aviation gas

The military refers to it as motor fuel or more specifically motor gasoline and most folks know how the military is about abbreviating things. This is their acronym for motor gasoline and has been for many years. The military had to supply mogas, avgas, JP4 (jet fuel), and diesel fuel for many years so they had the acronyms. Now days, almost all army vehicles use either diesel or JP4 but they still use modified civilian vehicles for hauling small groups of people around in various locations around the planet so mogas is still a necessary fuel at times and under certain circumstances.
 
rotorwrench said:
The military refers to it as motor fuel or more specifically motor gasoline and most folks know how the military is about abbreviating things. This is their acronym for motor gasoline and has been for many years. The military had to supply mogas, avgas, JP4 (jet fuel), and diesel fuel for many years so they had the acronyms. Now days, almost all army vehicles use either diesel or JP4 but they still use modified civilian vehicles for hauling small groups of people around in various locations around the planet so mogas is still a necessary fuel at times and under certain circumstances.
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JP4 is high altitude jet fuel(50% gasoline/50% JP5)
JP5 is jet fuel(kerosene -40F freeze point)
 
If I ever knew just what JP4 was, I guess I've forgotten. Besides running it in the helicopters, we used it to heat c-rations and in our homemade bunker stove. Always did think it burned pretty good.
 
mrtexas said:
JP4 is high altitude jet fuel(50% gasoline/50% JP5)
JP5 is jet fuel(kerosene -40F freeze point)
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Hey Neighbor....I know that you messed with this kind of stuff professionally. Since we're already discussing different types of turbine fuels here, how does "Jet A" fall into this line-up, as well as maybe a comment or two on the nuances of, and the precautions necessary with JP7? DD
 
The Army uses mostly JP4 for it's helicopters. It's a military designation for jet propellant. Jet A is a civilian designation for the most common form of jet or turbine engine fuel. It is mostly kerosene with a smaller percentage of gasoline (Naphtha). Military JP4 is mostly gasoline as described with a bit lower percentage of kerosene. Jet B isn't as common in the civilian world but has additives and blending to prevent freezing at high altitude.

Turbine fuels can start to gell or freeze at very low temperatures so they are blended for where they will have the best use. The military can afford the JP4 so that's what they use all the time. Jet A is the most common in the civilian world. Turbine fuel also has a tendency to form fungus so additives and different blending can reduce that risk. It shouldn't be stored for long periods due to this.

There are other forms for other purposes. The SR-71 had its very own type of fuel since it also used it as a coolant. It was JP7.
 
V8COOPMAN said:
Hey Neighbor....I know that you messed with this kind of stuff professionally. Since we're already discussing different types of turbine fuels here, how does "Jet A" fall into this line-up, as well as maybe a comment or two on the nuances of, and the precautions necessary with JP7? DD
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Jet A and JP5 are both kerosene. JP5 has a lower freeze point as military jets fly higher than commercial jets. The freeze spec we made Jet A to was -40F. Flash max was 100F. Can't comment on JP7 as we didn't make it. There is no such thing as off spec jet fuel in a refinery. Off spec gasoline maybe but oil companies don't want their fuel to be blamed for plane crashes.
 
can some one please explain the desire to use av gas in an engine that averages 7to 1 compression or less maybe we are spoilt here in aussie as 98 octain [non ethanol] is available out the pump most everywhere i run mine on 91 and its happy as ??
 
Most folks are just looking for a way around the alcohol content if they don't have any gas stations that sell plain no lead gas. The 10% or higher alcohol level plays hell with the fuel system if the car sets too long. I don't know if the folks down under have to deal with anything like that or not. The EPA here in the US won't be happy until we are all driving electrics. What kills me is that coal fired power plants still generate the lions share of the electric power here. Wind and solar ore OK but the sun doesn't always shine and the wind doesn't always blow.
 
rotorwrench said:
The EPA here in the US won't be happy until we are all driving electrics. What kills me is that coal fired power plants still generate the lions share of the electric power here. Wind and solar ore OK but the sun doesn't always shine and the wind doesn't always blow.
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Did you say something about 'blowing'? Where's the 'smarts' behind This blowhard governor mandating "non-fossil" fueled cars (one would almost have to assume that to mean ELECTRICS) by 2035? Hell, they can't even keep the battery chargers POWERED-UP full-time NOW-a-days. How will the people evacuate for the fires with dead batteries in their cars? Duhhh! I guess that by then, all the smart ones will have headed east long ago! DD
 
I was a fuel system mechanic on SR71 for 4 years. I can tell lots of stories about JP7

Sent from my SM-T550 using Tapatalk
 
Habusailor said:
I was a fuel system mechanic on SR71 for 4 years. I can tell lots of stories about JP7
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I'm 'all ears' for some of that! Stories I've heard state that besides those things weeping fuel while sitting on the ramp, that the nearly 300 degree F. fuel temps reached in it's six tanks (I believe) during speeds above roughly 2.6 mach necessitated a 100% inert atmosphere of pressurized nitrogen to prevent ignition of the JP-7. Is that true scoop? DD
 
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