GAMI Fuel to replace AVGAS??

[Jabawocky]

Keep your eyes on this as an alternative to TEL enhanced fuel.

A New Fuel Breakthrough? G100UL

http://www.pprune.org/newspics/100llsample.jpg

As the industry continues to wring its hands about a replacement for soon-to-be-extinct 100LL, an Oklahoma-based modification house says it has a fuel worth looking into. George Braly of General Aviation Modifications Inc. told us Friday that his company has run a promising new fuel in its test cell that's at least 100 octane or better. The fuel appears to have good anti-detonation characteristics and, on paper at least, would be in range of meeting ASTM D910, the avgas fuel specification. So what is this stuff? Braly declined to offer details other than to say the new fuel is based on 95-octane blend stock with an additive that's not lead but that might be obtainable economically through conventional refining processes.

Is it some offshoot of Swift Fuel, the much lauded but so far non-existent bio-fuel announced a couple of years ago? Nope, says, Braly, nothing to do with Swift Fuel. Oil industry insiders have consistently said petrochemical-based octane enhancers are chemically feasible. Indeed, Swift Fuel is just that—a bio-derived material that uses acetone as a feedstock to make an enhanced isopentane fuel. What has stymied such efforts in the past—and indeed, may yet kill Swift Fuel—is the economics. If the additive can't deliver 100-octane fuel at a price similar to tetraethyl lead, the whole exercise is just another chemistry experiment. Braly said Friday that he's filed a patent on the process and that it's being shopped to the refinery industry to flesh out the economics. Meanwhile, Braly said the fuel will be ready for wider demonstration in about a month.

[rioncentu]

George is da man so I'd definitely keep an eye on it.

[Ultralights]

We are already using a replacement. BP Ultimate 98 RON.


Oh,I forgot, most GA use old tech engines....


BP 98 is the only mogas guarenteed to be 98 Ron or higher, hence it's the only mogas approved by Jabiru and Rotax.

[Bounceferret]

"AVGAS 100LL or Auto Gas 91 Octane Minimum"

straight off the Jabiru website

[YPJT]

Oh,I forgot, most GA use old tech engines....
Unfortunately, a Rotax with enough muscle to power anything more than a plastic RAA is yet to get up and running and those Thielerts have been a rip roaring success haven't they?

[Jabawocky]

Most Lycosaurus and TCM's have a low enough compression ratio to run unleaded, and would actually do much better on some PULP in their diet.

Now the vapour locking or just the surges from it boiling off in the lines is bad enough with AVGAS.........let alone PULP :eek:

The GAMI boys will know if they are onto something that works, but its the economics that will dictate.

J:ok:

[Fueldrum]

Jabawocky,

I'm a big fan of GAMI and they may have found a way of overcoming the problem that MOGAS has an inadequate octane rating for most piston aero engines.

However, that leaves at least three problems still to be solved.:ugh:

Firstly, most MOGAS nowadays has ethanol inside. Atmospheric humidity dissolves into ethanol. As an aircraft climbs, the outside air pressure and outside air temperature will normally fall. This causes the water in the ethanol to condense and collect at the bottom of the tank:eek:. Also if the OAT has fallen below zero the water will form ice crystals in the fuel system:sad:

Secondly, different brands of MOGAS have different resistance to vapour lock. How do we know if the MOGAS will vapourise if we don't know how much resistance to vapour lock it has???

Thirdly different batches of MOGAS have different ingredients and hence different energy content per volume. This will lead to differing fuel flow rates at a given power setting. If these differ materially from the assumptions used in drawing up the performance/fuel flow charts, the risk is that the aircraft will suffer fuel exhaustion.

In any case for this to work well the energy content will have to be close to that of AVGAS, otherwise the weight of the fuel needed for a particular journey will increase aircraft weight, leading to the need for a larger (and heavier) engine with higher fuel consumption, leading to the need for larger (and heavier) wings to carry the extra weight, which causes more drag and thus needs a larger engine (again) and so on:=

Like I said I'm a big admirer of GAMI - there have been too few real innovators in GA for far too long. Still I think there's a long way to go before there's really a substitute for AVGAS.

