New engine on a newly built airplane?

D

DMD3.

Pre-takeoff checklist
Joined
Nov 8, 2014
Messages
474
Location
Tifton, Ga
Display Name
Display name:
DMD3.
When building an experimental, how do builders deal with both performing the engine break-in procedure and flight testing the aircraft? Seems like I read that with a new Lycoming, they preheat the engine oil, tow the aircraft to the run up area, then have the pilot become airborne ASAP, keeping the throttle firewalled the entire time. Sounds tricky on a first flight for both the airframe and engine as well.

I realize that some builders install used engines (perhaps all of them do?). And that with some engines such as Rotax, the break-in procedure is done on the ground.
 
actually most assemblers (with all the pre-punched, pre-glued, pre-drilled kits now days, people don't build, they assemble) are going with brand new engines. somewhat due to the limited supply of used engines, and also the changes in the direction of EAB's trends in general.

this brings up the question that you have. what is needed to break in a new engine is pretty much opposite of what you need to be doing on a first flight of an airframe. which is mainly keep it firmly in the center of the predicted flight envelop with the exception of approach to stalls to determine a idea of landing speed of the aircraft. a new engine needs to be run as hard as you can, while keeping it in temp range. that is kind of hard to do while trying to keep airspeed in the middle of the range.

the good thing is with the latest cyl manufacturing processes, break in seems to happen a lot quicker than in days past. chrome cyls use were famous for taking forever to break in. rings tend to break in a lot faster it seems.

the best way is to limit ground runs, limit taxi time and keep the first flight short so a lot of the first flights are spent in climb with high power and lower airspeeds. its a balancing act for sure.
 
The easy way is to have the builder run it on a test stand. I haven’t heard anyone do what you describe. CHT management is the key as heat is the enemy which can lead to glazed cylinders. What I did was a quick initial flight to establish basic controllability and system functions, landed and let the engine cool down. My next flight I did a flat climb to roughly 3000 feet and did wide orbits over the field at 75% power. Here’s a good write up on a solid procedure from Russ Mahlon who worked for Mattituck. http://www.rvplane.com/pdf/EngineRunin.pdf
 
Lycoming had run my engine for an hour in a test cell. My first flight was a lap around the airport to check systems. After that it was high power cruise for 20 hours. No slow flight. Minimum taxi and low power approaches. Phase 1 testing for me was 40 hours. Plenty of time to do a break-in and airplane performance testing. I learned a lot about CG in that airplane in the early hours. Lots of adjustments to flaps, landing gear, and ballast. Nothing scary that prevented running it hard.
 
Last edited:
My engine was run on a test stand after it was OH'd. That said, I did not do much slow flight for the first couple hours of Phase I.
 
New unproven engine; aircraft never flown before plus pilot never flew it before.

what could go wrong?

A bud took a 3k SMOH “O-320 H” that had been used for flight instruction and banner towing. Flew about 200 hrs and then flew NY to AK. Eventually he went to
Lycoming School and o/h himself.

I agree with unsaferguy re in flight breaking-in procedures if no test cell/ club available.
 
An engine might be test run and checked for leaks on a test stand, but not broken in. Who's gonna pay for 50+ hours of test stand time??
 
pfarber said:
An engine might be test run and checked for leaks on a test stand, but not broken in. Who's gonna pay for 50+ hours of test stand time??
Click to expand...

50+ hours for a break-in? That’s ridiculous. The piston ring seal is really what we’re talking about and at 75% power you’re gonna do that in less than an hour, not 50+.
 
Last edited:
First flights of certificated total restorations and E-AB builds are equally fun. As a mechanic once told me (as he was cranking trim nose down, he said it was safer to need to pull than push,) I’ve probably never flown a more airworthy airplane. Everything is new. When driving to the first flight of my exp Cub, End of the Innocence came on the radio. That was a sign if ever there was one. Love it!

