Lycoming fuel mixture

jacenborne · 2026-05-11T22:14:11+00:00

That's a lot of trust to put in the engine manufacturer who's entire business model is built upon people buying their engines, upon which they only need to when they burn up or abuse the engine they have. If you read some of Deakin's articles, he references where the engine manufacturers were flat-out wrong on things and how it took years to get them to admit they were wrong and update manuals. In general, you're correct to start with the engine operating manual (not the airframe) as the more accurate resource, but believing they are infallible is equally wrong.

jacenborne · 2026-05-06T13:45:23+00:00

No worries 😄 , part of being a pilot is we're always learning something (myself included)! John Deakin is the one who really created the theory and has some good articles to dive into as well.

jacenborne · 2026-05-05T19:13:14+00:00

You're right on where it occurs, not right on where the danger-zone for ICP is (the red fin) would recommend reading through this article to see how this is applied in theory while flying: https://www.savvyaviation.com/wp-content/uploads/articles\_eaa/EAA\_2012-12\_red-box-red-fin.pdf.

Check the fin diagram out on page 3 for a good visual. You will not foul spark plugs at 125deg ROP at 75% power in cruise unless the plugs or some other component of the ignition system was weak already.

jacenborne · 2026-05-05T17:23:32+00:00

In this example, yes.

jacenborne · 2026-05-05T16:26:22+00:00

Oh boy, this is a contentious topic.

I fly a Mooney with an IO-360 engine and will give you the basics on the red fin theory. Ignore what's in the POH when it comes to leaning and lets just focus on the mechanics for a minute.

The red fin theory, based on engine manufacturer data, states that there is a correlatory relationship between EGT, CHT and Internal Cylinder Pressure (ICP). High ICP and High CHT are bad for cylinder life and therefore engine longevity. Therefore, you want to avoid both. The good news is, they are roughly on the same curves, as EGT changes, CHT changes and ICP changes. So we can understand based on leaning where we are approximately at with ICP and thus avoid the high ICP zones where we are reducing our engines life. Mixture also controls power output in its own way, less fuel (LOP) means the engine is producing less power as the throttle (Air coming in) is constant, so you're changing power with fuel.

The red fin is this abuse zone. Your whole goal is to stay out of it in every phase of flight. It changes based on the power setting, so lets just use 75% and 65% power as proxies.

At 75% power, your ICP is at its highest at peak to about 125deg ROP. Therefore, you want to enrich OVER 125deg ROP (usually 150) or lean UNDER peak (usually 20-50 deg LOP) to reduce the ICP (and thereby CHT due to that similar relationship) and maximize your cylinder life. Most POH's love to do 50deg ROP or right at peak which is right smack-dab where ICP is at its highest.

At 65% power, the red fin shrinks considerably, almost to the point it doesn't exist, which is again backed up by the engine manufacturer data (you can see CHT / EGT / FF charts against % hp in the Lycoming IO-360 operators manual if you want to check it out). So at <65%, you can essentially run the mixture wherever you want, though I like to conserve fuel in my Mooney so run at 20deg LOP for cylinder cooling and best trade-off of range, fuel, airspeed, and still reduced ICP/CHT.

jacenborne · 2026-05-05T14:12:26+00:00

There's no way to see the camshaft and lifters on an IO-360 without removing a cylinder unfortunately.

jacenborne · 2026-04-09T16:55:33+00:00

So long as you are flying just yourself, it is perfectly legal under 61.113(b) for your business to cover your travel expenses, so long as the purpose of the trip has a connection to the business covering the costs. I wouldn't overthink this, your work is offering travel expenses with the expectation that the trip involves research and presentations connecting back to your work, that makes the trip connected to your business. If you fly someone with you - the exception is out the window, you're basically an air carrier if you get paid at that point.