Best wishes and blue skies :ok:

[Old Akro]

There are a few things that need to be straightened out.

Firstly the AVGAS octane scale & Mogas octane scales are different. 100 Octane Avgas does not = 100 octane Mogas.

Secondly, I'm very confident that the 98 Octane of Shell & Mobil is 98 or more. You can download the technical document sheets for all fuels from the websites and see for yourself. There is also a national fuel standards website somewhere. It is worth noting however that only BP, Shell & Mobil refine 98 octane in Australia. The rest either buy it from one of those 3 or from overseas (usually Singapore and often on the spot market). The BP Kwinana refinery is regarded as having particularly good process control which leads to it being regarded as the pick of the 3. However there is (or was) a fuel trading scheme in place between the petrol refiners so that they each swapped fuel to minimise freight, so you may actually be taking fuel refined by another company. Australia was very late in establishing National fuel standards (maybe 1 Jan 2007 - I forget). Before then there was a large variation in fuel. Now its all pretty good.

Lead in Avgas has more to do with valve lubrication than octane rating.

The mogas formula varies during the year and between states to take into account seasonal temperature variations. Essential mogas has less volatile components in hot weather when they evaporate more rapidly. Alpine areas get a different fuel again. The fuel companies publish a table that details this, its no secret.

The vapourisation requirements of mogas and Avgas are completely different. Consider that most cars will have a submerged fuel pump in the tank with the fuel rail pressurised to around 60 psi vs gravity feed for many aircraft. The new direct injection car engines have much higher fuel pressures. Also, the mogas formula has a requirement for easy starting that is more critical than Avgas (cars get more starts per hour & short trips than aeroplanes).

Its all very well to poke fun at Lycoming & Continental, but the specific torque rating of these engines is as good or better than any modern engine and point me to any other 200 Hp+ engine that can produce 75% of its rated power indefinitely. There are no car engines that will do this and while Rotax are (now) pretty good, they are low power engines. What's the alternative to an IO-560?

[Jabawocky]

Very true...........but what is an IO-560? :E Is that what I get when I bore out the IO540 and fit oversize pistons and rings:}.......Look out Forkie! Or maybe one of these....
http://www.lycoming.com/images/engine_series_720.jpg

The other problem you have with PULP, after a week or two in a container that is not fully sealed, the light ends evaporate off and you end up with ordinary unleaded or somewhere in between.

AVGAS is far mor stable over a longer period.

Its hard to get past the old juice! :ok:

[185skywagon]

jaba,
i know of an Lyco IO-580 installed in a 114 Commander. bloke is very happy with it.

185.

[Jabawocky]

Do you think I need an upgrade 185? :}

By beer o'clock on Saturday we can discuss if thats necessary! :ooh:

[27/09]

Or maybe one of these.... the IO720

Real singles had these fitted at the factory. By the way I'm not thinking of the FU24-950.

[Peter Fanelli]

Are there still any PA-24-400's still flying in OZ?

They were getting pretty scarce by the time I left.

[Octane]

Sure is;

1. There are 3 types of Octane engine and methods used for testing gasoline octane quality in refineries during manufacture. The Research Octane Number or RON engine, the Motor Octane Engine or MON engine and finally the Supercharged or F4 engine.
So, when an octane rating is quoted for a particular fuel, the method must also be quoted. For example, regular ULP must have an octane rating higher than 91.0 RON whereas Avgas must be higher than 100 MON. Now the MON method is a more severe test on the fuel than the RON method (900 vs 600 rpm, high inlet temp and more advanced ignition timing) so for any given fuel the MON rating will always be lower than the RON rating. 91.0 RON ULP typically has a MON of around 82. The difference between the 2 is known as the sensitivity of the fuel. Conversely, Avgas (>100 MON) would give an octane result of well over 110 RON if tested on the RON engine (which it's not). So you can see that 100 MON octane Avgas actually has a much higher octane rating or resistance to detonation than the 98 RON octane fuel available from petrol stations. Please do not think you can get away with using 98 RON fuel in place of 100 MON fuel because the difference is only 2 numbers....!
Out of interest, gasoline in the USA is sold based on the average of the two octane ratings i.e. (RON+MON)/2 while here in Oz only the RON is quoted.

