Ron Patrick's Street-Legal Jet Powered Volkswagen Beetle (2006) | Hacker News Reader

Ron Patrick's Street-Legal Jet Powered Volkswagen Beetle (2006)

ronpatrickstuff.com

271 points1317135 comments

Seems like a good time to ask this question that has been bugging me forever, since all the HN jet nerds will be drawn to this thread:

Why hasn't anyone made a hybrid car that uses a gasoline-powered turbine generator to charge its batteries instead of a piston engine?

I'd imagine that hooking up such an engine directly to the drivetrain like in a Prius would be difficult, but surely a small turbine with one hell of a muffler running a generator (similar to a natural gas power plant), both running only at their peak efficiency RPMs, would yield a very efficient car that could still use the extant gasoline infrastructure.

I'm sure there are very interesting reasons, either due cost, noise, reliability, or durability, that this idea hasn't taken off, and I'm very interested to hear y'all's thoughts on the subject. Or maybe there has been progress in this area, and I'd love to see some links!

I think someone is making this, or maybe I misunderstood your question. The Ariel Hipercar uses a jet engine to power it’s 4 electric engines. I think it’s just used as a range extender, and last I saw they didn’t have it working yet. It’s been a while since I checked up on the car.

EDIT: I just read this article from 2023 that says the turbine engine still isn’t working: https://www.evo.co.uk/ariel/206120/ariel-hipercar-prototype-...

I don’t have the source at hand, but a gas turbine is ridiculously inefficient for variable loads. At idle, fuel consumption can be ~35% of what it is at full power.

It would only need to charge for short time, and subsequently shut off. When a charge top-up is required, startup would be another rigamarole.

Now, rotary engines, that’s a different story…

https://www.mazda.co.uk/cars/mazda-mx-30-r-ev/

> As Mazda’s first fully electric vehicle, the MX-30 is the complete opposite of a hit in North America. The company’s U.S. division has in fact decided to axe the model after just two years.

No R-EV on this side of the pond either.

i think even the tiny, model jet engines used in radio control planes are both very hot, and move lots of air. both of which are hard to tame to the point of making them comfortable to coexist with on a city street in large herds.

I still want one. direct the exhaust forward, dump in a little extra fuel, and instant snowblower / flamethrower. Makes that pesky crosswalk crowd just melt away.

And turns it into a skating rink five minutes later. You want the snow to go away, not to change into liquid water on a sub-zero stone substrate.

Excellent point, but i must rebut: (a) i'm already on my way by then, and (b) FIRE! </beavis>

It's a(t least one) thing. Test run before the snow gets too deep:

Jet Powered Blower https://www.youtube.com/watch?v=BcEkt5vQTVQ

Having an ICE that drives a generator (alternator?) to power a traction motor(s), without being mechanically linked to the drivetrain, is how diesel locomotives operate. I believe the concept also has been (is being?) explored for linehaul trucks. But I'm not sure what constraints there are on passenger vehicles though... I'm also curious.

If I had to guess, I would bet that the constraints are more commercial than physical... hybrids are already very efficient, so the market for such a vehicle would probably not justify the engineering costs. But that's just a guess!

Union Pacific tried using turbines in the 50s[0] but fuel consumption was an issue (I think they had to keep the turbine idling and maybe throttling wasn't as easy?). Also mentioned in the wiki article was the low-grade fuel they were used was able to be used for plastic manufacturing instead of just burning it.

The bigger difference between locomotive applications and GPs question is around charging batteries as opposed to running motors or directly turning the wheels. Efficiency of the smaller turbine is mentioned in another comment - but I have to imagine you'd also see some loses going from turbine to generator to battery and then to electric motor.

[0] https://en.wikipedia.org/wiki/Union_Pacific_GTELs

Diesels idle pretty efficiently whereas jet turbines have very high minimum amounts of power.

In terms of efficiency losses between the turbine, generator, battery, and motor - no, not really; look at most modern hybrid cars.

Lithium ion battery coulombic efficiency is in the high 90's percentage-wise, by the way.

I would imagine that we might see hybrid turbine locomotives as battery power density and cost continue to improve.

