83
votes
Accepted
Why is jet fuel cheaper than piston fuel?
Jet-A (and all turbine fuels) are far cheaper than 100LL (at least in bulk; retail prices vary due to local supply and demand as well as different regional tax regimes on aviation fuel) for several ...
31
votes
Why is jet fuel cheaper than piston fuel?
There are a number of factors that go into it:
Economies of Scale
Jet-A is used in a much higher volume than 100LL. All the jet engine commercial aircraft each day burn through orders of magnitude ...
- 36k
25
votes
Accepted
How to safely handle AVGAS (100LL)?
If you don't crawl underneath and breathe in the exhaust fumes from the engine, you'll be fine. If you do crawl underneath and breathe in the exhaust fumes, you'll be dead from carbon monoxide ...
- 126k
20
votes
Can I assume that AVGAS can be used without any problem when the engine manual suggests RON 95 or higher?
Yes it will run fine, but...
Lots of drag racers use Avgas in their cars to get the octane rating to run 12 - 14:1 compression ratios in high performance engines (At the airport I used to hang out at ...
- 126k
16
votes
Avoiding leaded gasoline in aviation
You could fly gliders. They don't use leaded fuel. In fact, they don't use fuel at all.
- 36.2k
13
votes
Accepted
Can I assume that AVGAS can be used without any problem when the engine manual suggests RON 95 or higher?
This question comes up regularly in automotive circles.
There is no advantage to using fuel with higher octane number than your engine requires, though in automobile engines there may be a minimum and ...
- 17k
10
votes
Why is alcoholic gasoline such a showstopper for aviation?
The modifications required are just not economically viable.
The main issue is vapor lock, because ethanol has a lower vapor pressure (i.e. more likely to vaporize) than gasoline. Worse, mogas ...
- 27.6k
9
votes
Accepted
What is the freezing point of 100LL Avgas?
ExxonMobil China says their Avgas 100LL will not freeze above -58°C.
The 'typical' freezing temperature is not given, but I would expect we'd be more interested in the maximum freezing temperature.
- 570
8
votes
Accepted
Avoiding leaded gasoline in aviation
J. Hougaard's answer is a bit of a smart @ss but it is one way to fly without using leaded fuel minus whatever is burned in the engine of the tow plane. But there a few more alternatives as well.
Do ...
- 72.8k
8
votes
Avoiding leaded gasoline in aviation
This is a long answer but I think it explains a viable, realistic alternative to 100LL and Jet-A.
There is a common alternative to 100LL: regular gasoline!
Many airplanes, particularly trainers, can ...
- 6,018
7
votes
Accepted
Do different grades of leaded avgas differ in ways other than their lead content?
Gasoline (both avgas and mogas) grades are distinguished solely by octane rating and lead content.
In theory, the octane rating is the amount of actual octane (C8H18) it contains, with the remainder ...
- 27.6k
6
votes
Accepted
What implications does automobile electrification have for the supply and cost of Avgas?
I have not seen any studies on this, nor would I expect to as Avgas is such a niche product and the price of it is not heavily dependent on the price of the underlying fuel itself. If you look at this ...
- 52.9k
5
votes
Accepted
How should Isopropyl Alcohol be used as an AvGas Fuel System Icing Inhibitor?
FAA Advisory Circular AC No: 23.1521-1B deals with use of IPA for Part 23 aircraft. It states:
ASTM D 910, Standard Specification for Aviation Gasolines, allows the use of isopropyl alcohol ...
- 100k
5
votes
What happens if you put car gas in an airplane?
First, it's important to note that the octane rating for aviation gas has nothing to do with the octane rating for car gas. This is because octane isn't calculated, it's measured. A specialized piston ...
- 12.8k
5
votes
Accepted
Does a diesel piston engine's power decrease more slowly with altitude than with an AVGAS engine?
Welcome to the community! Because the Austro Engine AE-300 is a diesel engine,(JetA/Kerosene and Diesel are very similar) it is equipped with a turbocharger.