2. Lead or more correctly Tetra Ethyl Lead (TEL) in gasoline most definitely has a postive impact on the octane quality of the fuel. That's why it's added! That the lead acts as a valve seat lubricant is merely a beneficial side effect.

3. All fuel/ gasoline/ any refinery products for that matter, that are made here have to conform to the same very strict Australian standards. To claim gasoline from one particular refinery is '"better" than that from another is just plain wrong.

Cheers

Octane

[Jabawocky]

Yep...... they call it 87 from memory at the pump!

Keep the godd info coming, makes for a good thread!

[OZBUSDRIVER]

Continental where playing around with 100LL AVGAS with no TEL...94UL.

An excerpt from an article by Robert Goyer last month-
Continental President Rhett Ross tells me that the company will be ready for the unleaded change. Continental's team believes that with some workable changes to the valve seats in some models and to the combustion and ignition systems in others, and with no changes to some models, its gas piston engines will be compatible with the new fuel. Of course, because 94UL is lower in octane than 100LL, its potential energy will be lower across the board, regardless of whose engine the future fuel is being used to power.

That said, the performance of the SR22 I flew on 94UL was impressive. Not only did it produce a good deal more power on takeoff and in climb on 94UL than the factory SR22 does on 100LL, but it also ran cooler, even at power settings in the high teens.

There are a lot of questions to be answered here, and one of them is how 94UL will do on a hot day at high altitude and a high power setting. The answer for us was "great." Had we climbed into the 20s (which we did not do), the book likely would have required some limitations on power settings to maintain the required detonation margins, says Continental's Keith Chatten.

According to Ross, the company has a plan to have its engines ready for 94UL when the time comes, and the TSIO-55 will be among the first to get approval.


Maybe 94UL will be the go?

[Fueldrum]

Perhaps 94UL will become available, but what is the advantage :confused:

I thought the problem in the first place was the declining availability of AVGAS because declining demand for it is making suppliers reluctant to invest in special ad hoc bowsers/tankers/trailers/drums. If regular MOGAS could be used it might solve this problem because special equipment wouldn't be needed, but MOGAS won't be 94UL. 94UL will still require special ad hoc fueling equipment, so we will still see declining availability:ouch:.

Some people think that 94UL will be more environmentally friendly, but that is debateable. Unleaded fuel reduces lead emissions but if the compression ratio of the engine must be lowered, or the ingnition timing retarded, to use 94UL then carbon emissions will increase accordingly:=. This isn't really environmental progress:ugh:

You would have to replace the whole AVGAS supply system, plus modify the GA fleet's engines to use 94UL, then replace high performance AVGAS planes like Chieftains with JET-A1 planes like the Pilatus PC-12 (because high performance AVGAS engines can't be modified to use unleaded fuel). This would cost a fortune.

You could buy a lot of solar panels with that much money. I think that would be much better for the environment.:ok:

[Octane]

I'm assuming 94UL means 94 MON octane fuel with no TEL added. Quite possibly fine for low power output engines. Tiger moths no prob! Certainly not suitable for turbo/ supercharged engines.

Modern engines with knock sensors and digital engine management systems will derrate engine power output (reduce ignition advance) to prevent detonation.
Great if you're a little high and hot and you think you have enough room to go but you're down 50 Hp or so because the EMS doesn't like the fuel...

Older, less sophisicated engines, depending upon the compression ratio, will just detonate..

What a can of worms..

