Why do they call it a "runout engine"?

SixPapaCharlie

SixPapaCharlie

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I hear that label applied to high time engines.
I am not sure I understand what the phrase runout really means.
 
SixPapaCharlie said:
I hear that label applied to high time engines.
I am not sure I understand what the phrase runout really means.
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Well, if new engines are "run in", I suppose old engines are "run out".
 
SixPapaCharlie said:
I hear that label applied to high time engines.
I am not sure I understand what the phrase runout really means.
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The engine has "run out" of time compared to TBO, either in hours of service or calendar years; otherwise is in condition of needing overhaul regardless of hours. It basically means the engine is in need of overhaul, and the plane should be valued accordingly.
 
I know what a run up engine is
 
If you are going to "run out" on your wife and get a divorce you want your plane to have as little value as possible so she doesn't get it in the settlement. :eek:)
 
"Run out" is a generic term commonly used to describe equipment and vehicles that are worn near the point of being unserviceable.
 
Interesting.
Does an overhaul make no longer "runout" in the case of airplanes?

Or does runout mean it is a trash engine?
 
Major overhaul resets the runoutedness.

Runout means get ready to replace/overhaul.
 
EdFred said:
Major overhaul resets the runoutedness.

Runout means get ready to replace/overhaul.
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Or keep running for another 500hrs past TBO and have no issues. Run out simply refers to an engine that is near or at recommended TBO times. The engine may have perfect compressions and wear on it with no reason to overhaul, but it should be priced out as if the engine will need to be overhauled.
 
If you're operating the plane, runout is more defined by Ed Fred's definition. It's runout when it's going to need an overhaul soon.

If you're buying a plane, it's runout when the compressions are low, the hours are close to TBO or any other excuse you can use to get the price down a bit.
 
Run out engine, technically, means that the rotating assemblies within the motor no longer rotate exactly in line with the main axis; for example, the main bearings are worn.
 
Maciej said:
Run out engine, technically, means that the rotating assemblies within the motor no longer rotate exactly in line with the main axis; for example, the main bearings are worn.
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Actually, "runout" in that sense is the measurement of how much excentricity there is in the rotation. It doesn't often get used there without some qualification.

Actually run-out in the first sense brought up here predates aviation. It refers to land that is no longer fertile, providing a poor yield. General term for used up
Dates back to the late 1700's.

Runup as Maciej points also has its origins outside of aviation (used in various machine rotating part descriptions). This term however originated in the mid-twentieth century.
 
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Well, "technically...."

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flyingron said:
Actually, "runout" in that sense is the measurement of how much excentricity there is in the rotation. It doesn't often get used there without some qualification.
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Correct, different term and context.
 
I'll call your Merriam-Webster and raise with the OED:

No longer useful or worthwhile; spec. (of land) no longer fertile, exhausted through use (cf. to run out 12a at run v. Phrasal verbs 1); (of a crop) providing a poor yield.

1795 J. Holt Gen. View Agric. Lancaster vii. 55 This was a poor run-out field.
1826 Amer. Farmer 12 May 60/1 Here my scheme for the improvement of run-out potatoes was for a moment frustrated.
1853 H. D. Thoreau Jrnl. 21 Mar. (2000) VI. 20 What shall I name those run-out pastures—those arid downs, where the rein-deer lichen fairly covers the whole surface?
1878 Trans. Illinois Dept. Agric. 14 144 The long, lank hog of the old, run-out breed has given place to the improved Poland China.
1912 Nature 22 Feb. 541 The system of management..consisted in ploughing up the run-out pasture land and planting maize.
1921 Res. Bull. (Univ. Nebraska Agric. Exper. Station) No. 24 49 The close proximity of the run-out stock did not seem to have an adverse influence upon the yield of tubers in 1921.
1950 N.Z. Jrnl. Agric. Feb. 165/2 Chou moellier can be grown from lea soil if the run-out grass paddock is shimmed very lightly in late autumn.
2002 Daily News (New Plymouth, N.Z.) (Nexis) 22 Aug. 18 The first thing to consider when re-grassing is, why am I doing this? Is it due to damage caused through pugging, past damage, a nutrient imbalance, or genuinely just a run out pasture?