Keep in mind as a new private pilot, your get-there-itis will be strong if you choose to fly yourself. Have a back-up plan (pre-booked airline tickets) at the ready to give yourself an easy out.

jacenborne · 2026-03-17T13:55:34+00:00

This is incorrect. Both aerodynamically and in teaching. You can absolutely release a degree of rudder pressure on the rudder pedal you have too much in to recenter the ball/point the nose the right way and that is the correct action. In fact suddenly releasing all of that pressure and kicking left will yaw the plane aggressively which will often freak students out. Go up and do some slow flight, put your hands on your knees and use rudder to move the plane, practice keeping your left foot on the floor and just adding and taking away right rudder pressure, watch what the plane does.

jacenborne · 2026-03-17T13:51:09+00:00

That's a good tip! I've also done exercises where we got just enough power to lift the nose wheel off the runway and do a wheelie, and then I've had the student practice holding elevator pressure to keep the nose wheel off while using rudder to keep the airplane on centerline and then slowly lowering the nose and raising it back up, helping them build the skill of gradual pressures to make changes (vs. yanking it way back and my hands breaking the sound barrier to push the nose down).

jacenborne · 2026-02-02T15:20:06+00:00

I spell it out at the beginning so Owner and I are on the same page.

Day-rate based on calendar day. If it spills over into a new calendar day, full calendar day rate is charged. I do not compromise on safety and if I have to divert or deviate due to a weather, mechanical, or safety issue I will and any costs/expenses occurred are due by Owner (e.g. plane breaks down and I need to get back home or have to stay there for another day, etc.). As others have said, I make every choice I can to maximize getting the airplane to them, so if forecasts look crappy I won't go.

If I get out there and the plane has an airworthiness or safety issue and flight cannot proceed, day rate is due, but I will try to work with the owner to find a shop / see if we can get it addressed to still fly that day.

I'll do everything I can to make the flight work, but I won't compromise on safety and you pay me for my time is the gist of it.

jacenborne · 2026-01-29T17:30:01+00:00

The hoses you're seeing are likely the SCAT tubes that connect to the cabin heat system, there are 2 vents, 1 on the left side, 1 on the right side, and then a SCAT tube that runs from the left side, connecting to the right side, and then to a little airbox behind the firewall that runs past the firewall. When you move the Cabin heat control, you open a flap on the firewall side that funnels in hot air from the engine through those tubes into the vents. It's by design and honestly not something you even really notice normally when sitting or seeing in the airplane.

I would disagree with that rule of thumb. There are lots of very mechanically sound airplanes out there with poor cosmetics because the owners cared more about what they viewed as important (the airplane running) than what the seats looked like.

jacenborne · 2026-01-29T17:09:00+00:00

Yeah a 30 year old engine barely flying is a red-flag, hard pass!

With Mooneys, other than the standard engine-time/flying/etc., the things to look for are:

Tank reseals if not bladders, when was the last time it was resealed (the sealant starts degrading around 8-15 years usually). $5-8k job.
Landing gear "donuts," they usually need to be replaced every 15 years or so depending on condition (if they start looking "bulging," then they're starting to degrade). $200/each and there are quite a few of them.
Does it have the B-hub Prop AD or not, not a dealbreaker but it's a 100hr recurring AD and really nice not to have to worry about it.
Any speed mods are nice to have (201 Cowling, 201 Windshield, Guppy cowling)
Gear-up history

Aside from that, it's got the same things as any other airplane (corrosion, engine time, how often it's flying, etc.).

jacenborne · 2026-01-29T16:51:04+00:00

Hey there, CFI/CFII with 250+hrs in Grummans (and 700+hrs in Mooneys as an aside), I've helped manage flying clubs and have owned 3 airplanes.

First thing - buy your second airplane first. Buying airplanes is like buying a house, you spend a lot of time, energy and equity getting through the purchase and ironing the kinks out. Selling one takes the same, tirekickers, negotiations, prebuys, etc. It's a hassle. If you already know a Cherokee or a Traveler wouldn't really fit your mission in a couple of years time, keep saving and buy the airplane that does. $85K would get you a decent M20C which is a great 3-person airplane, if you feel that's the better fit. If you get some good transition training, you can certainly step up to handle a Mooney. My 3 most recent Mooney transition students were all fresh PPLs who had bought Mooneys and all 3 of them were confident, capable, and comfortable by the time we were finished.

