climb power

[Planegary]

I was flying with a younger instructor the other day and he wanted me to pull my climb power back to 25/25.  I read I believe in a Continental and Lycoming book to climb at firewall on settings back in the 90's. Have I missed an update or is it that this young guy got old info ? don't want to do anything wrong but I have been flying this way for years and I believe even the climb charts are for firewall power. Any input would be appreciated

[Hank]

That's how I climb--all levers fully forward. Doesn't matter if it's leaving the airport, or if ATC told me to go higher.

[Fly Boomer]

36 minutes ago, Planegary said:

I was flying with a younger instructor the other day and he wanted me to pull my climb power back to 25/25.  I read I believe in a Continental and Lycoming book to climb at firewall on settings back in the 90's. Have I missed an update or is it that this young guy got old info ? don't want to do anything wrong but I have been flying this way for years and I believe even the climb charts are for firewall power. Any input would be appreciated

Some might pull the prop back a bit during climb or cruise climb, but many leave the throttle firewalled until they want to come down.  If you are normally aspirated, the manifold pressure will come down with increasing altitude, so not much benefit to pulling it back prematurely.

[Pinecone]

25/25 climb is VERY old school.  It is what I used in the 80s.  More up to date is to climb full throttle, full RPM.  For turbo, full rich.  For NA, lean to about the same EGT as take off once at a moderate altitude'

 

[N201MKTurbo]

I climb at 30" 2700 RPM full rich.

[BDPetersen]

Funny how ancient ideas carry forward and never die,

[N201MKTurbo]

It amazes me that people take the word of a freshly minted flight instructor that has never been out of the training environment, as sage advice.

[Shadrach]

We are flying the same power plant so I will give an exact SOP.

 

1. All knobs forward for take off. 
2. Positive rate, gear up
3. Flaps up ~85MIAS.
4. Pitch for desired climb speed. I use ~120MIAS for cruise climb. Less if I’m light.
5. If noise is a concern reduce RPM to 2500 as soon as practicable 
6. Reference leanest Cylinder and maintain EGT ~1250 +/-30° depending on hottest CHT.
7. Cowl flaps closed 25’ below target altitude.
8. Level and set desired RPM and mixture

[Shadrach]

6 hours ago, N201MKTurbo said:

It amazes me that people take the word of a freshly minted flight instructor that has never been out of the training environment, as sage advice.

Flying with a 250hr CFI is a weird dynamic. I’m guessing it’s much like a seasoned NCO having to answer to a green officer fresh out of OCS. 

I’ve flown with some really good, low time instructors, they know they are there to observe that I am meeting standards. Beyond that, they are eager to learn.

[Planegary]

Exactly how I have done it. On climb out I dial the prop til I see a movement and stop there but the instructor wanted the manifold at 25. I explained that in a minute it would be below 25 (I am naturally aspirated) but he wanted power reduced  I explained that was a reduced power climb but I cannot for sure remember where / when I got the update to fly max not 25/25 just that it was mid 90’s. Anybody remember reading about it?

[midlifeflyer]

1 hour ago, Pinecone said:

25/25 climb is VERY old school.  It is what I used in the 80s.  More up to date is to climb full throttle, full RPM. 

 

This.
 

The only power reduction I teach is an optional  reduction in prop RPM for an enroute climb with a little less noise and vibration. 

[N201MKTurbo]

You could refer to the POH.

 

[TheAv8r]

I was also taught the 25/25, for me it's more temperature dependent than anything, I always go full power to 1k feet for safety to get up to altitude as quickly as possible, after that if the engine is running hot I will often reduce power and pitch down to keep the engine cool, particularly because my airport is under the Bravo and I often can't jet right up to altitude as quickly.

[Shadrach]

22 minutes ago, N201MKTurbo said:

You could refer to the POH.

 

I have and it unfortunately it says:

 Recommended power setting for normal climb is 2600 RPM and 26 inches manifold pressure.

That climb setting works but it seems optimized for a specific set of outcomes...namely reducing climb performance and increasing oil and cylinder head temperatures. On the upshot, at least it gives you more to do during the initial climb phase.

[Fly Boomer]

1 minute ago, Shadrach said:

On the upshot, at least it gives you more to do during the initial climb phase.

And, really, who wouldn't want more to do?

[Pinecone]

1 hour ago, N201MKTurbo said:

It amazes me that people take the word of a freshly minted flight instructor that has never been out of the training environment, as sage advice.