And then we read about first flight accidents where the ailerons were rigged backwards. I don’t get it.
 
tsts4 said:
50+ hours for a break-in? That’s ridiculous. The piston ring seal is really what we’re talking about and at 75% power you’re gonna do that in less than an hour, not 50+.
Click to expand...
Read some lycoming manuals, not Internet wives tales. 50 hours is the time frame cited.
 
pfarber said:
Read some lycoming manuals, not Internet wives tales. 50 hours is the time frame cited.
Click to expand...
I do read them, do you? The Lycoming break-in service instruction, SI1427C, says, "To seat the piston rings in a newly overhauled engine, cruise the aircraft at 65% to 75% power for the first 50 hours, or until oil consumption stabilizes." I don't know of anyone who's had to go the full 50 hours to comply with the SI, most report considerably less time.

Nauga,
prepping to do it all over again
 
There’s more to break-in than ring sealing. That’s more an indicator for power settings. Exp guys have slow flight on the agenda, too.
 
nauga said:
I do read them, do you? The Lycoming break-in service instruction, SI1427C, says, "To seat the piston rings in a newly overhauled engine, cruise the aircraft at 65% to 75% power for the first 50 hours, or until oil consumption stabilizes." I don't know of anyone who's had to go the full 50 hours to comply with the SI, most report considerably less time.

Nauga,
prepping to do it all over again
Click to expand...
Are you sure you're reading rev C?
upload_2022-7-5_21-19-16.png
 
Just to add a data point, in addition to the SI, my 540 operations manual also reiterates this as well:

"New engines have been carefully run-in by Lycoming and therefore, no further break-in is necessary
insofar as operation is concerned; however, new or newly overhauled engines should be operated using only
the lubricating oils recommended in the latest revision of Service Instruction No. 1014.
NOTE
Cruising should be done at 650% to 75o% power until a total of 50 hours has been
accumulated or the oil consumption has stabilized. This is to insure the proper seating of the
rings and is applicable to new engines and engines in service following cylinder replacement
or top overhaul of one or more cylinder."

I stand by my assertion that proper ring seating occurs early and is the main concern of flying a new engine on a first flight if it hasn't been run at 75% power on a test stand.
 
When I installed a field overhauled engine the initial start instructions were to start it and run it to a certain rpm for a specified time, shut down, let cool, and do it again to a slightly higher rpm. After that? First flight and subsequent 25 hour instructions weren’t any different than a factory engine that had an hour on a test stand.
 
I've done this twice. First on my RV-6, where I rebuilt the engine and second on my RV-10, where I purchased an engine from Barrett Precision Engines.

In general terms, the goals of the early flights are to verify that the aircraft has decent flight characteristics while running the engine at a high power setting for break-in. On both of my airplanes, the first 20 ish hours were flown within gliding distance of an airport. During those 20 hours, I was breaking in the engine, putting hours on the engine/prop/airframe to weed out infant mortality issues, and examining flight and performance characteristics, all while flying at 65% power or better (landings and occasional slow flight tests excepted) for a proper break-in.

My experience has been that the engines and avionics have required a lot more attention and adjustment than the airframes.
 
Rather than guessing and following old salts' (not going to disparage wives) tales, why not follow the instructions the engine manufacturer provides?
 
I think my new Superior engine had 2 hours on the test stand. First flight I ran it hard mostly, but I think you're kind of obligated to do some slow flight. Short final on your first landing in the airplane is not the time to be checking how it handles in slow flight or when you drop some flaps.
 
nauga said:
I do read them, do you? The Lycoming break-in service instruction, SI1427C, says, "To seat the piston rings in a newly overhauled engine, cruise the aircraft at 65% to 75% power for the first 50 hours, or until oil consumption stabilizes." I don't know of anyone who's had to go the full 50 hours to comply with the SI, most report considerably less time.

Nauga,
prepping to do it all over again
Click to expand...

What part of the "cruise the aircraft at 65% to 75% power for the first 50 hours" is incorrect?

