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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 pro

by causi 4y ago

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?

SV_BubbleTime 4y ago
Add 10,000 or 20,000 lbs to the vehicle weight, does it all scale the same?
- causi 4y ago
  I'm not sure what your point is. The XTS-210 hasn't been put in a vehicle as far as I know.
shadycuz 4y ago
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.
- 93po 4y ago
  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.
  - seabird 4y ago
    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.
    - syrrim 4y ago
      If you had 18 such engines it would get you precisely 18x the performance, at precisely 18x the weight.
      - aidenn0 4y ago
        And precisely 1/18 the MTBF
        pas 4y ago
        but it fails gracefully, right? (only one engine fails at a time) it's like RAID, great until the RAID card itself fails
        aidenn0 4y ago
        It's probably most like losing power in a single cylinder; the effects vary from engine to engine.
        jacquesm 4y ago
        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.
        93po 4y ago
        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 when a single component of it fails that's worth fixing.
  - cjbgkagh 4y ago
    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.
  - kortex 4y ago
    > 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.
  - m463 4y ago
    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)
- ww520 4y ago
  The Camry engine has 4-6 cylinders for its size. A single cylinder is not much bigger than a basket ball.
- bluGill 4y ago
  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!
  - 0cf8612b2e1e 4y ago
    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)?
    - mcronce 4y ago
      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.
Syonyk 4y ago
> 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.
- causi 4y ago
  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?
  - Syonyk 4y ago
    If it's an aviation engine, it'd better be able to!
    - someweirdperson 4y ago
      Multiple thousand at max power? Typically, overhaul at 2000 hours. And maximum continous power isn't usually full load.
      - Syonyk 4y ago
        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.
bell-cot 4y ago
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.
- bluGill 4y ago
  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.
deleted 4y ago
[deleted]
codeflo 4y ago
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?
- bluGill 4y ago
  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.
  - codeflo 4y ago
    > 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.?
    - bluGill 4y ago
      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.
    - mcronce 4y ago
      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.
m463 4y ago
For the camry, is that just the motor? Does it require support, like say the cooling system?
pkphilip 4y ago
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.

by causi 4y ago

SV_BubbleTime 4y ago

Add 10,000 or 20,000 lbs to the vehicle weight, does it all scale the same?

causi 4y ago
I'm not sure what your point is. The XTS-210 hasn't been put in a vehicle as far as I know.

shadycuz 4y ago

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.

93po 4y ago
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.
- seabird 4y ago
  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.
  - syrrim 4y ago
    If you had 18 such engines it would get you precisely 18x the performance, at precisely 18x the weight.
    - aidenn0 4y ago
      And precisely 1/18 the MTBF
      - pas 4y ago
        but it fails gracefully, right? (only one engine fails at a time) it's like RAID, great until the RAID card itself fails
        aidenn0 4y ago
        It's probably most like losing power in a single cylinder; the effects vary from engine to engine.
        jacquesm 4y ago
        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.
      - 93po 4y ago
        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 when a single component of it fails that's worth fixing.
- cjbgkagh 4y ago
  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.
- kortex 4y ago
  > 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.
- m463 4y ago
  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)
ww520 4y ago
The Camry engine has 4-6 cylinders for its size. A single cylinder is not much bigger than a basket ball.
bluGill 4y ago
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!
- 0cf8612b2e1e 4y ago
  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)?
  - mcronce 4y ago
    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.

Syonyk 4y ago

> 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.

causi 4y ago
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?
- Syonyk 4y ago
  If it's an aviation engine, it'd better be able to!
  - someweirdperson 4y ago
    Multiple thousand at max power? Typically, overhaul at 2000 hours. And maximum continous power isn't usually full load.
    - Syonyk 4y ago
      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.

bell-cot 4y ago

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.

bluGill 4y ago
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.

deleted 4y ago

[deleted]

codeflo 4y ago

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?

bluGill 4y ago
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.
- codeflo 4y ago
  > 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.?
  - bluGill 4y ago
    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.
  - mcronce 4y ago
    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.

m463 4y ago

For the camry, is that just the motor? Does it require support, like say the cooling system?

pkphilip 4y ago

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.