Swift 94 fuel fails trial at UND

[Pinecone]

On 11/9/2023 at 1:17 PM, EricJ said:

That's an enormous school that flies many thousands of hours a year, so their previous history was an effective control group.

Then did not do the same monitoring/measurement for 100LL engines.

[EricJ]

1 hour ago, Pinecone said:

Then did not do the same monitoring/measurement for 100LL engines.

How so?   Control groups don't need to occur at the same time if the time displacement isn't a significant factor in the outcomes (i.e., the wear is not likely to be seasonal or different from one year to the next).   They've been flying their fleet for an awful long time, so they have established trends for things like exhaust seat wear.   If it changed significantly during UL94 use, and there aren't other confounding influences, then that's a significant result.     

[MikeOH]

2 hours ago, Pinecone said:

Then did not do the same monitoring/measurement for 100LL engines.

Please explain, if moving to UL94 was so wonderful, why UND went back to 100LL?  I seriously doubt it was because they had no meaningful historical data to compare with so they just dumped UL94 for no reason.

[McMooney]

they just need to go unleaded and get this over, this slow death thing is for the birds.  honestly what does this mean, i buy new cylinders at somewhere around 2000 hrs ?

 

[Pinecone]

As I understand it, they were not going similar monitoring before the switch

 

[GeeBee]

Tell you what. Dab you finger on a hot griddle, then quickly pull it off. Now put your finger on the same griddle and hold it there. Little more heat transfer? Did the skin cook a little more? (Hint: It's the interval and your blistered finger will tell you which interval had the most heat transfer)

[Ragsf15e]

So where does this leave g100ul.  They claim to have run thousands of hours and the engines are pristine.  Why isn’t UND trying that?

[ragedracer1977]

35 minutes ago, Ragsf15e said:

So where does this leave g100ul.  They claim to have run thousands of hours and the engines are pristine.  Why isn’t UND trying that?

UL94 is essentially just regular avgas without the tetraethyl lead and etheylene dibromide additives

From what I understand, GAMI at this point, doesn’t have a way to produce fuel in enough quantity for that kind of thing. My gut says they are trying to shield themselves from liability.  GAMI is not a company that could afford to defend a high $ suit.  They’re small.

Personally, I think Braly is a very smart guy.  If he says it will work, it probably will.  He’s not a spring chicken.  I don’t think he’s put this much time and money in with the plans to be the next Elon Musk.  I think he did it just to prove it could be done.  

 

[Ragsf15e]

42 minutes ago, ragedracer1977 said:

UL94 is essentially just regular avgas without the tetraethyl lead and etheylene dibromide additives

From what I understand, GAMI at this point, doesn’t have a way to produce fuel in enough quantity for that kind of thing. My gut says they are trying to shield themselves from liability.  GAMI is not a company that could afford to defend a high $ suit.  They’re small.

Personally, I think Braly is a very smart guy.  If he says it will work, it probably will.  He’s not a spring chicken.  I don’t think he’s put this much time and money in with the plans to be the next Elon Musk.  I think he did it just to prove it could be done.  

 

If that’s true, i kinda wish he’d sell the rights to it, take his well deserved millions, and let someone else produce it.  If there is anyone who actually wants to do it for our small market.

[EricJ]

45 minutes ago, ragedracer1977 said:

Personally, I think Braly is a very smart guy.  If he says it will work, it probably will.  He’s not a spring chicken.  I don’t think he’s put this much time and money in with the plans to be the next Elon Musk.  I think he did it just to prove it could be done. 

He's a lawyer and a tinkerer, not a chemist or engineer, although he does pretty well when he fiddles around with something.   I think the rush to sell the STCs a while back was a way to capitalize on the effort now, knowing that it was likely to not go anywhere else for a long time.   

[Fly Boomer]

40 minutes ago, Ragsf15e said:

If that’s true, i kinda wish he’d sell the rights to it, take his well deserved millions, and let someone else produce it.  If there is anyone who actually wants to do it for our small market.

GAMI has never had the ability to produce the fuel in quantity.  They don't now have the ability, and they have zero interest in it.  They found the right blend of existing hydrocarbons, and got the STC approved for all piston airplanes.  The plan is that someone else (almost certainly refiners) will "produce" the fuel in sufficient quantities for GA.  In this case "produce" just means blending the witches brew in the specified ratios, and transporting it to airports.  A remaining problem is that many (most?) small airports only have tanks and pumps for one fuel.  They can switch to GAMI gas at any time because it is miscible, but their customers must all buy the STC before they can pump it.  Kind of a chicken and egg thing.  As more airports outlaw leaded gas, the path forward will come into focus for all involved.

[ragedracer1977]

49 minutes ago, EricJ said:

He's a lawyer and a tinkerer, not a chemist or engineer, although he does pretty well when he fiddles around with something.   I think the rush to sell the STCs a while back was a way to capitalize on the effort now, knowing that it was likely to not go anywhere else for a long time.   

