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The best way to run-in an engine
Like the title shows, what is the best way to run-in an engine? Some said that you have to let it run for 1 minute full-throtle, and the other one says you have to build it up, every tank some more gas. I would like to hear the best way to run in an O.S. 46AX.
Thanks, Tom |
RE: The best way to run-in an engine
Tom,
I've had a few of the OS46AX engines and always did exactly what the manual says and all are still running to this day. The first one was sold to another club member and has well over 800 flights on it and still fires right up and makes great power. It's whole life has been using Byrons 15/20 fuel. In fact all my OS engines get that fuel. The other as far as I know are also still running |
RE: The best way to run-in an engine
Flightom,
The best way to break in any engine is to follow the procedures that are set out in the manual that came with that engine. If you don't have the manual for some reason you can find it at [link=http://www.osengines.com]OS engine website.[/link] Here is a cut and paste of the break-in procedure from the OS 46 AX manual RUNNING-IN (Breaking-in) All internal-combustion engines benefit from extra care when they are run for the first few timesknown as running-in or breaking-in. This allows the working parts to mate together under load at operating temperature. Therefore, it is vitally important to complete the break-in before allowing the engine to run continuously at high speed and before finalizing carburetor adjustments. However, because O.S. engines are produced with the aid of the finest modern precision machinery and from the best and most suitable materials, only a short and simple running-in procedure is called for and can be carried out with the engine installed in the model. The process is as follows. Install the engine with the propeller intended for your model. Open the needle-valve to the advised starting setting and start the engine. If the engine stops when the glow plug battery disconnected, open the needle-valve to the point where the engine does not stop.Run the engine for one minute with the throttle fully open, but with the needlevalve adjusted for rich, slow "four-cycle"operation. Now close the needle-valve until the engine speeds up to "two-cycle"operation and allow it to run for about 10 seconds, then reopen the needlevalve to bring the engine back to "fourcycle" operation and run it for another 10 seconds. Repeat this procedure until the fuel tank is empty. Re-start and adjust the needle-valve so that the engine just breaks into "two-cycle" from "fourcycle" operation, then make three or four flights, avoiding successive "nose-up" flights. During subsequent flights, the needle-valve can be gradually closed to give more power. However, if the engine shows signs of running too lean, the next flight should be set rich. After a total of ten to fifteen flights, the engine should run continuously, on its optimum needle-valve setting, without loss of power as it warms up. After the completion of the running-in adjust the carburetor at optimum setting referring to MIXTURE CONTROL VALVE ADJUSTMENT section and SUBSEQUENT READJUSTMENT section. Slowly advance the throttle to its fully open position, then gradually close the needle-valve until the exhaust note begins to change. (4-cycle to 2-cycle) At this point, disconnect the battery from the glowplug, taking care that the battery leads or glowplug clip do not come into contact with the rotating propeller. If the engine stops when the battery is disconnected, close the needle-valve about 30° and restart. As the needle-valve is closed slowly and gradually, the engine r.p.m. will increase and a continuous highpitched exhaust note, only, will be heard. Close the needle-valve 10-15° and wait for the change of r.p.m. After the engine r.p.m. increases turn the needlevalve another 10-15° and wait for the next change of r.p.m. As the speed of the engine does not instantly change with needle-valve readjustment, small movements, with pauses between, are necessary to arrive at the optimum setting. Ken |
RE: The best way to run-in an engine
Thank you! But how can you hear (?) the 'fourcircle' and the 'twocircle'?
Tom |
RE: The best way to run-in an engine
You will know it when you hear it. The 4 cycle will sound like it is firing intermittently at every second revolution while the 2 stroke will fire more steady at every revolution. :D
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RE: The best way to run-in an engine
You need to run it for 12 hours straight with low nitro - High oil fuel, while standing on one foot and swinging a chicken over your head.
