A64Pilot

Grumman, but it’s pretty similar on most all small GA. I only watched the first part but think it shows the issues

The inside of almost all aircraft mufflers have a tube that is full of holes welded to the exhaust entry of the muffler, the end of this tube is welded shut with a cap, so that all of the exhaust has to go through the holes, sort of a primitive baffle. ‘Anyway these tubes disintegrate pretty often, usually into smaller pieces that just blow out, but occasionally the pieces are big enough to get caught in the exhaust blocking exhaust and causing excessive back pressure. It’s something that should be checked frequently, easiest way is a borescope, if the muffler is used without the flame tubes often the shell burns through putting CO into the heater shroud and into the cockpit too of course, it can also cause a fire. ‘Sometimes a muffler can be rebuilt and new flame tubes installed You would be surprised at how many are flying around with burnt out flame tubes and don’t know it, it’s a common failure

I don’t think it’s much of a computer, just turns the pump on and off is all and maybe automatically turn the backup on if the primary isn’t pumping as indicated by pressure? Remember these are Certified aircraft, so we have to go STC, your not getting a field approval if an STC is available, for an Experimental I’m sure I could knock out an ADI for very little money, that pump in the Video is just a cheap Facet Automobile fuel pump. ‘But there is more to it, if running Mogas you have to ensure you don’t vapor loc, that’s one reason why I think 94UL and ADI is another answer to get us to lead free

Watch the above link. Most worst cases are taking off heavy at sea level and climbing to altitude for cruise. Above 5,000 ft approx you can’t get above 25MP without forced induction. So let’s say you take off at seal level and climb at 500 FPM to above 5,000 for cruise, your using the ADI for 10 min. I don’t know what the flow rate is, but again from memory a WWII fighter making 2500 HP used a little over 9 lbs per min. IF and it’s a big if, but we should I think use about 1/10 the amount as we are about 1/10 the HP, if so then we would use a little over 1 gl in 10 min. This is speculation, but the STC has a 5 gl tank. The cost of the fluid is or should be insignificant, about half the price of fuel if you mixed your own, and you might be mixing your own as it’s unlikely I think to be sold at most FBO’s.

I believe in WWII pretty much ALL Avgas was 80ish octane. The US I believe manufactured 100 Octane using a French process to a British Standard and it was supplied to the Brits just prior to the Battle of Britain, this gave the Merlin lots more HP being able to run at higher boost, that and the fact that the Brits were allowed to build a constant speed prop under license from a US manufacturer also made a HUGE difference, without those two things the 109 was a superior fighter, the prop and fuel really woke up the Spit. I think the Brits had a two pitch prop previously. I believe the Benz motor on the 109 couldn’t make enough boost for the 100 Octane to be as beneficial as it was on the Merlin. The Germans used ADI for higher power down low and I think maybe we adopted ADI from the German’s. At high altitudes the Germans used Nitrous Oxide for higher power. ‘Now all this is from memory from YEARS ago,so maybe I got it wrong.

Hot spots, like carbon or maybe a plug helicoil hanging down etc I believe technically cause pre-ignition, but as I believe that can quickly lead to detonation I think it doesn’t matter to the guy who pays the bill. Likely pre-ignition is more damaging but either way it’s destructive. I think it’s like arguing he didn’t die from a gunshot, he died from loss of blood Personal opinion

Issue with any Diesel conversion that I have seen is $$$, for the overwhelming majority of 4 cyl Mooney’s it’s likely WAY more than the aircraft’s value is. I don’t know because I’ve never looked, but I doubt the value increases by anywhere near the cost of the STC. Other detractors is at least when I was curious, most had TBR’s not TBO, the R stands for replace so when your engine times out or gets tired, you throw it away and buy another. But finally what would really concern me is that most of the Diesel engine manufacturers have gone out of Business. I had a Dealer years ago that was converting new 172’s as fast as they could and selling them to Africa, then the engine manufacturer went away. I guess there is no 100LL in Africa? About the same time Maule Certified a Diesel, but before they could sell any, the engine manufacturer went away, maybe they were the same manufacturer I don’t know, but the concern of the engine you just paid way over 100K for being orphaned would concern me.

