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Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by causi on Wednesday April 05, 2023 @11:28AM (#35455817)
Ok, so they're "shooting for" a performance of 1hp per 1.57 lbs of engine weight. A Toyota Camry engine produces 1hp for every 1.41 lbs of engine weight. It produces 1ft-lb of torque for every 1.94 pounds of engine weight, compared to 1.58 for the Camry.

How is this revolutionary motor being outdone by a mid-range sedan engine?

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by shadycuz on Wednesday April 05, 2023 @11:38AM (#35455976)
The engine is the size of a push mower.

> XTS-210 is about the size of a basketball, weighs in at 19 kg (42 lb), and displaces 210 cc.

So you are talking about a 26HP lawn mower.

While the Camry might make more power at its normal size. It would not if you scaled it down to the size of a basketball. I'm guessing it would make 1-3HP at that size.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by 93po on Wednesday April 05, 2023 @11:50AM (#35456158)
A Traxxas 5407 TRX 3.3 engine used in RC cars makes 1.42 horsepower, weighs 305 grams, and fits in the palm of your hand.

This is 1hp per 0.46 pounds of engine weight, nearly three times better than the camry engine.

Granted an RC engine runs on a mixture of fuel and nitromethane, and doesn't have any reasonable durability compare to a Camry engine. But it also only costs $200.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by seabird on Wednesday April 05, 2023 @12:09PM (#35456451)
You can't just make the Traxxas 18x bigger and get linear performance improvement. Trying to compare power/weight between engines with radically different weight constraints is silly.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by 93po on Wednesday April 05, 2023 @01:13PM (#35457356)
Ok, a Kawasaki H2R engine makes 326 horsepower and weighs about 160 pounds running regular fuel. That's almost identical to the Traxxas - 1hp for 0.49 pounds.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by seabird on Thursday April 06, 2023 @08:18PM (#35476403)
That engine is 4x heavier and supercharged. You're not comparing apples to apples.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by 93po on Tuesday April 11, 2023 @12:48PM (#35527725)
my point is that this ratio exists both much smaller and also somewhat larger. it makes sense this same ratio would be possible in the middle of the two as well. also diesels have super/turbo chargers all the time on production engines, why is that cheating?
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by syrrim on Wednesday April 05, 2023 @12:29PM (#35456736)
If you had 18 such engines it would get you precisely 18x the performance, at precisely 18x the weight.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Retric on Wednesday April 05, 2023 @12:44PM (#35456957)
No, because you would need to add structural elements, some way of combining power output, and cooling if you’re aiming for a similar form factor.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by aidenn0 on Wednesday April 05, 2023 @12:42PM (#35456932)
And precisely 1/18 the MTBF
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by 93po on Wednesday April 05, 2023 @01:05PM (#35457264)
In a way, sure. Often when a car engine fails people just replace it. If you were to replace all 18 when the first one failed, the same way you would with a regular car engine, it's not 1/18 the MTBF. And if it was just 1 failing prematurely and you replaced only that one, you also see that same dynamic with car engines.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by pas on Wednesday April 05, 2023 @12:54PM (#35457083)
but it fails gracefully, right? (only one engine fails at a time)

it's like RAID, great until the RAID card itself fails

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by aidenn0 on Wednesday April 05, 2023 @06:50PM (#35461546)
It's probably most like losing power in a single cylinder; the effects vary from engine to engine.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by jacquesm on Wednesday April 05, 2023 @06:55PM (#35461611)
They tend to seize and when they do and you gang them they'll likely break stuff in the other ones unless you add a freewheel or some other luxury like that.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by seabird on Thursday April 06, 2023 @08:13PM (#35476366)
That's why there's all sorts of widely produced performance vehicles with multiple independent engines!
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by cjbgkagh on Wednesday April 05, 2023 @12:10PM (#35456464)
I've read about a lot of people complaining about the difficulty of getting the mixture right, perhaps that might be a show stopper for a UAV that must reliably work unattended for a long time. Though the military should also be able to get such mixtures down to a science - so I don't know.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by kortex on Wednesday April 05, 2023 @01:47PM (#35457877)
> Granted an RC engine runs on a mixture of fuel and nitromethane