And many of them have no experience in a complex aircraft these days, as the Comm  requirement allows a TAA.  So you have have a multi hundred hour CFI that has never flown anything other than a C-172 or Cherokee.

[Pinecone]

24 minutes ago, TheAv8r said:

I was also taught the 25/25, for me it's more temperature dependent than anything, I always go full power to 1k feet for safety to get up to altitude as quickly as possible, after that if the engine is running hot I will often reduce power and pitch down to keep the engine cool, particularly because my airport is under the Bravo and I often can't jet right up to altitude as quickly.

I leave the power up and put the nose down a bit for more airflow for cooling.

[Pinecone]

1 hour ago, Planegary said:

Exactly how I have done it. On climb out I dial the prop til I see a movement and stop there but the instructor wanted the manifold at 25. I explained that in a minute it would be below 25 (I am naturally aspirated) but he wanted power reduced  I explained that was a reduced power climb but I cannot for sure remember where / when I got the update to fly max not 25/25 just that it was mid 90’s. Anybody remember reading about it?

I recall the shift starting in the 90s, but not taking firm hold until the early 2000s.

So you could have a new CFI telling you to do something that was debunked before they were born.

 

[PT20J]

A lot of light single engine airplane flight manuals call for climb at approximately 75% power. There may a reason for it (cooling, noise, ??) or it may be a carryover from higher powered engines that had time limits for takeoff power (common with radials).

If it’s not listed as a limitation, you don’t have to observe it. If a CFI insists, I’d do it his/her way and discuss it on the ground. Learning works both ways. Students have taught me lots of useful things.

[Shadrach]

1 hour ago, Pinecone said:

And many of them have no experience in a complex aircraft these days, as the Comm  requirement allows a TAA.  So you have have a multi hundred hour CFI that has never flown anything other than a C-172 or Cherokee.

Or more often than not, some obscure, eastern European, plastic airframe with a couple of big screens and a little Rotax out front. 

[Planegary]

1 hour ago, Shadrach said:

I have and it unfortunately it says:

 Recommended power setting for normal climb is 2600 RPM and 26 inches manifold pressure.

That climb setting works but it seems optimized for a specific set of outcomes...namely reducing climb performance and increasing oil and cylinder head temperatures. On the upshot, at least it gives you more to do during the initial climb phase.

I understand but on my plane it was from 1965 and the reading I had been doing was a little more current but this is what I needed. Info to see if I am not doing things properly or just using more current engine manufacturer information

[Shadrach]

19 minutes ago, Planegary said:

I understand but on my plane it was from 1965 and the reading I had been doing was a little more current but this is what I needed. Info to see if I am not doing things properly or just using more current engine manufacturer information

That line was copied and pasted from my 1967 Owner's handbook.  I do not think that full power climbs were recommended by manufacturers until sometime in the early 90s.  I say this because when I learned to fly in the late 90s it was still a somewhat contentious subject though not as controversial as LOP ops.

[Bolter]

3 hours ago, N201MKTurbo said:

You could refer to the POH.

 

Not the same engine, but the much higher power 310 HP Ovation POH (supplement with the STC) endorses running full throttle and 2700 rpm for takeoff and demanding climb conditions. 

[RescueMunchkin]

What are the pros and cons of full throttle climb from sea level? I was taught 25/25 and trim for 500fpm climb once clear of obstructions and have been using it to be easier on the engine (I'm never in a rush when flying).

[Ragsf15e]

25 minutes ago, RescueMunchkin said:

What are the pros and cons of full throttle climb from sea level? I was taught 25/25 and trim for 500fpm climb once clear of obstructions and have been using it to be easier on the engine (I'm never in a rush when flying).

Unfortunately the older POHs have some version of this, mine has 26/2600.  So there will always be a way for someone to say you should reduce power…

However, in the last 30-40 years, people realized that the engine is rated for max continuous power, so you’re not actually doing anything against the engine operating limitations by climbing full power.  Additionally, you climb faster, cooler and get to a cruise power setting that maximizes engine longevity sooner.  From takeoff, it only takes a couple thousand feet to get your MP below 26in anyway so that one is self limiting in the climb.

It is s little louder inside and outside the aircraft.
 

You will see a significant improvement in rate by using full throttle and full rpm in climb.  Depending on your aircraft and conditions, 110-120kts is good to keep the chts happy and have a comfortable attitude.

Edited May 23, 2024 by Ragsf15e