FAA: Unleaded fuel by 2018

[cujet]

The C20  and Torco 108 are not oxygenated, and the closest possible products but still fall short.

 

The higher octane choices from VP, Sunoco, Torco and others are oxygenated. They have excellent octane and excellent properties. HOWEVER, they will not work in our aircraft. Sunoco 260GT is 13% Ethanol, for example. 

There is no question some aircraft can use oxygenated fuels safely, an example might be a carb'd 172 operated in dry conditions and in constant use.

 

But there are all sorts of problems with oxygenates. They damage or destroy fuel cells, fuel tank sealant, certain fuel lines, including the common Stratoflex fuel line, common O-Rings swell, and the fuel absorbs and retains water that cannot be sumped out. This results in a high risk of corrosion and freezing. 

 

One major problem is that most unleaded fuels typically do not exhibit the same excellent high octane characteristics as 100LL, when used in an over rich condition. Such as in turbocharged aircraft engines under high boost.  

Edited September 11, 2018 by cujet

[Jerry 5TJ]

OP: 5 years have passed. It is 2018 & there’s no 100LL replacement.   Since the thread has drifted nicely I will toss in my speculation:  

I guess that no single drop-in, miscible replacement for 100LL will become available.  

I foresee 100LL production will continue in the USA until something disrupts the supply of TEL, or until legal risks excessively imperil the refiners.  

Then I figure many of the 2/3 of the piston GA fleet that can convert to E0 automobile gasoline will do so.  

For those piston engines that require higher octane I see no fuel.

 

I will be happy to be wrong — I hope that 100LL remains available.   

 

(Disclosure: I’ve already converted to a widely-available alternative aviation fuel.)

[N201MKTurbo]

33 minutes ago, Jerry 5TJ said:

OP: 5 years have passed. It is 2018 & there’s no 100LL replacement.   Since the thread has drifted nicely I will toss in my speculation:  

I guess that no single drop-in, miscible replacement for 100LL will become available.  

I foresee 100LL production will continue in the USA until something disrupts the supply of TEL, or until legal risks excessively imperil the refiners.  

Then I figure many of the 2/3 of the piston GA fleet that can convert to E0 automobile gasoline will do so.  

For those piston engines that require higher octane I see no fuel.

 

I will be happy to be wrong — I hope that 100LL remains available.   

 

(Disclosure: I’ve already converted to a widely-available alternative aviation fuel.)

I predict that electronic engine controls will eventually be available for retrofit. They will become affordable and widely used. They will negate the need for 100LL and it will eventually fade away.

[cujet]

On 9/10/2018 at 9:41 PM, N201MKTurbo said:

I predict that electronic engine controls will eventually be available for retrofit. They will become affordable and widely used. They will negate the need for 100LL and it will eventually fade away.

Direct injection can help mitigate knock, by injecting fuel quite late in the compression stroke. The problem is that our engines operate under high load conditions, requiring sufficiently advanced (before TDC) ignition timing and therefore sufficiently advanced (direct) fuel injection. Can't light what's not there. Point being, direct injection probably won't allow higher compression and high boost aircraft engines to operate on lower octane fuel. 

The use of knock sensors (and lower octane fuel) in high compression engines simply results in less timing advance and HP loss. 

I predict a drop-in fuel made mostly with the very same Aviation Alkylate as our 100LL,  high percentages of high octane components (trimethylbenzene, toluene, zylene etc) and the addition of lots of MMT octane booster. Along with components to scavange the residual MMT. 

Edited September 12, 2018 by cujet

[aviatoreb]

23 hours ago, Jerry 5TJ said:

I guess that no single drop-in, miscible replacement for 100LL will become available.  

I foresee 100LL production will continue in the USA until something disrupts the supply of TEL, or until legal risks excessively imperil the refiners.  

Then I figure many of the 2/3 of the piston GA fleet that can convert to E0 automobile gasoline will do so.  

For those piston engines that require higher octane I see no fuel.

 

But doesn’t that small fraction, the 1/3 of the fleet use something like 80% of the fuel since they are the twin work horses?  (Scheduled carriers, freight carriers, etc).

Edited September 12, 2018 by aviatoreb

[N201MKTurbo]

47 minutes ago, cujet said:

Direct injection can help mitigate knock, by injecting fuel quite late in the compression stroke. The problem is that our engines operate under high load conditions, requiring sufficiently advanced (before TDC) ignition timing and therefore sufficiently advanced fuel injection. Can't light what's not there. 

The use of knock sensors simply results in less timing advance and HP loss. 

I predict a drop-in fuel made mostly with the very same Aviation Alkylate as our 100LL,  high percentages of high octane components (trimethylbenzene, toluene, zylene etc) and the addition of lots of MMT octane booster. Along with components to scavange the residual MMT. 