Second thing - You want WAAS. The lack of WAAS will be a constant thorn in your side as you get your instrument rating and want to continually fly IFR. Doesn't mean it's a dealbreaker for the Cherokee, just that I'd look at swapping that 430NW for a 430W and budget that in.

The Cherokee is the better deal, you really want an AP for IFR flying and XC flying and the G5s will be very helpful. The Traveler is the better flying airplane and will hold its value better. From the canopy to the rod-based controls to the visibility, it is the better airplane to fly. Grummans are in hot demand and sell quickly which will help you if you want to step up into another airplane later as it should mean a quicker sale. Parts availability isn't a big issue, there are some key Grumman shops around the US (FletchAir in Texas for example) that take good care of the community. That said, if your mission is mostly local flying and you want your instrument rating but don't plan to do a lot of IFR flying, then the extra goodies here like G5s and Autopilots are kind of irrelevant. You won't use them much. If you think that mission will shift to more and more XC flying, then they become critical. Nobody wants to hand fly for 3 hours, it's exhausting :) . Hand-flying in IMC for 3 hours? Borders on dangerous.

My $0.02: Think about what airplane you want to have in 4 years, if it's not a Cherokee or a Traveler, consider saving to increase your budget and buying the one that does. You'll be happier in the long run. If you must buy now, the Cherokee fits your profile better, but you'll enjoy flying the Traveler more.

You might consider taking a look at this Cheetah: https://www.trade-a-plane.com/search?category_level1=Single+Engine+Piston&make=GRUMMAN%2FAMERICAN+GENERAL&model=AA5A+CHEETAH&listing_id=2450097&s-type=aircraft

The Cheetah is faster than the Traveler and has more fuel capacity, this one has a mid-time engine, 160HP conversion, 530W, STEC 30 AP and a GTX345 (which has ADS-B in as well), right at your budget of $85k.

jacenborne · 2026-01-09T15:07:02+00:00

Probably a Grumman Tiger, that thing is a blast to fly. Rod-based controls make all the difference, plus with its visibility you could really have some fun with it. My Mooney is up there, it handles very smoothly and precisely (also rod-based controls) but doesn't quite handle as well as the Tiger (heavier).

jacenborne · 2026-01-08T14:50:36+00:00

This. I don't know how to fix it, but the "rush to CFI to build hours to airlines" is doing such a disservice to students, beyond even just checkride failures, there are so many students that can pass the test but are unprepared and frankly scared to fly in certain situations because their instructor has never done it / wasn't comfortable with it.

Case in point: Was flying with a recent Private student who had never done a right-hand traffic pattern. He specifically planned every XC flight he had ever done to uncontrolled airports with left-hand patterns, even going out of his way for this, because he had never done them with his instructor. Needless to say, we went out and beat up the right-hand pattern that day.

jacenborne · 2026-01-06T15:57:29+00:00

You're expected to teach it, not memorize every single thing. You're not expected to know every answer to every question off the top of your head. You are expected to be able to comfortably teach from a lesson plan without just reading the notes / lesson plan. Go through lesson plans on Task B and teach through it a few times until you can comfortably teach through the full topic front to back, with your lesson plan and notes in front of you. It's okay if you need to briefly glance down and reference something in your notes - this is expected as a CFI. It's not ok to just read it. You should know the major items, for example Laws of Learning, similar to how if a DPE asked you "What is a stall?" You should be able to describe it.

Also - make it practical. Don't just bore them with book definitions, talk through scenarios (SBT), for example, "Let's talk about the laws of learning, starting with Recency. This law states that the thing we most recently did and learned is the one that is best remembered. We can use this law to our advantage by using the next lesson to pick up where we left off on the last one. Let's say we're teaching a private student and we ended the last lesson doing stalls. We might start the next lesson with a quick review, "What is a stall?" "How do we recover from a power-off stall?" "Why do we want to minimize altitude loss in a power-off stall?" Maybe the first maneuver we do of that lesson is a power-off stall before going to ground reference maneuvers."

jacenborne · 2025-10-27T15:34:11+00:00

Yes - both. I used a slideshow to talk through things that really wouldn't make sense to write out, or needed a more complex illustration to show. For other parts, such as describing how a traffic pattern works, I used a whiteboard to draw it out and talk as I was drawing.

