Jolly Green Monster 2

Anyone know the difference between AVTAG and AVTUR aviation fuel?

Just out of curiousity..

Cheers

JGM

Katana

Can we get in Shell?

TelBoy

This is no word of a lie, i have a friend who has a PhD in Rocket Fuel. Straight up. Fact. Independently verified. I'm off to ask him now. Back in a mo...

TelBoy

DOH!! He says he didn't study aviation fuel. Flippin eck, how different can they be? Sorry JGM, i thought i had this in the bag.

Thought i'd FINALLY found a use for his knowledge. Bah!

Jolly Green Monster 2

Thanks for trying Telboy..

I am surprized there is enough about Rocket Fuel to do a PHD on!

JGM

The_Max STi

My quick look on the net produced this.. ANYGOOD????


Why use AVTUR and not AVGAS in jet engines?

Answer:

Avtur has a SG of about 0.80 kg/litre, where as avgas SG is 0.72. This means that more weight of Avtur can be fitted into a given tank volume, than can avgas. This results in more range, as primary fuel mixture to the engine combustion chamber is mixed at a rate of 15 air to 1 of fuel by weight, not volume. Hence fuel flow expressed in KG, not litres/hr. Fuels with a higher SG have a higher "calorific value", ie: they have more energy to deliver per unit of volume. Avtur is less of a fire risk (ie: high flashpoint). Down-side is greater tendency to hold water in suspension, and avtur contains residual wax content that can block fuel filters (need to heat fuel through fuel/oil heat exchangers to stop wax solidifying). Also microbial infestations are a problem. Fuel contains an anti-microbial agent to stop formation of this). Also an anti-icing agent called "Prist".

Also a small bit here..

http://www.nato.int/docu/logi-en/1997/lo-15a.htm

[Edited cus I can't spell to save my life!!!]


[Edited by The_Max STi - 8/14/2002 3:41:00 PM]

The_Max STi

One More... But this is well over my head..

This could be about Landing on the moon.

http://yarchive.net/env/jet_fuel.html

Got to ask.. Why do you want to know!!! Taking up flying???

carl

Rockets have to carry their own oxidants. Liquid oxygen, N20, RFNA, etc. Aeroplanes have to make do with normal air.

TelBoy

Hello again Carl.

carl

This bit is actually useful for cars. If you know what makes a good oxidant for rocket fuel, then you know what's good stuff to inject in a NOS-type system in your car. Nitrous oxide is a good oxidant, as is fluorine and red fuming nitric acid (RFNA) but the second two tend to dissolve engines

TelBoy

How about a nice line in poly-3-nitrato-methyl oxetane?

If that doesn't get me to 300bhp, nothing will...!

Hos

iTrader: (1)

Been said above but this is what i was taught - taken out of my airline training manuals.

The difference between Avgas and AVTUR

AVGAS>
Piston engined aircraft use gasolene fuels - AVGAS (aviation gasoline) It is manufactured to conform with the exacting 'specifications that are used by the Directorate of Engine Research and Development (DERD). The specification number is DERD 2485.

The octane rating of the fuel is specified with grade ie - AVGAS 100 is a 100 octane fuel. Higher octane fuels are used with high performance engines having high compression ratios. Most popular grades of AVGAS readily available today are - AVGAS100LL : which has a peformance No. of 100/130 (which planes like cessnas use today) , AVGAS100 : 100/130 , AVGAS115 : 115/145. Each have a specific gravity of 0.72.

AVGAS100 (green) and AVGAS100LL (blue) are distinguished by colour.

---------------------------------------------

AVTUR> (aviation turbine fuel). Gas turbine engined aircraft use kerosene fuels. The two type of AVTUR in use are:

JET A1 - this is a kerosene type fuel with a nominal SG of 0.8 at 15 degrees C.

JET A - is a similar type of fuel but it has a waxing point of minus 40 degrees C, this fuel is normally only available in the USA. (from what i remember from the classroom this is good for high altitude flying due to the low waxing point)

there is also AVTAG with JET B but you haven't asked about that.

---------------------------------------------

Can go into alot more detail with things like effects of specific gravity , fuel additives, water in fuel, waxing, boiling but the above might have answered your questions..

Each fuels have main requirements...
a) ease of flow under all operating conditions
b) complete combustions under all conditions
c) high calorific value
d) none-corrosive
e) no damage to the engine from combustion by-products
f) low fire hazard
g) ease of engine starting
h) lubricity.

In practice the cost of satisfying all of them is prohibitive and therefore compromises are made. Each of the above can be disgussed further so if you want to anymore let me know..
Cheers,
Hos

[Edited by Hos - 8/14/2002 5:51:47 PM]

555 BOY

In a nutshell,

Avgas - very high lead/octane rating and expensive (£4 Gallish) can be used in petrol cars especially old ones requiring 4*

Avtur - Cheap (25p/Ltr) can be used in Diesel engines, advisable to mix with oil though

I've done both of the above with no probs, though not in a scooby

555

mj

555,

can you enlighten on the AVTUR - is it ok in VAG turbodiesels, whats with the oil mix, what type and ratio- or have i just been got?

Belf

AVTUR is for jet turbines and is essentially kerosene which chemically isn't that different to diesel. Your not supposed to stick it in a car because no tax has been paid on it, if customs and excise caught you doing it you'd be in big trouble. You can get diesel for about 25p/litre if it is bought for use in anything other than a car.

Jolly Green Monster 2

Thanks guys I think I have got enough info to satisfy my curiousity..

I can only say limited reason why I wanted to know other than I am currently working on a fuel computer for a pair of jet engines..

Sounds interesting but is as boring as hell..

It only takes AVTUR and AVTAG so no AVGAS but the info was relevant I think..

Too early to digest it all so I shall have another look later

Thanks again

JGM

ukhuskynox

avgas in 2-smoke race bike = good