John deakin engine management & ignition

You know the cliche: There are two kinds of retractable-gear pilots in the world — those who have landed gear-up, and those who will. Many thanks to those who wrote and said they missed my column, some even asking if everything was OK. For the personal, non-column stuff, please see the sidebar below on the right. Somehow the subject of gear-up landings of the inadvertent kind came up during one of these sessions, and it was probably the Margarita that prompted me to tell the story of how I once came very, very close to being the only person to land a with the gear up.

It is not fear, for fear keeps most people well away from such places. But I know the feeling. Never one to get to the point when my fingers are talking, a little history …. My folks were glassblowers Bohemian style in Matawan, N. He used his savings from that to convert a fruit stand to a cozy home with a small shop open to the public, selling the glasswork.

He also put a glass working shop and display area in the end facing Desoto Road. It was a wonderful place for nine-year-old. Rotten, old, WWII barracks everywhere, and piles and piles of rusted john deakin engine management & ignition that were pure treasure. I found a beat-up, bent, and rusty old bicycle on one pile, bent it mostly straight, and sanded it down with some used sandpaper coarse.

Found some leftover paint and brushes in another junk pile and smeared bright red paint all over it. That was my first airplane, for I would ride it with the wind in my face, making believe. Where there was a crack in the road, or a curb, I would approach it at a shallow angle, flare gently as if for landing, and just touch it as gently as I could, somehow mentally transforming the horizontal to the vertical.

Silly, I know. As my courage grew, and I ventured further away from home, I discovered the airport flight line, something over a mile away. From that point, and for the next eight years, that old bike wore a groove forming the shortest path to the flight line. All that separated me from heaven was a three-foot-high chain-link fence. Years later he would sign me off for my first solo, for my Private, and for my Commercial.

Someone else did my instrument instruction, for Harry never acquired the instrument rating, much less the Instrument Instructor rating. The Champ, NE, would become my second solo Cessna was first. I made a pest of myself there while he worked on the gadgets. I still remember the smell of micarta being drilled and cut. Basic route was south to the Venice airport another ex-military airportto Punta Gorda, north to Arcadia, then home.

Harry and Bob were my first heroes. I hated PanAm for that, and for their arrogance. One day Dad and I were outside the family mansion, and we saw a U. Navy Skyraider overhead, making his left base for runway 31 now The gear was still up! I hate government regulations. We have far too many of them. Too many of them are really silly ones, and it has become utterly impossible to avoid breaking some of them on ANY flight, no matter how religious you are about following them.

But, that's for another column. One regulation that would make sense to me is a requirement to have such an engine monitor on all engines used in commercial passenger service. I am utterly convinced that the Whyalla crash which I discussed in June and July would have never even come close to happening, if the airplane had been equipped with any of the engine monitors, and the pilot had modest training in their use.

The stage for the accident was set two months before it happened, and a monitor would have prevented that, too mis-set timing. With the information that pilot had available to him, I believe he acted with reasonable prudence. But if he'd had any engine monitor, and understood what it was trying to tell him, he would have known it was insane to continue that flight, and the causal chain of events could have been interrupted two months earlier.

He simply didn't have the information he needed so badly, and eight people died. So, let's run through a normal flight with a normally aspirated IO, almost certainly equipped with GAMIjectors, a good engine monitor, and an accurate fuel flow indicating system. I'm sorry, I have very little help or advice for those with carbureted engines.

I've flown one Cessna with such poor fuel distribution that leaning was hopeless at any altitude. One old trick is to operate high enough to use full throttle for cruise, but then back the throttle out just barely enough to detect the smallest possible drop in manifold pressure. That may cock the throttle plate just enough to induce a more turbulent flow, or a vortex where the fuel and air mix, and that may give better fuel distribution, allowing a bit more leaning.

I doubt that anyone has trouble with cold starts. If there is a problem, there is something wrong with the engine. Crack the throttle, mixture rich, hit the boost for a few seconds, and go. Hot starts come in several religious varieties, and everyone has a favorite. Some of them even work, some of the time or even most of the time. The only method I know for the big-bore TCM engines that works on real science is to run the electric boost pump for 60 to 90 seconds with the mixture off, then proceed with a normal cold start.

That requires an engine with a "vapor vent return line," as found on most of the TCM "big bore" engines. For the others, I cuss along with everyone else.

John deakin engine management & ignition: Aircraft engines and car engines both

Try hot-starting a big Merlin, sometime! All pilots should be familiar with ground leaning, because not all airports are at sea level. Even with a perfectly set idle mixture at sea level, operations at higher elevations will really need leaning. Many engines are not even set properly at sea level, and for these, ground leaning is a really good idea, all the time.

