Complex Engine Takeoffs and Altitude

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Derald Madson

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I recently purchased a 182 RG for the purpose of some good ol cross country cruising.

Here's my question: High Elevation vs Low Elevation Complex Takeoffs

High Elevation:
All my training in 182's / Complex was at my home field at high elevation 4,000 ft or more. I was instructed to perform takeoff in accordance with the POH. Leaned mixture above 3k ft, prop full forward, and throttle max. For normal climbout 23 inched on MP and prop 2400. Frequently the prop will exceed the POH limit of 2400 on these takeoffs. The instructors' technique was to reduce the RPM after liftoff. Most of the runways where I fly at high elevation are 5,000 ft long and have no obstacles. Since I own the plane I don't want to be pushing over redline on take off and potentially damaging the engine. Thus before takeoff roll I have experimented with cracking the prop back slightly. I still have plenty of power to get of the ground and I'm not pushing past the rpm redline. It feels iffy though because I am not following the POH.

Low Elevation:
Similarly for low elevation take offs, which I have only flown solo and not with a CFI, I initially followed the POH. I notice, however, the MP will reach 25.5-26 in. while the green arc stops at 23 in. So when I have plenty of runway and no obstacles I'll smoothly apply full throttle, check the MP, and then reduce it to 23. If I'm worried about trees or a short runway I'll stay full throttle till I feel comfortable about clearing the obstacles. Am I damaging the engine running at a higher MP than the green arc or am I overthinking this?

Am I way off on my procedures for Takeoff? I would like to both not perish and preserve my engine.
 
You're not "saving anything" by cutting the power prematurely in your low altitude takeoffs. I'm not sure why you would use 23" for climbs. That's very strange. You might get away with it in an older Continental powered 182, but you certainly DO NOT want to do that with the Lycoming engines. Lycoming specifically advises against it. Climbs are always done at WOT for cooling issues.
 
I would just follow the POH. That said, a couple of thoughts. Are you sure your tach is accurate? Have you checked it with some other means? If it is accurate it sounds like your prop governor may not be set or performing as desired. They're a little expensive, but an engine monitor will give you great insight into how your engine is performing and if you're getting close to any "red lines" you would need to worry about.
 
flyingron said:
You're not "saving anything" by cutting the power prematurely in your low altitude takeoffs. I'm not sure why you would use 23" for climbs. That's very strange. You might get away with it in an older Continental powered 182, but you certainly DO NOT want to do that with the Lycoming engines. Lycoming specifically advises against it. Climbs are always done at WOT for cooling issues.
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So climb at full throttle to keep the airspeed up for cooling? I was climbing at 23 in MP since it was in the POH climb checklist.
 
idahoflier said:
I would just follow the POH. That said, a couple of thoughts. Are you sure your tach is accurate? Have you checked it with some other means? If it is accurate it sounds like your prop governor may not be set or performing as desired. They're a little expensive, but an engine monitor will give you great insight into how your engine is performing and if you're getting close to any "red lines" you would need to worry about.
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Where's the best place to start looking? I only have digital CHT and EGT with no recording as of now.
 
Derald Madson said:
So climb at full throttle to keep the airspeed up for cooling? I was climbing at 23 in MP since it was in the POH climb checklist.
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You're going to get a lot of opinions. There has likely been a lot written about how to best manage your engine since the POH for your aircraft was written. I can't speak for your specific aircraft but I would think 23" is less power so less cooling required. At least that's what I see in my carbureted O-360 172. Cruise climb power settings are easier on engines and that's what would be in your POH. Personally I like to climb at higher power settings to gain altitude when operating in mountainous or urban areas and I feel I can do this without compromising engine longevity because I have an engine monitor and I'm watching CHT's closely...
 
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Derald Madson said:
Where's the best place to start looking? I only have digital CHT and EGT with no recording as of now.
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Until someone posts a better list of resources, I would start with either the Continental or Lycoming web sites. I know Lycoming as a lot of information related to their engines and how to operate them. You can also start here as a good resource: https://www.avweb.com/ownership/john-deakins-engine-related-columns/ Also look at some of the videos here: https://www.youtube.com/channel/UCc-IpamUhzvGsAfMzH2lIcA

Those resources are the opinions of individuals and debate can spark holy wars about the veracity of their opinions. But it will get you educated and you can continue self directed study. From there you can form your own opinions on what is right for you. If you're in doubt, stick to the POH...
 
idahoflier said:
You're going to get a lot of opinions. There has likely been a lot written about how to best manage your engine since the POH for your aircraft was written.
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You're 100% correct on the first part but I disagree on the second part. The information you’re referring to has been around a long, long time, it is just that the average pilot rarely went looking for it. Now there are a bunch of people writing things, acting like the knowledge they’re transmitting is something new.