No, they just have less advance at full power to get the detonation margins we need. It will reduce takeoff and climb power a bit, but there is no reason to reduce cruise power. If it was a 200 HP engine and you ran it at 150 HP in cruise, you can still run it at 150 HP. The engine is more than capable of making that much power without detonation on 94UL which is 100LL without the TEL.

[cujet]

3 hours ago, cujet said:

 

The use of knock sensors [and low octane fuel] simply results in less timing advance and HP loss. 

 

Corrected for clarity. 

The problem with reducing peak HP in an aircraft is self evident. Electronic control on engines like the higher compression IO360A1 series lyc's won't likely result in the same HP as we enjoy now, when coupled with lower octane fuel. 

[N201MKTurbo]

19 minutes ago, cujet said:

Corrected for clarity. 

The problem with reducing peak HP in an aircraft is self evident. Electronic control on engines like the higher compression IO360A1 series lyc's won't likely result in the same HP as we enjoy now, when coupled with lower octane fuel. 

You are correct, we would lose some peak horse power. But we almost never run it at peak horse power. By the time you climb a few thousand feet you are well below peak horse power. After the manifold pressure reduces some, the electronic controls can advance the timeing to the original value or more without worrying about detonation. The loss of power would be insignificant and have no effect on cruise speeds.

[Hank]

Loss of peak hp may not bother you turbo folks, but us NA people taking off heavy on hot, humid Southern summer days need all of the peak hp we can get! That allows us to climb up to where manifold pressure drops . . . . . Instead of going into corn / cotton fields, trees, rivers and lakes.

Or should we all adjust our allowable gross weights down???

[N201MKTurbo]

37 minutes ago, Hank said:

Loss of peak hp may not bother you turbo folks, but us NA people taking off heavy on hot, humid Southern summer days need all of the peak hp we can get! That allows us to climb up to where manifold pressure drops . . . . . Instead of going into corn / cotton fields, trees, rivers and lakes.

Or should we all adjust our allowable gross weights down???

Your engine already makes less than rated power. Even at the low elevation you live at you are still above sea level. 

The point I’m trying to make is with proper electronic control of spark advance, full power can be restored after the manifold pressure is reduced to where the detonation margins are sufficient. This probably means that your sea level performance would be slightly less, but above say 4000 ft (a wild guess) your performance would be the same as it is now if not better.

And it would not affect your gross weight, it would just increase your takeoff distance a little at low elevation airports.

Edited September 12, 2018 by N201MKTurbo

[Andy95W]

Hank- Actually, the Lycoming O360-A1D is approved to run on 94UL at full rated horsepower, so we already have an unleaded fuel available to us to use.

The problem is most avgas is bought by owners of very thirsty turbocharged or angle-valve injected engines which still need 100 octane without losing timing (and therefore, power).

Edit- correction for engine types

[cujet]

On 9/12/2018 at 4:03 PM, Andy95W said:

Actually, both the Lycoming O360-A1D and the IO-360-A1A are approved to run on 94UL at full rated horsepower, so we already have an unleaded fuel available to us to use.

The problem is most avgas is bought by owners of very thirsty turbocharged engines, which still need 100 octane without losing timing (and therefore, power).

As far as I know, no angle valve lyc's can use any available unleaded. 

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/299fa3d6aef0ba048625821e0072188a/$FILE/1E10_Rev_28.pdf

 

https://www.lycoming.com/sites/default/files/SI1070Z Specified Fuels.pdf

 

 

Edited September 15, 2018 by cujet

[Andy95W]

14 hours ago, cujet said:

As far as I know, no angle valve lyc's can use any available unleaded. 

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/299fa3d6aef0ba048625821e0072188a/$FILE/1E10_Rev_28.pdf

 

https://www.lycoming.com/sites/default/files/SI1070Z Specified Fuels.pdf

 

 

My bad, you're right, I was looking at the wrong row.  I'll edit my original post.

[Mooneymite]

September 27, 2018 View in browser | Subscribe | AINonline.com MagniX Reaches Milestone on Path to Electric Propulsion MagniX has continued to advance the future of electric propulsion systems for aircraft, successfully testing a 350-hp all-electric motor. Its motor was tested with a propeller mounted on a Cessna iron bird as a demonstration of the company’s ability to use the all-electric motor on a commercial aircraft platform. The company expects to install a 750-hp propulsion system on a Cessna 208 Caravan by next fall. According to MagniX, electric aviation will reduce operating costs while eliminating carbon emissions. The company estimates electric aircraft will fly up to 1,000 miles by 2024 and up to 500 miles by 2022. “From design to prototype, dyno test cell success to now turning an aircraft propeller, we are one step closer to powering the future of electric aviation,” said David Sercombe, chief design engineer for MagniX. Current technology, including both aircraft propulsion and batteries, and technology coming up in the next 18 to 24 months are “perfectly suited” for electric aircraft that can fly from 100 nm to 1,000 nm, according to MagniX CEO Roei Ganzarski. Read Expanded Version

