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

[A64Pilot]

11 hours ago, N201MKTurbo said:

The main reason ULSD is so expensive isn’t completely because of sulphur.  With standard fractional distillation there are more heavy distillates than the lighter fractions. Such as gasoline. At the same time that ULSD was mandated, most refineries installed advanced catalytic crackers and reformers. After doing that, they can turn just about anything into gasoline. After these changes, diesel was no longer a waste product, but just another product. Because it has more carbons in it, it takes more of the feed stocks to make it. Therefore it now costs more.

I’ll throw this out just as a thought.

Thrush many years ago Certified their Turbines to burn Diesel as Diesel was very similar to Jet, but much cheaper.

Well nobody burns Diesel anymore because Jet-A is much cheaper than ULSD, even off-road ULSD

So why didn’t Jet-A increase in price by the same amount that ULSD did?

I’m not saying your wrong with Refineries, you obviously have way more knowledge than I do, I just suspect that anytime something is created to be environmentally friendly it seems to be overpriced.

Take California Gasoline for example, average gas cost in the US is $3.16, yet the California special blend is $4.89.

https://gasprices.aaa.com/state-gas-price-averages/

Yes we all want to point to taxes but I think that’s not it, it’s the special blend California requires. I suspect that it doesn’t cost more than 50C a gl for the special blend.

‘From the below article

“The CEC says the national average for state gas tax is 32 cents, and California is about 58 cents”

I suspect there are other California only taxes but still it’s not near the more than $1.50 a gl

https://www.cbsnews.com/sacramento/news/why-is-our-gas-expensive-california-breakdown/

All this is just to say that I suspect that while it may only cost $1 a gl for a special blend unleaded Av fuel to produce that we will pay way more than $1 a gl when or if it becomes available. Heck I bet UL94 will cost more than 100LL, but I hope by not much.

Edited February 20 by A64Pilot

[Pinecone]

25 minutes ago, A64Pilot said:

I’ll throw this out just as a thought.

Thrush many years ago Certified their Turbines to burn Diesel as Diesel was very similar to Jet, but much cheaper.

Well nobody burns Diesel anymore because Jet-A is much cheaper than ULSD, even off-road ULSD

I remember a spray operation doing gypsy moth spraying in the early 80s.  They had 2 turbine Thrush aircraft.  The got deliveries of home heating oil to operate them.

I loved the placard around the fuel filler.  It read something like,  Use ONLY Jet A, Jet A-1, Jet B, Jet B-1, JP-4, JP-5, K-1 Kerosene, #2 Fuel Oil, Diesel Fuel,  80/87 AVGAS, 91/96 AVGAS, 100LL AVGAS, 100/130 AVGAS, 115/145 AVGAS, MOGAS

I loved the ONLY along with just about anything that would burn being listed as OK.

[A64Pilot]

14 minutes ago, Pinecone said:

I remember a spray operation doing gypsy moth spraying in the early 80s.  They had 2 turbine Thrush aircraft.  The got deliveries of home heating oil to operate them.

I loved the placard around the fuel filler.  It read something like,  Use ONLY Jet A, Jet A-1, Jet B, Jet B-1, JP-4, JP-5, K-1 Kerosene, #2 Fuel Oil, Diesel Fuel,  80/87 AVGAS, 91/96 AVGAS, 100LL AVGAS, 100/130 AVGAS, 115/145 AVGAS, MOGAS

I loved the ONLY along with just about anything that would burn being listed as OK.

Yeah Fred did that under Marketing pressure as many operators wouldn’t go turbine because of the cost, Thrush was the first Ag turbine aircraft. Diesel, home heating fuel etc was much less than Jet, but not anymore. There are Farmers now that have their own Ag planes burning Jet in their Tractors because Jet is so much cheaper than off road ULSD, so it’s a complete flip. Jet having such a high sulphur content I suspect may be even kinder on the fuel pumps and injectors, when ULSD came out it caused premature wear in many Diesel fuel injection systems, just as unleaded car gas caused valve recession.

‘Both new fuels caused engine design changes. I’m suspect that any unleaded fuel won’t, without an additive to prevent it, hopefully as we don’t have any emissions controls such an additive can be put in the fuel.

Edited February 20 by A64Pilot

[Pinecone]

Do you have a picture of that fuel placard?

[A64Pilot]

I retired from Thrush I think 2017, because I could see the Bankruptcy coming and didn’t want to be around for that. So no, but if you really want one call parts they should still have them for sale, it should also be in the placard section of the old POH’s We used to have them online for free, don’t know about now

I Certified just about all the Thrush models as new Aircraft increasing gross weight and V speeds etc. and in the new Certs we dropped the alternative fuels as they all came with disadvantages, Avgas built up lead on the turbines causing hot spots and possibly balance issues, Home heating oil varnished up the injectors causing them to “streak” instead of a fine spray and that caused hot spots unless you cleaned them much more frequently, and the Diesel that was Certified no longer exists.