No, contrary to some advice, you cannot cause detonation by ground leaning, and you cannot hurt the engine at even twice or three times the normal power used for taxiing. How do you know if you need to lean on the ground? The classic idle mixture test is done after flying, so the engine is fully and evenly warmed. The book usually calls for a low idle RPM for this test, aboutor so.

That's fine, but I prefer to set the idle mixture while running about 1, RPM, which is where I usually operate on the ground for taxi, and while waiting.

John deakin engine management & ignition: But in the high MP low

On most engines, this takes a LOT of mixture travel, and it happens just before the mixture shuts the engine down. What are we doing, here? We are leaning to "best power mixture" which really means we are leaning until the engine develops the maximum horsepower for the given throttle positionwhich will be reflected by an RPM rise, since the prop is not up to governing speed.

Watching for an RPM rise won't work in flight, because the constant-speed prop will maintain the RPM by twisting the blades as needed. Essentially, at any RPM below the prop-governing range, you have a fixed-pitch prop. If you see no rise at all during this test at a sea level airport, and the engine just shuts down, the idle mixture is either absolutely perfect, or too lean, but there is no way to tell which.

This is the reason we want to see a slight rise. That rise indicates you started out slightly rich, and leaning did cause a reaction. While a small rise is not perfect, it's "good enough. If you see a rise of more than about 50 RPM, then a drop as the mixture goes "too lean," your idle mixture setting may be too rich. You then have a choice of irritating your mechanic by asking for a minor tweak, or just ground leaning it yourself.

If you get the idle mixture setting too lean, it will make the engine a bit harder to start when cold, at sea level. This is the reason many manuals call for something like a RPM rise on this test. Seriously, you may want the richer mixture described in the manual for better starts in cold weather, and then just manually lean for all operations as the engine warms.

Another factor that may come into your decision-making is whether you start your engine in cold weather without preheat. I won't start my engine if the engine is below 40F, and I use preheat religiously below that. Even if you have your idle mixture setting adjusted perfectly at sea level, when you operate out of an airport above sea level, your engine will idle too rich if not manually leaned, and the higher the airport, the richer it will be.

At very high airports Leadville, at nearly 10, feetyour engine may not even start or run with a full-rich mixture setting. If you don't lean at high-elevation airports, then roughness and plug fouling are inevitable. So here is one of many choices you make as a pilot. If you operate almost entirely out of warm, sea level airports, it's probably worthwhile to bug your mechanic to diddle with the idle mixture setting, then you won't have to ground lean at all.

This may be as simple as reaching through a hole to set the screw, all the way to removal of an entire cowling to make this trivial adjustment. If you operate out of one high elevation airport exclusively, the same advice applies, but be aware that a foray to lower elevations may mean a hard-to-start engine from a mixture that is much too lean at sea level.

Extra prime, or boost pump operation, may be required. For an airplane that operates at a variety of elevations, it's best to set it properly at sea level. Or you can do like most of us, and just forget diddling around with it, and just ground lean all the time. My RPM rise is aboutthe last time I checked it, and I don't care, because I lean right after the start as a habit.

For renters, be grateful the engine starts and runs at all, and if the mixture lever actually works, use it as needed to keep it running. Mixture management is quite simple. The phases of flight to consider are ground, takeoff, climb, cruise, and descent:. Immediately after engine starts and stabilises, and also after landing, when the RPM is at idle, lean the mixture aggressively - almost to the point where the engine RPM starts to drop off.

The lean combustion keeps the plugs clean and delivers the fastest engine warmup. Due to the very low power setting at idle there is no john deakin engine management & ignition of engine damage. The engine handbook recommendation may be say RPM but this can result in an excessive taxi speed, but lower values may not charge the battery, so some tradeoffs are inevitable according to how long one expects to be hanging around on the ground.

Invariably, the problematic plug is one of the lower ones which needs the lower cowling to be removed However, to date, I have always succeeded in clearing a shorted plug using the traditional method of leaning to peak EGT at a reasonably high power setting. The takeoff is simple: always at maximum available power. The fuel metering system carburettor or fuel injection is factory adjusted so that when at full throttle, max RPM if a CS propeller is fittedand full mixture, the engine is running very rich, with an EGT which is around F ROP.

However, the power output of a normally aspirated engine falls off immediately as one climbs. It is less simple when departing from a high altitude airport! The takeoff is still done at the maximum available power but in this case it is not with the mixture full rich. The method is engine dependent but in general terms one leans the mixture until peak EGT is reached and that is the best power one is going to get.

