SHELL 100LL REPLACEMENT

[aviatoreb]

I realize we are way off topic, but you started it. When I said that the Lycoming was high strung, I was referring to other aircraft engines. There are not many engines out there that make more HP/Cubic inch.

 

IO-360 200 HP = .55   HP/in

IO-550 310 HP = .56   HP/in

 

Pretty much the same....

 

o-320 160 HP = .50 HP/in

 

Napier Saber 3500 HP = 1.56 HP/in

 

Now there is an engine!

 

Very interesting scaling relationship N201MKTurbo.  I only dispute your units.  Cubic inches please in the denominator.  Please don't blame me for being a math geek.  

[jetdriven]

What is the installed weight of the Edelbrock SBC ready to run?  I betcha it weighs a helluva lot more than an IO-360.  Apples and oranges, certainly.  What is the BSFC of the SBC at 180-200 HP?

If you built an IO-360 out of cast iron it would be under-stressed.  And weigh twice as much.  But how many IO-360 Lycoming's have been run for any length of time at 350-400 HP?  I bet it wouldn't make that kind of power for 1 continuous minute.   There's a reason that overboosting an aircraft engine as little as 5" of MP for ten seconds leads to "scrap all rotating components"  Because the design limits have been far exceeded, and the elastic limit of the parts as well. 

[DS1980]

I didn't start it! You started it! I'm telling on you.

 

Byron, this guy is saying that our aircraft engines are "fire breathing dragons capable of reversing the polarity of magnetic north." His words!!!

 

But seriously to compare, 180 HP at 2700, 350 CID. That's 0.51, not that far off from the IO-360.

[jetdriven]

I dont think that either, but at rated power the stresses on the engine are safe, but there is very little margin above that designed in.  It takes a lot of cylinder pressure to generate .55 HP/cu in at 2700 RPM. That's a cylinder pressure / torsional bending / rod stress issue.  

 

High  pressure boosted engines can do more, the TIO-541-J2BD (The certified engine with the lowest detonation margin) can do .64hp/cu in but as a former operator of those engines, they run 56" at full rated boost and will melt down if anything is not just right, and even at more conservative settings they can still shred themselves. FWIW when they want to test 100LL replacements, they use the -J2BD for it because it is the most critical.

 

Geared engines can make more, a 421 engine can do .72 hp/cu in but they can also be delicate. They overcome the high cylinder pressure with a higher 3,350 RPM at the crank, (higher RPM all else the same reduces cylinder pressure) but they have stronger rotating assemblies and an additional part, a gear drive, to do that.

[Danb]

Jeez u should at least wear a steel cap at 180 also hold on real tight

[N201MKTurbo]

Very interesting scaling relationship N201MKTurbo.  I only dispute your units.  Cubic inches please in the denominator.  Please don't blame me for being a math geek.

Just a lazy typist......

[AndyFromCB]

How can you say that. Your average car or motorcycle engine rated at that kind of power would grenade in short order if asked to make 100 percent power for more then a few seconds. 

 

I have a motorcycle that is rated at 160 hp and 1300 CCs. The only time it will continuously make 100 percent power would be WOT, at red line at sea-level. The only way to do that on the bike would be to run at 180 MPH on the PCH. How long do you think it would last? Do you think it would do a six hour leg? Do you think it would make 2000 hours doing that? Our Lycoming is rated to do just that.

 

Most car engines spend most of their time at less the 20% power. Even a sports car or bike running like a bat out of hell only gets to more then 80% power for a few milliseconds at a time just before you shift.

 

Automotive engines have had a terrible record in aviation conversions.

 

Actually it would probably do just fine like most jetskis and snowmobiles are run at 100% and go on, and on, and on and then cost $600 to overhaul ;-)

[carusoam]

How different is the continental IO550 from a Lycoming IO360 from a construction point of view?

The IO550(g) came ready to run 100 octane, no lead, as far back as 1994.

I have never seen 100 octane fuel without going to the drag strip.

How well is Exxon remembered for there last aviation product? How many engines did they replace?

No need to rush. No need to be first...

Maybe there is hope for everyone.

Price of fuel is dropping,

-a-

[scottfromiowa]

I just filled up company car at a Shell station. I am choosing to support a company that supports future of GA. Now, if the price delta between $2.79 (car) and $5.99 (last plane fuel) could move to middle. $4.50 for no led alternative. I could smile at that!

[wishboneash]

Of course it weighs more. What would a 410 HP Lycoming weigh? More than the Chevy.

What would be the BSFC for an IO-360 capable of 410 HP? Higher than the Chevy.

 

 Again, auto engine comparison is irrelevant, and I wasn't the one to bring it up.

