jlunseth

If you have that much fuel flow the best thing for you to do would be to climb full power full rich cowl flaps open. Your plane will thank you for it. I can’t count how many of those full power climbs I made on the old engine in my plane. Hundreds, and some were from 1,000, which is ground level around here, to 21 or 23. I climb at 500 fpm to keep the airspeed and therefore the cooling up. That meant operating at full power for 40-45 minutes on occasion. Never hurt the engine. It made it to 2300 hrs and probably would have gone further, but it was just time to replace the 22 y.o. engine. Breaking in a new one now. Pilots and mechanics are figuring out that it’s a really good little engine. Sure, it has its quirks because we have to manage MP all the time. But the reputation it earned in the early days from running at peak and pushing the CHTs high was simply not valid, we had to learn how to run it right. Thank you GAMI and the other experts who taught us that. The biggest challenge is the high hot climb, in other words, climbing out of a western town into the flight levels in the middle of the summer. When I tried a cruise climb for that years ago the temps were really bad. Seems counterintuitive, but the solution is to put in more power and full fuel, which gets the fuel flow up to max. Even then sometimes there would be one cylinder that would get up around 410, not ideal. I have had new baffling put in and so far it is helping with the cooling issue quite a bit.

Just guessing, but that looks like part of a larger STC that included the GB, KB, LB - maybe the STC for the Merlyn? The Merlyn Black Magic is STCd for several aircraft, including several Pipers. So when the AFSM was put together for your aircraft, they put the entire Merlyn STC in it, its up to you to find the section of that STC that pertains to your particular engine, either a -KB or an -LB, but not the KB section. I use a full power full rich climb to whatever my cruise altitude is. I tried reduced power (cruise climbs) when I first got the aircraft and particularly out west (e.g. AZ, NM, MT, CO, SD, WY) the temps were too high in the cruise climb. Many of us try to get our A&P to set the fuel flow higher than the POH specifies, say 25 or 25.5 GPH. The extra fuel slows the combustion process down, allowing the cylinders to run cooler. You can always dial the fuel flow down from the max at which it is set, but if the max is not high enough, you can't dial it over the max it was set for. It appears to me that there is a bump in the fuel flow as you get to full MP, 40 in your aircraft? In other words, the fuel flow increases more sharply as you approach max MP. So it may be counterintuitive, but to get best fuel flow and cooler CHTs you need to go to max MP and max fuel flow.

I agree with Paul. The 231s have a GB or an LB, not a KB.

12 and 14 volt are the same. 12 volt is the current but it requires a 14 volt potential.

Of those three, Bahamas is my favorite. There are too many security issues now, to enjoy Mexico. Try to sit on a beach and there will be a constant stream of vendors trying to sell you tourist trinkets. When you go to a foreign country you have to understand, before leaving, that the rights and privileges you have here in the US no longer exist. To keep it short, I would not trust my airplane to Mexico. Canada is fine, but unless you are a hunter or fisherman, there is not much to see up there and flying-wise there will be some bureaucracy you are not used to, like having to pay for ATC services. I am a fisherman and have gone to Can many times to fish, the very best fishing is a fly out somewhere and getting the gear there, and the rest of the people in your group, generally means driving. Bahamas, now there is a gem. Yes, you will encounter some bureaucracy but it is pretty benign. Stay away from the tourist destinations and explore the family islands, Abaco, Treasure Cay, Long Island, Bimini, and on and on. Everywhere you go you will find friendly, honest and helpful people. If you want to do something while there, go diving, fishing, shelling, generally sight seeing in beautiful wilderness settings where you won’t see another soul. Great rum and coke in the evenings. Even if you just sit and enjoy the scenery, well, you are sitting on a beach coming to understand the true meaning of “aquamarine.” Try bonefishing if you are good with a fly rod, you won’t regret it. There is a pilot’s guide to the Bahamas, it comes with all the paperwork and explanations you need to fly there. Fly to Ft. Pierce, pick up the required life vests and a raft for the flight over. Fly out over Grand Bahama, then Abaco, then on down the islands, you are never far from land. Always be sure to call and ask if they actually have fuel, don’t just assume they do because it is on a chart. Be prepared to slow down, not be demanding, and relax on Bahamas time for awhile.