[jaylw314]

6 minutes ago, Mooneymite said:

September 27 2018     MagniX Reaches Milestone on Path to Electric Propulsion MagniX has continued to advance the future of electric propulsion systems for aircraft, successfully testing a 350-hp all-electric motor. Its motor was tested with a propeller mounted on a Cessna iron bird as a demonstration of the company’s ability to use the all-electric motor on a commercial aircraft platform. The company expects to install a 750-hp propulsion system on a Cessna 208 Caravan by next fall. According to MagniX, electric aviation will reduce operating costs while eliminating carbon emissions. The company estimates electric aircraft will fly up to 1,000 miles by 2024 and up to 500 miles by 2022. “From design to prototype, dyno test cell success to now turning an aircraft propeller, we are one step closer to powering the future of electric aviation,” said David Sercombe, chief design engineer for MagniX. Current technology, including both aircraft propulsion and batteries, and technology coming up in the next 18 to 24 months are “perfectly suited” for electric aircraft that can fly from 100 nm to 1,000 nm, according to MagniX CEO Roei Ganzarski. Read Expanded Version

Motors are easy, though.  Large brushless motors are common now with electric cars becoming more common.  It's the batteries that will remain the issue.

[Mooneymite]

19 minutes ago, jaylw314 said:

Motors are easy, though.  Large brushless motors are common now with electric cars becoming more common.  It's the batteries that will remain the issue.

An loooong extension cord hooked up to your wind generator ought to keep the cost down.  

[Hank]

29 minutes ago, jaylw314 said:

Motors are easy, though.  Large brushless motors are common now with electric cars becoming more common.  It's the batteries that will remain the issue.

There are three issues with electric planes:

1. Battery capacity, size and weight. Slowly improving thanks to hybrid cars; electric cars are still non-viable toys.
2. Recharging time. A car that won't go >400 miles without a multi-hour charge is half useless. Ditto for a plane; I made 5 legs last Thursday totaling >1100 nm. Can't (won't!!) wait hours to recharge. 
3. Install STC. This will probably eliminate every plane from consideration that isn't built with the motor . . . .

Other than that . . . .

[jaylw314]

7 minutes ago, Hank said:

There are three issues with electric planes:

1. Battery capacity, size and weight. Slowly improving thanks to hybrid cars; electric cars are still non-viable toys.
2. Recharging time. A car that won't go >400 miles without a multi-hour charge is half useless. Ditto for a plane; I made 5 legs last Thursday totaling >1100 nm. Can't (won't!!) wait hours to recharge. 
3. Install STC. This will probably eliminate every plane from consideration that isn't built with the motor . . . .

Other than that . . . .

1 hour charge times are at least theoretically possible with lithium tech--practically, of course, this is not done.  RC hobbyists will routinely recharge Li-polymer batteries in 30-60 minutes without major decrease in battery life, but that technique is certainly not ready for mainstream use...

It will be interesting to see if graphene ever pans out as a battery.  AFAIK, its application would be as a super-efficient capacitor for storage, so in theory it could be charged in seconds.  The cynic in me thinks that's doubtful, though.

[Mooneymite]

3 hours ago, Hank said:

There are three issues with electric planes:

1. Battery capacity, size and weight. Slowly improving thanks to hybrid cars; electric cars are still non-viable toys.
2. Recharging time. A car that won't go >400 miles without a multi-hour charge is half useless. Ditto for a plane; I made 5 legs last Thursday totaling >1100 nm. Can't (won't!!) wait hours to recharge. 
3. Install STC. This will probably eliminate every plane from consideration that isn't built with the motor . . . .

Other than that . . . .

Hank, all of these problems will be overcome by a simple fusion STC.

Don't make this more complicated than it already is.

[1964-M20E]

3 hours ago, Mooneymite said:

Hank, all of these problems will be overcome by a simple fusion STC.

Don't make this more complicated than it already is.

Mr. Fusion to be precise.  Than and the flux capacitor.

[cliffy]

Dilithium Crystals!

[Hank]

1 hour ago, 1964-M20E said:

Mr. Fusion to be precise.  Than and the flux capacitor.

 

34 minutes ago, cliffy said:

Dilithium Crystals!

Any of these are fine with me, just don't put HAL in charge . . . .  

[cliffy]

What about Robby                

[aviatoreb]

14 hours ago, Mooneymite said:

Hank, all of these problems will be overcome by a simple fusion STC.

Don't make this more complicated than it already is.

Cold or hot?

[BKlott]

On 9/27/2018 at 4:25 PM, Mooneymite said:

An loooong extension cord hooked up to your wind generator ought to keep the cost down.  

Can’t we just install mini wind turbines across the top of the wings and horizontal stabilizer instead?