Personally, I never go for all of that stuff. Run it very rich at half throttle for a tankfull, then lean it out but leave it a few clicks rich and fly it. After 3 or 4 flights, tweak it up and fly the heck out of it. Never had one fail yet (And I've been doing this for a while) |
RE: The best way to run-in an engine
For sport flying and such, follow the instructions as you see them. Or use Minn's method. :)
For getting the absolute max power out of an engine, there are "better" ways to do it. But unless you are racing or something, it's not worth the trouble, and you should follow those instructions. The reason for the difference comes from the ABC (or ABN, same thing) construction. Basically, ABC engines have a tight piston/liner fit at top-dead-center (TDC) when cold but losen up to the proper fit when they heat up. When you run the engine rich or cold, you're wearing the piston down faster than you need to, and making the fit looser than it has to be, reducing power. (by a small amount). So with an ABC engine, you want to get it to proper teperature as fast as you can. However, that conflicts with the other purpose of breaking in an engine, getting the connecting rod/crank/wristpin/bearings etc to all seat correctly. You want extra oil on those parts when they are new to avoid having something seize up and break. And finally, the casting and maching process of engine parts leaves internal stresses in the metals. The first few runs should relieve all those stresses. The best way to do that is with a temperature cycle, ie warm up the engine, cool it down, warm it back up, etc. So, if you talk to guys who are out to get every last RPM from an engine, you'll find they have some different break-in procedures that can result in measureable performance gains. But it's pointless for 99% of the guys out there, so don't worry about it. Oh, ringed engines also break in a little differently than ABC engines. For a ringed engine, you want to keep it colder and run it nice and rich for a longer period of time than for an ABC engine. But you don't need to worry about that here either. |
RE: The best way to run-in an engine
ORIGINAL: MinnFlyer You need to run it for 12 hours straight with low nitro - High oil fuel, while standing on one foot and swinging a chicken over your head. Personally, I never go for all of that stuff. Run it very rich at half throttle for a tankfull, then lean it out but leave it a few clicks rich and fly it. After 3 or 4 flights, tweak it up and fly the heck out of it. Never had one fail yet (And I've been doing this for a while) Dauntae |
RE: The best way to run-in an engine
Ooops, sorry, my mistake. Using a chicken will result in 3 less RPM... But you get breakfast with it :D
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RE: The best way to run-in an engine
I have a new OS 46AX and a Thunder Tiger Pro 46. Similar engines and have spent a LOT of time with them both on the test stand trying to "dial" them in to peak performance. I have only been doing this for about 6 months so far and have really, REALLY tried to find that "point" where everyone says it breaks from 4-cycle to 2-cycle and quite frankly, I simply have not heard it yet. I have sat there one day just practicing and shutting my eyes and SLOWLY leaning it in to see if I could hear some kind of change, and the ONLY change that my ear can detect is the RPM decrease. I KNOW that sound and once I hit it, I back off several clicks just as I should be.
Does anyone have any wav files they could share with us with a distinct transition from 2 to 4 cycle? |
RE: The best way to run-in an engine
Cisco Kid,, i don't have a 46AX , but i do have a TTpro46, so to get to hear the 4 stroke firing mentioned , start your engine, open the throttle fully , now start to open the needle valve bit by bit until you hear a drop in engine rpm. While standing behind the engine , you should start to feel the cold unburnt fuel coming out of the exhaust, along with an increase in the exhaust oil, Now at this point you should hear that the engine isn't running sweetly, but is in fact running very rough, that is the 4 stroke point, to get back to 2 stroke running wind the needle valve in slowly, an eighth of a turn at a time until the engine peaks out at full revs, then open just a couple of clicks and go fly.
Bill form down-under in Australia. |
RE: The best way to run-in an engine
ORIGINAL: Cisco-Kid and SLOWLY leaning it in to see if I could hear some kind of change |
RE: The best way to run-in an engine
MinnFlyer, what breed of chicken is best to use , and what weight should it be? Down -under where i am we may have different breeds , so the weight factor might be critical. All information will be of great help in this lesson.
Thankyou , Bill from down-under in Australia |
RE: The best way to run-in an engine
I've used the following on OS 46's (three of them), OS 50, OS 60, Super Tigre 75, Evo 100, and Evo 40. All the same as far I can tell and all run just fine.
Fuel up, start the engine, let it warm up about 30 seconds, go to full throttle, rich it till it starts to 'four stroke', smokes like hell, run for 60 minutes CROSS THAT OUT.. make it 60 SECONDS.. (edited by DS) at full, close the needle to run leaner for about 10 seconds, go back to rich and shut it down. Wait about 5 minutes and recycle as above. Do this for two or three tanks and go to the field and forget about it. If you baby it, it will run lousy. Break it in as you would fly it, but do it a tad rich. Once 'broken in', refuel, start the engine, let it idle a few moments then remove the glow driver. Go to full throttle and listen to the engine. Momentarilly pinch the fuel feed from the tank to the needle valve (if rear mounted needle valve). The engine should accellerate a couple hundred RPM. Pinch means just squeeze the fuel line tightly then release it right away. If the engine does not increase in RPM, it is to rich. If it starts to die, it's to lean. Adjust the needle valve a little bit at a time until you hear that slight increase in RPM when pinching the fuel line. If you get it there, it's pretty much ready to fly. I've tried the chicken trick, but what works best in New Jersey is the cat toy mouse, the one with the leather tail.[X(] DS. |
RE: The best way to run-in an engine
ORIGINAL: Dauntae ORIGINAL: MinnFlyer You need to run it for 12 hours straight with low nitro - High oil fuel, while standing on one foot and swinging a chicken over your head. Personally, I never go for all of that stuff. Run it very rich at half throttle for a tankfull, then lean it out but leave it a few clicks rich and fly it. After 3 or 4 flights, tweak it up and fly the heck out of it. Never had one fail yet (And I've been doing this for a while) Dauntae |
RE: The best way to run-in an engine
ORIGINAL: CGRetired I've used the following on OS 46's (three of them), OS 50, OS 60, Super Tigre 75, Evo 100, and Evo 40. All the same as far I can tell and all run just fine. Fuel up, start the engine, let it warm up about 30 seconds, go to full throttle, rich it till it starts to 'four stroke', smokes like hell, run for 60 minutes at full, close the needle to run leaner for about 10 seconds, go back to rich and shut it down. Wait about 5 minutes and recycle as above. Do this for two or three tanks and go to the field and forget about it. If you baby it, it will run lousy. Break it in as you would fly it, but do it a tad rich. DS. |
RE: The best way to run-in an engine
OOps....yeah, 60 seconds... sorry about that. Must be that chicken.