Andre, if it helps, I ran 71% power LOP in my 231 for years at cruise. Not only did it not hurt the engine, but the engine, which is otherwise notorious for running hot and needing new top overhauls periodically, made it to 2300 hrs, which is 500 over TBO. It was 20 years old so I just replaced it, we will see if the new engine likes LOP as much as the old one did. I liked that old engine, never let me down. Follow the GAMI guidance in my earlier post, it is directly out of their seminar materials. Don’t listen to the rest of the noise. Best of luck and fair winds.

The notion that it is necessary to reduce power to 60-65% to be safe for the engine when running LOP is an apparently widespread OWT. What the GAMI people actually teach is that if you keep the power at or under 65% you can run the engine anywhere you want, whether ROP, LOP or directly at peak. That is because the Internal Cylinder Pressure at 65% is low enough at any power setting that it will not harm the cylinders. It is no more “unsafe” to run at 70 or 75% LOP than ROP so long as you run LOP enough, or ROP enough. And unless in very cold weather conditions you can generally determine if you are far enough ROP or LOP by cylinder temps, if they are at or under 380 dF you are good. The problem in a normally aspirated engine with trying to run, say, 75% LOP, is generally that you can’t generate sufficient manifold pressure at cruise altitude. The problem in a turbo is that temps, particularly Turbine Inlet Temp, will rise too high in the higher altitudes, because the air is thin and does not cool well and because the turbo is having to work harder to keep the manifold pressure high enough. At 70% power the GAMI people suggest running at least 125 ROP or 20 LOP. At 75% at least 175 ROP or 40 LOP, and 40 LOP is about as far as most engines can go without running rough, some less than that. I have used their 70% guidance in my turbo 360 for some time with nothing but good results. All this assumes that you are following their guidance to use a good engine monitor that reads out the EGTs of each of the multiple cylinders, so that the cylinder closest to peak is the one that is used to measure degrees ROP or LOP.

Hey, Merry Christmas everyone. We can argue about engine management again tomorrow, today is a day for rest, good cheer and a little egg nog.

You should see the airfield, esp. on a Saturday morning in the summer. Beehive. Can't sit on the runway while you make decisions or they will have five go-arounds from behind you.

OK, I have heard that name also.

I have a completely different and more manual setup, but maybe it gives me the perspective to answer what is going on. I have a KFC200, which is capable of coupling to a GS in APR mode, but not capable of using VNAV to make a descent. I have to do that manually. I also have a GTN750 Xi that controls the AP, and a standby 430 that used to control the AP buts no longer does (it is not connected to the AP by any means). (Before the 750 was installed, the 430 would Autoswitch, and now, apparently because I don’t have a G500, CDI switching must be manual.) So think about what the GTN and AP are doing when you switch into APR mode to fly an ILS. The control signal for a GPS approach (or any other GPS direction) is a digital signal from the GPS computer. The ILS is analog. It comes from the Nav radio in the 750, not from the GPS brain. So when you switch from RNAV mode to APR, you switch off the digital signal and switch on the analog signal from the localizer. You would not want the digital signal from the GPS to control any longer, because you would have two potentially conflicting control signals operating at the same time. At any rate, and I would have to go back and check the regs, but I am pretty sure they prohibit using the GPS signal to legally fly an ILS, so Garmin does not have a choice, the AP has to use the analog signal. What I do to make a FAF intercept altitude, if it is lower than the FAF, is to simply use the trim switch on my AP to make the descent. The way my AP works, this has the advantage of acting as a “dead man’s” switch, so if I take my finger off it, it holds altitude at that point rather than diving lower while my attention is distracted by something else going on. Or I use the lazy pilot route and just let the AP couple to the GS at the higher altitude and fly down to the FAF.

