jaylw314

I mean, geez, Dugosh is Dugosh. When I told my friend who was ferrying the plane that I had the prebuy done there he said that made him feel a lot better FWIW in the US, IA's can say the same thing during annual, so that part doesn't sound different

I was wondering more so if the Atkinson would improve detonation margins at full power than efficiency, since we're having issues with 100LL. It sounds like without turbo, no, since the motor would have to be larger. With turbocharging? The wikipedia entry for Miller cycle engines mentions it might, especially if the intake charge is intercooled. That would be interesting in that it is simply a different valve timing, we have turbos and intercoolers otherwise. I realize, though that the risk/benefit ratio is unlikely to be there for R&D regardless. This was strictly in the territory of 'thoughts while on the toilet'

Apparently you can, but then it's called a Miller cycle engine? Never heard that term before Obviously, VVT Is a no-go in aircraft engines, I was thinking just about mechanically simple ideas

Turbochargers could make up for that, though, right?

Random thought, but I'd never heard of Atkinson cycle engines until recently, and now it looks like they're coming out of the woodworks. Is there any reason other than design inertia that we don't hear about them in aviation? My understanding is that the original idea would have been too complicated, requiring additional shafts to make the intake and exhaust cycles different lengths. It looks like most implementations in cars now simply have the intake valve open for part of the compression cycle to reduce the volume of the fuel/air mix, which seems like a mechanically simple technique. Aside from slightly better efficiency, it seems like the main benefit in aircraft motors would be to reduce or obviate the risk of detonation, since the intake compression ratio would be significantly lower before combustion. I've read that low-end power suffers in comparison, but that would not be much of an issue in aircraft. Is this a thing anywhere in aircraft already?

I wonder if there was a change to the system in the last few years, because when I filed by phone in the past to do practice approaches at my home airport, the controller said he needed some destination separate from the departure just so it'll go through. That's interesting about the Redbird letter, the local EAA has an old Elite simulator and just got a Redbird FMX simulator, and the FAA ATD letter from both specifically states that requirement about approaches to minimums being a requirement for IFR currency. I just figured the FAA used a stock letter, but maybe there are different agreements.

I'm pretty sure they need a different departure and destination if you're going to file IFR. If I'm just going up for approaches, I put something to that effect in the remarks. There are some approaches that ATC doesn't allow for repeated approaches, like Newport, OR. It's on the coast, non-towered, and great for getting bad weather, but I assume they don't allow it because of the Coast Guard station. I've never found it written down anywhere, but I've been told that by ATC a couple times when I've tried. The few BATD's I've seen have FAA letters requiring approaches to minimums if used for IFR currency.

If you want to go down the math rabbit hole, this guys does an excellent series of videos on the math part of machine learning:

If you have an LED landing light that has to be wired in one direction, it would be nice to have one wire be a knife connector and the other a spade connector. That way you'd never get it backwards when you put the cowl back on, which has never happened to me before

FWIW, the regular household red-nosed sprayers work fine with mineral spirits. I can attest to this almost gassing myself the last couple weekends spraying down the motor. https://www.amazon.com/dp/B07HJ7YTDH Nothing dissolves or falls apart, but I'm sure some of the plastics seals swell in the solvent, so I empty it out the bottle and sprayer after use. I'm still on the first spray bottle after a year, it still seems to work fine

I was researching Deltahawk about 20 years (!) ago when I first started thinking of an RV project. It looks like they took down a lot of the technical description on their website, but I vaguely recall the idea was that it was similar to other 2-stroke diesels except both the intake and exhaust were ported, e.g. no exhaust valves. The supercharger is only used for starting and as a failsafe if the turbo fails.

FWIW, my understanding is that the supercharger doesn't do anything except help the motor start, it just freewheels from the turbo under normal operation. The turbo is actually required for the induction airflow, but I'm by how much the intake pressure is actually boosted.