The MBTA uses jet engines as giant hairdryers to melt snow off the Mattapan High Speed Line [0]. I’m not sure if it’s also serving as the prime mover, but even if not it’s still an interesting and unusual application.

[0] https://youtu.be/DL6jKOCeVec

Arnold Schwarzenegger’s Hummer from the early 2000’s is setup like this — 100mpg with bio-diesel. I think this is the original article I read about his car’s creator, Johnathan Goodwin, from years ago.

https://www.autoblog.com/amp/2007/10/20/biodiesel-turbine-su...

Per the article, he claimed the Hummer would get 60, the 100 number was aspirational based on ideas he had for future designs.

(Still pretty awesome. If it didn't likely cost more than what truck is worth I'd want it too)

Sounds like you just described a hybrid, only needs a larger tank.

I've been wondering about this very same question a lot myself and accidentally stumbled across the answer just a few days ago: Efficiency of turbines smaller than grid scale is simply not anywhere close to what piston engines can do at e.g. car size. Even at naval scale, turbines only win in use cases where power density is more important than fuel efficiency. Helicopters are deep in the (specific) camp of power density beats efficiency because carrying a heavier but more efficient engine would easily eat the fuel savings. Fixed wing aircraft gain range by climbing high, but up there both efficiency and power density of piston engines decreases dramatically with decreasing air density, so they are also in the camp of power density over efficiency (turbines are also affected, but not quite as much).

Note that despite all this, the Otto Aviation 500L that is all about fuel efficiency at high altitudes uses a piston engine (they probably put a lot of effort into their turbocharger, those can lessen the impact of thin air)

Celebrity and Cunard built a few Cruise ships that use turbines to generate power to its electric motor propulsion.[1] They regret the endeavor owing to cost of operation.[2]

[1]https://www.ge.com/gas-power/industries/cruise-lines

[2]https://www.airliners.net/forum/viewtopic.php?t=1202425

The bit about the naval use and efficiency isn't quite accurate.

The issue isn't that they're not efficient. It's that they are only efficient at high power level, and the minimum power level they're efficient at (and even their minimum power level, period) - is quite high. To compare: Britain's current aircraft carrier has four diesels that total 40MW...combined those diesels equal one of its two 40MW turbines.

This minimum power level is why jet airplanes have an APU, and often taxi with just one engine running, with the second started up with enough time to get up to operating temperature for takeoff.

Example: https://en.wikipedia.org/wiki/Rolls-Royce_MT30

~40MW, minimum efficient power level 25MW.

25MW, even if it's very efficient in terms of turning kerosene into shaft power, means the ship is moving really fast, and thus there's enormous fuel consumption and drag.

I don't think that it's just inefficiency at certain power levels:

The big table on https://en.wikipedia.org/wiki/Brake-specific_fuel_consumptio... has the Marine Trent rated less efficient than some car engines. And that table is peak efficiency, not efficiency at some arbitrary inconvenient power level.

But you are right in so far as efficiency at the low end of the power range is very important in commercial shipping. Because the energy demand (at the drive shaft) of a given trip is highly dependent on the desired speed and if going show ruins your engine's efficiency any dip in demand will ruin you economically (because others on the market are much better at compensating the dip by "slow steaming")

Then wouldn’t they just have a 5MW turbine and run it at its peak efficiency?

Another reason many navies like turbines is that big diesels produce a lot of low frequency noise which travels very far underwater, so submarines can hear you coming from a very long distance.

Although many navies do operate combinations of diesels and gas turbines (CODAG etc.), in such cases the diesels need to be installed on special shock absorbing mountings, in some cases even with a diesel-electric drive to avoid coupling the vibrations of the engine to the hull via the propeller shaft.

To add to the discussion - the M1 Abrams tank uses a turbine. I don't know how that's linked up to the tracks though.

Former M1 Abrams crewman (19K). It has an automatic transmission.

I recently stumbled into a couple of YouTube videos on turret design for tanks.