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RE: The best way to run-in an engine
my dad was an old school mechanic that worked on rolls royce p 51 d engines in world war 2 and diesal and all types of gas engines as a mechanic for 35 yrs at a dodge dealership and he told me once how to break a engine in a car was to run it at different throttle settings ie50mph then 30 mph for 5 or ten mins each time til it had about 100 moles on it then drive it normaly for next 500 miles not drag racing style but then he went on to say if u had a lead foot just floor it its gonna break any way u drive it so it wont matter anyway ur engines will always be in the shop a very wise no nonsence man i think
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RE: The best way to run-in an engine
my dad used to look into the engine exaust and of it was yellow it was too lean if it was orange it was about right cant do that now though
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RE: The best way to run-in an engine
treedog,
Keep in mind that large gasoline engines and small glow engines break in totally differnetly. The procedures that are right for one can kill the other. Different fuels, different lubircation systems, differnet metalurgy (sp), differnet method of making compression (ringed vs abc), differnet operating RPM, different temperaturs, differnet bearings (larger gas engines ususally use bearings in the conrod ends, while small glow engines use bronze bushings), the list is endless. |
RE: The best way to run-in an engine
Another engine/prop question: If I have an 46 AX, what is the best prop size, and what diameter of spinner do I need? I thought about an 10x6 propellor, with an 50 mm spinner. Is this alright?
Tom |
RE: The best way to run-in an engine
Btw, the break from 2-stroke to 4-stroke running as you change the mixture isn't an "all at once" thing for most engines. If you start from the lean side, you'll go from a "clean", constant sounding whine to starting to hear a little "roughness" or scattered low rumble coming from the engine, then as you richen more, the whine goes away and the exhast note changes.
If you tach the engine as you richen it, you can see it go through the transition. If the tach reacts fast enough, you'll see the engine hold a constant rpm when leaned out. Then richen a little and pause. The engine will against settle on a lower, but constant RPM. As you richen further, many engines will get to a point where the rpm is jumping all over the place. What's happening is that the engine is 4-stroking for a few revolutions, then 2-stroking, then back. Some engines that I've seen will jump back and forth as much as 2,000rpm during this period. Then, if you richen the engine more, the rpm will settle back down. Note, some engines won't show this much. It depends on the carb design and other things. Oh, you also hear the transition a lot more clearly if you put on a smaller prop. Large props keep the top engine RPM down, and result in a smaller change in RPM as the engine is leaned out. Smaller props also have less of a flywheel effect, which means that the engine can change RPM faster, making the transition more obvious. |
RE: The best way to run-in an engine
Tom,
The spinner is set by the airframe, what fits the plane, either fitting the cowl, or just looking right. The engine size doesn't really matter when picking spinners. (well, with in reason. I don't think I'd put a 5" spinner on a .15 engine). For prop, feel free to mess around and try a bunch of different sizes. What prop to use depends a lot on the airframe and your flying style. Check the directions on the engine for a place to start, but don't be afraid to try props that are even a little bigger or smaller than the instructions say. A 10x6 on an OS .46 is a tad small, but not out of the question. You'll get a lot of RPM and noise out of that prop. You might try an 11x6, or 10x7 or 10x8, depending on what you want to do and what the airframe is. I'm running a 12.25x3.75 on a TT .46 in my Sukhoi for example. I also tried a 12x4, which was ok, and an 11x6 which I didn't like. I didn't bother with a 10x7, since that would result in a higher airspeed and less climb than I wanted with my Sukhoi. |
RE: The best way to run-in an engine
very true monty i think i was trying to say be easy on new engines and follow the manufactuers guidelienes but theres always that 1 idiot that never opens the owners manual and wonders why his engines break all the time lol and of course theres always the chick swinging is that clockwise or counterclock wise he he :)
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RE: The best way to run-in an engine
It's for a trainer, my first to be precise. I just don't want to go to fast, or having an enormous amount of power, while learning to fly :D. But a 10x7 will do the job?
Tom |
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