A64Pilot

The primary driver in extended auto oil change intervals is the extraordinary clean burn they have plus very reduced blow-by and nearly zero oil burn, when was the last time you cleaned the carbon off your plugs in your car? Auto engines come out if the box with near perfect tolerances now, they require no break in etc now because of that. You just can’t draw comparisons with auto engines, unless you compare to ones built just after WWII. Yes I’m aware of the doubling of oil change interval and I’m certain doing so the engine will still make it past warranty. But we don’t I believe know what the Gami fuel will do to oil either

Military aircraft, at least the AH-64 are or were painted with a two part epoxy primer, it’s not uncommon primer. We used it on repairs all the time They were top coated with CARC paint “Chemical Agent Resistant Coating” I believe back in my day it was a two part Epoxy paint. Thrush has always Alodined every piece of aluminum in big tanks approx 5 ft wide 8 ft deep and 30 something feet long, it was 5 or 6 tanks. Beech used to alodine their aircraft not sure now, Cessna would alodine seaplanes but not land planes, I believe both may have just wash alodined, you really can’t do a good job without tanks. I used to build my own oil separators, the one one the left was run through the alodine tanks, brush or wash alodine doesn’t get near the same reaction. Sorry it’s the only pic I have of tank alodine parts. I think the one on the right was wash alodined, but it’s been a long time so I don’t really remember

I don’t think it matters actually if it was correctly painted or not, depending on how you define correct I bet most of our aircraft aren’t correctly painted. From my experience many Aircraft paint shops aren’t real professionals, from what I have seen most Auto paint shops especially those that do a lot of classic cars, show cars etc are much better. What matters in my opinion is that it went I assume years with 100 LL without damage, but the Gami fuel damaged it. Plus this damage didn’t occur slowly over months or years, it happened pretty quickly. If it takes correct tank sealing or correct paint to not be damaged I bet a lot of us are in trouble. My fuel cells are apparently made from Nitrile, now we know what the effects of the Gami fuel is on Nitrile O-rings, it’s logical to assume that fuel cells made from the same material are at risk. But here is what concerns me, it’s the fact that some problems have been reported very quickly after this fuel was put into use, I would have expected it to take months at least. I need to get off my Butt and take a pic of the top of the wing of my C-140 that burns Auto fuel, the C-140’s fuel vent is two holes in the fuel cap, so fuel is siphoned out in flight if the tank is full. I have brown / yellowish fuel stains on my Jet-Glo painted wing, but even if I leave it there for months it polishes off telling me it’s not dissolving / eating into the paint. But it’s my understanding that the Gami fuel stains don’t polish out, telling me that it’s dissolving / eating into the paint. If it “eats” Jet-Glo that’s troubling, because that stuff is nearly impervious to a lot of pretty aggressive chemicals.

I understand that “true” Syn oil, PAO’s won’t put lead into suspension, or at least they won’t in our engines. They do fine in Automobile engines though. I was stationed in Germany from 93 to 96 and every station had leaded fuel then and many ran PAO oils. Mobil 1 found that out the hard way, it was FAA approved of course, but obviously wasn’t adequately tested. It doesn’t take much mineral oil to prevent the problem, so blends are fine. What I am saying is that if you remove the lead, yes you can most certainly run PAO but it shouldn’t significantly increase your oil change interval, because we, very much like Diesels don’t change oil because it’s worn out, changing viscosity or the additive packages breaking down, we change oil to get the carbon etc out, carbon as I’m sure you know is very abrasive. Diesels trash their oil with soot, especially newer ones with EGR Some turbo motors are the exception, some turbo motors if they are run hard (hot) are hard on oil and can cause it to prematurely break down, those possibly could run normal 50 hour change intervals with PAO oil. All I’m saying is if or when we go to unleaded fuel, it’s unlikely our oil change intervals will change, we aren’t Rotax engines