6. Engin. Deviation of a wheel, drill, etc., from its proper course, esp. wobble of a wheel as it turns; the extent of such deviation.



1941 Pop. Sci. Monthly Apr. 237/2 (advt.) Headstock spindle... Held to very strict run-out tolerances.
1946 W. H. Crouse Automotive Mech. xxiv. 512 Wobble or ‘run-out’ of the wheels can be checked by spinning the front wheels and holding a piece of chalk against the rim or side wall of the tire.
1975 G. Bram & C. Downs Manuf. Technol. vii. 194 An important point of design is to reduce end thrust, to prevent bowing and flexing, producing as a consequence hole run-out and short drill-life.
1997 Metalworking Production Jan. 34/3 The aim of workholding for turning is to clamp the work as near as possible to the spindle bearings to minimise run out.
2001 Tractor & Machinery Jan. 33/2, I checked the rim of the wheel for truth by slowly turning it on its taper, while watching it for wobble, or runout.
 
SixPapaCharlie said:
I hear that label applied to high time engines.
I am not sure I understand what the phrase runout really means.
Click to expand...

It has 'run out' of time on the TBO clock or calendar, that is all, nothing more in regards to how the term is applied here. It doesn't mean much to Pt 91 operations, however it is used in dermining the value left on the engine. If it has 'run out' of time on the TBOs, it is assigned 'core' value. That 'run out core' could still measure well within service limits, running perfectly, and still be a "run out".

It is a measurement of time (or cycles as you get more complex planes) not physical limits.
 
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Henning said:
It has 'run out' of time on the TBO clock or calendar, that is all, nothing more in regards to how the term is applied here. It doesn't mean much to Pt 91 operations, however it is used in dermining the value left on the engine. If it has 'run out' of time on the TBOs, it is assigned 'core' value. That 'run out core' could still measure well within service limits, running perfectly, and still be a "run out".

It is a measurement of time (or cycles as you get more complex planes) not physical limits.
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What Henning says. Runout when used to describe an engine doesn't mean serviceable or unserviceable. It only means the tach or calendar is approaching the time the manufacturer recommends for overhaul. It can remain serviceable for an indefinite time or it could fail the next hour. Many engines never approach getting runout as they end up needing overhaul/major repairs much sooner. Many engines go well past manufacturer's RMOH. As has been mentioned, how close or how far past an engine is to manufacturer's recommended overhaul time can be used as a negotiating point for price. Part 91 operators can keep an engine in service forever just replacing or repairing what gets worn out without actually ever complying with an official, legal overhaul. Of course such an engine would not command a price as high as a freshly overhauled engine with all the paperwork.
 
Bunk. I know lots of guys here will run their 30 year old engines past TBO hours and say they're running fine. Here's a testimonial from the flip side. Find guys who've replaced good running engines for TBO hours and ask what they thought of their new engines. The standard answer? Wow! Because the new engine is making rated power and the old one wasn't. Airworthiness has little to do with performance. I need my engine to make all the power it can. When it starts to decline I deal with it. Similar to airworthy low compression cylinders. Some famous airplane writers will tell you those cylinders make full power. Come fly over tall obstacles from short strips and tell me if you agree. I don't. And so it goes with high time and high age engines. Just because they start and run doesn't mean they're good. Runout is a universal term for past it's prime. Tired. Old. Expired. Needing renewal. These apply whether you're buying it or flying it.
 
