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Based on the G100UL fuel leak thread what's your position?


G100UL Poll   

116 members have voted

  1. 1. Based on the G100UL fuel leak thread what's your position?

    • I am currently using G100UL with no problems
      2
    • I have used G100UL and I had leaks/paint stain
      2
    • G100UL is not available in my airport/county/state
      96
    • I am not going to use G100UL because of the thread
      22


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Posted

Interestingly, this showed up on my FB feed the other day.   Back when I was looking at how the Germans got the Daimler DB605 to make 1800 hp on high boost and relatively low-octane fuel, it appeared that combinations of methanol injection and aftercooling (intercooling) were frequently cited for being enabling technologies.

This graphic suggests that variations of the same were used on the Packard-Merlin in the P-51.   The aftercooler around the centrifugal supercharger at the rear of the Merlin is not new to me, but I'd not seen the ADI injection before.  I'm wondering if that wasn't a postwar modification for the air racers. 

May be an image of aircraft and text

 

Posted
4 hours ago, EricJ said:

Interestingly, this showed up on my FB feed the other day.   Back when I was looking at how the Germans got the Daimler DB605 to make 1800 hp on high boost and relatively low-octane fuel, it appeared that combinations of methanol injection and aftercooling (intercooling) were frequently cited for being enabling technologies.

This graphic suggests that variations of the same were used on the Packard-Merlin in the P-51.   The aftercooler around the centrifugal supercharger at the rear of the Merlin is not new to me, but I'd not seen the ADI injection before.  I'm wondering if that wasn't a postwar modification for the air racers. 

May be an image of aircraft and text

 

Definitely post war. Nothing like that on the two P-51’s we had. 

  • Like 1
Posted
22 minutes ago, Sabremech said:

Definitely post war. Nothing like that on the two P-51’s we had. 

That was my suspicion, which suggests that the wartime Packard-Merlin engines were making ~1700 hp mostly with intercooling (aftercooling) with 100/130 fuel and ~60" MAP.   The air racers run much higher MAP so maybe this was a modification that enabled that.

Posted (edited)
5 hours ago, EricJ said:

Interestingly, this showed up on my FB feed the other day.   Back when I was looking at how the Germans got the Daimler DB605 to make 1800 hp on high boost and relatively low-octane fuel, it appeared that combinations of methanol injection and aftercooling (intercooling) were frequently cited for being enabling technologies.

This graphic suggests that variations of the same were used on the Packard-Merlin in the P-51.   The aftercooler around the centrifugal supercharger at the rear of the Merlin is not new to me, but I'd not seen the ADI injection before.  I'm wondering if that wasn't a postwar modification for the air racers. 

May be an image of aircraft and text

 

I have a bit of experience in this area, as I spent 2003-2015 crewing on numerous aircraft at Reno (including several that won Unlimited Gold) and supplying telemetry systems to them. I also worked as a party to the NTSB investigation to the 2011 Galloping Ghost crash because I built the telemetry system.

That aside, ADI was a system adopted for the high power race engines. On the Merlins, the after cooler was removed in favor of a tube induction system after the supercharger. It usually had an automatic system that would come on with a manifold pressure switch and feed the ADI fluid into an area of the supercharger (if I recall correctly). Failure of this at 130” MAP for a carbureted system would result in a pretty instant catastrophic result if not caught quickly. On the  other hand, a fuel injected 3350 on a Sea Fury actually would not suffer the same instant fate if the ADI failed and induction temp resultingly increased. I remember we ran a good portion of a lap when the ADI system failed at high power on the Sea Fury. The real time telemetry saved numerous engines because of system failures.
 

I just feel the extra complexity could be an issue for GA because it’s another system to maintain, care, and feed. One needs to carry methanol to mix with water, or have a supply at airports. It’s another preflight item.

Edited by mluvara
  • Like 1
Posted (edited)

So, what’s the plan for you California guys when they outlaw 100LL then?

Hope isn’t a plan.

FAA says G100UL is perfectly safe and viable for ALL piston aircraft?, George says it’s readily available. What do you think some Judge that has zero knowledge of GA is going to rule? Do they have a choice? Just asking as I’m no Lawyer but if I understand they may be only one way this could go, unless the FAA steps in and temporarily blocks the sale or similar.

I believe the number of States that follow California CARB wise is 17? Think they will follow California in banning 100LL? Is that enough market share for the refining of 100LL to no longer be viable?

I have no idea but think this could get ugly, I hope not, but hope isn’t a plan

Edited by A64Pilot
Posted
1 hour ago, A64Pilot said:

Mind telling me which of the 106 pages cover it?

HINT: There's an Index a the end. Look for "Coolant system.":D

Posted (edited)

You could have just said page 24.

I saw no mention of ADI.

It’s my understanding that ADI in US Military aircraft didn’t become a “thing” until they had motors capable of pulling enough boost to require it even with the higher Octane fuel available, ref the below link on the 4360 engine ops. Before then engine design was driven by available fuel.

Look under wet or dry T/O and climb, ADI reduced fuel flow by 500 lbs an hour yet increased HP by 250 HP. They didn’t have to have ADI with I think 115/145 Octane fuel but it saved fuel and increased power. Assuming they had the torque available, the big motors had gear box limits like turboprops do.