That's a huge difference. The main limiting factor in engine power is mass air flow, not fuel. Engines are as much air pumps as they are containers for extracting expansion from explosions. Nitromethane provides extra oxidizer in liquid form, putting nitro engines in some ways closer to rocket engines in terms of power-to-weight ratio.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by m463 on Wednesday April 05, 2023 @06:29PM (#35461317)
I'm not familiar with that engine, but I remember having little glow-plug engines and they didn't even have piston rings. (and were not efficient)
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by ww520 on Wednesday April 05, 2023 @12:59PM (#35457170)
The Camry engine has 4-6 cylinders for its size. A single cylinder is not much bigger than a basket ball.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bluGill on Wednesday April 05, 2023 @01:52PM (#35457952)
Every motorcycle mechanic I've seen has a sign in the shop: speed costs money, how fast do you want to go. That sign isn't referring to the costs to modify an engine to go faster so much as the cost to constantly rebuild the engine after they modify it to go fast. I've seen two identical engines, one rebuilt to stock and one rebuilt to max speed - the cost for both rebuild jobs was about the same (the parts for speed were more - but not much more compared to the labor which was the same), but the engine rebuilt to stock ran for thousands more hours, while the one rebuilt for speed has the mechanic bragging that it lasted a whole 80 hours!
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by 0cf8612b2e1e on Wednesday April 05, 2023 @04:02PM (#35459671)
What is done to modify an engine for speed? What kind of improvement can be seen for speed (accelerates XX faster? YY higher top speed)?
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by mcronce on Wednesday April 05, 2023 @04:40PM (#35460084)
Simplifying things in this comment a fair amount, but...

Extracting more power is, most commonly, a matter of burning more fuel, which requires more oxygen. This increases combustion chamber pressure, which drives the piston down with more force; that force is converted to rotational torque and ultimately drives the wheels harder, pushing the vehicle forward faster.

More oxygen can be added in any number of ways; less restrictive intake/exhaust parts, larger valves, cams that are more optimized for whatever load/engine speed you want to produce peak power (or are more optimized for output than, say, economy or emissions), supercharger, turbocharger.

Adding fuel is more straightforward: A higher capacity pump and/or bigger injectors/carbs.

You can also switch to pistons that will compress the air/fuel charge more. This also increases combustion chamber pressure.

You can also run the engine at a higher speed, which will often warrant different cams, stronger valve springs, etc. May also require bottom end uprated components that can handle that task (connecting rods, pistons, bearings, crankshaft).

On the subject of bottom end components, depending on how much you increase cylinder pressure, you may need to upgrade those.

You can also increase output power by reducing losses - a lighter flywheel is a common example with enthusiasts.

Every single one of these involves a trade-off. A lighter flywheel impacts drivability; removing intake/exhaust restrictions and adding forced induction components will both make more noise; etc.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by madog on Wednesday April 05, 2023 @05:35PM (#35460690)
Right. Generally more air and more fuel, produces bigger explosions and bigger forces, so the engine would output more power and torque.

These greater forces cause more stress to factory engine components, so generally at a certain level you will need to replace engine internals with uprated parts e.g. stronger rods and pistons.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by qup on Wednesday April 05, 2023 @04:46PM (#35460151)
Bigger cylinders, forced air systems, lighter weights, etc.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by sliken on Tuesday April 18, 2023 @06:19PM (#35621190)
Normal cars are designed from wide temperature ranges (something like -30F to 130F), -100 to 14k feet altitude, with a wide range of sand, dirt, snow, ice, hail and a wide variety of roads surfaces and steepness. Generally they seem designed to last 100k miles under normal use and terrible things don't happen if you forget an oil change.

You can do a chip tune that might get you more HP across a wide range of RPMs, but you won't be as robust, will need maintenance more often, and will likely wear through oil, gas, differentials, clutches, and related more quickly.

There's MANY things you can do that all basically come down to burning more gas+o2 in less time. Higher intake airflow (turbo, supercharger, better/missing air filters, scoops, etc), bored out cylinders for more engine displacement, more gas (increased fuel pressure/pumps), increased RPMs, and decreased exhaust pressure (better pipes, decreased or missing cats).

Trick is, more gas+o2 burned = more heat, more wear, more stress, hotter oil, faster clutch wearing, faster tire wearing, and generally faster brake wearing. Turbos are driven by exhaust, spin at crazy RPMs, increase air intake pressure, and generally are harder on the engine and oil and make cooling more of an issue. Higher RPMs require more precise timing, better valves+springs, better balanced cam shafts, etc. So what might seem like a cheap/easy change like increasing turbo boost from 10psi to 15psi might like a good idea, but have major impact on engine life and maintenance costs. A single blown head gasket from the increased temp, increased vibration, and increased pressure can be very expensive.