There are no high altitude airports in the UK but there are some elsewhere in Europe. Note that due to the U. Traditionally, the climb is also done with all three levers fully forward until top of climb. But there is a problem which manifests itself on higher altitude climbs:. As one climbs, the air pressure falls, and the fuel metering system detects the lower airflow and it reduces the fuel flow to maintain the mixture ratio and thus the engine operating point in this case, F ROP.

Unfortunately, it doesn't get it quite right. The air:fuel ratio is based on mass flow. It is trivial to measure mass flow of the fuel because at that stage it is still a liquid, and a liquid is virtually incompressible and thus its density is very nearly constant - even over wide temperature changes avgas expands just 0. So any mechanism measuring liquid flow velocity or pressure in a fixed orifice will do, more or less.

But mass flow of air is much more elusive; it is highly compressible and its mass flow cannot be directly measured with any simple mechanical device. There are modern electronic methods but you won't find one of these in a s engine design Both a carburettor and a fuel injection servo measure something halfway between mass flow and volume flow, and varies with altitude and temperature.

Some fuel system designs incorporate altitude compensation but even they don't do the whole job, and introduce a nasty failure mode: a failure of the barometer diaphragm which stops the engine by flooding it with fuel. The result is that as one climbs full-rich beyond say ft, the engine runs progressively richer and doesn't run properly, and may eventually stop.

The traditional solution is to climb full-rich to a few thousand feet and then transition to a "cruise climb".

John deakin engine management & ignition: › sape › pilotage

There is nothing wrong with this, but it is not a comprehensive solution to high altitude climbs say, ft because regular additional leaning is required even during the cruise climb. A smarter way is the constant-EGT method. Very shortly after takeoff within the first ft or so note the EGT of any particular cylinder. Obviously, this assumes one has an engine EGT instrument of some kind.

Then, as the climb progresses, the EGT would naturally fall but one leans the mixture to restore and maintain the original EGT value. With a multicylinder monitor such as an EDM, it doesn't matter which cylinder is used for this purpose but you have to stick to the same one all the way, and it is smart to use the one whose cylinder head temperature CHT is the hottest; on my engine it is 3, but 5 or 6 are more common as they are right in the back of the engine.

Practically, one can do the mixture adjustment every ft or so; it isn't really critical. The following pic data downloaded from my EDM shows the general idea:. As can be seen above, the constant EGT also results in a nearly constant CHT which is a highly desirable situation because many engine installations have difficulty controlling the CHTs during climb - especially in the summer.

Here, the CHT can be seen to actually drop slightly as the climb progresses, which is probably due to the reducing engine power and the cooling air getting colder. The stepped nature of the EGTs during the above climb shows that the mixture was adjusted only periodically. The article full of BS, where Lycoming tell you its perfectly all right to run LOP, and they do it all the time, but the pilot community are too dumb to do so.

Yes experts are everywhere. And guess who Lycoming were poking fun at there? Despite its numerous pages. Never lean the mixture from full rich during take-off, climb or high performance cruise operation unless the airplane owners manual advises otherwise. However, during take-off from high elevation airports or during climb at higher altitudes, roughness or reduction of power may occur at full rich mixture.

Prior to engine shutdown run up to RPM for one minute to clean out any unburned fuel after taxiing in. Last edited by Jabawocky; 15th Feb at Find More Posts by Jabawocky. Volumex - what's the registration of your Airtourer? They are a great little plane. Clinton - I'm always reluctant to deviate from the POH and official publications. The Lycoming Engineers know their stuff and their publications on the Lycoming Engines website are gold.

Jabawocky - did you forget your medication tonight? Clinton, leaning reduces the amount of fuel so the Lycoming statement seems right, am I missing something? Find More Posts by blackhand. A Squared. Nothing wrong with that. The might have included a little more detail. The reason it's rough is that the fuel air mixture is not even for each cylinder, some tend to be leaner than others, as you lean, the leanest one will reach the point where it's too lean to for combustion, so that cylinder stops producing power, and the engine runs rough because it's running on 5 cylinders instead of 6, just like if you'd pulled off a sparkplug john deakin engine management & ignition.

Find More Posts by A Squared. Before this thread descends into some rabble, lets clear up a point. Clinton is pretty much on the money. So the notion suggested above that they immediately shut down and caused rough running because the mixture is so lean it would not support combustion is not quite how it happens, or certainly in the vast majority of cases.

So CMchocky frog for you Peter C. Your comment about publications written by engineers would be correct, if only the manuals were written that way. It may pain you to learn that far too many sales and marketing and legal department folk are the reason for such poor manuals.