Just to follow up on this: I cleaned off the bottom half as best I could, and let the mineral spirits evaporate overnight before test running the motor a couple times. When I went to check the oil level today, lo and behold, it was about a quart higher than last week. If that's the case, then my oil consumption is actually about normal?? I recall last time when I checked the plane had been sitting about a week as well, and was down to about 6.2, now it's back up to about 7.0 quarts. I'll be keeping a close eye on that, obviously. However, after test running and doing a few circuits, there is definitely a new oil drip from the firewall after shutdown. I'm not noticing the belly any dirtier, and the exhaust is dry inside, but it looks like it's coming from the accessory area and dripping down. The magnetos look dry, as does the oil filter and oil cooler connection. The drainback tubes stayed dry. The fuel pump had oil on it, but its mounting pad looked dry. I couldn't tell if it was coming from the fuel pump or something above it. Anyway, I'll have to figure out who to take it in to to narrow down the leak.

Cool beans, I'll be on the lookout for that, thanks!

Yes, I was trying to follow it, but the bottom half was oily enough there was nothing obvious. That's when I gassed myself spraying things down with mineral spirits . I was going to come back and test run the motor after it dried, but I started feeling kind of wonky. I'll go back and do that this weekend By drainback tubes I assume you're talking about the breather tube? That runs down the left side, and the left side was clean

Yeah, I usually tell the shop to only put in 7 quarts but I forgot last time. That should result in oil coming out the breather and onto the belly, though, not onto the nose gear. Admittedly, I flew so little for most of the last 4 months that my impression of sudden 'change' in oil consumption may not be accurate

I do get a pretty oily belly, but it's always been that way and tough to tell if it's changed Luckily, it's pretty clear looking on the cowling bottom that there's no oil dripping down the left side of the cowl at all, but there's a small oil stain on the right side. In retrospect, when I saw the drop in oil level, it was at 8 qt after sitting for a few weeks, and at 7.5 qt after only a few days. It's hard to imagine, though, that all the oil will not return to the sump within 24 hours

I am sadly pretty sure there are some serious family health issues involved so I am guessing not, but I was going to call him next week anyway to see if he had people to suggest. FWIW, I forgot to feel inside the exhaust, but it looked clean. I'll double check that tomorrow and keep looking elsewhere, I just had to quit today because I was getting high on mineral spirits

So I posted earlier that my IA retired and is closing his shop. Naturally, I noticed the next couple flights that my oil usage seemed to go up (about a quart after 3-4 hours) and that I was getting more oil dripping onto the nose gear when I come back to the plane. Normally there's about a teaspoon's worth of oil on the nose gear, but this time it looked more like a tablespoon. The motor has always been pretty oily in bottom half of the cowling, but I only go through a quart every 8-10 hours normally so I never thought much of it. I took the cowling off and noticed some oil seepage around the upper half of cylinder #3 that I'm pretty sure is new. I wiped around what I assume is the oil pressure relief valve and couldn't find any oil on the valve itself, which I assumed would be the more likely source. The right lower half of the motor is all pretty oily now, so it's pretty tough to see anything obvious, but it's definitely worse than the left side. If this is the source, how could it suddenly increase like this?

It's not rare for a prop to require overhaul at a different time from the motor. Ask me how I know It should be in the prop logs though

Yes, I'm just complaining about change because I hate change

Thanks guys, it does sound like one of his A&P's is taking a lot of his equipment and going to be doing work out of another leased building, but I don't know the details and obviously annuals will still be an issue. Luckily, I still have 6 months to sort it out

Dang it!!!!!! I've spoken before about Mike Ward, my IA that runs Flitewing in Salem, OR. Well, I just found out he is retiring, and actually selling the building, so it looks like I will need to be finding a new shop this year Bad for me, good for him. Just wanted to complain

I just use a couple drops of car wash soap I bough at Costco 10 years ago into a half-gallon of water. I use the same solution for car detailing and clay bar treatment. I put it in one of those 2L pressurized hand sprayers and take it with me on flights. I just spray the windshield a lot, then spend 5 minutes spraying and wiping the wings and cowl with a microfiber mophead. Then I come back to the windshield, spray it again, and by now it's softened all the bug stuff enough I can just wipe everything off with a microfiber cloth. Don't have to use any pressure wiping if you've let it soak for the 5 minutes.

FWIW on warm/hot starts, I don't give it full mixture, I only give it about half mixture and it seems to start fine, even in 95 degree summers. Probably not a real benefit to doing that other than economy of motion, but it puts in perspective how easy it should be.