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How did you balance engine break-in with test flying?

How did you balance between engine health and personal safety?

  • Bought a used engine, no break-in required

    Votes: 4 5.9%
  • Did taxi and land-back testing without regard for CHT

    Votes: 2 2.9%
  • Kept CHT below 300 during taxi and land-back testing

    Votes: 8 11.8%
  • Went directly to flight, watched for sign of break-in, then did power-off stalls

    Votes: 13 19.1%
  • Went directly to flight, performed break-in procedure, and landed without doing stalls at altitude

    Votes: 41 60.3%

  • Total voters
    68

iamtheari

Well Known Member
I am building an RV-14 with a brand new IO-390. Lycoming specifies a break-in procedure that requires 2.5 hours of flying at cruise or higher power settings on the first flight. That is at odds with the concept of doing high-speed taxi tests, land-backs, and then a first flight including stalls at altitude.

Rather than an endless debate, I am curious just to poll the group what you did to balance these two competing issues.

Please feel free to post ideas other than those I came up with for the poll. Thanks!
 
I am building an RV-14 with a brand new IO-390. Lycoming specifies a break-in procedure that requires 2.5 hours of flying at cruise or higher power settings on the first flight. That is at odds with the concept of doing high-speed taxi tests, land-backs, and then a first flight including stalls at altitude.
Rather than an endless debate, I am curious just to poll the group what you did to balance these two competing issues.
Please feel free to post ideas other than those I came up with for the poll. Thanks!

Unfortunately flight testing a new aircraft with a new engine does not correlate into a good realm. You are correct in your assumptions.
One word of caution. You should NOT do stalls on the first flight. You should test slow flight down to your proposed landing speed. Do not slow beyond the first indication of a stall. You can investigate stalls after you have tested stability.

I strongly recommend that you get with an EAA Flight Advisor and discuss.
 
What Mel said.

My process was to do a very short engine run prior to the first flight, just to check for any leaks or issue. This included a tail down (climb attitude) at full power just to check and make sure there is no issue with fuel delivery and also to make sure my governor is set to produce the right RPM (2700 Max)
First flight was a roughly 30 minute flight at high power, land and de-cowl to make sure no leaks or any other issues. This followed by a 2.5 hour flight at full power which the last 30 minutes of that changed the power to different settings. Land and de-cowl again.

The 390 cools very well with CHT, but the oil temp runs a bit hotter so I would keep an eye on that if any.

Good luck, got to be very exciting time.
 
Many have this dillema. I did limited ground runs (30 minutes per Mahlons procedure, as I overhauled myself and it had no test stand time). First flight, I orbitted the controlled airport (always within glide range) at 75-80% power for an hour. It was a 7K' runway, so lifted off in grd effect to confirm everything felt right before pulling up (still had plenty of runway to land if it didn't). Shallow climb to 3800' (just below bravo airspace) and did laps. Just before landing, I did a bit of slow flight to confirm that stall was above what was to be expected. Carried an extra 10 knots of airspeed on first landing. Repeated for second flight then started doing testing and high power break in in my test area.

Larry
 
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As others are saying.
-Brake in your brake pads on way out for first flight. Just warm them up, don't over heat them.
-Please don't High Speed taxi test! I've heard so many horror stories about this.
-Set up a circuit above the airport within gliding distance, maintain high power settings. Only near the end of your flight, slow down to approach and gradually let down the flaps to test and feel control response.
-If engine readings looks good and feels good (& nobody on the ground see's trailing smoke) continue flight as long as you can, the longer the initial engine run, the better.
-Land, pull the cowlings, if all looks good & while engine is still hot, go again.
During all the information overload with your first take off - remember P Factor - you have 2 feet, use them!
Have a great first flight experience.
 
Only addition to all this good advise is use 90kts and flaps 0 (no reflex) downwind, 80kts and half flaps on base and 70kts and full flaps on final. 65kts over the fence and you will be plenty safe for 1st flight. Just be aware, you need lots of up trim as you extend flaps and plan full aft stick as you touch down. The plane takes a lot of up elevator at lower speeds (I have flown 3 different -14a's and all are identical in this regard).
 