* What actually IS an “Oscillating” turret? https://youtu.be/46k7uhPHpLY

* What happened to Rear-Mounted Turrets? https://youtu.be/g5DOf2eZW3Y

At 4:24 in the rear mounted turret video it touches on the aspects of modern transmission.

Interestingly, that engine has good power to weight ratio, has a better noise profile (higher pitched noise, that doesn't transmit far, albeit louder locally), can operate with a variety of fuels, and can handle arctic conditions.

The downside is that it consumes 50% more fuel than a comparable diesel engine.

The turboshaft is linked to reduction gearing. I’m not sure how it’s linked to the sprocket that drives the tracks but it’s probably a chain, like on a motorcycle.

As mentioned in a sibling comment, turbines don't scale down very well. Boundary layer friction gets relatively worse for smaller turbines, and AFAIU small turbines have relatively larger inefficiency due to air leaking past between the blades and the casing, etc.

There's a couple of companies working on recuperated turbine engines for small aircraft in the few hundred kW range, remains to be seen whether any of these will succeed.

> Why hasn't anyone made a hybrid car that uses a gasoline-powered turbine generator to charge its batteries instead of a piston engine?

Because turbine engines have some pretty serious downsides. Compared to a piston engine, they guzzle fuel [1], they're pretty complex to repair (which is one of the problems Ukraine is facing), they spin at absurd RPMs which means that they need some serious housing to not turn into a shrapnel dispenser in case of an engine failure or accident, and they produce an awful lot of hot exhaust gas at high velocity that needs to be dissipated somewhere - down isn't OK because it will melt the asphalt, sideways is not OK because it will melt or injure anyone and anything next to the car, and upwards carries serious risks as well (e.g. if you're in a tunnel).

[1] https://www.augsburger-allgemeine.de/politik/panzer-vergleic...

The military has made several "micro turbine generators" Here is a report on one:

https://apps.dtic.mil/sti/citations/ADA515623

My guess the answer to your question would be cost.

But they have

https://en.m.wikipedia.org/wiki/Jaguar_C-X75

Turbines get more efficient as they get bigger.

Wrightspeed did this a while (10 years?) ago. It looks like they have since pivoted to fully electric powertrains for buses, but when they first started they were doing range-extending hybrid powertrains for heavy trucks. I found an article the describes the system at the time:

  https://www.e-hike.net/tr/content/wrightspeed-unveils-new-turbine-range-extender-medium-and-heavy-duty-electric-powertrains-30

With a range-extender hybrid system, you can keep the turbine closer to its peak-efficiency operating point, since it only has to handle steady-state load while the battery takes up the spikes. Not sure how it would do up a long grade, but I imagine they designed for that.

Video of a Wrightspeed truck: https://www.youtube.com/watch?v=sIAosHyqARA

It's been done a few times, as listed here.

One not mentioned was someone in Southern California who got an old aircraft APU (probably a Solar T-62[1] or similar) and made an electric hybrid back in the 1980s. The APU charged the battery, and shut down when the battery was full. Worked OK, apparently.

The trouble with turbine engines is that, below bizjet size, they don't seem to get any cheaper. Not for lack of trying in the 1990s. NASA, Williams International, and Eclipse tried hard. There were a few prototype planes, but no commercial success. There are today what are called "very light jets", but this means 4-6 people and and a price around $2 million.

General aviation is still mostly piston-powered. There are tiny jet engines for R/C planes, but they have very short operating lives.

[1] https://en.wikipedia.org/wiki/Solar_T62

> The trouble with turbine engines is that, below bizjet size, they don't seem to get any cheaper.

That's because of the lack of demand. GA is extremely conservative, most designs date back to the 50s-70s and the more modifications you make to a design the more extensive and expensive certification becomes. They're still flying with leaded fuel, many decades past the removal of lead in car fuel, because up until last year there hadn't been a certified alternative (and the one that is is not suspected to be readily available until 2027+).

For a jet engine powertrain on a plane the size of a Cessna, you'd need to redesign the whole frame, you'd need to design appropriately sized engines and maintenance procedures, and you'd need to re-train all the pilots. Before that happens, GA will go electric.