While there is certainly room for improvement, the OEMs weren’t stupid when they came up with the procedures outlined in the flight manuals. I’d suggest following the procedures as written, rather than deviating, unless there is a good reason for the deviation that can be backed up with data to prove why the proposed method is superior. Of course this is just my opinion and approach to things after 15+ years in engine development for an OEM.
 
mondtster said:
You're 100% correct on the first part but I disagree on the second part. The information you’re referring to has been around a long, long time, it is just that the average pilot rarely went looking for it. Now there are a bunch of people writing things, acting like the knowledge they’re transmitting is something new.
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Well, yes, the information was known since ~ WWII? I wasn't trying to imply it's "new". That said, I don't think it was as available as you're implying, i.e. just go look for it. Even today you find people creating new articles and videos on the topic that aggregate and condense the work of others...

mondtster said:
While there is certainly room for improvement, the OEMs weren’t stupid when they came up with the procedures outlined in the flight manuals. I’d suggest following the procedures as written, rather than deviating, unless there is a good reason for the deviation that can be backed up with data to prove why the proposed method is superior. Of course this is just my opinion and approach to things after 15+ years in engine development for an OEM.
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Agree with your POH sentiment. My thought is that the POH's were written based on aircraft manufacturers not adequately instrumenting their aircraft as well as not having to include a tome of information in the POH. I think I understand the reasons behind this. Today aircraft may be fitted with quite capable and relatively inexpensive engine instrumentation which may allow a pilot to operate an engine based on conditions present vs a one size fits all approach that is found in POH's written decades ago. Is there any validity to these thoughts?
 
idahoflier said:
Agree with your POH sentiment. My thought is that the POH's were written based on aircraft manufacturers not adequately instrumenting their aircraft as well as not having to include a tome of information in the POH. I think I understand the reasons behind this. Today aircraft may be fitted with quite capable and relatively inexpensive engine instrumentation which may allow a pilot to operate an engine based on conditions present vs a one size fits all approach that is found in POH's written decades ago. Is there any validity to these thoughts?
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I’d say some of that, some of the fact that gas was cheap, so going fast was the goal, some of the fact that flying LOP wasn’t actually necessary to prevent having to ditch in the Pacific, and some of the fact that they maybe expected pilots to have some knowledge of flying and operating engines, and probably a few other factors.
 
Your RG already has a 2400 rpm limit and with a lower RPM the rate of climb will suffer a lot. You are also running a big O-540J3C5D engine that is only producing 235 hp at sea level.

Your POH provides for both a Maximum and Normal data. Do not hesitate to use Maximum Climb in a 182RG to altitude. You are not going to hurt that engine doing so.

You definitely want to lean for high altitude takeoff.

Smart maintenance for the O-540J3C5D is 40 hour oil changes, cleaning and gapping plugs every 80 hours. The engine are well known to go TBO with no top work.
 
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Back to the OP’s original question. My preference when I don’t need a max performance take off is to just set the power and RPM for my selected climb configuration on the takeoff roll. With a bit of practice I know where to set the prop control and throttle to get this close and can fine tune it once above 1000ft. It creates less noise and is less for me to mess with after takeoff. Many planes I use 25” and 2500 rpm. The OP says he uses 23” and 2400rpm, which I recall is appropriate for some 182’s.

What settings to use during climb is a whole different discussion, but generally if CHTs are staying below 380 I think you doing fine.

Brian
CFIIG/ASEL
 
idahoflier said:
Well, yes, the information was known since ~ WWII? I wasn't trying to imply it's "new". That said, I don't think it was as available as you're implying, i.e. just go look for it.
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The information wasn’t secret. But you had to know it existed and had to be resourceful to find the information. The internet has changed that significantly, some for the better and some for the worse.

idahoflier said:
Agree with your POH sentiment. My thought is that the POH's were written based on aircraft manufacturers not adequately instrumenting their aircraft as well as not having to include a tome of information in the POH. I think I understand the reasons behind this. Today aircraft may be fitted with quite capable and relatively inexpensive engine instrumentation which may allow a pilot to operate an engine based on conditions present vs a one size fits all approach that is found in POH's written decades ago. Is there any validity to these thoughts?
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The flight manuals were written to tell a person how to successfully run an airplane and it’s engine, based on the instrumentation provided. It was not written to teach engine theory. Generally speaking, you would need to go look for that sort of information outside of aviation circles, although some of the writings for this market have gotten pretty good.

With or without the instrumentation available currently the procedures really haven’t changed, at least from my point of view. People just think they have changed because they’re reading more and understanding a bit more of what is happening instead of just performing rote procedures. My advice and what I teach students is to understand what the engine is doing, then read the flight manual closely. Most questions (including what I believe the OP is after) will be addressed with this approach.

Your recommendation of getting the engine operators manual from the manufacturer is a good idea to supplement the aircraft flight manual. It should however be noted that airframe manufacturers may end up having to place some limitations on the engine and how to run it for various reasons. This is one of the big reasons I suggest reading, understanding, and following the flight manual rather than making things up as you go. Deakin’s writings are also quite good.
 
Follow the ACTUAL POH and not some checklist a prior owner may have made.

Unless someone here is an owner or operator of a similar engined-machine I’m not sure how much wisdom you can glean from random dudes on the interweb.

My plane has a whole different set of numbers, so I can’t even compare.
 
Follow the POH if your RPM is going over red line call your mechanic tomorrow and let them know. You probably need your prop Governor adjusted, should be a really quick adjustment just let them know how much it’s going over into red line.
 
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