The reason you need such a high power setting is that the internals are splash lubricated, and the oil is needed to ensure the rings don't damage the barrel.

But, as per the manual, the 50 hour number is correct.

I'll add:

Nauga,
not reading the manual
 
Apparently pfarber isn’t reading the manual either. There’s nothing magical about 50 hrs. The manual and SI both say 50 OR oil consumption has stabilized which will probably happen significantly sooner than 50 hours. In any event, the issue the OP brought up is more about seating the rings which will most likely already happened if it was run on a test stand, than wearing in all of the engine parts and systems which will happen in due time. If the engine hasn’t run on a test stand, kind of rare these days, then there’s a process beyond what’s in the manual to do it efficiently and effectively even on a new E-AB.
 
Thr qUOTE="tsts4, post: 3283039, member: 5432"]Apparently pfarber isn’t reading the manual either. There’s nothing magical about 50 hrs. The manual and SI both say 50 OR oil consumption has stabilized which will probably happen significantly sooner than 50 hours. In any event, the issue the OP brought up is more about seating the rings which will most likely already happened if it was run on a test stand, than wearing in all of the engine parts and systems which will happen in due time. If the engine hasn’t run on a test stand, kind of rare these days, then there’s a process beyond what’s in the manual to do it efficiently and effectively even on a new E-AB.[/QUOTE]

From a random lyc rebuild manual

Compliance Requirements
FOR CORRECT ENGINE MAINTENANCE, COMPLETE THE NECESSARY
MAINTENANCE PROCEDURES IN THIS MANUAL AND APPLICABLE
SERVICE DOCUMENTS. LYCOMING ENGINES' SERVICE DOCUMENTS
WRITTEN AT A LATER DATE OVERRIDE PROCEDURES IN THIS
MANUAL UNLESS OTHERWISE SPECIFIED.
PROCEDURES IN THIS MANUAL MUST BE DONE BY QUALIFIED
PERSONNEL WITH THE REQUISITE CERTIFICATIONS.

So you also must comply with SBs. The SBs CLEARLY state a 50 hour break in.

What part of this is not correct? Because saying its not in the manual is incorrect. Anyone thats done GA knows all to well that there is rarely a single document you must comply with.
 
You keep ignoring whats clearly written in the current Lycoming Operators Manual and applicable SI/SBs.
 
So when are you comfortable changing away from mineral oil? Adding Camguard or using semi-synthetic oil? I've broken a couple of engines in using XC20-50 but in my IO-390 I went with straight weight 100 mineral for 50 hours. I did 20 hours or so at >65% power before I did any slow flight. I don't know how anyone can judge stabilized oil consumption in less than 20 hours or why anyone thinks it isn't safe to land a plane without doing stalls or slow flight. My opinions, my engines, my planes.
 
pfarber said:
What part of this is not correct? Because saying its not in the manual is incorrect.
Click to expand...
In essence, the information that you are referring to has been superseded. You are referencing old data.

The Operators Manual (March 2009) says "Cruising should be done at 65% to 75% power until a total of 50 hours has accumulated or oil consumption has stabilized." However, the Operators Manual also says to refer to Service Instructions for updated information.

SI1427C (Dec 2010) only says "operate the aircraft at 65% to 75% cruise power until oil consumption is stable." with absolutely no mention of 50 hours anywhere.
 
My IO-390 manual mentions 50 hours repeatedly. Motor vintage 2020. My take is that it allows <65% power ops once oil consumption has stabilized. So back to my question. When do you change to products known to inhibit break-in? One hour? Two hours? It’s only a $70K engine. Don’t tell me what you THINK. Tell me what you DO!
 