You'd be better off with an engine specifically designed to be efficient. Turbines are great at many things, but they are complex and don't scale down very well. They were primarily used where high torque and power is required, and they just aren't practical outside of that.

A better option would be a constant speed ICE engine running at it's peak efficiency (like a diesel-electric train).

I worked for a company that did this in the 1990's. Small gas turbine, the size of two show boxes (200hp) powering a generator, which charged the batteries and/or electric motors.

The advantages are efficiency, low weight and no gearbox is needed, as the turbine spun at over 100,000 rpm and the generator was fine with that.

The main disadvantages were noise and turbines need more maintenance than piston engines. No LiIon batteries back then either.

The project only built 1 finished prototype.

Volvo did this back in 1992 but only as a concept vehicle https://en.m.wikipedia.org/wiki/Volvo_ECC

>Why hasn't anyone made a hybrid car that uses a gasoline-powered turbine generator to charge its batteries instead of a piston engine?

The current engine formula (2014-) in Formula 1 racing might be of interest to you.

> During acceleration of a Formula 1-car, the turbo charger is performing at its peak and is spinning at about 100,000 rpm. The MGU-H (Heat) functions at that moment as a generator. This is connected to the turbo charger and converts the energy, generated by the turbo, into electricity; that, in turn, is stored in a battery or sent directly to the MGU-K.

> This MGU-K (Kinetic), connected straight to the crankshaft of the turbo engine, acts as an electric motor that supplies extra power to said engine. This MGU changes into a dynamo, which stores the energy that is released during braking in the battery. This stored energy, can later be used to support the turbo engine during acceleration or overtaking.

Discussions on similar submissions:

Jet Powered Volkswagen Beetle https://news.ycombinator.com/item?id=28349589 (August 29, 2021 — 2 points, 1 comments)

Ron Patrick's Street-Legal Jet Powered Volkswagen Beetle (2006) https://news.ycombinator.com/item?id=16513835 (March 4, 2018 — 156 points, 60 comments)

Street-Legal Jet Powered Volkswagen Beetle https://news.ycombinator.com/item?id=5384390 (March 15, 2013 — 6 points, 2 comments)

Street Legal Jet Powered Beetle (2006) https://news.ycombinator.com/item?id=831185 (September 18, 2009 — 76 points, 23 comments)

Thanks! Here's a great subthread from one of those: https://news.ycombinator.com/item?id=16524533

(I just added it to https://news.ycombinator.com/highlights)

@dang I wonder why we don't just generate these things at the bottom of every article? My extension does it already, but I feel like it would help a lot as a core feature.

The lists that I post, and that most users post, are reviewed to include only the interesting threads. This makes them more valuable to readers, since the odds of going on a click trip to something boring are much lower.

Rather than autogenerating them, I think what we'll do is add software support for the community to collaborate on the 'related 'list for a post. And it needn't just link to related HN threads - it can be related URLs on the same story, for example.

When we'll actually get to this is another question of course...

Good points. Previously [0], in your list, it doesn't include the number of points, as well as the calendar day, which is something that my generator includes and helps prevent click trips.

To filter further, the list could just include posts with some points + comments ratio math. Also filter out similar posts within a short timeframe, if two posts happen within a week of each other, pick the one with the better ratio math.

No need to involve the community in moderation a second time, since they've already involved themselves with points/comments to begin with.

[0] https://news.ycombinator.com/item?id=37768936

Wouldn't help me unfortunately, as I am reading HN on an android app. But good idea.

and still no videos online.... fishy

> You have to give the California Department of Motor Vehicles (the DMV) credit for creativity on this one. A DMV insider has disclosed to me that the DMV has made a formal request to a federal agency to rule if my Beetle constitutes a threat to national security based on what could happen if it got into the wrong hands. This raises three questions in my mind: #1 Does this mean I’m the right hands? #2 If someone with the name "b_laden13" is the highest eBay bidder for my Beetle can I refuse his offer even if he has the prestigious eBay Red Shooting Star feedback rating (the highest)? #3 Would this affect my eBay rating?

Wonder if they ever found a way to give the guy a ticket.

