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Engine Break In and First Flight

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  • Engine Break In and First Flight

    Question for those of you that have installed a new/overhauled engine on you BH and had to break it in congruently with flight testing. I have the EAAs new flight test manual and I'm not sure it is possible to follow their recommendations while properly breaking in my fresh engine.

    So, how did you guys handle the first flight? What procedure did you develop or follow?

    The break procedure for my engine says for the first flight to takeoff normal, climb shallow then maintain level cruise at 75% power and best power mixture for 1 hour. Minimum safe altitude for me is 6500msl so I'm looking at WOT and max cruise rpm (2600) to even get close to 75% power. I'm not too thrilled about flying circles around my airport at 1500agl and max cruise speed for an hour in a untested air frame. I'm sure the controllers in the tower won't be too thrilled about it either.

    I know lots of guys have been through this exact thing before so I'm really interested to see how you handled it.
    Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

  • #2
    Whee, we did the same as what your saying you should do. Having a new to me electronic display made matters a bit overwhelming. I would find the nearest non towered airport and fly over it for an hour. We flew a circuit between two non towered airports and checked out some things like flight stability while doing that. Don't worry too much about all the other stuff, that hour will go by a lot faster than you think and there will be plenty of opportunity to finish all necessary flight testing. Keep in mind not all things that are going to fail, fail immediately. Over time vibrations take their toll as well as hard landings and so on, so post and preflight inspections are really important. Breaking the engine in properly the first time is also really important. I believe the first 15 minutes is as important, so keep your ground runs to a minimum. As far as my first flight and actually every flight since, I always say if I can get back on the ground with everything I left with, it was a good flight. ;-) I'm sure your workmanship is above and beyond, so have confidence in it. I'm pretty sure it won't come apart. Good luck and have fun with it. Trust me, you won't be able to wipe that smile off your face!!!

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    • #3
      Whee, I know those are the recommendations of engine manufacturers and overhaulers. I like to make a short 10-15 minute flight first. Then land to de cowl and check all fuel and oil lines etc for leaking. Then I feel more confident to go up and spend an hour circling the airport. The controllers will be OK with what you want to do on a first flight of your plane. Mark

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      • #4
        Thanks Mark and Donna!
        Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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        • #5
          Whee, this is still fresh in my mind, having done my 1st flight last November.
          I also had to deal with a freshly OH engine, bolt-on to a untested air frame…In my case, I did stay within reach of the airfield for flight 1 to 4. Made arrangement with the controller prior to the 1st flight and the game plan was to circle the airfield at 1000ft above circuit altitude.
          I’ve run my engine harder than what you’ve suggested. I’ve read a lot about that, and there is a lot of different approaches suggested by different eng mfg. In my case, I ran the engine between 75 % to 100 % for the 1st hour, cycling from one setting to another every 5 minutes or so. Everyone agreed that CHT should be kept as low as practical. In my case, OAT was below freezing level, so my CHT never exceeded 380.
          One critical thing that you haven’t mentioned in your post is: Ground runs prior to 1st flight.
          I suggest to read an extract from Russel Mahlon on that subject. He also suggest a run-in schedule prior to the 1st flight. The take away form that is never exceed 350F CHT during any ground operation. Lack of cooling on the ground will glaze the cylinder walls and prevent actual break in from occurring during you actual flight runs. In my case, I’ve limited my CHT on the ground to 320 F.

          One observation as well about Brake Break-in…It took me 3 ground runs (following the brake mfg break-in procedure) in order to achieve reasonable braking action. So plan for some level of ground runs prior to the 1stflight.
          Good luck
          Mike
          -----------------------------------------------------

          Hope this helps!This is how I would do the initial runs. I have used this procedure thousands of times with complete success.
          Good luck,
          Mahlon

          CYLINDER RUN-IN INSTRUCTIONS FOR CHANNEL CHROME,
          CERMICROME, AND CERMINIL BARRELS

          1] Install mineral oil in ALL normally aspirated engines and all Teledyne Continental turbocharged engines. Install AD oil in all Textron Lycoming turbo charged engines.

          2] Start engine, run at 800 R.P.M.'s for three (3) minutes, shut down, check for leaks.

