Recommended Posts
oldwomanc6 52
StumpyI'm curious what "green math" is.
I suggest its "any science I don't want to agree with"
I always understood that "green math" is follow the greenbacks to those who can fund the studies to say what they want to say....
lisa
WSCR 594
FB 1023
CBDB 9
WSCR 594
FB 1023
CBDB 9
billvon 2,991
.thumb.jpg.4bb795e2eaf21b8b300039a5e1ec7f92.jpg)
> So, if we do an atom balance around a good engine, with sufficient O2, how much of
>the carbon ends up as CO2?
Immediately in a stochiometric engine? As far as I know, about 95% with the remainder being soot, unburned hydrocarbons and carbon monoxide. Eventually? About 97%, since the CO eventually reacts with atmospheric hydroxyls to create CO2 and hydrogen. (Which is a problem for climate change as well; hydroxyls also work to clear methane out of the atmosphere and CO sort of 'uses it up.')
In an engine with a three way (i.e. modern) catalytic converter it's very close to 100%, since the catalyst converts CO and HC to CO2 and H20.
>the carbon ends up as CO2?
Immediately in a stochiometric engine? As far as I know, about 95% with the remainder being soot, unburned hydrocarbons and carbon monoxide. Eventually? About 97%, since the CO eventually reacts with atmospheric hydroxyls to create CO2 and hydrogen. (Which is a problem for climate change as well; hydroxyls also work to clear methane out of the atmosphere and CO sort of 'uses it up.')
In an engine with a three way (i.e. modern) catalytic converter it's very close to 100%, since the catalyst converts CO and HC to CO2 and H20.
billvon 2,991
>I have yet to see a mixture control in a Caravan.
Good point; I read 206 instead of 208.
>I think you will find the mechanical efficiency of the turbines to be FAR superior to that
>of the piston engines.
Mechanical efficiency? Agreed; there are fewer losses in a turbine engine, mainly due to the lack of piston rings. Turbine engines have a loss that recips generally don't (reduction gearing) but that is small in comparison.
Thermodynamically? Good turbines require about 50% more fuel per kwhr than reciprocating engines, both operated at their most efficient point. However, turbines are so much better in other respects (size, weight, reliability, maintenance etc) for aviation applications that in usage they are about equivalent.
>Long story short, if you are an environmentalist type, and a skydiver, you are a
>hypocrite, plain and simple.
Sorta like being a skydiver (or skydiver pilot) who is into safety, eh? Hypocrites, all of them!
Good point; I read 206 instead of 208.
>I think you will find the mechanical efficiency of the turbines to be FAR superior to that
>of the piston engines.
Mechanical efficiency? Agreed; there are fewer losses in a turbine engine, mainly due to the lack of piston rings. Turbine engines have a loss that recips generally don't (reduction gearing) but that is small in comparison.
Thermodynamically? Good turbines require about 50% more fuel per kwhr than reciprocating engines, both operated at their most efficient point. However, turbines are so much better in other respects (size, weight, reliability, maintenance etc) for aviation applications that in usage they are about equivalent.
>Long story short, if you are an environmentalist type, and a skydiver, you are a
>hypocrite, plain and simple.
Sorta like being a skydiver (or skydiver pilot) who is into safety, eh? Hypocrites, all of them!
Quote
> So, if we do an atom balance around a good engine, with sufficient O2, how much of
>the carbon ends up as CO2?
Immediately in a stochiometric engine? As far as I know, about 95% with the remainder being soot, unburned hydrocarbons and carbon monoxide. Eventually? About 97%, since the CO eventually reacts with atmospheric hydroxyls to create CO2 and hydrogen. (Which is a problem for climate change as well; hydroxyls also work to clear methane out of the atmosphere and CO sort of 'uses it up.')
In an engine with a three way (i.e. modern) catalytic converter it's very close to 100%, since the catalyst converts CO and HC to CO2 and H20.
That high? Wow. Where are you getting this from?
We are all engines of karma
Iago***
Quote
> So, if we do an atom balance around a good engine, with sufficient O2, how much of
>the carbon ends up as CO2?
Immediately in a stochiometric engine? As far as I know, about 95% with the remainder being soot, unburned hydrocarbons and carbon monoxide. Eventually? About 97%, since the CO eventually reacts with atmospheric hydroxyls to create CO2 and hydrogen. (Which is a problem for climate change as well; hydroxyls also work to clear methane out of the atmosphere and CO sort of 'uses it up.')
In an engine with a three way (i.e. modern) catalytic converter it's very close to 100%, since the catalyst converts CO and HC to CO2 and H20.
That high? Wow. Where are you getting this from?
ONLY on DIZZY DOT COM, can we turn a discussion on 'skydivings impact on climate change' into a detailed thermodynamic discussion of recipricol vs turbine airplane engines.
Man, this place can be REALLY COOL somtimes!
Plus BOOBIES!
~ If you choke a Smurf, what color does it turn? ~
I have yet to see a mixture control in a Caravan. Kinda hard to run a turbine rich when you cannot control the mixture.
Just sayin...
So in case you meant Cessna 206, here are some comparisons just for arguments sake.
I think what you are looking for is the Specific Fuel Consumption. That is the true measure of an engines efficiency.
On the PT6A-114A powered Cessna 208 Caravan, it is about .67 pounds of fuel per hour per horsepower.
Whereas the Continental IO-550 runs about .56 pounds per hour per horsepower, as best as I can tell from online performance diagrams...
Don't forget, 100LL weighs less per gallon versus Jet A1. So in the long run, the engine (fuel) efficiency is actually pretty close.
Once you take into account actual engine weight per horsepower versus specific fuel consumption, then it is a whole different ball game.
The dry weight of the IO-550 is about 430 pounds dry, and the PT6A-114A is 270 pounds.
300 HP vs 675. Twice the horsepower, half the weight.
Therefore the PT6's rule.
I think you will find the mechanical efficiency of the turbines to be FAR superior to that of the piston engines.
Long story short, if you are an environmentalist type, and a skydiver, you are a hypocrite, plain and simple.
Commercial Multi-Engine Sea, Single Engine Land
Private Glider
Share this post
Link to post
Share on other sites