First flight power settings

Blue skies for your first flight!
I PM'ed you power setting suggestions I got from Lycoming for first flight.
75%: yes we heard so, but translate that to RPM, Manifold pressure, MSL, OAT and humidity.
 
Blue skies for your first flight!
I PM'ed you power setting suggestions I got from Lycoming for first flight.
75%: yes we heard so, but translate that to RPM, Manifold pressure, MSL, OAT and humidity.

Hello,

I'm following the thread on first flight and break in. Would you mind sending me the numbers you got from Lycoming?
 
Lycoming manual:
New engines have been carefully run-in by Lycoming and therefore, no further break-in is necessary insofar as operation is concerned; however, operate new or newly overhauled engines using only the recommended lubricating oils. Refer to Oil Requirements, Section 8.d.
NOTE
Cruise at 65% to 75% 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 as is applicable to new engines and engines in service following cylinder replacement or top overhaul of one
or more cylinders.

I orbited the airport, first hour @75% next 30min alternating between 65%-75%. And as previously mentioned, with full flaps be sure to trim aggressively and keep the stick back.
 
I am building an RV-14 with a brand new IO-390. Lycoming specifies a break-in procedure that requires 2.5 hours of flying at cruise or higher power settings on the first flight. That is at odds with the concept of doing high-speed taxi tests, land-backs, and then a first flight including stalls at altitude.

Rather than an endless debate, I am curious just to poll the group what you did to balance these two competing issues.

Please feel free to post ideas other than those I came up with for the poll. Thanks!

My engine builder is running/break-in for 3 hours on the dyno/test stand. Didn't see a voting option for that.
 
With all the 1st flight hyperventilating of the pilot, there was no chance to overheat the engine. :eek:

But seriously, new engine, taxi test, brake break in, high speed taxi test, 30 min 1st flight high power, subsequent flights all high power. Can't remember how many hrs before backing out of that and getting on with envelope testing. Log book not handy today. Oil consumption settled in to around 13 hrs and has stayed there for 850.

I am a proponent of high speed taxi because it helped me mentally prepare. I taxi tested with the nose off the ground for the full 8000 ft runway. Easy to feel the controls.

Before doing high speed taxi I asked a fellow builder and AF pilot about the frequently stated safety concerns. He asked me if I was a pilot or a passenger. DONE.
 
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Fairings On/off

I?ve got a question that hasn?t been hashed out here yet , since Van?s state most of our rides will gain 12-15 mph once we install our gear fairings & wheel pants , what is the general consensus on having them on for our initial flights to gain airflow over our engine and oil coolers or leave them off and make that engine work harder at 75% power, I left mine off thinking I?d rather make it work harder but was amazed at how much my cylinder head temps dropped off once I installed them , even though this may have had something to do with the break in being complete after 15 hours aloft ,
 
I vote for running the engine on a test stand first. I had the new engine run 5 hours on a test stand - worth every penny. First flights are stressful enough without having to worry about a new / untried engine.
 
I’ve got a question that hasn’t been hashed out here yet , since Van’s state most of our rides will gain 12-15 mph once we install our gear fairings & wheel pants , what is the general consensus on having them on for our initial flights to gain airflow over our engine and oil coolers or leave them off and make that engine work harder at 75% power, I left mine off thinking I’d rather make it work harder but was amazed at how much my cylinder head temps dropped off once I installed them , even though this may have had something to do with the break in being complete after 15 hours aloft ,

I am in the camp that a few flights must be done without fairings to establish a baseline for the yaw imposed by the raw airframe at cruise speed. This is then compared to the yaw imposed with the fairings on. This is really the only way to tell whether or not your fairings are aligned correctly.

Larry
 
Many have this dillema. I did limited ground runs (30 minutes per Mahlons procedure, as I overhauled myself and it had no test stand time). First flight, I orbitted the controlled airport (always within glide range) at 75-80% power for an hour. It was a 7K' runway, so lifted off in grd effect to confirm everything felt right before pulling up (still had plenty of runway to land if it didn't). Shallow climb to 3800' (just below bravo airspace) and did laps. Just before landing, I did a bit of slow flight to confirm that stall was above what was to be expected. Carried an extra 10 knots of airspeed on first landing. Repeated for second flight then started doing testing and high power break in in my test area.