          3] Start engine, run at 1,000 R.P.M.'s for three (3) minutes, shut down, check for leaks.

          4] Cowl aircraft.

          5] Start engine, run at 1,200 R.P.M.'s for three (3) minutes, shut down, park into wind.

          6] Start engine, run at 1,400 R.P.M.'s for three (3) minutes, shut down, park into wind.

          7] Start engine, run at 1,400 R.P.M.'s for five (5) minutes, run up to full power, check all engine parameters, retard power to 1,000 R.P.M. for one (1) minute, shut down.

          8] Check for leaks The engine has now had it's Test Cell run time and is ready for other ground runs, taxi tests, adjustment runs, etc., observing the precautions from the post

          All runs should be made into the wind.

          At no time during these runs should CHT exceed 350F.

          Between all engine runs, allow adequate cool off time.

          Before proceeding to next run, you should be able to hold your hand on a rear cylinder head for three to five seconds.

          CYLINDER RUN-IN FOR STEEL,
          NITRIDED OR REBARRELED CYLINDERS

          1] Install mineral oil in the engine.

          2] Start engine, run at 800 R.P.M.'s for three (3) minutes, shut down, check for leaks.

          3] Start engine, run at 1,000 R.P.M.'s for three (3) minutes, shut down, check for leaks.

          4] Cowl aircraft.

          5] Start engine, run at 1,200 R.P.M.'s for three (3) minutes, shut down, park into the wind.

          6] Start engine, run at 1,400 R.P.M.'s for five (5) minutes, shut down, park into wind.

          7] Start engine, run at 1,400 R.P.M.'s for ten minutes, shut down, park into wind.

          8] Start engine, run at 1,400 R.P.M.'s for five (5) minutes, run up to full power, check all engine parameters, retard power to 1,000 R.P.M. for one (1) minute, shut down.

          9] Check for leaks The engine has now had it's Test Cell run time and is ready for other ground runs, taxi tests, adjustment runs, etc., observing the precautions from the post

          All runs should be made into the wind.

          At no time during these runs should CHT exceed 350F.

          Between all engine runs, allow adequate cool off time.

          Before proceeding to next run, you should be able to hold your hand on a rear cylinder head for three to five seconds.

          This is some information on running after completing the above schedule:
          Knowing this crucial information allows us to make practical decisions regarding ground runs and flight profiles from the new or newly overhauled engine point of view.
          To put it simply, if we get the ring to cylinder interface too hot from too hard of running, lack of cooling or another reason we will glaze the cylinder walls and prevent actual break in from occurring. Because, we are dealing with multiple independent cylinders on the engine, these conditions can happen to one cylinder, all cylinders or anything in between on the same engine. So our job above all other aspect of engine operation during the break in phase, is to keep the cylinder's as cool as possible. If we do this we will not have any problems or issues with the engine as far as break in goes. During any and all ground runs we should limit the duration and actual temps we encounter to prevent glazing from happening. We tell our customers to keep all ground runs less than 10 minutes. Don't run the engine above 2000 RPM unless you are doing a momentary full power check, high speed taxi tests or actual take off runs. If the CHT goes above 350*F or the oil temp goes above 180*F at any point during the 10 minute max. duration ground run, or at the expiration of the ten minute time limit, that run should be terminated. Then, park the aircraft faced into the wind and allow the engine to cool, until you can place your hand on the cylinder heads and barrels for 5 seconds without hurting or burning you hand and the cylinders feel relatively cool to the touch. After the engine has cooled, continue with the last run where you left off. Obviously, from what we have learned about temperature, running the engine more conservatively will not cause any problems and may even help the break in process but operating within these restrictions, on the ground, should prevent any glazing issues. These limitations apply to an engine that has had a test cell run before any ground runs are attempted. If your engine hasn't had any test cell time, then I can supply you with a ground run schedule, to replace the test cell run, which can be performed on the aircraft. If you want or need that information, just email me privately and I would be happy to send it along.
          When it comes time to fly the aircraft, once again we want to observe the ground run rules, for taxi and warm up. Once we are ready to fly, we want to use full power for take off and initial climb and then we want to reduce power to climb power(normally around 85%) until we reach a safe altitude above the airport. Keep the climbs, as flat as possible, to maintain as much cooling as possible. Remember that heat is our major enemy and we can control that with climb speed. After establishing an appropriate altitude, reduce power to 65% to 75% ( preferably 75 % if speed restrictions will allow it). If we see temps, exceeding 15% of our ground run limitations, in initial flights, we should reduce power to control those temps and land the aircraft. Then, double check all cooling associated equipment, repair as necessary if you find a defect, let the engine cool off and fly it again, taking up from where you left off, observing the same restrictions. The first flight shouldn't be any longer than 10 or 15 minutes maximum, even with good cooling that would allow a longer flight. The first flight is a "test flight" and after landing you should do a through visual inspection of the engine and its installation, for leaks and any other operational issues like interference fits that showed up under power, chafing of lines etc. After the first flight issues are checked, we are ready for further flights under the same ground run and flight restriction's we have been observing. The key issue once again is heat. If we control the heat by power setting, airspeed, step climbing or any other means at our disposal we will not glaze the cylinders and we will successfully break the engine in. If we operate the engine at too low of a power setting, to seat the rings, we will not harm the engine or the eventual break in process, unless we develop enough heat to glaze the cylinders. In another words, operation at a low power setting, isn't a deterrent for break in unless we have the heat
          .