Pratt still allows Avgas as an Emergency fuel so I sometimes had to do a Hot fuel test with 100LL, as we had no use for it I got a free couple hundred gls of Avgas  after the test. I only had to do the test on one Model, the S2R-T660, the Worlds only FAR 23 Ag plane, maybe because it was part 23 I don’t know. I learned early on unless you were going to contest it, don’t ask the FAA why. Just do it, that gave you credit if you will that you could cash in on a test you didn’t want to do.

We think that aircraft Certification is a list of flat ass rules you must comply with but in truth it’s a negotiation, lots of give and take, of course many you must do, but for example in the Thrush we didn’t test for head injury criteria. We require a helmet and instead of 1,500 lb three point belts we had a 5,000 lb four point (5 point on the S2R-H80) between the harness and it being stronger and wearing a helmet I think we were safer and the FAA agreed.

 

[A64Pilot]

The list of fuels is also on the TCDS of course look under S2R-T34

I’d cut n past it but can’t a .pdf?

If your curious also look under note 13 on the TCDS the aircraft was only Certified to 6,000 lbs but I believe CAM 8 allows a 31% overload if flight tested and it has the performance to do so, note 13 allows operation in the Restricted Category increase from 6,000 lbs to 8,500 lbs.

The S2R-T34 is also the only dual Category Ag plane Certified in both the Normal and Restricted Category. Story is some wealthy person that lived in an Airpark in Colorado I believe bought one as a toy, well his neighbors got their nose bent on there being an Ag plane on their exclusive Airpark and the Home Owner Association ruled that only Normal Category aircraft were allowed, so the guy paid Fred to have it Certified in the Normal Category.

There are two sections in the POH, one for Restricted and a separate for Normal. It can’t be Certified in Utility because No Thrush has ever been officially spin tested, for an aircraft that’s mission is that close to the ground there is no point, and apparently the FAA agreed.

I’ve been told that they recover from a spin better than most though, I suspicion it’s because of the huge rudder, but I have never spun one myself. They don’t roll well though, you would think they would as they have a very high initial roll rate, but after about 90 degrees roll dampening kicks in a the roll rate past about that does not accelerate so they roll slow. People have a hard time understanding this but they are not an aerobatic aircraft, it’s best to think of them as heavily loaded trucks. What other aircraft has a useful load exceeding its empty weight?

Edited February 20 by A64Pilot

[A64Pilot]

18 hours ago, Marc_B said:

Going by my MAPA key numbers idea, 4" MP drop equivalent to a 10% HP drop...that would equate to about 35% loss of takeoff power for me (39"-->25").

I’m pretty sure that a “True” turbo has a much lower compression ratio than a Turbo normalized engine does as the purpose of a “True” turbo is to increase power not just maintain it like a normalized Turbo.

So if I’m correct then your MP limit will be higher than 25” while a Turbo normalized engine might be 25”.

Sorry but I have to beat this dead horse, that’s where ADI comes in, it will maintain your current MP limit as long as you don’t mind the ADI running, but one assumes that you wont cruise with it on, so your cruise limit ADI off might be lower than your now allowed.

Running LOP will complicate things of course, but I wouldn’t expect it to be addressed in an ADI STC unless your POH allows LOP and has a procedure, then it might.

The LOP is speculation on my part, whether or not ADI will allow full boost isn’t.

[N201MKTurbo]

5 minutes ago, A64Pilot said:

I’m pretty sure that a “True” turbo has a much lower compression ratio than a Turbo normalized engine does as the purpose of a “True” turbo is to increase power not just maintain it like a normalized Turbo.

So if I’m correct then your MP limit will be higher than 25” while a Turbo normalized engine might be 25”.

Sorry but I have to beat this dead horse, that’s where ADI comes in, it will maintain your current MP limit as long as you don’t mind the ADI running, but one assumes that you wont cruise with it on, so your cruise limit ADI off might be lower than your now allowed.

Running LOP will complicate things of course, but I wouldn’t expect it to be addressed in an ADI STC unless your POH allows LOP and has a procedure, then it might.

The LOP is speculation on my part, whether or not ADI will allow full boost isn’t.

ADI can work fine for takeoff and climb, but it will take a lot of fluid to do it for the whole flight. 
 

Do you know what the flow rate is for the fluid?

[A64Pilot]

This says 6 GPH, if you carry 11 gls so you have just less than 2 hours, half that for the small tank

https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/

But I’m sure of a few things 

1. ADI flow rate surely is HP specific, meaning that I doubt a 300 HP and a 200 HP motor need the same. I think the flow rate they have is based on 300 HP as my C-210 was rated at 300 HP for 5 min and the STC back in the day was for bigger motored Cessna’s often in Alaska etc where 100LL is hard to get and stupid expensive, so car gas and ADI. So maybe it would be lower for lower HP motors or maybe they want to field a one size fits all kit? I think probably the latter at first.