Larry

I did similar to this for my shop rebuilt O-360 with no test run. About 30 min ground run with a cooling shroud and club prop. Shut down when cyl head temps got into the high 300's, let it cool and run again. Basically the same as Larry in the air. Straight to the runway after runup. Stayed around the airport at 3500' and 75% power within gliding distance for the first hour. Took about 15 hrs on the new nitrided cylinders before the temps came down and stabilized around 350*. Still running around the same temps after 400+ hrs. Add 1L of oil about every 20-25 hrs.

FAIRINGS:
Most guys on the field have done the test flights without the fairings in order to better evaluate the effect after installation. I flew mine fully dressed the first time figuring that it's a proven diesign which I built to the drawings so if it did not fly straight I would then remove them and figure out why. Flew straight with a slightly heavy but very trimmable left wing so I guess I got lucky.
 
Thank you for all the votes, responses, and private messages on this so far.

The data points I am working from are the Lycoming IO-390 manual and the Vaughn Askue book "Flight Testing Homebuilt Aircraft," which I purchased from Van's Aircraft.

The engine manual specifies two test runs on a new engine. The first is a ground run:
* 3 minutes at 1,000 RPM
* 15 minutes at 1,500 RPM
* Check magnetos
* Cycle propeller
* 10 seconds at "full static power"

The second is a flight run:
* Full power takeoff
* Reduce to climb power as soon as possible (25" / 2500 for the RV-14)
* Shallow climb to ideally 5,000 feet, no more than 8,000 feet DA
* 1 hour at 75% power (26.3" / 2350)
* 1 hour alternating between 75% and 65% power (23" / 2350)
* 30 minutes at maximum continuous power
* Descend at 65% power

By contrast, the Askue book strongly advises doing land-backs, a variety of flight speeds, and some stalls during the first flight. Those are the items in conflict with the engine manual.

I took the RV-14 transition course and I have stayed current and proficient in a variety of planes, including a few different taildraggers, so I feel comfortable with my ability to recognize abnormal behavior in the RV-14 as well as to safely get the plane on the ground and stopped from any reasonably normal behavior it exhibits in the air. But obviously I want to minimize the risk of being in the air in an uncontrollable airplane to the maximum extent I can without compromising the health of the engine.
 
A few things make doing the engine break in before doing to much slow flight handling acceptable is that this is an RV with many that have flown before you and, as long as you ground check the controls to be per the plans, there should not be any surprises on low speed handling. I know I’ll get flamed as you can’t assume all RVs are equal or that they are all built to plans.

Also this should not be your first flight flying an RV and your first experience on how an RV handles in slow flight. You should have already done several, if not dozens of slow flight and landings in transition training.

Different story if you build a one of a kind experimental and not one of 10,000+ flying.

There should be no stalls on first flight.
 
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Thank you for all the votes, responses, and private messages on this so far.

The data points I am working from are the Lycoming IO-390 manual and the Vaughn Askue book "Flight Testing Homebuilt Aircraft," which I purchased from Van's Aircraft.

The engine manual specifies two test runs on a new engine. The first is a ground run:
* 3 minutes at 1,000 RPM
* 15 minutes at 1,500 RPM
* Check magnetos
* Cycle propeller
* 10 seconds at "full static power"

The second is a flight run:
* Full power takeoff
* Reduce to climb power as soon as possible (25" / 2500 for the RV-14)
* Shallow climb to ideally 5,000 feet, no more than 8,000 feet DA
* 1 hour at 75% power (26.3" / 2350)
* 1 hour alternating between 75% and 65% power (23" / 2350)
* 30 minutes at maximum continuous power
* Descend at 65% power

By contrast, the Askue book strongly advises doing land-backs, a variety of flight speeds, and some stalls during the first flight. Those are the items in conflict with the engine manual.

I took the RV-14 transition course and I have stayed current and proficient in a variety of planes, including a few different taildraggers, so I feel comfortable with my ability to recognize abnormal behavior in the RV-14 as well as to safely get the plane on the ground and stopped from any reasonably normal behavior it exhibits in the air. But obviously I want to minimize the risk of being in the air in an uncontrollable airplane to the maximum extent I can without compromising the health of the engine.