The chief reason we change oil at 50 hours, 25 if we have no filter isn’t lead. The cutting the interval in half for no filter is a clue as a filter doesn’t filter lead out. It’s carbon and other combustion by products, see we have very loose, sloppy cylinder to piston tolerances that result in a very high rate of blow by when compared to most any water cooled engines. Being air cooled and rather huge bores (V8 displacement with 4 cylinders) and the fact that no matter how badly the pilot abuses it, it isn’t allowed to seize means we have to have sloppy tolerances, that’s why we run such thick oil. 0W-20 would go past our rings at an astonishing rate. Not saying getting rid of lead isn’t desirable, but I’m not extending oil change intervals, oil is just too important. I don’t fly a lot of hours and change mine every 25 hours myself, if I flew long flights then I’d probably do 50. Ref Syn oil, there isn’t any. Perhaps maybe there will be after some time but I’d be surprised if there was, the market is so small I don’t think there is real money in it, or Exxon would still be selling Elite. Besides there is very little actual Synthetic oil anymore since years ago Castrol marketed their mineral oil as Synthetic and got away with it, even Mobil 1 had to sell mineral oil as Syn because they couldn’t compete price wise if they didn’t. http://xtremerevolution.net/a-defining-moment-for-synthetics-by-katherine-bui-lubricants-world-1999/ I think Amsoil may still be PAO Synthetic, but not sure, but there are very few actual PAO base stock oils out there anymore.

I think you’re probably correct, my experience with Jet-Glo is that it’s impervious to almost anything. It may be the primer that’s failing. But it doesn’t fail with 100 LL, and in the end does it matter? I’ve never seen UL Avgas, but whatever I have to use I’d prefer if it didn’t turn my old aging paint brown, cause it to bubble up and come off, whether it’s the primer or paint the end result is the same. My concern would be what’s happening to the rest of my fuel system, my bladders which by the way are made from the same material as normal O-rings that we know it causes to swell, and the other components that I cannot change like the seals and diaphragm in my fuel pumps, fuel flow sending unit, and my fuel pressure transducer, my Servo and divider and I’m sure there are other things I’m missing. It’s not O-rings that concern me. It may be that decades of sitting immersed in 100 LL has weakened these polymers and that if everything is new the Gami fuel is fine, but I can’t replace everything Who knows, but my opinion is that I’d avoid this fuel until we know for sure if it’s going to be problematic or not, give it a year or so at least.

A couple of more things, it wouldn’t be Test Pilots you would want to hear from but the Structural Engineer who designed it. Probably more often than not the weak link as in what gets damaged isn’t the flap but underlying structure, like maybe the aft spar?

If by that you mean once or rarely exceed that number won’t cause damage you’re certainly correct. I know someone in a J model that did a low pass close to VNE with the flaps in the T/O position and they weren’t harmed. By mistake obviously. Although CAR 3 doesn’t require fatigue to be calculated it does require that it “be considered” so one hopes that Mooney put the white arc where they did so that if obeyed you would get many years and thousands of flap actuations without undue fatigue damage. I bet every Mooney out there has had the flaps stepped on too, but it really should be avoided. On edit but it’s important to note that the limits on CAR 3 aircraft were set for new aircraft, there is no life limit in CAR 3 aircraft. My Mooney is old, I plan on keeping it until I can’t fly anymore and then pass it onto someone else. I think it prudent if you desire to keep something for a very long time that your personal limit is a little lower than the published limit. Your allowed to but I don’t cruise at 2700 RPM either for example. It’s been my experience that the last few percent of performance come at the expense of longevity and within limits the further you back off the longer a component lasts. By within limits I mean I don’t cruise at 2000 RPM either.

All Military, I was speaking of civilian aircraft, but particularly larger Commercial and used the word most, because there are always exceptions, Mooney obviously being one.