Original ADI STC was back in the 80’s when Auto fuel STC’s were common and cheap. Peterson used to charge $1 per HP of the motor for his Auto fuel STC

2. That 25MP and 400F is very conservative as there is no harm if it’s not needed and engine damage if it’s not on when needed so lean towards super conservative

3. All engines are not the same, some are much more likely to detonate than others, so the only way to come up with blanket numbers is to test the worst case engine and use it’s limits, that’s the mose conservative and as the fluids cost is minuscule the best idea I think.

‘I think taking off in my case a sea level that I would need it for 5 or 6 Min as at 1000 FPM it takes 5 min to get to 5000ft where you only have 25 MP, but let’s use 10 min as a nice round number and for extra safety. 10 min consumes 1 gl even, I like whole numbers. That means I can get 11 takeoffs before I run out, so let’s use 10, if using the big tank, cut it down to 5 if using the small tank. I would use the small tank

I don’t know about you but in my World 10 takeoffs is plenty even if the fluid isn’t available at FBO’s because at first I don’t think it will be.

Edited February 20 by A64Pilot

[N201MKTurbo]

1 hour ago, A64Pilot said:

This says 6 GPH, if you carry 11 gls so you have just less than 2 hours, half that for the small tank

https://www.avweb.com/features/the-return-of-anti-detonation-water-injection-adi/

But I’m sure of a few things 

1. ADI flow rate surely is HP specific, meaning that I doubt a 300 HP and a 200 HP motor need the same. I think the flow rate they have is based on 300 HP as my C-210 was rated at 300 HP for 5 min and the STC back in the day was for bigger motored Cessna’s often in Alaska etc where 100LL is hard to get and stupid expensive, so car gas and ADI. So maybe it would be lower for lower HP motors or maybe they want to field a one size fits all kit? I think probably the latter at first.

Original ADI STC was back in the 80’s when Auto fuel STC’s were common and cheap. Peterson used to charge $1 per HP of the motor for his Auto fuel STC

2. That 25MP and 400F is very conservative as there is no harm if it’s not needed and engine damage if it’s not on when needed so lean towards super conservative

3. All engines are not the same, some are much more likely to detonate than others, so the only way to come up with blanket numbers is to test the worst case engine and use it’s limits, that’s the mose conservative and as the fluids cost is minuscule the best idea I think.

‘I think taking off in my case a sea level that I would need it for 5 or 6 Min as at 1000 FPM it takes 5 min to get to 5000ft where you only have 25 MP, but let’s use 10 min as a nice round number and for extra safety. 10 min consumes 1 gl even, I like whole numbers. That means I can get 11 takeoffs before I run out, so let’s use 10, if using the big tank, cut it down to 5 if using the small tank. I would use the small tank

I don’t know about you but in my World 10 takeoffs is plenty even if the fluid isn’t available at FBO’s because at first I don’t think it will be.

Is the fluid just water and alcohol? I know just water works pretty good.

Never mind, I read the article.

[N201MKTurbo]

So, with UL94, MP limited to 25” unless you have ADI, then WOT. that seems reasonable.

[Pinecone]

1 hour ago, N201MKTurbo said:

So, with UL94, MP limited to 25” unless you have ADI, then WOT. that seems reasonable.

Maybe for your J.  But I cruise at 29 - 30 inches.  And that is for a 65% power.  If I want to go faster, it will be higher.

[Pinecone]

4 hours ago, A64Pilot said:

The list of fuels is also on the TCDS of course look under S2R-T34

I’d cut n past it but can’t a .pdf?

No problem.  It would be cute to have if simple, but I don't need it for anything.

FYI, Windows has a tool called Snip.  Search in the took bar.  You then hit New, and highlight the area you want to copy and it puts it in the clipboard.  You can then either paste it into a message (on some forums) or paste it into Paint and save as a JPEG.

I remember that the T-38 allowed X number of hours running AVGAS.  But longer if you added a bit of oil to the AVGAS.

[N201MKTurbo]

1 hour ago, Pinecone said:

Maybe for your J.  But I cruise at 29 - 30 inches.  And that is for a 65% power.  If I want to go faster, it will be higher.

Yes, your numbers would be different. 

[N201MKTurbo]

I seem to remember that ADI keeps your cylinders and exhaust clean too.

[GeeBee]

18 hours ago, philiplane said:

As a Service Center director, I was directly involved in repairing some brand new Mooneys in that time frame. The factory tried some new methods during assembly, and we had several 2005-2008 Mooneys with seeping tanks. Including brand new S Type Acclaims. Which did not go over well with the owners. Those planes went back to the factory for repairs and repainting.

