# Is there a special kind of fuel needed to obtain high efficiency engines?

Are there any special kinds of fuels that manufacturers are considering in order to make high performance, high efficiency jet engines?

• ساخت موتور جت کم مصرف با قدرت بالا . سوخت چه چیزی باشد Construction of energy-efficient high-power jet engines. What is Fuel Apr 29 '16 at 7:20
• I know I edited this a lot, but I'm fairly confident this is what the OP meant to say. Just trying to help get it translated into English... If someone who speaks Arabic could go ahead and translate his actual text in the above comment, that would probably be even better... Apr 29 '16 at 13:21
• NOTE: that's no Arabic, that's Farsi (Persian) [I have some friend that speak it, I will see if they can help]
– Federico
Apr 29 '16 at 13:33
• @Federico ......oops. So, yeah, what I said above except, you know, Farsi. Apr 29 '16 at 13:37
• @JayCarr from a friend of mine: "Apparently he wants to know what kind of fuel must be used in order to make a fuel-efficient high power jet engine" [basically what you guessed] "Or which jet engines are high power and at the same time consume less fuel and which fuel would help do that"
– Federico
Apr 29 '16 at 13:50

Surprisingly, it isn't a big factor in GA or commercial aviation.

                            Specific  Energy
Energy    Density
MJ/Kg     MJ/L
Diesel / Fuel oil           48        35.8
LPG (inc Propane / Butane)  46.4      26
Jet fuel (Kerosene)         46        37.4
Gasoline (petrol)           46.4      34.2
HMX (Rocket Fuel)            5.7      10.8


Even high-performance long-range military aircraft like the U2 and SR-71 use some variant of Kerosene with additives, their fuels are optimized for high flash point, not for energy density or for specific energy.

Generally, availability and infrastructure trump efficiency.

• Has nobody designed a high efficiency engine off of liquid Hydrogen or Methane? Both have a higher energy density than Jet Fuel it looks like, and liquid Hydrogen is becoming more and more available all the time... Apr 29 '16 at 17:23
• @JayCarr You have to look not only at energy density but the safety aspect. There is a reason nobody is within miles of a rocket launch, when liquid hydrogen explodes, it explodes. JET-A is relatively stable, but even with that fuel there was a push a while ago to develop an anti-misting kerosene that was abandoned, but the goal was to develop a fuel that wouldn't atomize and burn in a crash. Apr 29 '16 at 17:33
• @RonBeyer They use liquid hydrogen in cars these days, both in hydrogen fuel cells and in vehicles that burn the hydrogen directly. I admit it's been troublesome in the past, but I don't know that those safety concerns matter anymore. Further, I'm only asking if someone may have given it a shot, a lab will care for less about how safe it will be in a car when they are first developing the technology. Apr 29 '16 at 17:36
• @JayCarr: The Tupolev 155 used three hydrogen-powered jet engines, and Wikipedia lists 10 more hydrogen-powered aircraft, most of which never came (or most likely never will come) to fruition. The Kusnezov NK-88 is my answer, but cryogenic storage pretty much nullifies the advantage of hydrogen's higher energy density. Apr 29 '16 at 19:52
• @PeterKämpf I wonder if that technology will significantly change as more cars switch over to hydrogen... I assume so, but I guess we'll see. Apr 29 '16 at 20:17