Do you climb at full power on big piston engines

My plan is to try and keep my CHTs on the O-470-50 below 410 on climb-out, and below 380 in cruise. Hoping that will give good engine life (it's at about 100 hours right now). Cylinder 3 seems to run about 20 degrees hotter than any of the others and it's that one I plan to use as the limiting one.
 
Thanks for the thoughts guys. My engine just came back from MOH and has about 5 hours on it so far. Im reading and talking to everybody I can get my hands on looking to extend the life as long as possible.
 
Run it like you stole it during break in. Continental has published lots of information about breaking an engine in but my favorite instructions were by ECI before Continental bought them. Don't baby the engine. Lay the whip to it and break it in right.
 
JCranford said:
Thanks for the thoughts guys. My engine just came back from MOH and has about 5 hours on it so far. Im reading and talking to everybody I can get my hands on looking to extend the life as long as possible.
Click to expand...
If you haven’t read Deakin’s stuff then add it to the list. Maybe read it a couple times. He captured a lot of experience in the articles.
 
Stewartb said:
Run it like you stole it during break in. Continental has published lots of information about breaking an engine in but my favorite instructions were by ECI before Continental bought them. Don't baby the engine. Lay the whip to it and break it in right.
Click to expand...

Hmmm, not 'exactly' what Ive been reading...
 
Clark1961 said:
If you haven’t read Deakin’s stuff then add it to the list. Maybe read it a couple times. He captured a lot of experience in the articles.
Click to expand...

Yeah, that's the Pelican's Perch stuff I was referring to earlier: 'Those Fire Breathing Turbo's' Im working through a second reading of it.
 
My instructor said to ease off a bit at 500' and that is what I usually do. Continental 670
 
Just one data point. I had a Husky that made 3000 hours and it indicated as high as 468 in a climb in the summer. The limit was 500, posted right on the panel above the CHT gauge. But yes, run it as cool as you can.
 
Clark1961 said:
If you haven’t read Deakin’s stuff then add it to the list. Maybe read it a couple times. He captured a lot of experience in the articles.
Click to expand...
Yes, I am reading his stuff and have started several threads recently based on the articles for more info. Thanks for the replies....

"It's not the power you pull that determines maintenance, repairs, and TBO, it's the temperatures and internal pressures you run, and how you abuse your engine with cold starts to instant high RPM. Sadly, during the last ten years or so, it has been more an issue of quality control at the factories than engine management. Lycoming and TCM crankshafts have broken, and factory-installed exhaust valves on TCM engines appear to fail prematurely, no matter how you run the engine.

Please get away from that feeling that you are somehow abusing your engine, and that you need to reduce from takeoff power right away to "save the engine."

The sole exception is when you have an engine with a LIMITATION regarding takeoff power, sometimes five minutes, sometimes less. Please do observe that limitation, there MAY be something the factory knows. Again, I refer ONLY to a genuine LIMITATION, in the "Limitations" section of the POH, and NOT the text written in the "How to fly" section.

I will also repeat from the previous column, YOU MUST BE GETTING FULL REDLINE FUEL FLOW at full takeoff power AT SEA LEVEL! In truth, the factory redlines are often a bit on the low side, and flows should be tweaked up just a bit. Even a half-gallon per hour makes a BIG difference in CHTs during climb.

In general, and speaking very roughly, if you see EGTs anywhere over about 1,300°F (lower will not hurt a thing and is probably “better”) during a sea-level takeoff, or CHTs above about 360°F right after takeoff, YOUR FUEL FLOW IS TOO LOW. Having a good understanding of the proper relationship between the EGTs and the fuel flow at very rich mixture settings will always give you a good cross-check on whether or not you are getting adequate fuel flow -- even if your fuel flow needle breaks off and falls to the bottom of the instrument!

If your fuel flow is too low on takeoff, don't let your mechanic talk you out of setting it up a bit, and if necessary, find a mechanic who will do it. VERY few mechanics understand the importance of this. Far too many mechanics consider the fuel flow redline a maximum, and they consider a little bit less as "good," or "better for the engine," thinking they are being "conservative." After all, we all like to stay a little bit (or a lot) away from all sorts of redlines, right? That fuel flow redline is a MINIMUM, not a maximum. Treat it as such."
 
DanWilkins said:
My instructor said to ease off a bit at 500' and that is what I usually do. Continental 670
Click to expand...