He had it listed on Craigslist a few years ago... for $550k. Anyone know the current status of it?

https://www.autoevolution.com/news/get-yourself-the-iconic-j...

It's still sitting in his shop. RP is not going to sell it.

I think it's more that like most modded / custom car owners, he thinks that it's reasonable to set an asking price according to the following formula:

(Cost of car) + (Cost of Mods) + (My time x some magical hourly rate) = reasonable asking price

The more sane of them add in a multiplier, like say .5 to .8. Or leave out their time.

Reality is:

What 1 person among the people who hear about the sale will pay = reasonable asking price

Yeah things like that are always the same.

It’s the sellers dream, rarely anyone else has the exact same dream.

If they have a similar dream all they see is the differences and what they’d do differently.

How on earth is it street legal to emit a high-pressure plume of jet exhaust behind you?

’Murica

Its street legal to drive using the standard motor with the jet engine OFF.

Oooh, it's a hybrid!

"Hmmm, the car has two engines making the car a hybrid so maybe we can drive in the commuter lanes along with the Toyota Priuses. "

Imagine being the cop who has to argue over the ticket with that guy ^^

"I'm... gonna park a little further back."

There's a paragraph and photo of this very thing in the TFA

> That doesn't stop me from the occasional blast on the highway though.

Something being road-illegal doesn't stop you from doing it anyways...

We live in a society where things are legal by default. Why would adding a jet engine to a car be a priori illegal? If he harms somebody or otherwise causes damage, that itself is what's illegal and he'd be liable regardless of motor vehicle regulations. If this mod became a larger trend, especially consumer-available, then regulations would be implemented to head it off. But for a few lone instances it's not particularly necessary.

I am not in the US, but where i am afaik anything that modifies the car like this would have to go through some sort of recertification process.

It would be perfectly legal on private property but not public roads

Well not sure where you are, but where in EU I am, you can modify the insides of your car (people attach entire apartments to the insides of their cars...), and there's nothing wrong about stuff sticking outside - you just need to attach a red flag if it's over 1.5m out of the car (maybe red flame would be enough?).

The modified rear door might be a problem, but where I am you could simply keep the original open, or detach it.

Road traffic laws are absolutely not harmonized across the EU.

French, Portuguese and German rules of the road for example are all different in statutory strictness and enforcement strictness.

I’d guess that’s true in the US too, if you modify the engine or transmission or exhaust system, etc. But adding something to your car without modifying the existing systems has no regulation and no certification process, which he sorta talks about in the article re: police inability to enforce. As long as there aren’t other laws you violate, hanging a big fan out the window might not count as modifying the car.

20 years ago in Australia my car got canaried because I had LPG and a pod filter, which was illegal because you were only allowed 1 modification to the intake system. I am 100% confident that if I strapped a jet to the car, it would be illegal. As it should be. If you want to do extremely dangerous modifications, do it on your own property. Not a public road where you risk killing a family of 5.

You're speaking from an Australian perspective about what is, to make an otherwise unsupported argument about what should be in the US. I'll be one of the first to point out problems and blindspots from the American conception of "freedom", but in this case it seems highly appropriate. You yourself even got bit by overregulation for something seemingly reasonable and forward-looking, and yet you're still reflexively defending it!

In my estimation your example "family of 5" is at much more risk from widespread unnecessarily-high bro-dozer trucks than a single engineer personally adding a jet engine to his car while seemingly being very in touch with the dangers of operating it. In fact given the severe disparity in other vehicle crash survivability statistics between coupes and trucks, I've got to wonder if this car isn't still individually safer than a casually-driven pickup truck.

As an Australian-American living in the US I can confirm that the Australian concept of law (aka Nanny State) would ensure that this modification is illegal by default. Think of the children.

Children don't really fit in the intake so it shouldn't be a problem

I was shocked as a Brit American living in the US how nanny state Aust is. Even more than Britain. Certainly when it comes to cars and driving. The whole ‘anti hoon’ thing seems shocking to me with my now mostly American sensibilities.

But I guess that’s why we both live here rather than blighty or down under.