I mentioned that fact on this very forum and how without precision bucking of the rivets, the sealant was squeezed out and the tank failed. Some people here told me I was wrong. The entire saga was related to me by Edison at Wet Wingologists. Thanks for verifying what that there were indeed problems.

 

[A64Pilot]

3 hours ago, Pinecone said:

Maybe for your J.  But I cruise at 29 - 30 inches.  And that is for a 65% power.  If I want to go faster, it will be higher.

Maybe

I do not know your compression ratio, and the bigger the cylinder the more likely detonation is, so my example should be conservative. Motorcycles can run very high compression ratios largely from modern combustion chambers but also because they have tiny cylinders compared to our motors

An R-1340 is allowed to pull I believe 36” of boost from its Supercharger. It has again from memory a 6 to 1 compression ratio and it can do this on 87 Octane car gas. Now car gas and Aviation fuel Octane ratings are different, 100LL I believe if rated as car gas would be more than 100 Octane, likely the reason why we don’t just switch to 100 Octane unleaded race gas. It’s been around for years and I believe even higher than 100 Octane exists https://www.sunocoracefuels.com/fuels/fuel/ss-100 apparently as high as 109 https://racefuel.boostane.com/products/109-octane-fuel

I do not know what your limit will be but am sure the actual limit will be higher than 25”.

Then we are assuming 25” for 94UL, the 25” is very conservative and was I’m sure picked more for it being a number people can live with as most Big bore Continental bush pilots won’t cruise higher than 25 squared, but the ADI original STC’s were also established for Auto fuel, which I’d bet are lower Octane and more likely to detonate than 94UL.

Will they find the actual limits and Certify for them? I doubt it because it raises the probability of failure and would cost time and money but doesn’t get them anything.

Everything at this point is speculation 

[gabez]

quick update. my tanks are resealed and running 100LL with no leaks for 2-3 weeks now. Switching gear to repainting the bottom now. I just went for a quick flight so this pictures are the latest, post resealing. All the stains are from G100UL. 

Edited February 21 by gabez

[PT20J]

Clearly the evidence shows that the G100UL stains and damages paint. However, if it also damages tank sealant, it's curious that the tanks would not continue to leak after returning to 100LL.

[Igor_U]

1 hour ago, gabez said:

quick update. my tanks are released and running 100LL no leaks for 2-3 weeks now. 

 

Please help us understand:

Was that a typo and were the tanks resealed and no w not leaking? How much work was it done and what condition was the sealant?

 

Thank you.

[gabez]

12 minutes ago, Igor_U said:

 

Please help us understand:

Was that a typo and were the tanks resealed and no w not leaking? How much work was it done and what condition was the sealant?

 

Thank you.

sorry I meant resealed. just corrected it. I resealed the tanks and have not been leaking post fix. I gave them 2-3 weeks with 100LL in it. 

If you ask me the sealant was fine before using G100UL. I had just gone through an annual. then both tanks started leaking after 80 gallons of G100UL. I think putting all assumptions on the sealant aside, the damage to the paint is obviously real. 

[PT20J]

3 minutes ago, gabez said:

sorry I meant resealed. just corrected it. I resealed the tanks and have not been leaking post fix. I gave them 2-3 weeks with 100LL in it. 

If you ask me the sealant was fine before using G100UL. I had just gone through an annual. then both tanks started leaking after 80 gallons of G100UL. I think putting all assumptions on the sealant aside, the damage to the paint is obviously real. 

Ah, now I understand. Thanks for the clarification.

[Igor_U]

Ah, that makes sense. I was actually referring to the sealant condition after using 100UL. IIRC on that test video #3, A/P is claiming that after after 100UL softened the sealant, using the 100LL made sealant hard (cured) again. I hope i remember right.

 

Thank you

 

[gabez]

14 minutes ago, Igor_U said:

Ah, that makes sense. I was actually referring to the sealant condition after using 100UL. IIRC on that test video #3, A/P is claiming that after after 100UL softened the sealant, using the 100LL made sealant hard (cured) again. I hope i remember right.

 

Thank you

 

you do remember correctly. Well the copilot tank is completely resealed so the old one is gone. the pilot aux is still the same so I can check it out once I burn some fuel. 

[mluvara]

23 minutes ago, Igor_U said:

Ah, that makes sense. I was actually referring to the sealant condition after using 100UL. IIRC on that test video #3, A/P is claiming that after after 100UL softened the sealant, using the 100LL made sealant hard (cured) again. I hope i remember right.

 

Thank you

 

What I believe you are referring to is what one of the RV-6 owners reported to me, is that the sealant appeared to harden after removal of G100UL. I have no first hand testing of that at this point in time. 

 

Edited February 21 by mluvara