Or out of someplace else? When you run at 75 vs. 65 you are increasing the pressure inside the engine, which is vented through the breather. That pressure can push the oil out pretty much anywhere there is an exit. Do you have oil on the belly? Have you checked the quick drain, or the rocker covers? Sure, it could be something internal to the cylinders but that is not the only possibility. Had the same sort of problem when I first got my 231, turned out the quick drain was not sealing. Got rid of that problem, and the engine went from a quart an hour to a quart every oil change at 25-35 hrs.

Can’t help you with a seaplane, but about a decade ago I was at a resort in the Bahamas and had dinner with two pilots from Germany. They had rented a land plane in FL. As I recall, there was some minimum daily mileage they had to put on the plane, so every day they would fly out to a new island and explore. Have not done it myself (I have flown my own plane over there a number of times). Here is a thread I found with several rental places mentioned. https://www.euroga.org/forums/flying/11431-aircraft-rental-in-florida-or-bahamas Remember there are tides in the Bahamas, so you can’t plan on just pulling up to an island and hopping out for a few hours. Depending on the island, the locals might also recommend you not leave the plane unattended.

University of North Dakota is one of the best in the country. On a par with Embrey. Minnesota State University at Mankato has built up an excellent aviation program but not yet on a par with Embrey and UND. Did not go to an aviation school myself, but talking to many who did, UND and Embrey are the two names always mentioned as being the top, and I don’t know who else would be in that league.

COVID may have gotten the company, I know they were around in 2021.

Are you sure Merlyn Products is out of business? I haven’t tried to contact them and we haven’t needed any parts, but they look alive to me - https://www.merlynproducts.com/magicprofiles.html

The Merlyn is the only one. It is marketed as “automatic” but more aptly termed manual. It does not maintain MP at a set number, the pilot must do that. I have the Merlyn. You will experience a slight MP rise on takeoff as the plane picks up speed, an inch or less. You will need to reduce MP very slightly (or start off a little lower than max). It probably would be helpful toward the end of controlling MP if you only have the fixed wastegate. The Merlyn does two things. First, it controls bootstrapping, which increases MP simply because the engine is putting out more power. That would help with controlling MP on takeoff, although it does not completely contain the problem. Two, it is capable of fully closing, unlike the fixed wastegate that is always partly open. This increases the critical altitude by quite a bit, from about 15k to about 22,5k. However, if you do not also have the intercooler you will likely see the Compressor Discharge Temp reach redline somewhere in the range of 17-19k (depends on day temps) so not much CA gain without the intercooler.