Contrary to what someone said, there has never been 130 octane avgas.
If anyone would like to know more, I'll do my best to come back with an answer.


cheers

Octane

[OZBUSDRIVER]

AVGAS 20/20 (http://www.kitplanes.com/magazine/pdfs/0606-2935.pdf)

Octane...if there was never 130 (or 130 on aviation supercharged rich as in 100/130) or 115/145 then a lot of big radial recips would have died at birth. Maybe, you should rephrase your statment?

Like the article says...because of the off-optimum spark settings of fixed spark timing engines at certain power settings is the reason high octane fuel is required.

[Brian Abraham]

there has never been 130 octane avgas
Technically there is no such thing as a fuel with anything higher than 100 octane rating. Beyond 100 0ctane the figure is correctly known as "Performance Number", though "octane" is the common usage. During WWII fuel with a rating of 150PN (Octane) was in use.

The Aviation Rating is determined using the automotive Motor Octane test procedure, and then converted to an Aviation Number using a table in the method. Aviation Numbers below 100 are Octane numbers, while numbers above 100 are Performance numbers. There is usually only 1 - 2 Octane units different to the Motor value up to 100, but Performance numbers varies significantly above that eg 110 MON = 128 Performance number.

The second Avgas number is the Rich Mixture method Performance Number ( PN - they are not commonly called octane numbers when they are above 100 ), and is determined on a supercharged version of the CFR engine which has a fixed compression ratio. The method determines the dependence of the highest permissible power ( in terms of indicated mean effective pressure ) on mixture strength and boost for a specific light knocking setting. The Performance Number indicates the maximum knock-free power obtainable from a fuel compared to iso-octane = 100. Thus, a PN = 150 indicates that an engine designed to utilise the fuel can obtain 150% of the knock-limited power of iso-octane at the same mixture ratio. This is an arbitrary scale based on iso-octane + varying amounts of TEL, derived from a survey of engines performed decades ago. Aviation gasoline PNs are rated using variations of mixture strength to obtain the maximum knock-limited power in a supercharged engine. This can be extended to provide mixture response curves which define the maximum boost ( rich - about 11:1 stoichiometry ) and minimum boost ( weak about 16:1 stoichiometry ) before knock.

[Octane]

Exactly,

People are confusing MON octane number with performance number. So Avgas 100/130 is a fuel with a MON octane rating of 100 or higher and with a performance number of 130 or higher as determined on the supercharged or F4 engine. I've had the 'pleasure'of testing many batches of Avgas on these engines..

cheers

Octane

[Jabawocky]

Here is a video from the GAMI folk and AvWeb :ok:

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[Jabawocky]

AVwebFlash Complete Issue (http://www.avweb.com/eletter/archives/avflash/1670-full.html#202845)

Pelton, Fuller Take A Look At GAMI's G100UL



Cessna CEO Jack Pelton and AOPA President Craig Fuller flew into Ada, OK on Wednesday to get a look at a new 100LL replacement proposed by General Aviation Modifications Inc. As we've reported previously (http://www.pprune.org/avwebflash/news/AVwebFliesNewG100ULFuel_201982-1.html), GAMI's G100UL appears to perform similarly to 100LL and the company claims it's producible using conventional refining methods. GAMI invited Pelton and Fuller to Ada to view a detonation test cell run comparing G100UL to other fuels. In an evening e-mail to other GA leaders and the press, Pelton said "We participated in a thorough brief along with a test cell demonstration running three types of fuels, 100LL, min spec 100LL and G100UL. At the conditions we observed, it was very interesting to see the data on the engine characteristics for the three fuels. I would characterize the conditions as worst-case sea-level tests. In general terms, G100UL out-performed min spec 100LL and seemed to be about the same as straight-from-the-FBO 100LL." Pelton said in his view, G100UL "looks to be a fuel that can be refined and distributed within the existing infrastructure we have here in the states. I would guess it could be produced in many other international locations also."