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Stewartb said:
Bunk. I know lots of guys here will run their 30 year old engines past TBO hours and say they're running fine. Here's a testimonial from the flip side. Find guys who've replaced good running engines for TBO hours and ask what they thought of their new engines. The standard answer? Wow! Because the new engine is making rated power and the old one wasn't. Airworthiness has little to do with performance. I need my engine to make all the power it can. When it starts to decline I deal with it. Similar to airworthy low compression cylinders. Some famous airplane writers will tell you those cylinders make full power. Come fly over tall obstacles from short strips and tell me if you agree. I don't. And so it goes with high time and high age engines. Just because they start and run doesn't mean they're good. Runout is a universal term for past it's prime. Tired. Old. Expired. Needing renewal. These apply whether you're buying it or flying it.
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Most of the time the engine isn't 'old and tired', it just has emphysema from running ROP. Disassemble, the cylinders and clean everything up nicely, give the valves a fresh lap, re assemble and boom, you have fresh clean flow, now reset the mags and get them back to where they should be, and you get all your power back for some labor and $20 of solvent and lapping compound. While you have the pistons off, you can tap on the rods and give a listen, you'll hear if something isn't right. If they all sound the same, you could even plastigauge one rod and see where you lie there.

Performance and worn out have very little to do with each other.
 
Using it in a sentence always seems to help:

I bough this Cirrus and discovered the engine is runout :D
 
"The motor in my plane is old and sluggish. I'm going to run out and buy another one."
 
The only 2 engine failures I have ever had were both a few hours after I replaced perfectly good 'runout' engines with new ones.
Stephen.
 
My engine "run out" of power 5 hours after a major overhaul (which seems to be fairly common) at around 500 feet AGL right after takeoff, but fortunately the rest of the machine was on my side and felt a survival instinct and got me to a runway. The airplane and the engine argued with each other briefly but in the end, the three of us made it down in one piece and taught that engine a big lesson, SERIOUSLY fixing its problems and forcing it to be dependable once again.
 
Bonanza said:
The only 2 engine failures I have ever had were both a few hours after I replaced perfectly good 'runout' engines with new ones.
Stephen.
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Fascinating.....tell us more
 
TEFLONSEAN said:
Fascinating.....tell us more
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While not exactly a "common occurrence", statistically most catastrophic engine failures are "infant mortality" issues in the first few hours, then the rate tapering down to around 200 hours after which it stays pretty steady.
 
If it hasn't been said in one way or another already.
"Run out"( as in clock/hobbs ) means out of time such TBO ie. (2,000 hrs.)
The clock can be reset as in overhaul/ top overhaul or rebuild.(per specs)
You may elect to keep running it, but be prepared.
Look at it as your alarm clock went off this morning ,doesn't mean the clock stopped . It just reminded you what time it was. As in aviation goes it means get prepared to re mortgage your home or sell one or two kids:yes:
 
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el con said:
If it hasn't been said in one way or another already.
"Run out"( as in clock/hobbs ) means out of time such TBO ie. (2,000 hrs.)
The clock can be reset as in overhaul/ top overhaul or rebuild.(per specs)
You may elect to keep running it, but be prepared.
Look at it as your alarm clock went off this morning ,doesn't mean the clock stopped . It just reminded you what time it was. As in aviation goes it means get prepared to re mortgage your home or sell one or two kids:yes:
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Also beware of rebuilt to spec (original) or rebuilt to minimum acceptable specs,
been there done that. The later does not go to TBO. Very painful to the pocketbook.
 
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el con said:
If it hasn't been said in one way or another already.
"Run out"( as in clock/hobbs ) means out of time such TBO ie. (2,000 hrs.)
The clock can be reset as in overhaul/ top overhaul or rebuild.(per specs)
You may elect to keep running it, but be prepared.
Look at it as your alarm clock went off this morning ,doesn't mean the clock stopped . It just reminded you what time it was. As in aviation goes it means get prepared to re mortgage you home or sell one or two kids:yes:
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"Honey, the plane is coming up on TBO, we need to have another kid to sell.":rofl:
 
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