My point was that our engines are low stress. How would you explain 70,000 engines hours running at 50 ROP without an engine problem?

 

 

The aircraft engine drives a prop that puts a lot of stress on it (even when perfectly balanced). The auto-engine drives a gearbox which is rotationally much less stressful on the engine bearings etc.

[Shadrach]

Of course it weighs more. What would a 410 HP Lycoming weigh? More than the Chevy.

What would be the BSFC for an IO-360 capable of 410 HP? Higher than the Chevy.

 

 Again, auto engine comparison is irrelevant, and I wasn't the one to bring it up.

My point was that our engines are low stress. How would you explain 70,000 engines hours running at 50 ROP without an engine problem?

 

 

The auto engine comparison would be even less relevant if you'd stop making assertions about them that you can't prove...

 

Moreover, you're completely hung up on power to displacement as a measure of how "stressed" the engine is.  That method of thinking does not tell the whole story or even much of it.  An IO360 (or just about any AC engine) is running at 100% load at all times other than taxi and descent. Which is one of the reasons why they have such excellent fuel specifics.

 

See the attached graph which is for a run of the mill 4 cyl auto engine, notice where the BFSC sweet spot is in terms of load? As AC engine operators we are in the sweet spot almost all of time and certainly at in cruise. More over we have a self adjusting brake hanging on the engine that maintains that sweet spot, we can then tune our F/A mixture for the best BSFC setting. WOT there are little in the way of pumping losses from the throttle body.  There are very few spark ignition auto engines that match our old air cooled flat 4s in terms of BFSC, but that is changing as new tech is developed and applied.

[kmyfm20s]

Of course it weighs more. What would a 410 HP Lycoming weigh? More than the Chevy.

What would be the BSFC for an IO-360 capable of 410 HP? Higher than the Chevy.

 

 Again, auto engine comparison is irrelevant, and I wasn't the one to bring it up.

My point was that our engines are low stress. How would you explain 70,000 engines hours running at 50 ROP without an engine problem?

High altitude.

[aaronk25]

And to think my plane is a couple knots faster on mogas whoops, I meant 100ll, ya that's what I meant.

I wonder seriously how a acclaim would run on 93 straight unleaded. My guess is 200kts would be ok. 220kts might be out of question do to higher CHTs.

[Cruiser]

It would appear from the press releases that Shell is working on a similar fuel that GAMI has (G100UL) been working on. Some have suggested they are working together. Anyway, the description of the fuel chemistry is very similar.

 

Watch the two short videos, in the lower right hand corner is the NMPG readout. No change in efficiency that I can see. I suspect Shell and GAMI have very similar formulations and most likely similar performance results.

 

http://www.gami.com/g100ul/operatingcharacteristics.php

[DS1980]

The aircraft engine drives a prop that puts a lot of stress on it (even when perfectly balanced). The auto-engine drives a gearbox which is rotationally much less stressful on the engine bearings etc.

Again, not a good comparison is it?

 

But we are talking about cylinder pressures, not bending forces.

[DS1980]

High altitude.

Yep, low stress due to altitude. See post #22.

[DS1980]

The auto engine comparison would be even less relevant if you'd stop making assertions about them that you can't prove...

 

Moreover, you're completely hung up on power to displacement as a measure of how "stressed" the engine is.  That method of thinking does not tell the whole story or even much of it.  An IO360 (or just about any AC engine) is running at 100% load at all times other than taxi and descent. Which is one of the reasons why they have such excellent fuel specifics.

 

See the attached graph which is for a run of the mill 4 cyl auto engine, notice where the BFSC sweet spot is in terms of load? As AC engine operators we are in the sweet spot almost all of time and certainly at in cruise. More over we have a self adjusting brake hanging on the engine that maintains that sweet spot, we can then tune our F/A mixture for the best BSFC setting. WOT there are little in the way of pumping losses from the throttle body.  There are very few spark ignition auto engines that match our old air cooled flat 4s in terms of BFSC, but that is changing as new tech is developed and applied.

I would have to say that the relationship between HP/CID is a great measure of stress. Good point about load though, although this method does not tell the whole story or even much of it.

I just had to go there.

My point that aircraft engines are low stress due to the way we fly them is valid, and the comparison to auto engines is N/A. That was my whole point.

Bringing it back to the thread. They still will be low stress using Shell's fuel. Full circle.

[Shadrach]

I would have to say that the relationship between HP/CID is a great measure of stress. Good point about load though, although this method does not tell the whole story or even much of it.

I just had to go there.

My point that aircraft engines are low stress due to the way we fly them is valid, and the comparison to auto engines is N/A. That was my whole point.

Bringing it back to the thread. They still will be low stress using Shell's fuel. Full circle.

Just because you write it, does not make it so!