Much like CPUs of today, cars are generally designed carefully for their performance level and there's less spare performance left to be easily tweaked. Much like how older CPUs could be overclocked for substantial performance gains. Now both cars and CPUs will throttle if they don't have enough cooling or any of numerous other sensors detect potential problems. It's pretty common these days to see a car with 300hp, but 350hp for up to 10 seconds before the sensors reel you back in.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by sliken on Tuesday April 18, 2023 @06:22PM (#35621222)
My dad used to say the perfect race car would explode into a million pieces just after it crossed the finish line. Anything more robust is wasted weight.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by SV_BubbleTime on Wednesday April 05, 2023 @11:30AM (#35455852)
Add 10,000 or 20,000 lbs to the vehicle weight, does it all scale the same?
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by causi on Wednesday April 05, 2023 @11:35AM (#35455921)
I'm not sure what your point is. The XTS-210 hasn't been put in a vehicle as far as I know.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Syonyk on Wednesday April 05, 2023 @11:58AM (#35456281)
> How is this revolutionary motor being outdone by a mid-range sedan engine?

Go ask your Camry engine to make 100% rated power indefinitely, and see how long it holds up. That's the difference.

A typical car engine is designed to make 30-50hp sustained, and occasionally generate more power for reasonably short periods of time.

An aviation engine, generator engine, or any sort of "industrial" engine is going to be able to sit there, making full rated horsepower, for thousands of hours without any trouble at all.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by kube-system on Wednesday April 05, 2023 @12:16PM (#35456541)
IIRC some automakers do test automotive engines at 100% duty cycle (in a test stand configuration). And more than a few automotive engines are used in slightly modified variants for marine and aviation applications.

As I understand, the reason a typical car engine can’t sit at 100% duty cycle isn’t the engine itself, but usually the cooling and oiling configuration.

Examples:

https://youtu.be/GNPB3RtHN2M

https://www.vikingaircraftengines.com/engine-options

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by ghostpepper on Wednesday April 05, 2023 @12:57PM (#35457137)
The first time I learned you can increase, sometimes significantly, the performance of a car by upgrading the oil cooler blew my mind a little bit, but of course in hindsight it makes perfect sense.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Iwan-Zotow on Friday April 07, 2023 @07:17PM (#35488352)
WW2 planes engines
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Syonyk on Wednesday April 05, 2023 @12:57PM (#35457141)
I'm aware of some auto engine conversions - the 13Bs out of the RX-7s and related could do it, the older Subaru engines (EA81) would do it, but they're just a small aircraft engine in a car, design-wise...

Looking over the Viking engines, I don't think it's fair to call those "automotive engines," because my read of the description of what they do means they're pulling it apart and replacing an awful lot of pieces. They claim they're "based on" the latest Honda engines, and once you're starting to change the cylinder bore offset, custom hone the cylinders, replace your pistons and conrods, etc, it's no longer a car engine.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by kube-system on Wednesday April 05, 2023 @01:32PM (#35457660)
If changing those minor attributes makes an engine "not a car engine" then the majority of race cars also don't have car engines.

On their About page, they themselves say:

> Companies like Honda and Mitsubishi have spent millions of dollars refining and testing. We don’t claim that we can outsmart either company when it comes to the design of any internal running component of these engines. We don't change vital engine parameters around and claim we have different models. The compression, etc. is all stock. Every part is OEM Honda / Mitsubishi, nothing is new aftermarket from unknown origins.

> We start with the most up to date year engines with super low mileage, derived from fender benders across the US. When customers want the information about where there engine core came from and how many miles it had - we have all that documentation readily available to show.

Literally, every one of these engines came out of a car. I think that plainly qualifies it as a car engine.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by abfan1127 on Wednesday April 05, 2023 @01:34PM (#35457677)
those mods sound very similar to typical mods found in drag race cars.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bluGill on Wednesday April 05, 2023 @01:46PM (#35457863)
100% duty cycle doesn't really exists as stand alone concept. It is always in reference to the application. A typical car engine is at 100% duty cycle at around 30 horsepower, but the engine can produce 200+ horsepower for short bursts (enough to do the 0-60 test that everyone loves to quote). With more cooling you can run more power from the same engine, but the additional stress will mean the engine doesn't last as long before it breaks.

Marine applications generally means salt water, so they will run at higher power is the salt is what gets the engine eventually not the stress of high power output. Airplane engines are expected to be reliable and so they run at relatively lower power output. There are many small niches in between that have their own idea of what 100% duty cycle is.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by kube-system on Wednesday April 05, 2023 @01:56PM (#35458029)
I agree, it can mean different things. To be more specific, the video I linked says Kia tests at full load, WOT, and maximum engine speed for 300 hours continuously. Then they run it 10-20% faster than the specified maximum engine speed for another 10-20 hours.

This exceeds most definitions of "100% duty cycle".

