Marc_B

@802flyer look at the Surefly install manual. I believe you install it at 0 deg and the timing is controlled by the dip switches. But should be covered in the application install notes.

But at the end of the day, none of us want our paint to be damaged or stripped unnecessarily and most will go to appropriate measures to prevent this. If its known how and when you'll see damage, and how to mitigate this then you can prevent it outside of catastrophic cases of damage or spill. If the official word is that a product doesn't damage paint and you don't need to take mitigation steps, then that's an entirely different issue. i.e. if the word was that G100UL will leak and strip paint if your sealant is over 20 years old or if you have a leak, then you might choose to either 1) not use it, 2) have tanks resealed prior, or 3) use at your own risk. But the owner would assume a known risk. But having a fuel advertised as 100% drop in across the fleet without any modification may be an overstatement. Continental gives pause, Lycoming gives pause, Textron gives pause, Cirrus gives pause. This is a discussion about risk. The producer is trying to minimize risk, some people are trying to magnify risk...but we're all trying to understand risk. None of the Youtube videos or comments of this thread have better clarified this. There may be risk to elastomers, there may be risk to paint, there may be risk to valve seats...so you either trust the FAA process and jump in, you try to understand the risk so you can hopefully mitigate it, or you just say no. But FAA approval does not equal no risk. Give it 20 years and hindsight will be 20:20.

do you have a link or the highlights? Looks like it requires a subscription.

Which article? I don't think I saw that. Of course Don said he's had staining even despite following refueling. And I believe he said he couldn't get it to buff out using various compounds. I spoke with the AOPA staff and they said they didn't know if there was or wasn't any paint damage on the Baron leaks. But they said that you have to be very careful with fueling as G100UL stains pretty easily. Their fuel cap was yellow brown for the G100UL side from fumes and fuel. Haven't heard if anyone say if ceramics, wax or any particular products help mitigate this and more importantly, to what degree. https://www.aopa.org/news-and-media/all-news/2024/november/pilot/unleaded-fuel-what-we-have-learned

Garmin does a terrible job at an apples to apples comparison on this. If you go down the Jepp charts pathway it becomes WAY more complicated. OnePak with Flite charts gives all installed equipment all databases PLUS covers one portable on your subscription. vs PilotPak where you can get Jepp charts but you have to pay extra for a 4seat subscription to have Jepp charts on your portable. I might be interested in a OnePak plus Jep charts if they’d offered it like that. No clue why they don’t. for simplicity, OnePak with or without Flite Charts. Garmin should really simplify the PilotPak…it can be a confusing mess! (not to mention that some equipment you have to purchase a "key" to unlock the ability to use Jepp charts on your equipment ~1-1.5AMU)

I'd be interested in hearing more from the people who have used and are using G100UL and haven't had any issues. What type of paint do they have, what type of surface prep/wax/ceramic to they use, what is their fueling hygiene that they've found works, what's the age of the sealant and anything unique in their fuel system. That might help as well.

I'm not sure I follow your point here. Do we use Skydrol for hydraulic fluid in our Mooney's? Chemicals can be caustic. Not surprising. But if the statement is that 100LL is more dangerous for your paint/sealant/elastomers than G100UL, and that's not the case...that's a different issue. I think that a lot of pilots have used 100LL on their belly's to degrease, to clean the engine, etc. In the past I think that no one thought twice about a fuel splash on the top wing. And a seeping wing was something to monitor and consider patching when we "get to it" and and not cause for immediately addressing due to concern for paint damage. For the fuels of the future, I don't think this will be the case.

Braly didn't show where 100LL has caused paint damage in his video even when adding an extra "14-15%" toluene, although he's said several times that 100LL has high toluene and that's important. And each batch of fuel for any fuel likely varies to some degree. The issue is that there may be a conforming fuel mix that is more harmful to paint than others. There may be a formulation that is more likely to stain. More importantly there may be a way to help prevent this, preferable materials and elastomers to use, and certain aircraft to avoid use in until proper catch up maintenance has been done. Mr. Braly mentioned, the PAFI fuel spec didn't include playing nice with paint and elastomers. So any new unleaded fuel may have harmful effects...these early cases are the test cases that will help shape and mold further testing to see what is at risk and what is preventative. It's not blame...it's discovery of mitigation. But first you have to accept that there may be an issue. https://www.faa.gov/sites/faa.gov/files/PAFI_Fuel_Development_Testing_Lessons_Learned.pdf

GAMI's video was the same. You can't find it on GAMI's youtube channel. Not that I think that this is an "important" thing to point out. Neither one of these videos are scientific "proof" of anything. They're how you develop hypothesis, not how you test them. They don't help identify causation. They just develop concern for more testing. Both tests are simple observational, anecdotal evidence. Neither are how you run a scientific study to find usable, repeatable data. GAMI said enough testing has been done; these aren't issues you will face. If that's true, nothing to see. If that's not true we will continue to see more issues. My issue is that all along we've heard conflicting information that makes speculation easy. We tested with nitrile and it was fine and no issues...but we recommend Viton to just be sure. We haven't seen paint damage, but you need to use very thorough paint hygeine to be sure. We haven't seen paint damage, but if you do it's the old Mooney wet wings and paint that's not properly applied and the "corrosive" 100LL that has high amounts of toluene. I think that there is probably some truth in the cases we've seen. But we don't know all the details and probably never will.