Stewartb said:
So when are you comfortable changing away from mineral oil? Adding Camguard or using semi-synthetic oil? I've broken a couple of engines in using XC20-50 but in my IO-390 I went with straight weight 100 mineral for 50 hours. I did 20 hours or so at >65% power before I did any slow flight. I don't know how anyone can judge stabilized oil consumption in less than 20 hours or why anyone thinks it isn't safe to land a plane without doing stalls or slow flight. My opinions, my engines, my planes.
Click to expand...
I am pretty sure pretty much everybody recommends doing slow flight on the first test flight. It's kind of important to know what the prestall speed is and what kind of warning your new plane will give before it stalls. How else do you calculate your safe approach speeds? What if the ride gets a little bumpy and 65% power puts you over Va? In a perfect world you could get by running >65% power for most of the first 20 or 50 hours, but you also have to be safe and practical. You've got to slow down every time you land anyway, so you are already breaking the >65% power rule on every flight, what's another 10 or 15 minutes to do some slow flight?
 
Not me. My last two planes were a total rebuild and a new build with zero time engines and both were totally unfamiliar to me when I did the first flights. No slow flight until after 25 hours and I didn’t have any problems landing even on short strips. My current Cub lands in the low 20s. Power-on slow flight is under 20 mph. Not an important thing for normal landings. Max performance landings, sure, but not important in the initial hours of getting to know a plane. In this plane my first 25 hours were much more focused on CG and engine temps.
 
Stewartb said:
My IO-390 manual mentions 50 hours repeatedly. Motor vintage 2020. My take is that it allows <65% power ops once oil consumption has stabilized. So back to my question. When do you change to products known to inhibit break-in? One hour? Two hours? It’s only a $70K engine. Don’t tell me what you THINK. Tell me what you DO!
Click to expand...
IO-390-EXP? I see that it is dated June 2007, which is still before SI1427C (Dec 2010). Or is it IO-390-A? I see that one is June 2009.
 
I don’t get why you think it’s important to tell anyone what they do is wrong. Do whatever you want. I’ll do the same. This is a discussion. A sharing of ideas. I like hearing what other guys do.
 
Stewartb said:
I don’t get why you think it’s important to tell anyone what they do is wrong. Do whatever you want. I’ll do the same. This is a discussion. A sharing of ideas. I like hearing what other guys do.
Click to expand...
Aside from that last bit of snark, I'm not trying to tell anyone that they're doing anything wrong but rather that they're quoting the wrong document. <goes and does a quick author search to make sure I'm not misquoting myself :)>
 
Last edited:
asicer said:
Ok, you can do the 50 hours. The rest of us can follow SI1427C. :)
Click to expand...

I followed SI1427C exactly which came with my lycoming rebuilt zero time 0-320 H2AD motor July 2020.
I used a pressure tank and pushed fresh oil through my oil cooler before the first start.
I used aeroshell 15W50 oil for break in because it is a H2AD and will continue to use it forever.
Facing the wind I fired it up with the cowl off at 1000rpms until the oil was warm, about 10 minutes while checking for oil leaks.
Then put the cowl on. I ran it facing the wind for 15 mins at 1500rpm. All good after that.
Let it cool for about an hour.
Then fired it back up and taxied to the run up area and did the run up like normal. I took off at full power until 3000' and pulled the power back to 75% and cruised for 2 hours over farm fields. All was good after 2 hours so like paragraph 8 says I went to wide open throttle for 30 minutes.
Landed and it used 1 qt of oil.
The next day I flew it for 2 hours at 65-75% power and then wide open throttle for another 30 minutes. Landed and it used less than a half a qt of oil.
Then the next day I flew it for 2 hours like normal and landed. It didn't use any oil!!
My oil consumption stabilized at 5-7 hours.
Changed the oil for the first time at 18 hours. It was 'broke in" before 10hrs IMO.
I have flown it 421 hrs as of last week in 2 years time. It burns 1 qt per 12 hrs and I change the oil at about 55 hrs.
So far so good. Most recent oil analysis.

I did not use cam guard during break in.

(edited)_IMG_1951.JPG
 
Last edited:
You must log in or register to reply here.
Back
Top