Turbochargers compress the engine's intake ...
- 1,115
4
votes
Why is alcoholic gasoline such a showstopper for aviation?
The main issue, the one that bans ethanol blend fuel for use under the autofuel STC, is the effects of ethanol on rubber components in the fuel system. Ethanol is also mildly corrosive to aluminum ...
- 126k
4
votes
What is the Difference between mogas and avgas?
The main difference is avgas is based on completely different chemistry, paraffin (the flammable component of candle wax) and mogas is based on aeromatic hydrocarbons (like benzine). (Forget about ...
- 126k
4
votes
What is the Difference between mogas and avgas?
Chemically speaking, The difference in the fuels is the inclusion of lead-based additives that increase the Octane rating of the fuel, which are otherwise banned for use in other settings due to the ...
- 117
3
votes
How should Isopropyl Alcohol be used as an AvGas Fuel System Icing Inhibitor?
It seems as though there was an accident involving a PA-23-180 a while back that lead to this advisory. You can see the full report here (interestingly this was published by the NTSB not the FAA).
...
- 100k
2
votes
How should Isopropyl Alcohol be used as an AvGas Fuel System Icing Inhibitor?
I fly a PA-30 Twin Comanche regularly,and,since the POH does not discuss use of isopropyl alcohol or Prist,have contacted Piper repeatedly to seek approval.No response has come from Piper.AOPA and Int’...
- 21
2
votes
Why is AVGAS so much more expensive than car gas?
What's the reason for the huge increase in price between car and aviation gas?
There are many differences, as other answers mentioned, but not as big as the experienced prices show. But by only ...
- 555
2
votes
Accepted
Why does the FAA not support UL102 (formerly 100SF) unleaded av-gas as an alternative to 100LL fuel?
The problem is basically bureaucratic delays, helped along by easing of EPA timetables on the banning of leaded fuel, taking some of the pressure off, which has caused the developer of UL102, Swift ...
- 126k
2
votes
Why is alcoholic gasoline such a showstopper for aviation?
The Rotax line of engines are engineered to use premium automotive pump gasoline with 10% ethanol. Their engines can also use AVgas, but that tends to load the oil with lead and requires more frequent ...
- 21
2
votes
What happens if you put car gas in an airplane?
It depends on the engine type and the fuel the engine manufacturer has designed it for.
In the Cessna 172S PIM, it says:
WARNING
Use of unapproved fuels may result in damage to the engine and fuel ...
- 11.9k
2
votes
Does a diesel piston engine's power decrease more slowly with altitude than with an AVGAS engine?
It is not because it is a diesel engine, though diesels are more likely to be designed that way.
The engine is so called “flat rated”. That means its power is not limited by simply not being able to ...
- 56.2k
1
vote
Accepted
What happens if you put car gas in an airplane?
It depends. If the anti-knock rating is too low for the engine conditions then you will get detonation, which both limits power and causes major internal engine damage. ("octane" is a common ...
- 2,574
1
vote
Does a diesel piston engine's power decrease more slowly with altitude than with an AVGAS engine?
It's all about the air compression!
The graph that you mention shows two diesel/jetfuel geared piston engines, and one avgas direct drive piston engine, the Lycoming IO360. The two diesel engine ...
- 61.3k
1
vote
What is the Difference between mogas and avgas?
Mogas and avgas are very similar ; the difference is in ratio of high octane to lower octane components . The major group of high octane components are aromatics; the xlyenes with octanes well over ...
- 857
1
vote
Why is alcoholic gasoline such a showstopper for aviation?
It's not just big twins that have "high compression" or use turbos. Many four and six seat engines have higher compression engines also without turbos. My Lycoming O-360-A1F6D has no turbo. has 8.5:1 ...
- 8,765
1
vote
Do different grades of leaded avgas differ in ways other than their lead content?
Octane is is used as a reference only. That is to say 100% iso-octane (branched molecule) has an octane value of 100 by definition. A mixture of 100% heptane (straight chain) has an octane value of ...
- 11
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