Alkylate varies for G100UL as well and the amounts of Xylene and aromatics may vary in G100UL as well. Heck, the SDS for G100UL shows a range of 20-40% xylene. But taking a fuel that met an ASTM spec and just adding more toulene to it just to try to estimate a suspected range of toluene may not result in a fuel that still meets that spec. When testing fuel for comparative testing it should be pump to pump comparison. But again, none of the Youtube videos have been structured to have repeatable scientific data. They're observational anecdotal evidence. What would have happened if Mr. Braly took an extra 15% of xylene and added it to the G100UL sample?

I guess the hard truth is that the multiple threads and hundreds of posts about G100UL haven't really added much clarity, controlled test data, or underlying scientific data one way or the other. We have YouTube videos for both sides of the coin with multiple people presenting observational data to an inquisitive public, on a public forum, that just leads to more questions about details that may, or may not, be known. We've only been presented observational, anecdotal evidence rather than controlled studies. (not to suggest that this wasn't required for FAA Certification as I suspect that it was, and should be, and was hopefully very thorough) Trying to figure out how to protect staining, if you should worry about damage to paint, what parts of your fuel system has nitrile components and if this even makes one bit of difference... These are all questions that get generalized answers to specific questions; which leads to tons of speculation as we all try to learn more about this new reality that is coming regardless of if you like it, agree with it or feel like it's long overdue. The "tone" of the questions/comments are also tainted in the underlying sentiment of whether you are a fan of unleaded fuel mandates or not. So of course by nature these threads have political undertones as well. Unfortunately, political discussions often go in circles because there are various sides of the argument and they're usually both right and both wrong. In having public discourse on a (somewhat) anonymous forum, there will usually be critical questions, there may be apparent "trolls" and skeptics, and there may be vocal fans. But majority of the Mooneyspace visitors and members (including myself) come to learn from each other how to be safer pilots and better take care of a great aircraft.

Mr. Braly, If asking for clarifications on things that have been commented and answered in conflicting ways is attacking personal integrity, I apologize. (Perhaps I should have used "conflicting statements" in place of "double speak.") You speak on behalf of GAMI and for G100UL. You are the gateway for information regarding a new fuel that has lots of questions. If you misspeak or answer incorrectly, it matters. We appreciate your input and appreciate transparency and clarity. Thanks, Marc.

I think that it seems that the G100UL test with the 100LL sample that had "high toluene" may have been intended to show that 100LL with high toluene caused paint damage whereas the G100UL sample showed didn't?? I was very curious why GAMI wouldn't just test 100LL vs G100UL...why not just a simple "pumped fuel" vs "pumped fuel"?? Why add more toluene to one of the fuels, especially when the amount and concentration wasn't labeled? https://www.youtube.com/watch?v=zrOoq-sB1Ig

Mr. Braly, With all respect, the conflicting statements (edit) make it very difficult for us to distill fact from fiction. Earlier you said "Contrary to a lot of internet rumors and gossip -- Neither 100LL nor G100UL Avgas strip aircraft painted surfaces." The apparent truth is that under certain circumstances G100UL can strip paint, and has been shown to strip paint. What we'd like to know is what circumstances are we likely to see this happen, and what we can do to prevent it. It's clear that you have FAA certification for your product. It's not clear what test data was shared with FAA for certification. It's clear that you want to selectively share information and engage with GA pilots to help inform them of your product and increase sales of your STC and fuel recipe. But what's not clear is if your engagement is just advertising or if you're willing to share pointed information to help the GA public navigate this political transition to unleaded fuel safely and without signficant damage to our aircraft or wallet. Your ICA speaks of using viton and you openly have recommended viton products and say that you recommend "modern" maintenance recommendations (i.e. Bendix advisory you noted), but then say that your test data was done on nitrile components and tested fine. So if that's the case, why would you suggest changes and why wouldn't you just leave that liability up to the mechanics working on the aircraft?? I'm not sure if the conflicting statements (edited) are intentional, suggest a possible risk that you feel is low, or just lawyer speak, but it is very confusing to well-intentioned pilots who are just trying to make the best decision for themselves and their families. From your earlier post:

48 years on original sealant and finally some leaks prompting maintenance. Outstanding! Hope you took the poll above so your Mooney could be counted @Doug G!