The numbers are 25” MP and 400 F cyl head temp. The ADI STC’s I’m familiar with the ADI is off below those numbers. Could you takeoff at 25” MP? I guess you could, anyone operating out of an airport at 5,000 ft or higher does, but I don’t want to. Could you operate with 94UL at full throttle without detonating? Probably if you kept Cyl head temp down, but your safety margin is of course less and it’s not legal. But sometimes engines detonate operating on 100LL, engines with monitors. Why? I honestly don’t have an answer. People don’t understand ADI, it’s a very simple system, pretty much nothing to break, 2 pumps on different electrical busses, and the pump is the only moving part

Of course your altering the aircraft, but as it’s covered by factory drawings your maintaining the aircraft IAW it’s Type Certificate by removing the thing. Otherwise it would be a Major. I still have mine, but just don’t use it. I think the drag on a closed hole is insignificant. The break even point for ram air on motorcycles is roughly 100 mph, that’s the point where performance increase exceeds the drag, I’d expect the same for an aircraft. Ram air does work, look at the inlet of most turboprops for an example. I suspicion that it’s not very effective on a J because if you look at where the air filter is mounted, it appears it’s in the airflow and therefore is getting a ram effect so opening the ram air doesn’t do much. Just my guess. If you want to see if it works, watch fuel flow, if opening it increases fuel flow, then it works. How much HP does it add? Well assuming your LOP and if 1GPH is 14 HP when LOP, then it stands to reason if opening it increases fuel flow by 1 GPH, then your adding 14 HP. Opening it on mine doesn’t seem to effect the EGT by much if any, but I don’t have a monitor so my single probe just isn’t a precise instrument so it might. I do get a not insignificant increase in fuel flow though

Ref enforcements Often it occurs after an accident / incident Or probably more often when someone makes a complaint to the FAA, you would be surprised how often this occurs. But as far as the FAA police setting up traps like a local red neck Sheriff, your right that hasn’t happened, but be aware that if you have an accident or maybe even an incident that it’s likely an FAA inspector will be looking at your books, and possibly the aircraft. If they discover things in or on the aircraft that aren’t documented in the books, often they start digging, and very often the owner / pilot’s attitude determines how bad it gets. Yeah it’s very unlikely you go to jail, but they can pull your ticket and that can be hard and expensive to get back, they can fine you and enforcement actions don’t help your insurance bill either. I’ve been ramp checked, the Inspectors really do have a quota on ramp checks, Falcon Field near Atlanta is very close to the FSDO and as such gets more than it’s share of ramp checks

I think their theory is that EVERYONE pays, but only they get the money. Same concept of States and Municipalities getting Fed money, they see it as free money, but under normal thought processes somebody pays. BUT several political leaders have come to believe in or at least endorse a “new math” type of economics known as Modern Monetary Theory https://en.wikipedia.org/wiki/Modern_monetary_theory Part of the theory is that you can’t go broke, that you can print as much money as you want to stimulate the economy, and if that causes inflation, no problem, the way to control inflation is raise taxes. Think of it as justification of tax and spend. There are many sources of data about this theory, I linked Wikipedia, but there are many more. You can imagine which Politicians want to believe in Modern Monetary Theory, unlimited money to spend, controlled by increasing taxes, more money to spend

I’m no chemist, but a few questions. This intellectual material essentially can only be the blend of chemicals or possibly the way the are combined etc? Isn't that common knowledge? At least by any of the fuel blenders anyway, and how many people do you suppose that is? What other secrets could there be?