Australia's just fine with adding jet engines to cars and designing|building one million round per minute guns.

It's the mixing up of such things with the general unconsenting public that raises an eyebrow.

Hoon's can hoon - just out of earshot of people that want a quiet life and off the community car parks and roadways - there's no shortage of private land and designated drag strips | raceways.

https://aussieinvader.com/the-people/rosco-mcglashan-oam/

https://thewest.com.au/lifestyle/motoring/wa-built-1600kmh-j...

https://en.wikipedia.org/wiki/Metal_Storm

It’s important to understand most things happen for a reason, and as a Brit American living in the US you might be missing some context.

In the area I grew up, it was expected that your first car would be a V8. Hooning was ingrained into the culture. Back then it was a single spinner, no ABS, no airbags, basically no safety features at all. So what would happen is someone would get their licence, grab as many mates as they could, drive as fast as they could, and wrap their car around a tree killing everyone. Every week there was a news story about a multiple fatality P plate accident caused by hooning.

A culture of dangerous driving and dangerous vehicles led to Australia’s anti-hoon laws. It’s not just “ooh silly nanny state laws for no reason”.

It is likely to be safer simply because the one driving it is going to be a lot more careful than the average driver.

I recall seeing a study a while ago that showed how those who work on their own cars, especially for those who do major jobs like engine rebuilds, are statistically far less likely to get into an accident. Unfortunately I can't find it now.

> a single engineer personally adding a jet engine to his car while seemingly being very in touch with the dangers of operating it

What if a non-engineer who doesn’t understand the dangers makes this type of modification? This is is why it needs to be illegal. Just because someone straps a jet engine to their car it doesn’t mean they know what they’re doing, and _that_ is the risk, and why pretty much all laws exist in the first place. Many people could drive safely without speed limits, but we have speed limits to cater for people who can’t. My point is that if this type of modification truly is legal in America, that’s scary, and Australia got the laws right. A jet-powered car is not inherently safer in the US than Australia.

> What if a non-engineer who doesn’t understand the dangers makes this type of modification?

This hasn’t happened afaik in the last 15 years. I assume any non-engineer who doesn’t know the dangers also doesn’t have the technical know how to build this. Also the cost is several hundred thousand $.

History seems to indicate it’s a non-issue.

He didn't modify the car's original factory system. He simply added onto it, he added a second independent system.

Tbh I kinda agree this is a bit ridiculous to assume it's safe to drive on the road though.

In this case the law has already been written. It's not a CARB-approved, nor EPA compliant engine. You're not allowed to run it on the street. The law is written so that everything you do to a car's emission system is illegal by default. To make any engine modifications in California, the part must be CARB approved and have a compliance sticker on it. Engine swaps in California are legal, as long as the engine being swapped is at least as new as the engine in the vehicle and meets the same regulatory requirements. Which means you swap in another EPA/CARB approved engine, but not a jet engine.

The stock engine — and the emission control system attached to it — are entirely untouched.

In California, you have to register your car and have it pass a smog test. How would this pass that?

Just drive on the gasoline engine.

Doesn't the smog test require you to run your car at the peak power it can do, or something like that?

Floor the accelerator, yes.

Find a toggle for an unrelated afterburner? Not so much.

I’d hate to be the minimum wage tech tying to figure that out!

Aren't "inspections" nowadays done only by plugging into the OBD port? So, no problem?

Jet exhaust doesn't need to be high pressure. It depends. For example a turboprop engine doesn't provide any jet thrust and usually the exhaust is even pointed away from the direction of flight.

But it is very hot so exhausting it close to the ground or people is a serious problem.

This should be retitled "Now I'm going to finish adding jet engines to my wife's scooter."

The scooter seems like it could be a poor idea due to asymmetric thrust, and I have to wonder if he just mocked it up in jest. It does look pretty awesome though.

You could adjust the two throttles to trim it, preferably not while in motion.

This is wild, but I would strongly disagree on the aesthetic of it. In my opinion, he picked pretty much the worst possible car for this. Managed to make a jet-powered vehicle look... lame, somehow.