I think these wet tanks are WAY more robust when properly applied than we give them credit for! 48 years in a solvent and still kickin. Outstanding! (but certainly sounds like time for reseal!)

agreed 100%. same with bladders or fuel cells I'm sure as well!

When I did my Instrument checkride the DPE asked for one coupled approach (I have an autopilot). He said that he doesn't require an autopilot, but if candidates have one he expects that they should know how to use it. That being said, with instrument training with my CFII it was 99% hand flying and I had more KFC150 training with a fellow Mooney pilot. For single pilot IFR, the added safety and capability with use of an autopilot can't be understated. But that is 100% dependent on the pilot being knowledgeable to use it.

Has anyone ever noticed a big difference when they opened tanks to patch or reseal with regards to the top wing sealant and the bottom wing sealant? It seems there are two possible reasons that sealant covered in fuel would help protect sealant...better thermal regulation with the large volume of fluid that could absorb heat, and keeping the sealant wet to keep it from drying out. If the offered theory is that fuel is so damaging to the sealant, then it seems to reason that keeping tanks empty would be better...but I've never heard anyone suggest this... Not sure if any studies have been done on either theory, or if keeping wet tanks full is just an OWT/tradition for "best practice" rather than actual science??

I suspect it's a solution looking for a problem. Tons of Mooneys have been firmly planted on the ground compressing the shock discs that last 12-15 years. Long bodies shock discs don't last as long due to heavier engine and higher empty weight on the discs. None of the Mooneys need this. But perhaps it eeks out a few years on shock discs for long bodies with full fuel tanks? My hangar neighbor had their M20J covered in a series of Goodwill sheets tip to tail, wing to wing, and this kept their aircraft paint less covered in dust, less need to clean and scratch with dirt, and their original paint looked pretty factory fresh after 30 years. Sometimes it seems that an ounce of prevention keeps the "pounds" of time at bay! But @Vance Harral I'm with you, I can't imagine leaving my Mooney up on jacks routinely.

I've looked and can't find a specific expected life of fuel tank sealant, but I've found the round number of "20 years" used routinely regarding wet wings, bladders, and fuel cells. So I think the general "round number spitball" of wet wing longevity is over 20 years. So far the majority of poll responses have described that the Mooney wet wing can typically do that and then some. Yes, there are variances in construction (wet vs dry riveting), differences in material, differences in bladder vs wet wings vs fuel cells, etc. across the fleet; however, one can't say that "all Mooney's leak" and that's just the reason for any and every leak seen. A leak seen a couple months after sealing (as noted above) isn't the same as a leak in a 40 year old aircraft on original sealant. But wet wings lasting for 20, 25, 30 years or more without leaks certainly sounds like a high quality, high efficiency, low weight fuel storage solution to me! Sounds right in line with what Mooney represents: sleek, efficient, do more with less approach that is seen throughout our Mooneys! It's a personal judgement of patching vs. reseal, but in general if you are seeing flecks of sealant in your sumps with 30-40+ year old sealant; it sounds like it's time to consider a reseal. All sealant has a useful life and sometimes your tanks "talk to you" just like your engine does when it's nearing time for overhaul. ...and leaks with fuels of the future vs. fuels of the past may be different or similar...correlation does not necessarily imply causation...so more data and details are needed, and hopefully will be forthcoming with field reports of real world successes and setbacks.... Details regarding age/condition of sealant may be important as well...if nothing else than to help define the condition at risk. There's nuance to these discussions and we need to speak with details and avoid broad generalizations that don't apply. In my mind, Mooney wet wings work pretty darn well!

@LANCECASPER yes, I think that's the company. Although I didn't see anything about shock disc savers on his website. @Fly Boomer there's a company here in the US that sells them. I think Lance pointed out the vendor above. Not sure details of cost and availability though. But the pictures in the Australia company looked very similar to the models that were shown at MooneyMax 2024. Also came across an article from Kerry McIntire. Pretty good overview of tanks, patching, and bladders. https://knr-inc.com/shoptalk-articles.html?view=article&id=24&catid=25

There's someone that makes something like Mooney shock disc savers. They presented at MooneyMax this year...basically they slide inside the gear tube (like where you slide tow bar) and then you use a hydraulic jack to raise up a couple of inches and allow insertion of a clevis pin. https://kotzur.com/products/mooney-shock-disc-savers This was what I could find with a simple search, but isn't the vendor that was at MooneyMax... @LANCECASPER can you recall the name? My personal thought was this might make sense for storage if you're not flying regularly, but would be a hassle for those who fly a lot.

2 years ago.

added the option.