You're getting confused between RUN IN and BREAK IN. If you have a factory-new Lycoming, they will have done the run-in testing in their test cell. That eliminates what you describe as "a ground run"... It's already done for you.

Break-in is the process of the piston rings knocking the tops off the honing ridges so the rings seal tightly. This is what you should be doing on your first flight. Take off, climb over the airport to a reasonable altitude (I used 2500 feet because I've got controlled airspace over that). Do not climb high - you want the engine to be getting thick air so it can make power. Stay within gliding distance of the airport. Fly circles around the airport, or racetrack patterns or whatever will work for your particular airport. If necessary, coordinate in advance with the applicable ATC facility so they know what you are doing and why you need to drone around for an hour right up close to home base. You may need a second and third hour of the same thing to get the break-in process largely completed, but an hour for the first flight is plenty.

First flights should be boring. We're all too wound up for them to be truly boring. The last thing you want to be doing on that first flight is trying to check off test card items. Fly the airplane, watch the engine, fly the airplane. By the time you're 50 feet off the ground you'll have established controllablity of the airplane. You know from the hundreds of other aircraft built from the same kit what the stall speed will be - fly accordingly, giving yourself good margins of speed.

We've seen this question come up time and time again in this forum. Sure, we've sunk a fortune into our new airplane and we're scared of screwing it (and ourselves) up. This really isn't rocket science. Don't over-think it. Read Mahlon Russell's engine break-in guidance, follow it, and you will have good results. Keep it very, very simple.
 
Keep in mind those guidelines are for experimental (not the FAA designation) aircraft, for which somebody has made serious alterations to a known aircraft or have built a custom design. You've built a well known aircraft with accurate historical performance data. Somebody has already figured out most of that for you.

On first engine run, I ran the engine up, tested prop.

Second engine run was first flight, flew the first 5 hours 25^2.

My engine runs great and doesn't burn oil.
 
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30 minutes at maximum continuous power

The Lycoming manual and a previous post mentioned "30 minutes at maximum continuous power" as a part of the break in.

Neither Lycoming nor anyone else here that I have seen has defined "maximum continuous power." I am going to use 25 squared unless someone can convince me otherwise. The other option I was considering was 2700 RPM and max throttle, which I don't believe is considered "continuous" power.

I currently have two hours of flight on the engine. One at 75% power and some power changes down to 65% power and back during second hour.

Thanks
 
The Lycoming manual and a previous post mentioned "30 minutes at maximum continuous power" as a part of the break in.

Neither Lycoming nor anyone else here that I have seen has defined "maximum continuous power." I am going to use 25 squared unless someone can convince me otherwise. The other option I was considering was 2700 RPM and max throttle, which I don't believe is considered "continuous" power.

I currently have two hours of flight on the engine. One at 75% power and some power changes down to 65% power and back during second hour.

Thanks

Just keep your speed up on climbs and go to a cooler altitude. Ambient temps don't get much discussion but has a huge effect. Cylinder pressure is the key. I varied rpm from 2400 to 2700 over the first 10 hours. Varying engine speed is good. 2700 makes more heat so less time there. I did mine in winter and sometimes had 900F EGT, and had to lean a little to get up to 11-1200F. CHTs were always low for me.
 
With a new Titan 370 and RV-8, I did about 20 min of short ground runs to check operation and leaks and set the GA prop pitch. Flew first three hrs WOT then varied 75-65% for another five hrs. I did one stall on the first flight and only 1-2 min of slow flight turns at altitude to prepare for first landing. Have over 40 hrs now and engine is running very well. CHTs never went over 400* and I kept mixture full rich. Now CHTs run around 345* and OT 195* -205* in the hot Southeast.
 
First flight/Break in comments

Two things - first one is obvious - with so many RVs out there, get left seat time in type with someone willing and able before your first flight - increases your confidence greatly and makes your plane feel like no surprise, or if it does surprise you, something is wrong.

Second, breaking in a Lycoming I/O-390 - The classic Lycoming break-in behavior is a couple of hours high power flight, with the attendant variations and somewhat elevated CHTs due to increased ring to cylinder wall friction, followed by an obvious and relatively sudden drop in CHTs. When I broke in my 210HP I/O-390, it didn't have that obvious drop, and the oil consumption remained relatively high. I spoke with the LYC tech advisors and was informed that the 390 series uses very different piston rings, which are much harder, and which take much longer to break in. And in fact it took mine a good 50 to 75 hours until the oil consumption leveled off.
 