Did your instructor have any actual basis for suggesting you "ease off a bit" or was he just regurgitating what someone else told him? Depending on your engine, you could actually be doing more harm than good by reducing throttle "a bit" during climb. In some setups there is an enrichment feature that adds extra fuel in the wide-open throttle position to provide extra cooling. By pulling the power back just a little, you may be robbing your engine of that extra fuel/cooling.
 
Upon reaching 1000' AGL, my O-470 gets pulled back to 23" and 2450 RPM for climb, as per the POH.
 
I was flying with an instructor (it wasn’t an instruction flight) who gave me an ear full because I told him I like to climb at Vy in NA fixed prop airplanes. He gave me a bunch of mumble jumbo about being able to see better and better cooling. He also said that you’ll get a better climb rate and you’ll get there faster at a higher speed. I reminded him that Vy is (best rate of climb...) tough concept for people I guess. If the engine isn’t running hot, I don’t see any reason not to climb at Vy.

Now in a 350hp turbo. You probably don’t need best rate as it will be uncomfortable and it will heat up. T210 I fly in, we reduce the power after takeoff quite a bit to keep temps cool and not burn through all the gas in 1 hour lol. Still gets 1000 fpm climb, I think that is adequate in most scenarios.
 
bradg33 said:
Did your instructor have any actual basis for suggesting you "ease off a bit" or was he just regurgitating what someone else told him? Depending on your engine, you could actually be doing more harm than good by reducing throttle "a bit" during climb. In some setups there is an enrichment feature that adds extra fuel in the wide-open throttle position to provide extra cooling. By pulling the power back just a little, you may be robbing your engine of that extra fuel/cooling.
Click to expand...
I
I don't know the answer to your question. You do make a good point. I just feel better not pushing the hell out of her. My engine does not get very hot. I just follow the advice of those who have been flying these engines for years as well as the fellow who specializes and rebuilding them. I do not lean it when flying. I don't use carb heat when landing. We pulled a jug when there was almost no compression and the cylinder and piston were in great shape after 300 hours. The main issues I really focus on is letting it sputter and cough for a minute or two when it is cold...before I get all the cylinders firing. The other caution I take: try to avoid redlining it.
 
FastEddieB said:
At any altitude?

Would that not result in an overly rich mixture nearly all the time?
Click to expand...
I don't go much higher than 2500' AGL. Sometimes I'll go another thousand to have some inverted fun, but that is only for a few minutes. My set-up doesn't run real rich. The folks who prepared my plane said to just keep the lever on 'rich'.
 
[QUOT
bradg33 said:
Did your instructor have any actual basis for suggesting you "ease off a bit" or was he just regurgitating what someone else told him? Depending on your engine, you could actually be doing more harm than good by reducing throttle "a bit" during climb. In some setups there is an enrichment feature that adds extra fuel in the wide-open throttle position to provide extra cooling. By pulling the power back just a little, you may be robbing your engine of that extra fuel/cooling.
Click to expand...
Part of the easing off is required by the RPM limits. Full throttle on the W 670 will put you over red line RPM depending on how much you lower the nose on climbout.
 
Fearless Tower said:
This surprises me. You don't use carb heat on the W670?

That is contrary to everything I was taught flying W670s.
Click to expand...
I am not an expert in operating these things. I have a mentor and what he, or his boys say, I do. So far, so good. I try to keep it simple and pursue my dream of flying a splendid aircraft. In my travels I get pointers and tips. I listen to them all; however, there is always my home base (mentor) to lean on.
 
StanN45 said:
Upon reaching 1000' AGL, my O-470 gets pulled back to 23" and 2450 RPM for climb, as per the POH.
Click to expand...

Keep in mind what Deakin quoted above says. Those aren’t limitations in the POH for the O-470 usually.

They’re in that vague “how to fly it” section that often has no basis in anything from the engine manufacturer. Usually written by someone worried about noise abatement, not engine longevity.

Example: Many people think the prop RPM limit on older 182s with the O-470 is “top of the green” when in cruise or climb. It’s not. It’s the redline.

We see folks around here in summer taking off with DAs above 9000’ at the surface, pulling the RPM back and killing their climb at 1000’.

Or worse, they do it when trying to reach max performance in the mountains in summer when the DA at their altitude is approaching their service ceiling, and they’re trying to cross a pass.