If he actually sold an STC to every airplane, I think he’d be a pretty wealthy guy.  $2 a horsepower roughly, 150,000 piston engines or so, average 200hp - $60,000,000 ain’t bad.

That said, I don’t know that’s his goal.  I really think he just wanted to know if he could.

[A64Pilot]

I know nothing about Gami as a company, Years ago I did buy their injectors and put them in my C-210 and M6 -235 Maule.

I don’t think there was ever an intent for them to be a fuel producer, and any comments about what it will cost etc are at best guesses, and the aviation world is full of smart people that got that wrong, meaning just about every manufacturer, think Eclipse jet for a gross example.

In my opinion the intent is to sell the rights to produce when lead is outlawed, of course having an STC for a replacement fuel will certainly speed the elimination of lead, because the FAA has fought it for years because there was no viable replacement.

What do they have to gain by testing their fuel? It’s approved. However it’s possible testing could prove the fuel unairworthy and then where would they be? So further testing could only possibly hurt them. 

There is nothing for them to gain by testing.

In my opinion and it’s just my opinion but an STC for fuel is a very suspect way to develop a fuel. So far as I know there has never been an STC for a non existent fuel before, STC’s for existing fuels already in production and manufactured to an existing standard, sure but not for one that doesn’t exist.

I think eventually we will all make him very rich, money from the STC will likely be trivial, the real money will likely come from production royalties.

[jlunseth]

We need to take the UND results with a grain of salt. I have landed and taken off from there several times. They have two north-south runways each of which will have at least five students doing pattern practice on weekends especially. There is so much pattern traffic that they have their own language up there, like “Standard Taxi,” which does not really tell you what to do unless you have been taught what that means. Just going from memory, but I recall that it is one of the top four or five Delta towers in the country and probably in the top three. Of course, to get a PPL or CPL there are also cross country requirements, but from what I have seen at UND, their airwork is heavy on the full power, acceleration, deceleration, landing type of work, not really what we do in our Mooneys.

[A64Pilot]

40 minutes ago, jlunseth said:

We need to take the UND results with a grain of salt. I have landed and taken off from there several times. They have two north-south runways each of which will have at least five students doing pattern practice on weekends especially. There is so much pattern traffic that they have their own language up there, like “Standard Taxi,” which does not really tell you what to do unless you have been taught what that means. Just going from memory, but I recall that it is one of the top four or five Delta towers in the country and probably in the top three. Of course, to get a PPL or CPL there are also cross country requirements, but from what I have seen at UND, their airwork is heavy on the full power, acceleration, deceleration, landing type of work, not really what we do in our Mooneys.

Maybe not, but over and over I’ve seen that the motors that seem to last the longest are those in training, that as you say cycle constantly from wide open to low power over and over, which most would say is the worst way to treat a motor. I think these motors are among the best test cases because they are rode hard and accumulate more hours per month than most do in a year.

It’s like everyone knows most wear occurs at engine start, but pre-lubbers that were the rage in the 70’s didn’t seem to extend engine life and my little Prius which turned its motor off every time you took your foot off of the gas at 250,000 miles still didn’t burn a drop of oil, I only got rid of it because the car itself was worn out.

Its a data point, one we may not want to hear, and I’d bet lunch that they before the test figured that if there was a problem it would be with valve recession and sometimes if you look hard enough you find what you were looking for.

Valve recession is the problem that popped up in cars when we abandoned leaded fuel back in the 70’s, it is logical to suspect that it may be an issue when we abandon lead in Avgas.

Can it be solved? I think so, but it will probably mean early top overhauls to do so.

[AH-1 Cobra Pilot]

On 11/9/2023 at 8:08 PM, wombat said:

@GeeBeeThat may be true, but I don't think it's because it spends more time against the seat.

 

 

Also, a note about that article..... I don't know any tractors that produce significant power (> 20HP) that are gasoline..  I grew up on a farm and while I don't know everything about agriculture these days, the fact that he's talking about gasoline tractors makes me suspect something isn't right.  Also, most tractors run at 1,800 RPM, not 1,200.   So that is a bit weird too....

JD made a series that had diesel, gas, or propane in 40 hp, as I recall.

[AH-1 Cobra Pilot]

On 11/10/2023 at 8:12 AM, Utah20Gflyer said:

I thought that Lycoming switching to hardened valve seats a long time ago made lead unnecessarily for anything but octane rating.  I’ve never heard about people having this issue from running Mogas in planes that are approved for it.  I’d like to see more details about this problem.  

I was a part owner in a Cessna P-172, (GO-300 vice O-300).  We had an auto gas STC and did have sticking exhaust valves more than once.  I was told, (hence, hearsay evidence only), that the original engine had bronze valve guides, (and newer versions had steel valve guides), so they needed the lubricity added by the extra lead, (4:1, Avgas vs leaded auto fuel).  We never noticed valve seat recession, but were not looking for it, either.

