser energy, and they bear the brunt of the thrust produced.

Then you need to fill the space with air again, and not the weird soup you just ejected. That's why it's pulsed.

It is dangerous, still, but not as dangerous as a static laser targeting the car as it moves. In that case the slightest error may result in toasted spectators!

 

[Mt. Lynx]

The batteries could be of graphene type.
There are several in development. Li-ion with graphene anodes. Stores twice as much as conventional Li-ion batteries.
There are also graphene nanotubes that work like supercapasitors in the making.

 

[ViSiOGT]

Theoretically if we can predict to some degree battery and laser capabilities, & actual laser thrust capabilities, theoretically we can pic a point in time when they all would be sufficient to produce enough thrust to propel a car. Using this theoretical math we can also calculate theoretical thrust and convert this into horse power, these figures can be then used to calculate theoretical performance figures like 0 to 60.

The Vision Project for GM is looking into the future to deliver its vision, maybe a little further ahead then most Brands but the car truly embodies the essence of VisionGT

 

[Exorcet]

The Vision Project for GM is looking into the future to deliver its vision, maybe a little further ahead then most Brands but the car truly embodies the essence of VisionGT

Looking far ahead is not a problem, but GM so far hasn't revealed much about the technical side to explain how this will work and why it's better than what we have now.

It might just be more of a stylistic exercise than an engineering exercise.

 

[ViSiOGT]

I think it has many sides. As mentioned, no ramp up so similar to electric motors all power right off the line to the top but without the mechanical moving parts usually required weighing down the vehicle. With the addition of thrust vectoring upwards to push the car down on the track like downforce. They are using a "Winged Suit" style I also find interesting and reminiscent of "Rollerman" & using 4 wheel steering I predict this will recreate the angles of attack Rollerman hits the corners in, further enhanced with with the variable wings manipulating downforce and vectored thrust.

Like flying inches above the track.

 

[Aloha62_2]

Is exactly how it would work.

Target tracking and beam manipulation is already working. High power lasers already exist at the megawatt level. Check out the Boeing FEL.

All this car needs is a special prism to receive the laser energy. Imagine a large Pylon in the centre of the track with beams tracing each car. Obviously line of sight is an issue, but not insurmountable.

Power regulation is already achieved with pulse width modulation, clever manipulation of which can give you sounds we're all familiar with with existing racing cars, with a twist. The trouble will be any lag between driver input and laser output.

So a 747 flying over each track with a laser pointed at the back of each car!

 

[super_gt]

Before race all racing pilots have to make life insurance, the crowd must wear sunglasses and sunburn cream(laserburn cream)

 

[niky]

I understand that but, so? Why care? Tell me, why do you care?

Because I'm a nuts and bolts person. If you don't like discussing why this is or isn't possible, why do you care that we do?

Thats the thing though, Jet would make less sense than this, as far as a ground based, circuit driving thing on wheels and tires. You don't get enough modulation or reaction time using jet because of the ramp up/ramp down in thrust. This is possibly instantaneous on-off with possible different level of thrust in short amount of time.

It's basically a jet. (A pulse jet, actually, as Griffith500 pointed out) A jet running off of superheated air or plasma. It's still a powerboat sort of thrust, with no direct relation to ground speed, and lacking the same fineness of speed control as wheel-driven cars.

Also, the shape dictated by the cone means no thrust vectoring. But then:

stylistic exercise

Because Pod-Racer.

Realistically, on a non-wheel driven car, I'd expect four-wheel steering, so in corners, you could point the jet at an angle, giving you even more lateral Gs. Don't know how you'd model the control of that with a racing wheel. You'd need to map it out to the Dual Shock controller... One stick will control the angle of the jet, the other controls the steering. On the wheel, if you have paddle shifters, you can use the paddles to turn the cone sideways.

The "Air Generator"

I can imagine a generator running off of the air coming from the cone, trimming off any wayward air not going in the direction of the thrust. GM is being maddeningly unspecific here. You could even use the Air Generator and selective damping of the cone output for thrust-vectoring.

It is dangerous, still, but not as dangerous as a static laser targeting the car as it moves. In that case the slightest error may result in toasted spectators!

Toasted spectators are yummy.

Also... I doubt they've fully modelled the thrust-driven nature in game. But if you can make an AI car go backwards by sitting in front of him...

 

[ViSiOGT]

I cant wait to Fly the Nurb in it

 

[Griffith500]

If the focusing mirror is movable and the laser emitter pivotable, you can get vectoring in at least one plane - e.g. longitudinally up and down. Extra downforce.

The video shows four wheel steering which adds extra yaw from the thrust. The active aero should be fine and potent enough, plus it will surely have brakes (generators?).

The laser output will follow whatever signal is being amplified (e.g. "optical klystron"), and will be very finely tunable - it just wouldn't fit in the car without some totally novel emision / amplification method. Manufacturers are already pulse width modulating clutches to control LSDs and even creating phantom gear ratios (Ferrari FF, 991 dual-clutch box.)

Advanced control systems are possible in games already, so this should drive OK. This must have been so much fun to work on.

Regarding thrust, the car physics is not setup to receive such a force in a sensible way - see rollover physics and the rideheight / rake downforce speed exploit. Really interested to see how they sidestep that.