I have no idea, just was told they didn’t participate I guess that pretty much defines here say, doesn’t it. If you go back in one of these threads I was calling BS on the Youtube video before I even saw it, because most of Youtube is BS, people trying for their 30 sec of fame or whatever drives all of that crap like idiots parachuting out of a rare antique airplane for instance But I finally did view the video and I’ve done aircraft testing for most of my adult life and while it wasn’t lab level testing, I can tell you most of aircraft testing isn’t. I heated fuel for hot fuel testing with a Turkey fryer, an automatic transmission cooler, 50’ of fuel line and a fuel pump for instance with my Fluke recording fuel temp. You would believe how we tested for fuel pressure / flow in worst case nose up, min fuel. Anyway I think his testing was pretty good actually, and unless he rigged the tests for his 30 sec of fame, which I don’t think he did, because that type as soon as they get a crowd really go into overdrive, but this guy hasn’t that I’m aware of, so I don’t think he has an agenda. Anyway in my opinion, which of course is all any of us can state, there is enough hear say data that if at all possible I won’t use this stuff, I’ll avoid flying to locations where it’s the only fuel and if I lived where it was I’d get my fuel supply by whatever means necessary. The fuel staining isn’t by itself real concerning as Auto fuel also stains brown, my C-140 fuel caps have two holes in them, that the fuel vent and if topped off fuel gets sucked out onto the wing and it stains, but those stains do polish off. It just seems anything that gets into Jet-Glo and gets inside of the paint to where it can’t be polished off is in my opinion having some kind of reaction with the paint. O-rings aren’t the issue to me, the issue is bladders, tank sealant, and all kinds of components that have rubber and plastics in them that you can’t upgrade to Viton, like pumps, fuel servos, fuel flow meters, fuel pressure transducers, valves and I’m sure there are other items that I’ve missed.

I called someone the other day that I figure has some knowledge on this subject. He wasn’t in the office but called me back today We talked awhile and pointed me to this Website and told me that Gami did not participate in this testing. https://www.faa.gov/sites/faa.gov/files/PAFI_Fuel_Development_Testing_Lessons_Learned.pdf

Ref underground tanks. They are a nightmare, a ticking time bomb that once a leak is detected it’s going to cost huge amounts of money to rectify. We had one at Thrush that hadn’t been used in years, but had monitoring wells around it, checking for leaks of course for the empty tank, EPA required, why I don't know, that was before my time, it was a fiberglass tank. I dug it up with my old backhoe and disposed of it. I replaced it with an above ground tank, you have three options with those. Mobile as in on wheels, that has essentially no restrictions and was my temporary measure. For a fixed above ground tank it can be either a double walled tank with provisions for checking to see if the inner tank is leaking, or if single walled it has to sit in a concrete containment that can hold the entire contents of the tank, of course this containment has to have a drain for rainwater, most often you find them with the drain open. I went with the double walled tank, it was actually a little cheaper

Are you sure? There usually is, it’s tough now days to get above 90 without it. It’s easy to test, fill up a jar about 3/4 the way full of gas, put a significant amount of water in it, but leave room so you can vigorously shake it, mark the water level top when you out it in, shake the snot out of it and let it rest a minute, do it a couple of times, if the level of water rises it’s because the alcohol is combining with it, no alcohol = no rise in water level. In Florida there is Rec 90 fuel available nearly everywhere, it’s 90 Octane alcohol free fuel. I assume it’s 93 Octane premium, without the alcohol. However it’s significantly more expensive, I guess because they can charge more so they do. E85 is I believe 107 Octane, IF it’s 85% Ethanol, but E85 is allowed to be as low as 51% Ethanol

So what do you do when your policies leave your municipality broke beyond belief? Well you could become fiscally responsible, or you could just do this https://www.reuters.com/sustainability/new-york-fine-fossil-fuel-companies-75-billion-under-new-climate-law-2024-12-26/

Lead is a naturally occurring substance of course, there are areas where it’s mined for instance where people always have had higher lead levels than average. I believe that still the source of lead in peoples bodies is by an overwhelming margin old paint, but going after rich men’s toys is much easier and a pretty easy sell to the masses. It’s similar say to fluoride, in West Tx in particular average well waters fluoride levels are orders of magnitude higher than any treated water, it’s so high it causes their teeth to be stained. I’m sure there are areas where lead occurs naturally that are similar. It drives environmentalists nuts but the truth is the old adage “The solution to pollution is dilution” What I continue to not understand though is we don’t need Diesels, nor do we need some witches brew of chemicals to get rid of lead. So when will “they” realize that we don’t have any kind of emission controls on our aircraft? Will that be next?