[aviatoreb]

Why is it so hard to certify a fuel product.  Hasn't Gami had a front runner for years?!  And they have test stands and so forth to demonstrate its viability.  And switch grass has been around a while now too.  What is the FAA doing?

 

And how did Prist ever get certified fleet-wide piston and jet as a fuel additive if it is so expensive and hard to do so?  Did it used to be easier in the distant past?

[Shadrach]

Why is it so hard to certify a fuel product.  Hasn't Gami had a front runner for years?!  And they have test stands and so forth to demonstrate its viability.  And switch grass has been around a while now too.  What is the FAA doing?

 

And how did Prist ever get certified fleet-wide piston and jet as a fuel additive if it is so expensive and hard to do so?  Did it used to be easier in the distant past?

Just a WAG here, but the issue is not only detonation margins, think about volatility as well.  Avgas has to remain stable in rapidly changing conditions. Think about a fuel tank sitting out in the sun all day. The fuel is heat soaked and then you hop in your acclaim and rapidly climb to 20K were the where the ambient pressure is less than 50% of where you 25 minutes ago. The fuel has still not cooled but the ambient temp and pressure has decreased substantially. The fuel is a collection of hydrocarbons and all of those hydrocarbons must beable to withstand such temp/pressure swings without any component "boiling off".  Mix in the fact that all of those components must meet EPA and FAA regs and I can see why formulating a new product that meets or exceeds the old one while meeting regulatory needs and having a similar price point is not an easy task.

[scottfromiowa]

Just a WAG here, but the issue is not only detonation margins, think about volatility as well.  Avgas has to remain stable in rapidly changing conditions. Think about a fuel tank sitting out in the sun all day. The fuel is heat soaked and then you hop in your acclaim and rapidly climb to 20K were the where the ambient pressure is less than 50% of where you 25 minutes ago. The fuel has still not cooled but the ambient temp and pressure has decreased substantially. The fuel is a collection of hydrocarbons and all of those hydrocarbons must beable to withstand such temp/pressure swings without any component "boiling off".  Mix in the fact that all of those components must meet EPA and FAA regs and I can see why formulating a new product that meets or exceeds the old one while meeting regulatory needs and having a similar price point is not an easy task.

Not buying that a multi-billion dollar company can't jump through defined hoops to identify if "it" is "it". Hundreds of tests? Thousands? Millions? How many frigging hoops need to be jumped through? Just snap a photo of a slug and call it the process for replacing 100 low lead...Just Git 'er done.

[RJBrown]

How can you say that. Your average car or motorcycle engine rated at that kind of power would grenade in short order if asked to make 100 percent power for more then a few seconds. 

 

I have a motorcycle that is rated at 160 hp and 1300 CCs. The only time it will continuously make 100 percent power would be WOT, at red line at sea-level. The only way to do that on the bike would be to run at 180 MPH on the PCH. How long do you think it would last? Do you think it would do a six hour leg? Do you think it would make 2000 hours doing that? Our Lycoming is rated to do just that.

 

Most car engines spend most of their time at less the 20% power. Even a sports car or bike running like a bat out of hell only gets to more then 80% power for a few milliseconds at a time just before you shift.

 

Automotive engines have had a terrible record in aviation conversions.

A Lycoming IO-360 at 75% produces .417 horsepower per cu inch. A Honda F20C produces the same .417 horsepower per cu inch at 21% power and can produce 1.967 HP per Cu inch at full power. Which one is "High strung"? 

 The term "Lycosaur" was coined for a reason. Our engines really are pre-historic technologically.

[DS1980]

Just because you write it, does not make it so!

Does too!

But really, it's a a large displacement engine  putting out modest horsepower, at low RPMs, at constant RPMs, being constantly monitored for oil temp, oil pressure, CHT, EGT, fuel pressure, ect., at altitudes that it cannot possibly produce 100% power, all of this after going through a start checklist, being warmed up, having a low RPM run up to see if everything is working properly, and having gentle throttle movements. If I had to be an engine, I would be a Lycoming!

[Shadrach]

A Lycoming IO-360 at 75% produces .417 horsepower per cu inch. A Honda F20C produces the same .417 horsepower per cu inch at 21% power and can produce 1.967 HP per Cu inch at full power. Which one is "High strung"?

The term "Lycosaur" was coined for a reason. Our engines really are pre-historic technologically.

"A Lycoming IO-360 at 75% produces .417 horsepower per cu inch. A Honda F20C produces the same .417 horsepower per cu inch at 21% power and can produce 1.967 HP per Cu inch at full power." And yet the Lyc still has a lower BSFC...

[kmyfm20s]

Yep, low stress due to altitude. See post #22.

The question was asked on post #24.