Two things - first one is obvious - with so many RVs out there, get left seat time in type with someone willing and able before your first flight - increases your confidence greatly and makes your plane feel like no surprise, or if it does surprise you, something is wrong.

Second, breaking in a Lycoming I/O-390 - The classic Lycoming break-in behavior is a couple of hours high power flight, with the attendant variations and somewhat elevated CHTs due to increased ring to cylinder wall friction, followed by an obvious and relatively sudden drop in CHTs. When I broke in my 210HP I/O-390, it didn't have that obvious drop, and the oil consumption remained relatively high. I spoke with the LYC tech advisors and was informed that the 390 series uses very different piston rings, which are much harder, and which take much longer to break in. And in fact it took mine a good 50 to 75 hours until the oil consumption leveled off.
Thanks. I agree, get time with an experienced RV instructor in a properly sorted RV. Even if you're the world's greatest pilot, you will still benefit from a baseline for how the plane is supposed to fly so you can identify if your plane is abnormal in any way.

I have the 210hp IO-390. Did Lycoming give any indication of how hard to push it during the longer break-in period? Did you cruise at 2700rpm WOT for 75 hours? I can think of a few trips I'd enjoy taking at that power setting. :)
 
Break in new IO 390

RV 14, dual P mags, Hartzell prop. 16 hours thus far.

First 5 hours mostly at 5 000' MSL.
WOT, 2490 RPM, leaned to best power as soon as leveled off (used the take off EGT to lean to, so roughly 100-150 F ROP) for the first 2 hours.
After 2 hours, mixed it up with runs at 50-70% power, still leaned to best power.

Oil consumption stabilized at about 8 hours and now stays around the 6 qrts level. It blew off the top 2 qrts in a hurry. Following this I started on the test cards of the EAA Flight test manual.

Thread drift.
OAT 10-15C. At WOT, leaned for best power the Oil Temps were always 185-195F.
Slowing down to 55% / 17.5 MAP , 2490 RPM, 130 KIAS, the Oil T pops up to 202-204F.
Seems she wants you to stop loitering, to cool better :)
 
Breaking in an I/O-390

Thanks. I agree, get time with an experienced RV instructor in a properly sorted RV. Even if you're the world's greatest pilot, you will still benefit from a baseline for how the plane is supposed to fly so you can identify if your plane is abnormal in any way.

I have the 210hp IO-390. Did Lycoming give any indication of how hard to push it during the longer break-in period? Did you cruise at 2700rpm WOT for 75 hours? I can think of a few trips I'd enjoy taking at that power setting. :)

Surprisingly, when I bought the engine and was not yet cognizant of the supposedly different ring behavior of the -390, I was given the usual Lycoming instructions, and after the typical break-in time of a couple of hours, I did not push it any harder for a longer time period, although it got flown at 75% fairly consistently. I believe that I was advised, though, to keep flying with the straight mineral break-in oil for at least the first 50 hours, and it was during that time that I noticed the oil consumption starting out rather high from what I was expecting, and slowly improving to its stable current state. It all seemed rather strange, but I did get the same info, about the -390 rings being different, from Lycoming, on several different occasions and from different technical advisers. Talked with one at great length at Oshkosh on this topic. I wonder what other folks experience has been with the -390 break-in? I'm running about 12-13 Hrs./Qt., which I'm not totally happy about, having had 172s with -320s that used virtually NO oil between changes, but I guess this is the way with the angle valve engines.
 
I had a rebuilt engine for first flight. (Rebuilt engine had new cylinders and rings.)

There were several ground runs that gave me confidence in the engine to fly the airplane. I did keep a watch on CHT and Oil temperature making sure they never got too hot.

I did a full stall series on the first flight.

I also ran a full test program. I did try to run as much power as I could but my option was to fly the tests program and use as much power as possible when not flying a test profile. My option was if I glaze the cylinders, it would not be a big issue to pull cylinders and hone each over again. Yes I may need to buy new rings but wanted a safe airplane.

After the end of the test program (Phase I) the airplane was using a quart of oil every 25-hours.
 
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