I don’t switch tanks frequently at cruise. My tank switching strategy is driven in part by the accuracy (or lack thereof) of my instruments, and partly by the fact that the plane does not care how far out of balance the tanks might get, it does not slow down or become hard to maneuver, it just ignores any imbalance. On the ground prior to takeoff, I switch tank three times. I use the fullest tank on startup and on the ramp. I switch tanks to taxi. Then at the hold short I switch back to the fullest tank for the run up and takeoff. This method insures that I have good fuel in both tanks. I have never experienced water in the fuel in my 231, but sure saw it in a rental J with bad cap O-rings several years ago. Then I fly on the fullest tank for the entire climb, however long that might be. If I go into the flight levels it can be as long as 45 minutes. Once I level off, or if the climb is shorter, when I have used about 10 gallons from the first tank, I switch to the second tank and run on that tank for the next couple of hours. My JPI930 annunciates Low Fuel when a tank reaches 10 gallons, and then there is not way to stop it from showing Low Fuel even when the other tank is full, so I will run the first cruise tank down to just above the 10 gallon mark and then switch. Alternatively, if I am nearing my destination and it is time to begin the descent I will switch tanks for the descent and landing. That way, if something goes wrong with that tank, I know I have another tank with a good ten gallons to make it to the airport. I use fuel flow to track how much fuel I have, at least on a long trip of a few hours. If I am able to cruise LOP at 11.1-.3 GPH my 75.6 gallons of full fuel is good for around 6 and a half hours, way more than I have ever needed. The on-board bladder(s) can never make it that far. I make a little chart on paper with 37.6 at the top of two columns and then when I switch tanks I get the fuel USD from the 930 and subtract that from the tank, so I know exactly what is left in that tank. I don’t switch frequently because (1) as I said, the plane does not care, and (2) makes it too complicated to track fuel usage. KISS works best. I have CiES senders and a JPI 930 so you would think that the fuel gauges would be a great way to track fuel. The senders are certainly better than the old senders, but not so accurate that they beat the fuel flow meter for tracking usage and fuel remaining. Before I started using fuel flow, I tested by flying three consecutive flights of a couple hours, then refilling the tanks myself, to test the fuel flow. Total fuel used was around 50 gallons and the fuel flow meter was .1 gallon off on the conservative side. In other words, I have tested my systems and know which one is more accurate, and then used that to create a really simple method for use in the cockpit that does not require remembering to switch frequently, or to set timers. I don’t run tanks dry as a matter of course. High altitude restart, according to the POH, may not be simple. The engine may simply not restart until below 12k, if then, because the turbo is not spinning and MP will be very low. I don’t want to ever deal with that, so no tank emptying. I have at lower altitudes emptied a tank out and quickly switched. It is worth doing so you know how much fuel your tanks really hold, as opposed to what is in the POH. You would be surprised.

Healthy spark is very important to LOP operations. The mixture is harder to ignite. Most people find that fine wires work best. If I fly a lot during a given year from one annual to the next, sometimes the engine’s LOP performance is not as smooth toward the end of the year, until the annual is done and the magnetos get a going over. Then all is good again.

Don’t forget, if you yank it, a new W&B may need to be created. That is one reason why stuff is sometimes left behind that is no longer needed (so the W&B does not have to be modified). The math is not that hard, but I believe it does require a sign off.

I follow my checklist. (I wrote it.) My checklist says to switch to the fullest tank for start up and the part of the checklist that I do on the ramp, then switch to the other tank for taxi and run-up, then switch back to the fullest tank for takeoff. Now, in addition to having sumped the tanks, I have verified that there is good fuel in both tanks. That way not only do I insure I have good fuel for takeoff, but I have also insured that I don’t get down range somewhere and over the middle of nowhere, and then change to an untested tank. I used the basic format for checklists that the school where I got my PPL uses for its Pipers, Warriors, Archers and Arrows and modified it for my 231.

You would be surprised. As I mentioned before, I have a new engine that I am just breaking in, so no LOP experiments for awhile. The old engine had a Delta of 85 degrees from hottest (#2) to coldest (#6) at cruise. I experimented quite a bit to find out if I had a fuel flow difference that could be causing that and could not see one. The real suspect was a wrinkle in the baffle above the #2 cylinder. Knowing the engine was going to be replaced I just put up with the Delta, as it turned out for more than 500 hours. The engine was retired at 2300 which is 500 over TBO for the old 231 engines. Guess which cylinder, predictably, was showing low compressions (the hot #2 of course). The Delta in the new engine is about 35 degrees. We replaced the baffling. One contributor to the large Delta was that #6 sits dead center in the “big hole” in front of the cowling in my 231. There are two holes of the same size of course, but the starboard hole is about 50% blocked by the induction air structure while the #6 is unblocked. Also, the new engine of course has a new fuel system (same old GAMIs) so there is no real way to know what caused the difference. But based on what I saw over the years, it appeared to be cooling and not fuel flow. Not suggesting your surmise is wrong, a fuel flow difference is where I would start looking also ( and did in my old engine) but a Delta that large due to cooling is possible I think.