Imagine an El Camino or even an AMC Eagle with this contraption in the bed, how much cooler that would look? But really, how could you not use a Delorean as the base for this project??

https://en.wikipedia.org/wiki/Camp_(style)?wprov=sfti1

> The car was built because I wanted the wildest street-legal ride possible

> The Beetle was chosen because it looks cool with the jet

It really does sound to me like this person was genuinely going for "cool" and "wild", not "campy"

Apparently the post is from 2006. I wonder if this contraption is still street-legal.

what I really want to know if he ever finished his scooter!

It would be legal to run it on the factory engine, at which point the jet is just cargo. If you start the jet on a public road, it could be considered a public nuisance, reckless driving, etc.

If a the vehicle presents a clear and present danger of any kind it is a-priory a ticketable offence at least. With the jet off, it poses no such danger.

I'm certain an officer could find all sorts of reasons to ticket that vehicle if inspired.

You can own a car, you can own a flamethrower, you can't fire your flamethrower out of your car while driving on public roads.

And for California, don't forget "Exhibition of speed" which is a rather nasty ticket to end up with.

Comments from 2018:

https://news.ycombinator.com/item?id=16513835

Can someone ELI20 how one would convert a turboshaft engine to a turbojet engine?

Basically you just remove the shaft.

And put a nozzle on the exhaust.

Ah, that makes sense. Thank you!

This is a hacker classic. Would be curious to know what eventually became of it.

"The car has two engines: the production gasoline engine in the front driving the front wheels and the jet engine in the back."

Careful wording to give the impression that the drive shaft of the helicopter turbine would be connected to the rear wheels, without actually claiming that it is. So it's a car with a large flame thrower in the back, minor The Boring Company vibes.

Well possible that the author might have had more fun writing than building/driving. (I do love the incredulous tone of "#1 Does this mean I’m the right hands?")

I don't think so. In another part he mentions

> This is a helicopter turboshaft engine that was converted to a jet engine

I can't see a way to get rotary power out of this engine after the modifications.

Any turboshaft engine is a jet engine if you don't connect anything to the shaft and point the exhaust in the right direction. Just not a very good one, at zero bypass.

If you think there is anything done in this project to increase performance you are missing the point of the joke: woah, jet engine! Woah, rated 1350 horse power! Heh, retro novelty compact with a truly glorious amount of hot air.

Will the turbine exhaust noticeable push the car? Sure. Even a piston engine exhaust does, e.g. some versions of the Merlin engine claim extra 70 HP from exhaust thrust.

Is the author having great fun (and readers who get it) by brandishing the rated rotary power of the turbine over and over again, while carefully avoiding any mention of actual performance of the car? Absolutely. But it's not mean deception, it's friendly trolling. Which is basically the essence of the entire hot rod idea. I dislike the waste (of a good car, and the occasional kerosene burn, the turbine was probably beyond airworthyness certification and thus scrap anyway), but I find his "friendly trolling" charming in a surprisingly deep way.

For a stunt car like this there's not a huge need or desire to have it powering the wheels at all.

The direct air thrust will push the car just fine, doesn't need a transmission, has zero issues with wheel spin or traction, and so then doesn't require re-engineering the wheels/tires and then the suspension and/or chassis to handle 1350hp.

Yeah imagine the rubber! They’d need American drag racing tyres!

It produces thrust in the normal way a jet engine aircraft does... with high exhaust velocity. From the videos you can see shock diamonds, so it is producing supersonic exhaust.

Fun read!

I would rather not follow a car like that on the road, hell, even driving by it.

The looks don't signal the intent. Guess what will it do next when either light starts blinking, or both? There is no known signal for kicking on the jet engine! From the back it looks like a gigantic cannon too, BeachBuggyRacing kind.

Just for kicks, I'd also put a "Student Driver" decal on the rear window :).

Awesome project, but are there any actual videos of it running the jet engine?

He says the jet engine moves 11,000 CFM of air, but that air can only come through the windows and the sunroof. Pulling 183 cubic feet of air per second through those little openings while sitting in the drivers seat isn't going to work. Just try to do the math on how fast that air would have to be moving through those windows.

