mtsupilot09
"We lookin fo you. We gon find you!"
Another question. What's the difference between JP-5, -8 -7, etc and Jet-A. I know on XCs you can't always find military grade jet fuel, but it can't be too different than Jet-A, right?
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Stupid questions and smart answers about jet fuel (JP-4, 5, 8, etc)
- Thread starter mtsupilot09
- Start date
MasterBates
Well-Known Member
JP-5 is more or less JetA, but with a higher flash point.
JP-8 is JetA with FSII (Fuel System Icing Inhibitor)
Both are more or less really clean Kerosene, although on the Diesel fuel scale of Kero being K-1 or D-1 and Normal Diesel being D-2, JP-5 is closer to K-1.5.
JP-4 is Jet B, which is a lighter turbine fuel more akin to gasoline. Not commonly seen, but there are a couple places up north my dad delivers it to.
JP-7 is some voodoo stuff used by the SR-71, and won't even light off using conventional ignition, and has to used a catalyst (TEB?) to light off.
JP-8 is JetA with FSII (Fuel System Icing Inhibitor)
Both are more or less really clean Kerosene, although on the Diesel fuel scale of Kero being K-1 or D-1 and Normal Diesel being D-2, JP-5 is closer to K-1.5.
JP-4 is Jet B, which is a lighter turbine fuel more akin to gasoline. Not commonly seen, but there are a couple places up north my dad delivers it to.
JP-7 is some voodoo stuff used by the SR-71, and won't even light off using conventional ignition, and has to used a catalyst (TEB?) to light off.
Xtndr50boom
Voted 8.9 average on the Hot-or-Not scale
Not so much. Think of the big boys in this regard -- Try gravity feeding 340K pounds of JP-8 or Jet-A into a KC-10 or a C-5. Or a 747, for that matter
Xtndr50boom
Voted 8.9 average on the Hot-or-Not scale
Yes, there is. No, there isn't. That's what the valve is for. Can't remember the name of it, but it's a poppet valve with some teeth in it to keep the probe in place until enough force is applied for them to give up when the receiver disconnects.
Valves, yes. Gravity, no. Don't know about buddy tankers, but the big boys (KC-10, tristar, VC-10, and the ....KC-135) all have AR pumps inside the fuel tanks that send fuel, at ~ 50 PSI, to the hose or iron maiden.
Good questions, though :icon_mi_1
mtsupilot09
"We lookin fo you. We gon find you!"
Is that not just prist?
Sorta, they do the same thing. The only restriction I can remember on Prist is that it can only be used if pre-mixed in the fuel, which makes is basically the same as FSII. If it's in the spray cans it can't be used.
Unfortunately, not all the linemen even understand the distinction between "pre-mixed" and any other means of putting it in. Generally, since it's attached to the nozzle at the fuel truck, I know it's pre-mixed, but I would always ask in the T-34, and I'd say better than 50% of the time, the answer would be "no, it's not pre-mixed." So, I'd say no thanks (and shake my head in my inner monologue).
There is also JPTS, which is a fuel used only by the U-2. As I understand it, it is basically JP-4 with an additive that gives it a lower freezing point, and will prevent the fuel from getting slushy at the low temps it will be exposed to for hours.
MasterBates
Well-Known Member
You guys too good for a JP number for that Huggy?
What I thought that was interesting in "fuel history" is that the USAF used JP-4/Jet B long after it had stopped being the primary commercial fuel.
What I thought that was interesting in "fuel history" is that the USAF used JP-4/Jet B long after it had stopped being the primary commercial fuel.
The H-2 had an adjustment on a miscellaneous fuel control device in case we were stranded at some out of the way USAF facility and had to fill her up with JP-4.
MasterBates
Well-Known Member
When I was flying civilian Bells, they would pretty much run on anything you dumped in it. Can't recall any adjustments we had to do other than watch EGT.
If I remember, I saw higher TIT on JetB than JetA for similar torque.
If I remember, I saw higher TIT on JetB than JetA for similar torque.
We could make adjustments on the H-3, too. But then they tended to hot start, because of the JP-5 in the lines. And if there was JP-4 in the lines, and the fuel control was set for JP-5, they would tend to hang up on starts.
Thanks, USAF!!
Not that it matters, but we used JP-4 when shore based and JP-5 aboard ship, pretty much all the time as I recall ....
We would sometimes have to manually switch the fuel controller from -5 to -4 or vice versa when refueling at an AF base on a XC or on a Det.
We would sometimes have to manually switch the fuel controller from -5 to -4 or vice versa when refueling at an AF base on a XC or on a Det.
phrogpilot73
Well-Known Member
There's an adjustment on the fuel control and fuel flow divider on the Phrog for selecting JP-4/5. You can fly without adjusting it if it's a small number of times (number escapes me off the top of my head, but it's something like 3 refuelings).
These days, it's JP-5 ashore
Friendly Fuel Truck at Oceana on Wednesday (before the rains came)
HJ Photo