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          • #6
            I wasn't too concerned about cylinder break-in until attending MIke Busch's webinar Breaking Good last week. His take on it is keep idling and ground running to an absolute minimum. Once in the air fly at as close to 100% power as possible while keeping cylinder head temps below 420 for Lycomings and 380 for Continentals. Use mineral oil or AD oil without any anti-scuff additives. Multiviscosity oil is OK. He said if you can fly 60 min at a time and ideally no higher than 2000' ASL. With steel cylinders the majority of the break-in should occur within two hours, break in is indicated by drop of 15-20 deg in cylinder head temps. This doesn't work for me on many levels. For one thing our airport is at 6500'. I am only 50 miles from Western Skyways in Montrose and I know they have an engine test cell. I am going to call them and see what they would charge to put a couple hours on the engine at full power to get the break in started before I install it.

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            • #7
              Thanks Mike. Lots of good information there. I have followed Continentals ground run procedure which is somewhat similar to what you posted. Because of some valve noise and a fuel pump failure I have one or two more ground runs that need to be completed.

              Continentals 75% power break in procedure is close enough to everything else I've read and know from personal experience that I'll likely stick to it as close as possible. I may break it into two 30min flights depending.

              Rod, Thanks for posting about Mike Busch's webinar. I typically listen to all of them but have gotten behind. I'll make it a point to listen to his most recent one. My airport (4740msl) isn't as high as yours but it is still high enough that making more than 75% power will be difficult while maintaining a safe flight altitude. I think running the engine in a test cell would be a great option.
              Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

              Comment


              • #8
                Whee,

                Sometimes A&P schools have test cells that if you went in and talked to them, they would let you run it...it gives the students and opportunity to see new stuff and you would have hand to help hang and run it.

                This was back in 1990, but I went to A&P school in Cheyenne (now Redstone college out of Broomfield Colorado). We ran a number of engines for homebuilders to check for leaks, break-ins and trimming and rigging everything from the props to the mags.

                Just a thought...

                Andy

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                • #9
                  It's unfortunately not possible to comply with the ideal break in and an ideal flight test simultaneously. For me I selected a compromise that most heavily favored the flight test, being that the engine served no purpose if I wrecked the airplane. One builder told me that his engine supplier would do the break in on a stand for an extra $1000, so there's one data point. If I were in the same position today and found a similar offer, I'd definitely consider it.

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                  • #10
                    Unless the pattern is empty a traffic pattern can take about up to 8-10 minutes, the hour is eight laps or so around the airfield. The hour will go by really fast, mine certainly did! It will feel like there are a thousand things you need to pay attention to, but to side with Jared you don't want to wreck the airplane. I suggest planning on flying full throttle as much as you feel safe doing so. And try to reduce all the other distractions. For example, if you have an EFIS with an EMS it will record your engine data for you, nothing needs to be written down. If you are not familiar with a glass cockpit most will be set to display a standard six instrument configuration.

