Diesel Fuel
 

Can diesel fuel be used in a jet engine?

Some older turbojets were certified for it; I don't know of any current ones off hand.

OTOH, the new General Aviation Diesel engines are being certified on Jet-A.

No. Despite diesel fuel and Jet-A/Jet A-1 being classified as "kerosene-type" fuels, they are refined to different standards... and diesel is refined to different standards in different countries.

In the U.S., the original Diesel fuel standard as set by the ASTM in 1931, is ASTM D975. Diesel did not exist as a fuel formulated to a standard, prior to this date. Any heavy oil, refinery residue, could be called Diesel, prior to 1931.

This ASTM standard has been modified over the years, in particular with regard to ever-lowering levels of sulfur. The U.S. diesel ASTM standard is now D975-10c.
Originally, allowable sulfur levels were up to 2%. It was found that high sulfur levels were detrimental to engines and the environment, and sulfur is gradually being reduced to barely measurable, low PPM levels.

Diesel is refined into 7 grades in the U.S. - many more grades than other countries, due to severe climatic extremes, market demand, and the size of the market.
Each Diesel grade is aimed at a specific market and has relatively narrow parameters in the standard, as compared to aviation fuels.

Diesel in Europe is refined to European Standard EN 590.

Diesel in Australia is refined to the Australian, "Fuel Standard (Automotive Diesel) Determination 2001", which is more closely related to the European fuel standard for diesel.

Jet A/Jet A-1 are refined to ATSM D1655. The differences between D975 and D1655 standards are typically in the following parameters...

Freezing point
Flash point
Cloud point
Water and sediment level
Carbon residue
Ash level
Viscosity
Sulfur level
Copper corrosion
Cetane number
Lubricity
Conductivity

The differences in freezing point levels in the refining standards, between Jet A/Jet A-1 and Diesel are substantial.

Jet A-1 freezing point: < -47°C (-52.6°F)
Jet A freezing point: < -40°C (-40°F)

Diesel fuel, because it is refined to numerous grades, has a varying freeze point.
However, even the lowest Winter grade diesel will begin to gel and clog filters at -30°C to -40°C. For this reason up to 3% methanol is added to Diesel tanks of diesel road vehicles, in those countries with severe Winter temperatures, to prevent gelling.

Jet A/Jet A-1 have additional, or increased additives, as compared to Diesel, such as lubricity improvers and corrosion inhibitors, specifically designed to combat the extreme, or peculiar operating conditions inside jet engines at high altitudes and extremes of temperature, that are not regularly encountered on the surface of the Earth.

Deisel fuel can be used on gas turbine engines just not in aircraft. The marine world use diesel fuel all of the time for gas turbine engines which are a derivative of the aero engine. When I say diesel I mean gas oil, similar to that which you would put in a "diesel" powered vehicle. Diesel is really dirty gas oil and from lower on the tower. (32sec to 38/40 sec Redwood.) Jet A1 being about 28 sec Redwood - I think.

From what I understand the simple difference between diesel and Jet A is lubricant. We used to dump a few quarts of oil into a 500 gallon tank of sumped jet a and run our GSE off it.

Onetrack is correct but just that, you asked can you and I would say hell yeah, now over time these additives may clog up small fuel controll ports, performance may not be the same but I do believe any engine, jet engine would run on diesel. I just can not say for how long.....

The simple answer is yes, you can. In most cases, it's a simple fuel control adjustment. Diesel #2 runs just fine in turbine engines.

Insofar as legality, that really depends on the circumstances and place.

My answer was based on the jet engine being used in an aviation environment. A jet engine running in a relatively static ground position, within moderate temperature ranges (above freezing; 32°F or 0°C) would run on Diesel... however, the internal components lifespan may be affected, and you would possibly no longer have an engine certified for flight, after running for a period, on a fuel that was outside the manufacturers specified fuels list.

Diesel is a heavier fuel, and has a higher energy content, pound for pound, than JetA/Jet A-1, and burns for longer during combustion, and at a higher temperature.
The major restriction on Diesel energy output is the amount of air fed in with the fuel.
Jet fuel has an S.G. of .62 -.88... Diesel has an S.G. of .82-1.08.

Yes, mine was, too.

Not true.

Onetrack, just one amendment,

Jet A1 freeze point is -47C and Jet A is -40C.

Diesel is an approved fuel in some applications. Here is one such TCDS http://rgl.faa.gov/Regulatory_and_Gu...$FILE/E3WE.pdf

We had a scooter (J-52 powered A-4) fueled with diesel in California from a fuel truck with the wrong load that ended up flying back to ABQ. No one had a clue until fuel samples were taken at home plate following the next fueling.
Corrective action was to completely drain and refuel with JP-4-- so it appears that the engines don't really see much difference.
Good thing he didn't encounter fuel freezing.:ooh:
With a single stovepipe, that wouldn't be good.

Pratt and whitney has certified P-50 as an alternative fuel for the PT6. it is #2 arctic diesel thru a 50 micron filter. I have the SB, but can't get the pdf to work.

Here you are rigpiggy.www.mmopa.com/gallery/160_SB1244R21.pdf

Q. Can diesel fuel be used in a jet engine?
A. Yes.

Q. Can diesel fuel be used in a jet engine-powered aircraft?
A. It depends.

For the ENGINE, the correct grades of fuel together with the alternate types of fuel (if any) that can be used, plus the time limits and mix ratio of alternate fuels, will be found in the engine maintenance manual.

However, this does NOT automatically mean that they can be used in the AIRCRAFT. For this, the correct grades of fuel together with the alternate types of fuel (if any) that can be used, plus the time limits and mix ratio of alternate fuels, will be found in the aircraft flight manual. These requirements, if different from those of the engine manufacturer, and they occasionally are, take precedence.

It is as well to distinguish several different meanings of the word "can". Various of the answers here refer to those different meanings.

1. Will the engine produce thrust if you inject it?

2. Will the engine run for a substantial period of time, say a short flight, using it?

3. Will the engine run for a substantial period of time using it, without suffering major structural disadvantages or maintenance problems?

4. Is it allowed by some ops manual (through STC)?

You have to ask the same questions for the use of mogas in small-aircraft Otto-cycle engines. Caveats there have mostly to do nowadays with ethanol content and vapor lock. Given the lack of context of your question, I imagine the biggest caveat might well be temperature, since diesel fuel for ground use isn't really suitable for environments with the substantially low temperatures found at the flight levels at which jets are most efficient.

PBL

Thanks guys,
It's that I was watching Apocalipse Now last night and they put diesel fuel
from a boat in a UH-1 helicopter and I didn't know if that can be done.

Big difference if you are doing low-altitude agricultural work vs. long-range stratospheric flight.

No. 2 Diesel is used in ag operations.

The biggest difference isn't in the fuel purity, but in the fuel control setting. It's a simple adjustment in most cases.

As for upper atmospheric work, the USAF has been doing long range research and work using biodiesel. You're not going to toast an engine.

Additives can be provided for lower temperature use, and there's always fuel heat.

You bet it can be done. If it's a military craft, chances are that it's already using JP-4.

JP-4 is a cut fuel; kerosine and gasoline, and the approximate equivalent of civil Jet B. One of it's chief advantages is a low freezing point.

JP8
 

Anyone know if JP8 is in use yet please?

JP8:

According to Wiki, yes, it's in use.

See JP-8 - Wikipedia, the free encyclopedia