Got AvGas?

[Turboswede]

Just found this forum and I wanted to ask about something I have wondered about ever since I first bought by T2K V1 boxed set back in the early 80’s. One of the basic tenets of the T2K game in all its alliterations is that from about 1998 on the world’s airpower was grounded because of damage to petroleum refining capacity and that aircraft required high octane “Avgas” to fly.

The problem is that only piston engine aircraft use high octane Avgas. Turbines burn JP4 which is basically kerosene, but can be adapted to run on diesel or paraffin. So, if you can run the turbine of an M-1 on methanol, why not the turbines of a UH-60 or Mi-8?

I know it’s a silly question, but can anyone provide a good rationalization for why aircraft are grounded?

[kato13]

Welcome aboard, glad you found us and posted. The M1 engine was designed from the ground up to be a multifuel engine. Most aircraft in order to keep a low weight to power ratio use engines optimized for a single fuel type. I think the power loss that would come from using an unusual fuel would cripple most aircraft. Not to mention different corrosion and temperature characteristics would wreak havoc on such finely tuned systems.

I was always a little irked that GDW did not differentiate between kerosene and aviation gas but it pales in comparison to my utter disappointment in finding out that their methanol production ideas were pure fantasy.

My Methanol Thread

[Raellus]

Originally Posted by Turboswede

I know it’s a silly question, but can anyone provide a good rationalization for why aircraft are grounded?

Welcome, Turboswede.

To address your question, in terms of game mechanics, the game designers wanted to make travel as difficult as possible. If the PCs could just jump on board a Blackhawk, escaping from Kalisz (or wherever) wouldn't be much of a challenge.

[Turboswede]

Originally Posted by Raellus

Welcome, Turboswede.

To address your question, in terms of game mechanics, the game designers wanted to make travel as difficult as possible. If the PCs could just jump on board a Blackhawk, escaping from Kalisz (or wherever) wouldn't be much of a challenge.

I totally understand the reason for the rule, and it let them leave out rules for air strikes and air-to-air combat. The use of the terms “high octane” and Avgas in relation to gas turbines just always bugged me. My understanding is that one of the benefits of gas turbines in aircraft is that JP-4 is far less flammable than Avgas and is much safer as well. I am not a chemist, but I would think converting a turbine to run on Methanol would be easier than converting a 95’ Dodge Ram.

I always thought a better reason (and the one I used in my campaigns) would be the scarsity of aircraft. If you assume that the US industrial base is gone (or extremely damaged) after 1997, the ability to refine aluminum, let alone build an entire aircraft, goes away. In WWII the Germans managed to continue aircraft production all the way until the end, but I think that Soviet..err…um...Russian strategic weapons would be much more effective than the US and British bombing campaign of the 2nd world war.

In addition, the use of tactical nukes against airbases would knock most of the staging areas for fixed wing NATO aircraft.

[Grimace]

I did aircraft refueling for a while earlier in my life. Yes, AvGas isn't used for most military aircraft. Certainly not for helicopters or combat aircraft. JP4 is the fuel of choice. And in general terms, yes it is like kerosene, though JP4 is much more refined...less dirty.

So the reason you can't run anything other than JP4 in those engines is due to the residue left over from the intense burn temperatures of those engines. While, technically, those engines would run on diesel, kerosene and maybe even ethenol (not methanol though...way too "dirty") it wouldn't run for very long. The soot buildup from burning the fuels would quickly clog the inner workings of the engine and you'd have random cut-outs, engine shut-downs, and possibly even engine seizures. While such an event isn't that major of thing for a vehicle like a tank, you really don't want to have your engine cut out on you while you're flying a helicopter or jet aircraft.

Basically, a jet aircraft could probably only burn through half a tank before the build-up started to take effect.

Also, you'd have to take into account the sheer quantity of fuel that would be needed. I refilled a Sikorsky CH-53 and it took well over 1300 pounds of fuel. Trying to make that much of ethenol would take quite a while. Plus, it would burn through that amount of fuel in about a quarter of the time that it would take to go through a full take of JP4. So the amount of alternative fuels you'd need would be staggering. And, unless you have a death wish, you wouldn't want to fly for very far on anything but the "good stuff".

[Sanjuro]

While modern jet fuel is a very specialised thing, a good rule of thumb for gas turbines is "If it's runny and it burns, you can run a gas turbine on it."
However, for the reasons given above, after a quite short time using the wrong fuel will degrade the engine badly. If you want to add aircraft to a campaign, small turboprops are a good idea; the DHC6 Twin Otter can use short, rough fields (I have landed one on a beach, in scheduled airline service), has a derated (less powerful, but even more reliable) version of the Pratt and Whitney PT6, carries a decent load (20 seats, or a comfortable 2 tonnes; up to 8 tonnes if you want to seriously overload it- and it will still fly!), or the turbine Islanders used by the British Army.
If you want to make aircraft possible in your T2k, but explain their absence, just remember how lethal the two sides' SAM networks were; the few aircraft left now are just too valuable to risk, with no guarantee that the SAMs are all used up...

[raketenjagdpanzer]

In the warzones, avgas stocks on both sides are going to get a good pasting.

In the CONUS, I think there's going to be a good amount left. Relatively speaking there are fewer pilots than drivers, and fewer still who'd fly by eyeball once fancy navigation systems crapped out due to EMP. The military would seize as much as they could, but there are places where it'd cost more in fuel to get it out than you'd get, so generally it would sit there.

The JMC stuff I've been tinkering with has most of the AvGas in the metro Orlando, FL and surrounding areas at the disposal of the JMC. They currently have only a couple of flyable helos (but are looking to get more and/or possibly an airplane or two operating), so the massive volume at McCoy/Orlando Int'l, Sanford Int'l, and Orlando Executive will keep them flying well into the mid 2000s if not beyond. Sure there will be some spoilage, and some will be appropriated for other things (possibly - I'm not sure what else AvGas is good for except aircraft engines, although I could have something about it also being used as a backup fuel for hospital generators) but couple small airfields in (and there are a great many here as well as all across the country) and you see AvGas isn't a huge issue, just so long as you're not trying to keep thousands of fighters and hundreds of bombers aloft.