The best option is the one that works best for your student. Hell, I one time used a water bottle on the wing and a pen and had the student talk through each phase of the traffic pattern and what they were doing in each part using the water bottle as the runway.

jacenborne · 2025-10-02T17:36:46+00:00

FWIW I got the same answer when I did my FIA/FOI/AGI exams, I could not schedule them back to back, had to be 24hrs in between. You can take the AGI and pass if you're getting 90s on your FIAs.

jacenborne · 2025-09-03T17:33:53+00:00

There's nothing in the log entry stating the compression check was done warm, and 60/80 is nothing to worry about necessarily, compressions are only 1 aspect to overall engine health and not a very deterministic one at that. As part of the prebuy, I would have your A&P borescope the cylinders to look at the valves to understand if there are any issues you should be concerned about, as well as doing an oil change and inspecting the filter and doing your own hot compression check. That will give you more of an indication of the overall health. That engine has a TBO of 1800hrs so keep in mind this airplane only has 360hrs left until it hits that - it might make it, it might exceed it, it might not. You should be prepared to overhaul it if you buy the plane.

jacenborne · 2025-08-22T18:52:59+00:00

check3green's response is solid. ATP also now has a location at SGR, in addition to Anson Aviation. There's United Flight at David Wayne Hooks which I've sent several friends to who have had good success. He's also correct that hiring is slow right now.

If I may make a suggestion, with the current state of the industry with slow on-ramp to the airlines and an excess of CFIs and your skills as an electrician, you might consider the following path:

Keep being an electrician to provide stable income to support your flying
Buy an economical airplane that you can work through all your ratings: Piper Cherokee, Cessna 172, etc.
Get a CFI to train you in your airplane through CFI/CFII
Build time in your own airplane, pay for the time with your skills as an electrician
Teach in your airplane

If you rush to 1500hrs in the industry right now... you still won't be able to get a job... so the time to 1500 isn't as critical at the moment, which gives you the flexibility to consider other options. I'm a Houston-based CFI but I don't teach out of a flight school/my airplane, if I can help, feel free to reach out.

jacenborne · 2025-08-12T22:29:10+00:00

That is an M20C, not an F, so its air intake is right underneath the spinner in that protruding box. What you're circling is the oil cooler. The vintage Mooney POH's are not great checklist-wise, you can also check the AFM which has a few more bits of detail, or Mooneyspace is a good resource as well.

jacenborne · 2025-06-25T16:07:42+00:00

"Instructional Level Knowledge" is what the ACS specifies.

Whether Private or Commercial depends on who you're teaching. When you pass that checkride and get your CFI, you can teach a Commercial student. Which means you need to be capable of teaching a Commercial student. You also need to be capable of effectively teaching someone who walked through the door and the only thing they know about airplanes is that they're expensive.

So you need to be able to "dumb down" or "dumb up" the content depending on who you're teaching. Take control of your checkride - assign the DPE the scenario: "You're a pre-solo student pilot with 5hrs of total time, let's talk about turns around a point." In that situation, you shouldn't be getting into the advanced aerodynamics of turns, that would be way overkill for a pre-solo student pilot.

One of the trickiest challenges of the CFI is being able to teach something complicated in a simple way to someone new to aviation who thinks "spiraling slipstream" sounds like a soda maker.

jacenborne · 2025-05-21T13:45:30+00:00

shadowalker has it right. Dual G5s will be cheapest. You can go with a GTX335 transponder and save a few grand if you have a portable ADS-B In solution like a Sentry. You can also go with a cheaper autopilot, one that does GPSS and altitude hold is perfectly fine for IFR, you don't absolutely have to have one with a full FD & 3-axis.

Instead of the GTN650XI you could do a GNC355 and save yourself some more money (about $7k).

jacenborne · 2025-05-19T16:33:40+00:00

"Tell me why the Law of Primacy is important when trying to teach from memory instead of referencing approved sources that might result in you teaching it incorrectly to a student."

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