Analyzers can’t get % power not really, best they can do is best guess, they just don’t have the data input, sure they can have algorithms to try to get closer, but without a torque meter we just can’t get there, we have to deal with charts. Garbage in - Garbage out. Having spent a lot if my flying life doing test flights for data acquisition I can attest that any chart is mostly extrapolated, most test points aren’t flown, your Certifying an Aircraft, survival and success of the company relies on getting it done, so any charts are “close enough” then of course there are variations in everything equipment wise so close enough is often about as close as you can get. I would throw this out there as a thought experiment. % power = airspeed IF density altitude and a couple of other variables are the same then airspeed will correlate to % power Since we can determine % power decently close when LOP, go out and fly say from 50% to as high as you can get at your average cruise altitude in 5% steps. Graph speed vs % power, then anytime your flying at the same density altitude you should be able to determine % power from the speed you have as long as other variables are close to being the same, weight and CG probably being the biggest ones, not perfect but perhaps close enough In truth we can only get close determine % power by fuel flow when LOP because the lower the RPM the lower the friction losses of the engine and prop, but it’s likely close enough for getting an idea how hard you are working the engine. Of course this isn’t necessary, I haven’t done it, but for those that like to “play” it might be worth doing, just as a learning exercise. What I’m saying is that if 55% power equals 130 kts, then any combination of mixture, RPM and Manifold pressure that gives you 130 kts is 55% power.

For anyone who confuses what torque is, the above is one of the best explanations I’ve seen. Torque is important for say getting a heavy truck moving as at low or zero speed they are gear bound, by that I mean the motor can’t turn up high RPM until the truck reaches a speed where the gear allows it. An aircraft has a propellor of course, a prop can and does slip and allows significantly high RPM prior to the aircraft beginning to roll, a constant speed prop of course allows even higher static RPM, so low RPM torque isn’t as relevant in an airplane as it is in a heavy truck. Torque is simply a twisting force, but torque alone doesn’t do any work as there is no movement, combine torque with speed of movement and you get HP. As direct drive aircraft engines are very much RPM restricted, in order to get more HP as you cannot raise RPM you have to increase torque, so they are in fact pretty high torque engines. However by displacement they are actually pretty low power motors. Our IO-360 at 200 HP is decently high compared to many aircraft engines, but we only produce roughly .55 HP per cu in. Long ago bikes and I believe cars by now have eclipsed 100 HP per Liter which is 1.65 HP per cu in. largely as they are not RPM restricted. But also an airplane motor can make full power for a long time whereas Auto’s and bikes cannot. RPM and torque are inseparable torque is just force applied, HP is force applied with movement, noting more complex than that.

There are a number of detractors, for example Diesels have a very high torque pulse due to the high compression, this wrecks transmissions in trucks so dual mass flywheels etc are used to absorb the pulse, airplane props and prop hubs take punishment, NVH for a Diesel is high. As they are a compression engine often they can’t restart at high altitudes, Jet-A is a very dry fuel and is hard on injection pumps and injectors. Go-arounds can be problematic as there is turbo lag, cooling can be an issue. Some have very high drag cowlings to introduce enough cooling. Weight of course comes off of useful load. Germans in WWII built a Diesel bomber I believe as it’s sort of ideal for a big airplane, but weight I think was the detractor. https://www.historynet.com/luftwaffes-high-flying-diesel/ The Junkers design as a two stroke opposed piston engine was more advanced than today’s Diesels, in the 1930’s The 1930’s Zeppelins had Diesels so Aviation Diesels aren’t a new concept. Sure if weight and money aren’t a detractor a Diesel may fit the bill, but until they become more mainstream even if I could afford it I would stay away just due to parts availability and lack of trained mechanics.

Good question, as an IA it turns me away from such an engine, just because I can’t save money and do my own overhaul. New private buyers will likely never face replacement, but I can’t afford an airplane that costs the same as my house, so I have to buy used. I suspect liability, Jim Bob overhauls an engine, it fails, pilot dies and as Jim Bob has no assets the manufacturer is sued, sure so is Jim Bob but he is judgement proof. It’s a Jury trial and of course they feel sorry for the poor crying Widow with three children and a big judgement is given so she can live and raise the children in the manner they were accustomed. This is supposition but as Lawsuit happy as we are I suspect there is a grain of truth there.

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?