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Why the Roadster 2 won't fly (legally)

Over the weekend we saw the impossible happen.

Or did we?

In Tesla's second "unveiling" of the Tesla Roadster 2, just nine short years after the first stillborn attempt, Elon Musk wowed the crowd with demonstrations of his all singing, all dancing "flying car".

And the crowd went wild.

So what did they see, what did they really see and what does this mean to the future of Tesla and EVs in general?

The demonstration started with the Roadster 2 climing a vertical ramp and easing into an inverted position. It was defying gravity and hanging upside down.

The presenters had told us that this car would break the laws of physics... had it just done so? Was the force of gravity now optional?

Well no. It was explained that the Roadster 2 has a set of electric fans that create a suction of "two Gs" and hold the vehicle firmly to the road or whatever other surface it's on.

This was the first alarm bell that what we're hearing and seeing contains a high degree of "snake oil".

You don't measure suction or downforce in "Gs". A "G" is a measure of acceleration, not a measure of force.

Now some might think that this is just semantics but I believe it clearly shows that Musk's target audience for this unveiling and perhaps purchasers of this car are those who slept through high school science classes. There was no benefit to using the term "2 Gs" rather than just "4,600Kg of downforce" so perhaps Musk himself doesn't know the difference, despite his claim to be an "engineer".

After backing down the ramp, the car then drove up again and launched itself, inverted, into the air.

The crowd drew a sharp breath...

An instant later, the "cold gas thrusters" kicked in, rotated the car to an upright position and lowered it gently to the ground.

And the crowd went wild (again).

OMG... it's really a flying car! Elon Musk has delivered on his promises!

Next we saw a different car drive towards a line-up of other parked vehicles including a Tesla Semi-truck. Then it lept into the air and did a full 360 degree roll while soaring over all of them -- before once again lowering itself gently to the ground amidst the clouds of ice crystals formed by the adiabatic cooling of the rapidly expanding high pressure nitrogen used in those cold gas thruster.

And the crowd went wild (again, again).

Surely now there could be zero doubt that this was truly a flying car.

Well I'm sorry to deflate so many fanboy bubbles but what we saw with these demos was a carefully choreographed piece of theatre.

The two vehicles used in these "stunts" were clearly lightweight "shells" designed to do nothing more than demonstrate the fan unit and gas thrusters. Some shots of the underneath of these two cars show that it was not the bottom of an EV but clearly a spaceframe construction designed to minimize weight at all costs.

Flipping and lowering a 500Kg shell of a car is much easier than doing the same with a 2 tonne road-going car.

Another dead giveaway were the wheels. On the stunt cars the wheels were clearly different to the ones on the *true* Roadster that was driven on stage by two employees. The real wheels were much heavier road-wheels, "mags". On the stunt cars these would have added too much weight so they were replaced with ultra light-weight versions.

Musk also told the adoring audience that the Roadster 2 would "pump itself up", refering to refilling the high-pressure tanks that hold the compressed air that powers all the aerobatics yet, in an interview with BBC's Top Gear, we were told that in order to refil the tanks the car would have to visit a specialist refilling facility -- there was no onboard recharge capability.

I find it kind of sad to see all this puffery and deception because, if the specs are to be believed, the basic Roadster 2 looks to be a very competent sports/GT EV with great performance. The thrusters and cold gas jets are the sort of thing that an eight-year-old might value but I doubt any more than a tiny handful of potential purchasers will be buying a Roadster for these features. What's more, the fact that Musk deliberately deceived his audience speaks to the mans intrinsic dishonesty -- telling lies when he doesn't have to.

At one stage he says you'll be able to buy this and use it on the road, albeit (to be fair) he does suggest that it won't be legal in all jurisictions. However, when you look more closely at this car, the more obvious it becomes obvious that none of the trick features will be road-legal, anywhere.

The version of the Roadster that has the lift thrusters is, by the FAA's definitions, an aircraft. This means that before it can be sold it will need to be "certified" and that is an extremely expensive and time-consuming procedure. The cost of certification would have to be amortized across the very small number of units sold, further hiking the price.

Also, you can't operate an aircraft weighing more than 250 pounds in the USA without the appropriate pilot's license -- a further cost and hurdle to use.

Finally, it's illegal to take off or land an aircraft on a public road, except in case of emergency and due to the highly experimental nature of the flying Roadster 2, you'll have to get a special permit from the FAA including a temporary flight restriction in order to fly it, each and every time you want to do a flip.

Even the base model Roadster without the rocket thrusters will be a disappointment from the "wow" perspective because you won't be allowed to use that suction fan on the roads to get better launch acceleration and cornering

Why not?

Well some simple math shows why not.

The amount of suction created by that fan when it's producing maximum downforce is four times the amount needed to rip a manhole cover from the road, if you happen to pass over one. That manhole cover would not only wreck the underside of your Roadster and perhaps cause a battery fire but it would also pose a risk to traffic behind you. From that perspective the use of the suction will not be "road legal" and to avoid potential litigation I'm pretty sure it will be geofenced so as to be inoperative on public roads.

Then there's those high pressure (10,000psi) gas tanks.

When charged with nitrogen, those tanks contain about 103MJ of energy (calculated with Brode's safety equation), thats about as much explosive force as you'd get from almost 20Kg of a high-explosive such as C4.

Also, because the car doesn't self-charge those tanks, you'll have to drive to a facility to get them pressurized and odds are many owners will be driving around with those tanks at the full 10,000psi. No imagine one of these cars is involved in a crash or perhaps has a battery fire -- and that tank ruptures with the equivalence of all that high-explosive.

Making these things road-legal will be nigh-on impossible.

This column is already far to long but I'm doing a video in which I'll attempt to explain the real reason for the Roadster 2 and it has nothing to do with flying cars but everything to do with massively increasing Musk's control at Tesla and his total wealth.

Carpe Diem folks!

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