Some thoughts. First a caveat, I don’t fly a Bravo, I fly a 231 which has a different engine, albeit a turbo. The power settings I may refer to in this post are not Bravo power settings. There seems to be some misunderstanding about leaning to peak EGT and leaning to peak TIT. The GAMI people teach - and it is true - that one should always lean to peak EGT. The reason is that in a multi-cylinder engine it is entirely possible that the fuel flows can be imbalanced between the cylinders, so one cylinder can be operating happily out of the red box while another is running in the box. That is why, in order to run LOP, it is always recommended to run lean tests on the engine first, to determine how balanced the fuel flows are, and if out of balance, to install GAMI’s to bring them within .5 GPH of each other. Once you have done that, and experimented with your power settings until you know what settings work and will give you balanced fuel flows, it does not matter any longer how you get there. I have not run a leaning operation on my engine in years, to determine which cylinder peaks first or last, but I almost always run LOP at cruise. To make my favorite LOP power setting, which is 34”/2450/11.1-.3 in my engine, I just put in the power setting and then I monitor TIT to keep it at or under 1600, with a slight allowance to rise up to 1610 so long as the rise is stable and the temp does not just keep rising on its own. But I am able to do that because I did the experiments, years ago, so I know with confidence what is going on with the individual cylinders. I can’t speak for Mike Busch, but when people with substantial experience with their engine talk about using TIT or doing the “big pull” (which I do to get to the lean side), they know what their engine is doing internally, and whatever indicator is easiest to use in the cockpit is the one they will use to manage the engine, whether that is TIT, or EGT, or something else (i.e. MP + FF). One recommendation I would make to the OP is that, unless you have an engine monitor that reads on each separate cylinder (sounds like you do not) you just should not experiment with LOP in that Bravo engine until you do (sounds like that is on the drawing boards). ROP will be as safer place to run the engine. There is some misunderstanding about the 1750 number. That is the redline limit, not a peak TIT. Actual peak TIT will vary depending on the power setting at which you do your leaning to find peak. In my engine, if I find peak at 28”/2450, that peak is going to be completely different than if I find peak at 32”/2450. The TIT limits in the POH are not there for the sake of the cylinders. They are there because of the metallurgy of the turbine. If the temp exceeds redline, the turbine blades become slightly malleable and can stretch because of the centrifugal force of the turbine. If they do that, they wear against the side walls and you will be needing a new turbine. There will always be some difference between the TIT, and the average temp of the EGTs. TIT will generally be hotter because there are secondary combustion events going on after the exhaust gas leaves the exhaust port (where EGT is measured) and before it gets to the turbo (where TIT is measured). So to summarize, TIT protects the turbine, not the cylinders, and actual temp of the gas at the turbine (which is different from temp at or in the cylinders) is used for that purpose.

You are correct, you can run at peak at 65% or lower. But I wasn’t thinking about low power settings. If you are trying to keep a cold engine warm in challenging low temps, depowering the engine to 65% just makes matters worse. The point I am making is that you want to run it hot, up around 75-80%. If you run at that HP and at peak (a “best power” setting per my POH) you are well into GAMI’s red box. Your point about not running at peak TIT is well taken. If you try to do that at 75% or better and at peak EGT, you will exceed TIT redline. I should say I have not tried that in the dead of winter. There is a definite cooling effect on the turbo and the TIT especially in the low altitudes. These settings are obviously different than what the OP would do in an E, or even what a pilot might do in the “big bore” Bravos and Acclaims. I don’t fly those and don’t have enough experience. My point though, is that you can choose to deliberately run the engine a little hot and bend some rules if you want to keep the CHTs and OT up in cold weather. In my engine the critical temp as I mentioned is the OT because it directly impacts the health of the turbine. So it is a matter of making some not-so-perfect choices. Run the engine colder than you should, or dip into the red box just a little to keep it warm. I dip into the red box a little, but not very far. Better than to damage the turbo. In an NA you might make a different choice. As far as the brake fluid is concerned, up here in MN we face a doubly whammy, icy runways and taxiways and very cold brakes. The brakes get very stiff in below zero temps, better to warm the fluid. Critical, however, to warm the air/oil separator.