Cool show piece though.

Yes, there's video online.

https://www.youtube.com/watch?v=TCqxWhKe_tA

https://www.youtube.com/watch?v=5zNdkXwFQ3c

(Noise warning, for obvious reasons.)

I see

> I don't know how fast the car will go and probably never will. The car was built to thrill me, not kill me. That doesn't stop me from the occasional blast on the highway though.

but I am unsure if that means he has never driven it using the jet engine, or whether the engine even will power the car or just kinda runs on its own. I'm curious to see it go at all under jet engine power.

Edit: maybe this is it https://www.youtube.com/watch?v=R-ipYAl3o40

I think he means he's used it plenty, but hasn't tried to max out the speed.

That's my reading as well.

I have a vague memory of this site or an interview previously saying he got up to 130 mph once, before deciding he'd rather not find out what speed a VW Beetle lifts off the pavement.

That videos's an original Beetle, not a New Beetle.

Give 6 sq ft for openings, that's around 30 linear feet per second. ~30 feet per second is ~20 miles per hour. That's a stiff breeze, but it doesn't seem outrageous.

This not a typical low-bypass, cigar-type turbofan jet engine you see on airplanes, rather, it’s a modified turboshaft jet engine used for helicopters, intended to provide longitudinal rotational energy. The air it moves from the intake is a fraction of what it produces as the combustion process itself results in gasses being chemically formed. There is no propeller or fan on this engine - it’s closer to a rocket than what we think of as a jet.

> it’s a modified turboshaft jet engine used for helicopters, intended to provide longitudinal rotational energy. The air it moves from the intake is a fraction of what it produces as the combustion process itself results in gasses being chemically formed.

It's not a turbofan no but it's a jet engine burning fuel the regular way (using air), like the ones on a B-52 or Concorde. Very different from a rocket engine that carries its own oxidiser.

I’m fully aware of the difference. The only parallel I’ve drawn is the fact that it uses gases as a result of the combustion as propulsion rather than spinning a fan. Whether it has its own oxidizer is irrelevant for the purposes of this analogy as I don’t see this vehicle achieving any sort of space flight.

I'm a little shocked there's no 1/4 mile time.

Surely when you strap a jet engine to a Beetle you need to find out how fast it goes!

Quick, not fast. Low 1/4 times are mostly associated with acceleration, not speed.

> The Beetle was chosen because it looks cool with the jet and it shows it off well.

Subjective, but I would argue that the Beetle is a terrible choice and makes the jet engine look like a pole sticking out of a ball. A flat sports car would probably fit the look much better and mimic the aerodynamics of an aircraft.

How did Jay Leno not get this car on his TV show when he had it? He still is posting episodes to YouTube so it is still possible.

Jay has his own jet bike, https://www.youtube.com/watch?v=WDhoYXw2IPc

My buddy (a car guy) from Mountain View told me he could hear this thing on 280 late at night every now and then. Anyone else?

nice... does anyone remember a K Car with a supercar engine? that was not quite as crazy as this one, no jet engine, but it was nice. i can't seem to find it but i remember reading about this "sleeper car".

Crazy engine swaps are not uncommon. There are some Fiat 500s and such with v8 double motorcycle engines, wankels or even v12s and racecar v6s:

https://www.youtube.com/watch?v=A52W20Z38Bw

https://www.youtube.com/watch?v=D6SZuionhqQ

A turbine is relatively exotic, if only because they are even more impractical.

Even a snowblower with a HEMI...

https://www.ign.com/articles/2005/06/22/that-thing-got-a-hem...

IIRC someone put a turbocharged 7L smallblock V8 in the back of a Lotus Exige, though they had to lengthen the chassis to make it fit.

That is probably the Henessy Venom GT.

My favorite is the Ariel Atom V8, which swapped the Honda Civic engine for a hilarious 483hp 3L NA V8. In a 1300lb car.

The Venom GT was indeed what I was thinking of. 1451hp in a 2800lb car.

i know ron!

Tell him to make a YouTube channel or update us on that scooter ;)

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