We built our Spars with the layers wet, but didn’t shoot the skins etc wet, the Spars aren’t riveted but Huck bolted and the spars are about a foot wide. I don’t think you could shoot solids with wet sealant, so the Thrush is sealed after the wings are built too. It’s a pain too, there are often leaks, we tested our wings with a big homemade manometer, 5 ft or so tall U of clear vinyl tubing filled with food colored water, once they get fuel the difficulty of fixing leaks got a lot worse.

I can give you an idea about Thrush Crop Dusters, which have been built since 1965 and I believe there are more of them than Mooney’s. All are wet wing, a great many were Radials so therefore Avgas mostly, newer ones are turbines so Jet-A mostly, but just about everything from home heating oil to Diesel has been burned in them, so lots of different fuels. A difference between Thrush wet wings and Mooney’s is Thrush wings are sealed only with sealant that isn’t top coated with anything, if I had to put a number of years before significant leakage I’d guess 20, but honestly it’s all over the place, there seems to be a correlation between being under a shade and tied out in the Sun, majority of Thrushes are yellow and I think that color gets hotter than white. I’ve not seen any fuel that had any effect over long periods of time that degraded sealant, I think it’s mostly just time and maybe heat, but is it heat or metal expansion and contraction? I have no idea. We used the same fuel tank sealant inside of the hopper sealing the interior stainless steel braces, in the hopper some of the chemicals used eat sealant up and it’s very common to have to replace the sealant every year or so. I do not know which ones eat sealant and which ones don’t, just know some do, so sealant isn’t impervious to all chemicals. There is nothing that I know of that makes a Mooney wet wing novel, except maybe most wet wings are on larger aircraft? Small aircraft usually have metal tanks, maybe because their pedigree is from fabric covered wings? Many aircraft have bladders, bladders do seem to outlast wet wings.

They have deep pockets and could, a smaller company couldn’t. But that wasn’t my point, my point is that it took seven years for the issues to play out to the point that the product was pulled. We hope / expect for timelines much shorter than that, think “testing” can be done quickly, but sometimes especially materials compatibility effects take a lot longer to show up, we may not know for sure for a long time.

Most aircraft out there approach flaps come first as they are allowed at a significantly higher airspeed than gear. There are always exceptions, J model Mooney’s being one. What did you fly that gear came first? I was taught in a school that had an FAA approved syllabus part number I forget, it was 36 years ago, anyway as their purpose was to teach upcoming airline pilots and not Mooney drivers they wouldn’t allow speed brakes to be used and flaps had to come first, which meant you had to slow to 110 kts before glide spoke intercept or you would not make the approach. Everyone learned, that’s why I say it’s not all that hard to get a Mooney slowed down, you just have to plan it is all, start earlier than say a Cessna 172. Just looked it up part 141. https://www.ctcd.edu/academics/instructional-departments/aviation/ I went to this school Central Texas College in Killeen Tx to get my degree so that I could get promoted and stay in the Army until Retirement, and if I had to get a degree, why not in something I wanted. Anyway slowing to flap speed first and not being allowed to use the speed brakes was annoying, but you got used to it pretty quick

I understand, but to be clear this IA I know installed the engine, the bolts were intentionally left very loose. This seemed to be a very odd thing to do, still does

Just to confirm, four turns did give me 100 RPM

One way I see it could happen is we get 94UL, that I know could go into widespread distribution almost overnight, you just keep making the same Avgas you have for decades, just don’t put lead in it, shipping, distribution etc all remain the same. Those that don’t have high compression engines just burn it, those with high compression / turbo’s run ADI. That way you get honest Avgas that meets specs, the aircraft should require no mods to prevent vapor lock, it has the same storage life of 100LL, shouldn’t be any more expensive than 100LL, plus it will go into the same trucks and tanks etc that 100LL did as it’s just 100LL, without the lead I think? And we know it won’t cause any issues, except maybe valve recession, but I think any unleaded fuel may cause that, unless we leave a little lead in or add an additive, they exist. An issue with car gas as I see it is getting it, it’s one thing to be able to burn it and another to get it.