                    Good luck, you will have great time!
                    Scott Ahrens
                    Bearhawk Patrol Plans Built
                    #254

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                    • #11
                      I have been thinking about this same thing, and it seems that running an untested airplane up near VNE on its first flights might not be my first choice. Not a problem on a 180 hp 4 place, but it could be a big issue on a 540 powered BH, or a 390 Patrol. I would rather work my way up the airspeed ladder, slowly, and feel for vibration etc.

                      The last sentence of Aero-Tango's post said operation at a lower power setting is not detrimental to break-in. Most of the other things I have read said to run at or above 75%.

                      Conflicting information. I would much rather operate my rebuilt 540 at a much lower power setting, not for the engines sake, but for the airplane, and me.
                      Last edited by svyolo; 02-12-2019, 09:51 PM. Reason: This can't be a new issue. I can't believe a guy on his first flight in an RV-8 would want to tear around at 208 mph.

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                      • Aero_tango
                        Aero_tango commented
                        Editing a comment
                        No I’m not the author of the bold text in my post. This is from Russel Mahlon. He was, I think, product manager at Mattituck engine. He contributes a lot to the VAF forum, very well respected.
                        What Russ is explaining in is write-up, and the meaning of the last sentence is if you run the engine at low power setting (ground run as an example), it will not harm the eventual break-in process, as long as you keep the CHT low, and thus prevent glazing. If glazing happens, you’ll never be able to breakin your engine properly.

                    • #12
                      Most light aircraft normally fly around at 65-75%. It is no big deal to break a new engine in at 75% for them. I guess I am wondering how important the power setting is. I wouldn't care if the break-in took longer.

                      I am pretty sure an RV-8 wouldn't want to fly around at 205 mph for the airplanes first hour of flight either. This can't be a new issue.

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                      • #13
                        Originally posted by svyolo View Post
                        Most light aircraft normally fly around at 65-75%. It is no big deal to break a new engine in at 75% for them. I guess I am wondering how important the power setting is. I wouldn't care if the break-in took longer.

                        I am pretty sure an RV-8 wouldn't want to fly around at 205 mph for the airplanes first hour of flight either. This can't be a new issue.
                        I haven't watched Mike Busch's EAA webinar yet but no doubt he covers why the power setting is important. Simply put, it takes high cylinder pressure to properly seat the rings and high power settings are required to achieve those high cylinder pressures. I venture a guess that many engines aren't broke in properly but the owners never really know the difference. Typical airplane owners fly their airplanes so little that the engines die prematurely due to lack of use or operator abuse. High oil consumption is commonly found on aircraft engines and is generally accepted as the norm.

                        https://video.eaa.org/detail/videos/...autoStart=true
                        Scratch Built 4-place Bearhawk. Continental IO-360, 88” C203 McCauley prop.

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                        • #14
                          Yeah, I have read and reread a bunch of articles that say the exact same thing. Aero-Tango's post (I don't know if he was the author) at the bottom said lower power won't hurt anything as long as the CHT's are under control. That is the first time I read that.

                          I would like to at least get an hour or two to slowly increase the speed to make sure I don't feel any bad vibrations, and just get a feel for the airplane. I know that won't help break the engine in. I was just hoping it won't glaze the cylinders or keep the rings from seating. After a couple of hours, I will do the prescribed break in.

                          VAF has a bunch of old threads on break in. A few of them mention flying a new airplane around at high speeds on the first flights, but they don't expand on it much. Lycoming and Continentals also only talk about the engine aspects. They obviously are not concerned with an experimental aircrafts' first couple of flights.

                          I wish I had more tailwheel experience. I would just put 29's on for the first flight and I think the extra drag would address my concerns.


                          Last edited by svyolo; 02-13-2019, 12:38 AM.

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                          • #15
                            I’m going to take mine to Alaska Aircraft Engines and pay them to break it in. They will run it in their test cell. The last thing that I want to do is fly an aircraft that is brand new at 75% or more of available power of a brand new six cylinder fuel-injected IO-540 engine for 60-90 minutes, screaming along at 125kts plus. Too many things going on at the same time.
                            Last edited by alaskabearhawk; 02-13-2019, 02:24 AM.

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