I live in MN and I have a 231 (turbo). When the temps are below freezing it is important first, to keep the cowl flaps closed even on the ground and second, to run the engine for awhile on the tarmac with the cowl flaps closed to warm the engine compartment. (Does an E have cowl flaps?) There are components that work better and/or won't work at all unless they are heated to above freezing. Without going into all the detail, I once had the air/oil separator freeze resulting in oil blowing out of any available orifice in the engine because I failed to warm the engine compartment. Now if it is below freezing, and especially below 20 dF, I warm the engine compartment and have not had the problem again. Remember that your brake master cylinder is not heated either and it probably appreciates working with unfrozen brake fluid. If you think that is a joke or not possible, you should try flying when it is in the -20 dF range or worse, which we sometimes get here in the dead of winter. Our record low here in MN is -60 dF and it happened in my lifetime. I have had people jump in and say never run the engine with the cowl flaps closed on the ground, it will cause hot spots. I think they live on the east coast and "cold" is when you have to put on a sweater. When it is in the very cold range, from +20dF on down, you need all the heat you can get, never mind any theoretical hot spots. I also keep the cowl flaps closed in a climb during the winter cold so long as the CHTs are in the 380 range and the TIT stays under control. My A&P made an "oil cooler block" for me years ago (actually two) , and it is about time to stuff one in the oil cooler. It is just stiff foam with tape around it that fits into the block. Very important in cold MN temps, it stays there all winter. There is a metal plate that can be installed as I understand it, but why do that when you can make one that works for next to nothing. There is a normal operating CHT temp range in the POH for my engine. It is 250-460 dF. (That 460 maximum is silly, the temps should be around 380 and even in a high hot climb, no higher than 420 and then only for a short duration). However, there is no redline minimum CHT. There is a normal oil temp range in the POH of 100-240 dF. Although the stated OT minimum is not a redline minimum it is important not to go below 100 in a turbo because that can rob the turbine bearing of lubrication. Not your problem though. I do everything I can to keep the CHTs in the normal operating range. But in my aircraft the front left cylinder sits right in the open cowling intake hole with no obstruction. The hole on the right side is partially obstructed by the induction air intake. The front left cylinder can be difficult to keep in the normal operating range. Although I like to run LOP, there are times in the winter when that results in CHTs that are too cool. If that happens I will go ROP and on occasion run as hot as 100 dF ROP. You could run right at peak (and there are peak settings in the POH) but the GAMI people teach that doing so is not good for the engine. They say that it is possible in very cold temps to have cool CHTs while running in the "red box," but you are overstressing the engine all the same because the peak pressure during combustion is just too high in the cylinders. So far as I am aware, there is no harm to the cylinders from running them under normal operating temperature. What I have read in researching the issue is that leading (lead deposits) becomes an issue, so I try to keep the cylinders warm. I have on a few occasions grit my teeth and run with the OT at 95 and the lowest CHT at 220. This typically happens when I am forced to stay at say 2,000 AGL (3,000 MSL around here) because the cooling capacity of the dense air at low altitude is too good. I don't like doing that, on the other hand the mythical shock cooling has never happened either. If you are concerned about that, Lyc recommends setting the RPMs as low as possible in order to keep engine power (and thus temperature) up. I think I might try that the next time I am stuck doing a low altitude flight in very cold weather. Altitude can be used to fight off excess cooling, but easier in my 231 than an NA. I have been in the -54 dF range in the flight levels where it was so cold the heater and defroster could not fight off the frost. All the windows frosted over and it was one of those rare times when I have logged actual instrument time even though it was CAVU outside the aircraft. However, the engine was perfectly happy. The cooling capacity of the air up high is poor, so the engine stays warm. I use that trick when I can - go high to keep the engine happy.