Pelton added that "I know the devil is in the details. But this project is very interesting and very exciting. George [Braly] heard what the EPA said about 100LL is trying to do something about it for our industry." Pelton said he encouraged other GA leaders including GAMA's Pete Bunce to take a closer look at G100UL. The fuel is currently undergoing test in a Cirrus SR22 and GAMI has asked the FAA for an STC to move forward with wider fleet testing. It has also applied to ASTM for a formal fuel specifications approval.

[eocvictim]

Car related:
Octane you seem to have a good insight into aus fuels; when was the shift from unregulated fuels? I refused to use anything other than BP after having to replace 2 fuel filters when some dodgy Shell (vpower F1 "100 octane") fowled up my cars fuel system (went from clean to black in 1 tank). I also had a similar issue with Optimax fouling plugs, going off after a week and causing large power loss and idle hunting. I was using Mobil for a while but moved away from it after I found it limited the power of one car with quite severe pinging. All solve as soon as I filled up with BP. Hence why I haven't used anything other than BP for the last 5 years.

[Jabawocky]

What kind of car are you driving??

And where are you?

Having said that the BP Ultimate is the consistent preference of folk who have been fussy. I use the Caltex 98 in my bike....funny enough it hates AVGAS :suspect:. Runs terrible!

[RatsoreA]

Bp 98 Ron and shell 98 Ron are the same product, coming out of the same pipe. The only difference is the logo on the side of the truck they go into before the get delivered to servos!

[Jabawocky]

Have heard that also....mind you they may add different additive packs ....what about other locations? Its hard to know as they all cross supply around the country.

RatsoreA.....you wouldn't happen to work for a Shell refinery by any chance?

J:)

[43Inches]

Any contamination is more likely to be occuring at the point of sale, the service station itself. Most bad fuel has been linked to a particular station having contaminated underground tanks. Although BP was the one who stuffed up the AVGAS additives at the refinery back in 2000.

Which refinery the fuel comes from depends on where you live and some times its the same product. However the additives may vary in the product, this can be the main difference in what is sold at the pump.

[Jabawocky]

I thought that was Mobil.........:confused:

[Old Akro]

There are only 3 refiners of 98 Octane MOGAS in Australia. Shell, BP & Mobil. Everyone else buys from one of these or imports. Typical imported fuel is bought on the Singaporean spot market.

BP / Shell / Mobil may still do some fuel sharing (ie they swap fuel rather than having fuel trucks pass each other on interstate highways).

The BP Kwinana refinery is or was regarded as having the best process control of all Australian refineries.

Part of the wives tale of differences in brands I think dates back to the time before Australia had a National fuel standard (2004?) when there were different state based requirements and fuels differed widely. These days, I challenge anyone to pick the difference between BP/ Shell / Mobil 98 octane. The guy next door who builds race engines has a preferred fuel to get the most power on the dyne, but its not one of these and I suspect his results are due to the non-real world environment of the dyne room.

[Old Akro]

A question for Octane. Some years ago Peter Garrison's column in Flying magazine mentioned that the US was experimenting with fuel with a performance rating of 400 before jets overtook the turbo compound radials. Do you have any knowledge of this? Can you imagine the sight of a turbo compound radial at full noise on a dyne running these fuels?

Where it is allowed, competition vehicles run self oxygenating fuels (elf, Philips, etc). How does this impact on Octane rating? When I last used them (10 years ago) the cost topped out at about $15 / litre. I'd hate to think what it costs now.

[RatsoreA]

Have heard that also....mind you they may add different additive packs ....what about other locations? Its hard to know as they all cross supply around the country.

RatsoreA.....you wouldn't happen to work for a Shell refinery by any chance?

J

No, but my old man used to!

[pilot2684]

Old Akro, I think you're reffering to what is known, in the industry, as C16 Race Fuel.

I purchased a 25 litre drum of this for a dyno run a while ago and it cost me $250, and that was at mates rates too. Wasn't by any means cheap but yet... it proved itself. Good Stuff C16 is, Unleaded, with a 130-140 octane rating. Most Bang for the buck you can get

[Ejector]

Easy, pistons are to complicated anyway, install turbines. Grab a Walter.