Next time I talk to Todd Petersen, I will ask him about this.

[whiskytango]

3 hours ago, A64Pilot said:

There is nothing for them to gain by testing.

I don't know anything about GAMI either, but it would be interesting to know how the testing they conducted to get the STC compares with the "real world" experience of UND with UL94. I would think that the producers that GAMI would sell the rights to produce their fuel to would want to be reassured that there are no unpleasant surprises ahead.  For that reason GAMI may want to duplicate the UND operational program, assuming that they haven't done so already.

[Crawfish]

I thought embry riddle did some testing on G100UL back in the mid 2010’s? 

[cferr59]

It would be nice if articles about this had more information. For example, listing what was measured and the measurements over time for 100LL and 94UL. I read the article and am not sure what to think.

[GeeBee]

2 hours ago, Crawfish said:

I thought embry riddle did some testing on G100UL back in the mid 2010’s? 

They did with no problems.

[Shadrach]

17 hours ago, AH-1 Cobra Pilot said:

I was a part owner in a Cessna P-172, (GO-300 vice O-300).  We had an auto gas STC and did have sticking exhaust valves more than once.  I was told, (hence, hearsay evidence only), that the original engine had bronze valve guides, (and newer versions had steel valve guides), so they needed the lubricity added by the extra lead, (4:1, Avgas vs leaded auto fuel).  We never noticed valve seat recession, but were not looking for it, either.

Next time I talk to Todd Petersen, I will ask him about this.

What is a P-172? The 172P has a Lyc O320.  I thought only GO300 Cessna single was the 175. It turns out it the GO300 was the Powermatic option on the 172D (just a rebranded Skylark). Is the P-172 an obscure model or mod?

[AH-1 Cobra Pilot]

10 hours ago, Shadrach said:

What is a P-172? The 172P has a Lyc O320.  I thought only GO300 Cessna single was the 175. It turns out it the GO300 was the Powermatic option on the 172D (just a rebranded Skylark). Is the P-172 an obscure model or mod?

In 1960, Cessna made 69 of them.  I presume the airframe of the 172 was different enough from the 175 to try this combination.  It was, (as I recall), 8 kts faster and carried 100 lbs more than the standard 172 and had a constant speed prop.

[A64Pilot]

On 11/11/2023 at 5:55 PM, whiskytango said:

I don't know anything about GAMI either, but it would be interesting to know how the testing they conducted to get the STC compares with the "real world" experience of UND with UL94. I would think that the producers that GAMI would sell the rights to produce their fuel to would want to be reassured that there are no unpleasant surprises ahead.  For that reason GAMI may want to duplicate the UND operational program, assuming that they haven't done so already.

Depending on what the goal of testing is, you can usually get the results you want within reason of course. Germans have a saying, it’s statistics are like a lady of the evening, if your paying, you get what you want.

Unleaded fuel of any kind has long been known to cause valve reversion, that why automotive engines went to Stellite valve seats when unleaded fuel was mandated for cars. Lycoming and others will respond with hardened seats and through attrition the problem will go away.

Having said that many thousands of aircraft have been burning unleaded auto fuel for decades with seemingly no issue. I have burned auto gas most often in my C-140 but sometime toss in some LL if I know it will sit for awhile, it seems to make autogas store much better.

Years ago on the C-140 assn website it was shown that the difference in price between autogas and LL would pay for an engine overhaul, so burn car gas and overhauls are free. Run the numbers yourself and see.

Yes I know that alcohol is prohibited and I can tell you a whole bunch of alcohol fuel is burnt with no problem. Years ago I wasted a LOT of time searching the NTSB database looking for engine failures attributed to alcohol causing water or phase separation, degradation of fuel lines, O-rings whatever and couldn’t find any instances, perhaps I just didn’t know how to search, but I’ve just never heard of alcohol causing an aircraft accident?

I hope when LL goes away that there will be money in expanding the water injection STC, if or when that becomes a reality then I’ll buy it and the equipment and just burn premium auto fuel.

I personally believe when LL is outlawed that whatever is it’s replacement will just as a guess be $10 a gallon, blamed on supply chain shortages maybe, but premium car gas will be easily available, if all of us started burning it I doubt we would be 1% of the sales.

[1964-M20E]

On 11/11/2023 at 1:00 PM, ragedracer1977 said:

If he actually sold an STC to every airplane, I think he’d be a pretty wealthy guy.  $2 a horsepower roughly, 150,000 piston engines or so, average 200hp - $60,000,000 ain’t bad.

That said, I don’t know that’s his goal.  I really think he just wanted to know if he could.

There should be no STC needed.  The FAA needs to blanket approve an appropriate replacement.  As far as GAMI goes I'd take $0.02 to $0.05 licensing fee per gallon for research and profit.