“You’re not going to get there in time without pushing that prop up.” :)

They were already back to 23” or less before they reached pattern altitude... haha. Nothing to pull back there. That one is more useful at lower airports than here.
 
denverpilot said:
Keep in mind what Deakin quoted above says. Those aren’t limitations in the POH for the O-470 usually.

They’re in that vague “how to fly it” section that often has no basis in anything from the engine manufacturer. Usually written by someone worried about noise abatement, not engine longevity.

Example: Many people think the prop RPM limit on older 182s with the O-470 is “top of the green” when in cruise or climb. It’s not. It’s the redline.

We see folks around here in summer taking off with DAs above 9000’ at the surface, pulling the RPM back and killing their climb at 1000’.

Or worse, they do it when trying to reach max performance in the mountains in summer when the DA at their altitude is approaching their service ceiling, and they’re trying to cross a pass.

“You’re not going to get there in time without pushing that prop up.” :)

They were already back to 23” or less before they reached pattern altitude... haha. Nothing to pull back there. That one is more useful at lower airports than here.
Click to expand...

Agreed! I guess I should have qualified that by stating I’m a flat lander at 1300’ MSL with DA’s in the summer getting to the mid 3000’s +/-.

That power reduction is most definitely not a one size fits all procedure. Thanks for making that point!
 
Another carbureted O-470 here. My POH also says a normal climb should be done at 23"/2450. It later states in the "how to fly it" section that after takeoff, power should be reduced to 23"/2450 "as soon as practical to reduce engine wear." In another place, it says "maximum takeoff power should be limited to that absolutely necessary for safety." Still further, it states, "whenever possible, reduce takeoff power to normal climb power. So, the POH says 4 times to reduce power. I'm going with that. Now, you could argue that full power from the runway to 8,000 AGL is absolutely necessary for safety I guess. Here on the Great Plains, I just use max takeoff power to 1000 AGL or so, then pull back. The climb rate is still plenty adequate for a safe climb in my humble opinion. All that said, if I was at high altitude, had bad terrain, obstacles to clear, etc, I would probably stay at full power longer.
 
Last edited:
JCranford said:
Yeah, that's the Pelican's Perch stuff I was referring to earlier: 'Those Fire Breathing Turbo's' Im working through a second reading of it.
Click to expand...
John, I recommend you should read this article about operating your turbo 210 new engine. Also TCM recommends during break-in running hard at 75% power until your cht’s Stabilize between cylinders and oil consumption minimizes, usually 10 to 25 hours to insure your rings are adequately seated and minimal oil consumption afterwards. Fly cross country for the initial trips and not doing touch and go’s or no approach practice where the engine is babied. Other tips for naturally aspirated big bore Continentals in the article too.

http://www.swaircraftappraisals.com.../Operating Tips for Big-Bore Continentals.htm

Most of the suggested procedures from previous posts are duplicated but there are some others especially for the turbo’s. Hope you enjoy it!
 
OkieFlyer said:
Another carbureted O-470 here. My POH also says a normal climb should be done at 23"/2450. It later states in the "how to fly it" section that after takeoff, power should be reduced to 23"/2400 "as soon as practical to reduce engine wear." In another place, it says "maximum takeoff power should be limited to that absolutely necessary for safety." Still further, it states, "whenever possible, reduce takeoff power to normal climb power. So, the POH says 4 times to reduce power. I'm going with that. Now, you could argue that full power from the runway to 8,000 AGL is absolutely necessary for safety I guess. Here on the Great Plains, I just use max takeoff power to 1000 AGL or so, then pull back. The climb rate is still plenty adequate for a safe climb in my humble opinion. All that said, if I was at high altitude, had bad terrain, obstacles to clear, etc, I would probably stay at full power longer.
Click to expand...

They’re basically just saying 2600 RPM is more wear than 2450, which is also saying tach time is based on RPM. Which is pretty much in the “Duh” category.

Down where y’all have air pressure, the 23” is just so you don’t blow the silly thing up when you bring the prop back.

And then there’s the whole “oversquare” thing that carried over into 70’s manuals from radials...

But yeah. Climb rate is lovely down where you live. I really enjoy takeoffs down there. And seeing numbers over 30” on my MP gauge. Heh. It’s always both a surprise and not.

“Engine instruments in the green... ooooooooh lookie at that! Nice!” A minor distraction on the takeoff roll. LOL. “Oh, look rotation speed!” Haha.

If you pulling back to 23” and 2450 on the runway, you can simulate my normal takeoff power available. Hahaha.