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by causi on Wednesday April 05, 2023 @12:04PM (#35456382)
going to be able to sit there, making full rated horsepower, for thousands of hours without any trouble at all.

The XTS-210 can do that?

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Syonyk on Wednesday April 05, 2023 @12:24PM (#35456647)
If it's an aviation engine, it'd better be able to!
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by someweirdperson on Wednesday April 05, 2023 @12:43PM (#35456938)
Multiple thousand at max power? Typically, overhaul at 2000 hours. And maximum continous power isn't usually full load.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by Syonyk on Wednesday April 05, 2023 @12:52PM (#35457068)
It really depends on the engine, but almost all the general aviation engines you'll find (Lycoming and Continental 4s, and the smaller 6s) are rated for continuous operation at full power, and if they're flown regularly, will typically make well past the 2000-3000 hour TBO (which is a recommendation/expectation, not a legal requirement, though I believe some of the small diesels can't be operated past it).

Our flying club engines in the 172s typically make at least 3000, if not 3500 hours, and I think some of the overhauls at that point have been a "Well... it's still perfectly fine... but..." thing where the board was just starting to get uncomfortable with the hours on it.

And, yes, they spend a lot of time making less than rated power, because of density altitude, but they're still rated for full power operation, and since there's basically no wear going on with an engine in operation (almost all the wear is during starting), there's no real difference there.

It's not until you get into the really large engines where "maximum continuous" is a different thing from "takeoff power." The turbocharged 500s are about the smallest I know of with that sort of rating, and even then I don't think it's all of them. Most of the big radials have that limit, though. If you find a smaller plane with that sort of limit, it's either a possible resonance issue between the engine and prop, or a noise regulation for certification.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bell-cot on Wednesday April 05, 2023 @12:32PM (#35456773)
Their target market is the military - which has plenty of kerosene / jet / diesel fuels as part of its standard supply chain. The Camry engine will only run on gasoline - which the military neither carries, nor wants to.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bluGill on Wednesday April 05, 2023 @01:58PM (#35458052)
Toyota makes some great diesel engines (they don't put them to the US bound products in general), which could run on jet fuel with some small modifications.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by codeflo on Wednesday April 05, 2023 @01:20PM (#35457486)
I know this is off-topic, but I'm curious. I always had the impression that even in the US, standard units are used for engineering. Reading about "ft-lb" makes me think I was wrong (and my head hurt, tbh). Do you really compute stuff like torque in imperial units? Don't you need weird factors in every formula to make that work?
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bluGill on Wednesday April 05, 2023 @01:57PM (#35458039)
There are lots of weird factors in engineering anyway. We have different factors, but there are still factors. Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial.

Most engineering in the US is done in metric units. Then marketing applies a metric to imperial conversion.

I suspect China does more engineering in imperial than the US, both in total an per capita: most things I buy made in America are all metric (cars are all metric except for parts designed in the 1960s and the adapter bracket to make them fit on a modern metric car). Most things I buy made in China are imperial. I don't really know for sure, but that is my impression of industry.

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by codeflo on Wednesday April 05, 2023 @03:11PM (#35459027)
> Besides, nobody is calculating this, they are measuring and that is just a matter of what label you put on the dial.

That's why I asked about engineering, not driving. Nobody converts torque to power etc.?

Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by bluGill on Wednesday April 05, 2023 @03:55PM (#35459592)
The engineers who do that are using metric. Marketing might do this conversion, but they just plug it into a converter and have no reason to know anything more than bigger is better.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by mcronce on Wednesday April 05, 2023 @04:46PM (#35460159)
Torque to power is just (torque * RPM) / (some constant depending on the units inolved). With ft-lbs and horsepower, that constant is 5252; with N-m and kW, it's 9549. The only thing that changes is the constant.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by codeflo on Wednesday April 05, 2023 @05:08PM (#35460409)
You make it sound like you'd have to remember a 4-digit constant in either case. That's stupid, it's simply (torque * RPS * 2 * PI).
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by raketenolli on Wednesday April 05, 2023 @05:09PM (#35460416)
No, power is just torque times angular velocity. No constants involved.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by mcronce on Wednesday April 05, 2023 @05:34PM (#35460663)
If you ignore units, sure.
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by m463 on Wednesday April 05, 2023 @07:19PM (#35461839)
For the camry, is that just the motor? Does it require support, like say the cooling system?
Re:“Inside-out Wankel” rotary engine delivers 5X the power o... by pkphilip on Thursday April 06, 2023 @01:30AM (#35464508)
I think the primary advantage is the size (about the size of a basketball) and the number of moving parts (just 2), and also its ability to use a range of fuels.