I’ve read but do not know of course that the engine in the early model BF-109’s wouldn’t benefit from 100 Octane, it just didn’t make enough boost that it could, like the R-1340 for instance, being an old design engine, designed before there was 100 Octane you can run one at the same boost on 87 Octane car gas as you can with 100 Octane.

In short the Military use of ADI wasn’t to enable lower Octane fuel, but to enable increased power, on engines that could handle more power, which is honestly the same thing said differently but that took Turbo’s, Superchargers or sometimes TurboSuperchargers capable of pulling boost in excess of what even high Octane fuel could handle, and gearboxes etc that could take higher power.

https://enginehistory.org/Operations/R-4360Ops/r-4360ops1.shtml

Our use would be to keep current power on fuel that’s only 6 Octane lower, that’s a very mild and very safe use of ADI

Edited by A64Pilot
Posted
On 2/28/2025 at 8:52 PM, EricJ said:

That was my suspicion, which suggests that the wartime Packard-Merlin engines were making ~1700 hp mostly with intercooling (aftercooling) with 100/130 fuel and ~60" MAP.   The air racers run much higher MAP so maybe this was a modification that enabled that.

60” MP really isn’t that much boost, it’s only 15 PSI roughly, if I do the Math correctly, still drinking morning Coffee and brain hasn’t engaged fully yet.

My Motorhome for example pulls 30 lbs of boost, but automotive boost is PSIG so need to add the 15 PSI atmospheric to get to PSIA that aircraft indicate. 

So my Motorhome pulls 90” boost, yes it’s a Diesel and therefore not constrained by detonation margins because detonation in a properly operating Diesel isn’t possible. But it’s a Motorhome not any kind of performance motor.

Tractor pull motors can run as high as 300 lbs of boost, what’s that, something over 9,000” MP?

I wonder what the Reno racers pull? I would assume at least three times what the Military P-51’s saw? No idea really 

Posted
3 hours ago, A64Pilot said:

I wonder what the Reno racers pull? I would assume at least three times what the Military P-51’s saw? No idea really 

>130" at 3400 RPM. Highest I ever saw was 145" on one of the P-51 racers that I crewed on.

Posted (edited)
29 minutes ago, gabez said:

should be interesting to see what GAMI has to say. 

Note I’m not saying anything about Gami or George.

We had a saying in the Army ref being “caught”

It was Lie, Deny, and make counter accusations, until the hammer falls 

Edited by A64Pilot
Posted

As Mr. Luvara pointed out, GAMI and Mr. Braley dropped all pretenses of civility and transparency and switched to liigation as a strategy to mandate the use of G100UL. The attempts to shift blame for damage to aircraft to "poor design and maintenance" of the affected aircraft is particularly concerning. Perhaps it is  time for pilots to do the same and deploy litigation to stop this insanity. 

The evidence of damage caused by G100UL seems to be coming in and soon there may be enough to suport class action products liability suit seeking both monetary and injunctive relief. As someone noted earlierr, AOPA is probably going to be useless in such endeavor as they seem to collectively subscribe to the enviro madness of getting 100LL banned at any cost and willing to sacrifice flight safety for political reasons.  

Finding evidence that GAMI had knowledge of the design defect (material incompatibilities) yet decided to push the fuel into general distribution would be particualry damaging to GAMI. 

  • Like 2
Posted

Its unfortunate that GAMI wouldn't work together with PAFI.  GAMI's engine test facility would be a great contributor to the PAFI/EAGLE process of fuel development. 

But I suspect there was more attention paid to the test stand than to the comprehensive test protocols for materials compatibility that are highlighted by PAFI.  I suspect there was more testing with complete fuel "systems" rather than individual component testing; so outside of a catastrophic failure, the short duration tests would just be a pass/fail type of test rather than highlighting differential fuel effects.  In that respect I expect the testing highlighted with PAFI will be more enlightening.

  • Like 3
Posted

Assuming it's not postponed again, the 'fork in the road' is going to occur this Wednesday, 3/5, when the judge rules on the CEH consent decree.  If he's unbiased and rational, he will stay the order, in effect ruling that G100UL is NOT truly commercially available.  OTOH, if he is a liberal environut, and ignores the evidence we Kalifornia aviators will be the first to be screwed.

  • Like 2
Posted
8 minutes ago, MikeOH said:

Assuming it's not postponed again, the 'fork in the road' is going to occur this Wednesday, 3/5, when the judge rules on the CEH consent decree.  If he's unbiased and rational, he will stay the order, in effect ruling that G100UL is NOT truly commercially available.  OTOH, if he is a liberal environut, and ignores the evidence we Kalifornia aviators will be the first to be screwed.

I think we all know the genaral leaning of CA judges. Litigation against G100UL needs to be filed in federal court outside of CA to avoid the inherent bias of CA judiciary. 

Posted
12 minutes ago, IvanP said:

I think we all know the genaral leaning of CA judges. Litigation against G100UL needs to be filed in federal court outside of CA to avoid the inherent bias of CA judiciary. 

If G1 passes I will sell the plane. I am not putting myself or my family in it w/G1

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