I love going to lower altitudes and making some freaking NOISE with my O-470.
 
denverpilot said:
They’re basically just saying 2600 RPM is more wear than 2450...Which is pretty much in the “Duh” category.
Click to expand...

Still not sure that’s a given, in an engine without a limitation on max power.

The only way an engine can run for more than a few minutes is because there is virtually no metal-to-metal contact - all moving parts are separated by a thin layer of oil. As long as that’s the case and the engine is operating within its normal operating range, it would have to be demonstrated via testing that an IO-550 will exhibit more wear operating at 2,700 rpm vs 2,400 rpm, let’s say.

It very well might, but I don’t think it’s a fair thing to just assume.

Operationally, I saw/see no reason not to run my IO-550 or my ROTAX 912 continuously at maximimum continuous power. (Does that fall into the “Duh?” category?) That said, my Cirrus had a “sweet spot” at about 2,650 rpm, and my ROTAX seems to vibrate just a tad more over 5,400 rpm, so I would not typically cruise at rpm higher than those. But not because of any assumed increased wear.
 
Last edited:
Put me in the camp that believes higher power, higher rpms and higher temps shorten engine life.

Definitely follow the engine mfg recomendations.
 
Apparently Continental doesn't think so. The IO-550G and IO-550N have the same TBO. The N turns 2700 rpm and makes 30 more HP.
 
Briar Rabbit said:
John, I recommend you should read this article about operating your turbo 210 new engine. Also TCM recommends during break-in running hard at 75% power until your cht’s Stabilize between cylinders and oil consumption minimizes, usually 10 to 25 hours to insure your rings are adequately seated and minimal oil consumption afterwards. Fly cross country for the initial trips and not doing touch and go’s or no approach practice where the engine is babied. Other tips for naturally aspirated big bore Continentals in the article too.

http://www.swaircraftappraisals.com/MeyersForum/Engine Info/Engine Operation/Operating Tips for Big-Bore Continentals.htm

Most of the suggested procedures from previous posts are duplicated but there are some others especially for the turbo’s. Hope you enjoy it!
Click to expand...

That was a good read. Thanks!
 
denverpilot said:
They’re basically just saying 2600 RPM is more wear than 2450, which is also saying tach time is based on RPM. Which is pretty much in the “Duh” category.

Down where y’all have air pressure, the 23” is just so you don’t blow the silly thing up when you bring the prop back.

And then there’s the whole “oversquare” thing that carried over into 70’s manuals from radials...

But yeah. Climb rate is lovely down where you live. I really enjoy takeoffs down there. And seeing numbers over 30” on my MP gauge. Heh. It’s always both a surprise and not.

“Engine instruments in the green... ooooooooh lookie at that! Nice!” A minor distraction on the takeoff roll. LOL. “Oh, look rotation speed!” Haha.

If you pulling back to 23” and 2450 on the runway, you can simulate my normal takeoff power available. Hahaha.

I love going to lower altitudes and making some freaking NOISE with my O-470.
Click to expand...

Yeah, the thread is about "full power" operation, not full throttle or maximum available power. Obviously if altitude or any other limiting factor keeps you from achieving full power then you should use what you got. That said, I'm not convinced that operating at or near full rated power for longer than necessary is a good idea for any engine. Now, I don't condone babying an engine too much. It's made to run, and run pretty hard. Running at 75% power, in my opinion, is running an engine plenty hard enough IF that affords you an adequate climb to get you up and over obstacles, at to "safe" altitude in a timely manner.
 
Last edited:
Dads 182 owners manual specifies power reduction after positive rate of climb is established.
 
All else being equal (re-read that if you disagree)- high rpm is harder on certain engine parts.

Yes, oil pressure keeps a film between bearings and cams/cranks, so metal wearing down should be less there, but there is dirt in oil. Make a difference? I don’t know.

Also think about the cycles. More rpm means more times that the piston ring moves in the bore. More metal wear. If not, then compressions should theoretically not change over time.

Also consider the forces that a rod or crank or piston pin have to go through at higher rpm. It’s not just about metal wear. Is fatigue a better word? The pin has to absorb some major forces at top and bottom of travel when it is forced to change directions. Higher rpm increases the loads. It’s not all about the oil film. Cranks break. How many times has the poor crank had to cycle up and down, and how fast has it had to turn?

At least intuitively it makes sense. I don’t run my engines with any consideration to the above though, I follow mfg directions.
 
You must log in or register to reply here.
Back
Top