The place for technical discussions about GA and flying.
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#1882105
Mountains and mole hills.

How many GA flight hours are flown per year compared with the millions of ground vehicle hours driven/stuck in traffic in the UK?

During COP26 there was a list of things people could do to reduce the CO2 that were being read out on the tv news.... which conveniently skipped over the item to "keep your gardens" (i.e. not concrete/tarmac over them or replace with astro turf which many people do in the UK).
In more recent news, there is a place abroad flooded that is exacerbated by loss of natural drainage where people have removed the green space in the streets.

Several years ago a simple hedge along a busy road side in London was demonstrated to have improved the air quality inside the house. Suggests there are other green alternatives to planting trees to do our bit.
johnm liked this
#1884867
Fellsteruk wrote:Wow.
Thanks for all the info, agree 2.5kg/L seems a lot however a solid starting point to calculate how much co2 is produced from my flying.

Rather than trees, nothing against them I’ve been looking at https://climeworks.com which takes it from the atmosphere and stored underground.


Maybe doesn't work quite like that:
Warning/NSFW due to graphic scenes of calculator abuse, coal fondling action and occasional swears


The other issue of course if you only get CO2 directly with a suitable mixture - run too rich and you get more CO (which isn't very good for you)
Image
Mz Hedy liked this
#1885083
Flying_john wrote:It does seem counter intuitive ( for us non chemists) that burning 1 Litre (700grams) of gasoline produces approximately 2.3 kg of CO2

Imagine one molecule of petrol* and burn it. That splits the molecule apart and combines the parts with oxygen from the air. A high proprtion of the original molecule is carbon atoms which (if completely burned) combine with two oxgen atoms each - hence the term carbon dioxide.

An atom of carbon weighs about 12 units, and an atom of oxygen weighs 16; so each molecule of CO2 weighs 16+12+16 = 44 units which is about 3½ times the weight of your original carbon atom. 2.3kg / 0.7kg comes to about 3⅓ times so close enough for a forum answer.

Dadaah :-D

Does that help? You can look up the atomic weights etc on Wikithingy.

*OK, it's a complex mix but the idea holds

[Edit: chemistry]
JAFO liked this
By TopCat
FLYER Club Member  FLYER Club Member
#1885111
MikeB wrote:
Sooty25 wrote:I'm still trying to get my head around what a kg of gas looks like. :?:


1 cubic metre of CO2 at standard atmosphere and pressure weighs around 11kg. So 1kg is about 91litres.

This can't be right.

An ideal gas at standard T&P has a molar volume of 22.4 l.

A cubic meter is 1000 l, so will contain 1000 / 22.4 = 44.6 moles of CO2.

44.6 mol of carbon dioxide will therefore weigh 44.6 x 44 (weight in grams per mole).

That's a bit under 2 kg, not 11 kg.

CO2 won't be a perfectly ideal gas, but not so much so as to account for a factor of 5. Where did you get your 11kg from?

@Sooty25 A cubic meter of air weighs a bit over 1 kg, if that helps you visualise :)
#1885139
I now understand...............

............ why I crashed out of chemistry at school! :lol:


TopCat wrote:
@Sooty25 A cubic meter of air weighs a bit over 1 kg, if that helps you visualise :)


So, if you got one of those 1000ltr IBC tanks, and pulled a complete vacuum in it, it would weight 1kg less?
User avatar
By Flying_john
FLYER Club Member  FLYER Club Member
#1885143
So actually our 12 units of carbon in the unused fuel is still 12 units after burning but has combined with 16+16 units of oxygen. So we haven't got something for nothing . The total input was 12 Carbons and we still have 12 carbons, its just that once burnt we add in 32 Oxygens and get heat/energy out of the process.

Presumeably this energy was once supplied by the sun and plant/animal life on earth fixed this in the form of carbon.

So every time I go flying, all I am doing is using up this carbon, from the suns energy that happened to fall on the earth a few years ago (quite a few).

This appears to be a reasonable natural cycle, bit like changes in the weather.

All we need now is a decent estimate of how much of the suns energy is available still in the earth and how much we are using each year and calculate how long we have to go. If its more than 100,000 years - why worry.

:mrgreen: :mrgreen:
#1885239
Flying_john wrote:... why worry.

:mrgreen: :mrgreen:


This is where greenhouses come into the discussion. One of the things the sun does is radiate heat at a high temperature and very high frequency. Air is quite transparent to this frequency so the heat gets down to the ground and warms it (yummy), but the warmed earth radiates the heat back out at a cooler less high frequency. That's good or we'd be scorched.
BUT, carbon dioxide (and a lot of other stuff like methane) is less transparent to the lower frequencies of the earth's radiated heat and so some of that heat stays in the atmosphere. That's also good because it stops the earth getting too cold.
The trouble is, over the last hundred years or so we've been adding very old carbon back into the atmosphere by burning stuff which absorbed the sun's heat many millenia ago. This is in human lifespans and is, in effect, new carbon which is adding to the CO2 duvet. This means we're still getting the same amount of heat in from the sun but we're letting less of it out - and as far as I know, there isn't a thermostat to regulate the temperatures to within the human comfort zone.

At least that's my understanding of it . :pale:

Oh, and combining the fuel with oxygen by burning it isn't something for nothing. There is less free oxygen in the hot air blown of your exhaust than there was in the cold air sucked in through your intake. It's been combined with the carbon from your fuel tank. :compress:

Doubtless that was dealt with somewhere back on page 2 or so :eye: