Climb Setting question

[jaylw314]

5 hours ago, Hank said:

Target EGT requires writing down the EGT on takeoff in a standard day at sea level (or as close to it as you can get), this becomes your Target. As you climb, periodically lean to this particular Target EGT. Use this same Target EGT for subsequent takeoffs andnclimbs to altitude. Or use Bob's KISS method. 

Ooops, you're right.  I forget because my home bases have always been at or near sea level, and we get a lot of standard day type weather here in the Pacific NW.

[mike_elliott]

5 hours ago, gsxrpilot said:

For turbo Mooney drivers, it's one step easier. WOT, 2700, Full Rich... all the way to altitude, which might be in the flight levels.

except for the TIO360LB 231's

2 hours ago, Davidv said:

Anyone here with a Bravo to weigh in?  I was actually wondering the same thing since I've been using both low and high power settings but want to do what's best for engine.

David, reduce to 34" once out of the kill zone, then climb to cruise altitude. Once there, reduce to cruise settings with all of the money knobs.

[Davidv]

Thanks Mike! Yes, I go from 38 to 34 once over 500 ft but sometimes climb at 32 once I pass a few thousand to keep things cool.  I’ll try keeping it at 34 and stick with a richer mixture and flatter climb until I can level off and close cowl flaps.

[rxo188]

Max RPM and WOT. EGT 100+ish ROP. I've done lots of climbs to 12.5. Use your ram air in dry VMC.

[skydvrboy]

1 hour ago, rxo188 said:

Max RPM and WOT. EGT 100+ish ROP. I've done lots of climbs to 12.5. Use your ram air in dry VMC.

I'd study up a bit on Target EGT and the red box.   I got chastised pretty hard on here in my very first post for mentioning that I climb 125 ROP, being told that was too lean.  In looking at the engine performance charts (peak ICP & CHT) 100 ROP in a climb is just about the worst place for your engine to run.

Here would be a good start for reading. https://www.jpinstruments.com/wp-content/uploads/2013/05/Mike-Bush-Red-BoxRed-Fin.pdf

I'm sure someone more knowledgeable than me will be along shortly to point you to some better reading material.

[Shadrach]

9 hours ago, larrynimmo said:

if my plane weight is in the mid range, I typically can climb at about 800 ft per minute until I get to about 5,000 msl...leaning as I go and I am at full throttle by 6,500msl

So why do you reduce power for initial climb? What’s the benefit?

[Shadrach]

7 hours ago, Cyril Gibb said:

You might consider the possibility your instructor may be providing incorrect guidance on topics other than just the "squared" nonsense.  Perhaps trying a different instructor would be in order.

Instructors have to ride a fine line. Deviation from the POH can appear antiauthority. My POH recommends 26”x2600rpm. It’s an arbitrary power setting that is likely based on little more than the bygone notion that the climb should entail some sort reduction from takeoff power. I always climb WOT but sum times reduce rpm if departure control keeps me low over a populated area. 

Does any one know what the POH for the 77J model recommends?

My POH has a number of lousy recommendations. The drag and drop short field landing technique described is less than optimal.

[larrynimmo]

23 minutes ago, Shadrach said:

So why do you reduce power for initial climb? What’s the benefit?

only 12gph at a decent climb rate and forward speed, and achieving great cooling for the engine.  Also a lower RPM should result in longer engine life...(I would think)

[Shadrach]

2 hours ago, rxo188 said:

Max RPM and WOT. EGT 100+ish ROP. I've done lots of climbs to 12.5. Use your ram air in dry VMC.

An IO360 will handle that kind of abuse, but that doesn’t mean it’s a good idea. I know some old Bob Kromer articles suggest 100ROP in climb above 3000’, but it’s hard on the cylinders and gains you little in climb performance.

[Shadrach]

2 minutes ago, larrynimmo said:

only 12gph at a decent climb rate and forward speed, and achieving great cooling for the engine.  Also a lower RPM should result in longer engine life...(I would think)

As compared to what? I would wager that if you compared a WOT/max RPM climb to your reduced power climb profile, you’d find that you arrive at altitude later and hotter with only a small savings in fuel. The difference in RPM will have no effect on the life of those cylinders.

[MIm20c]

One thing I’m certain of is the io-550 and the o-360 create a lot more heat in the cylinders at 2700 vs 2500. This heat can normally be held to safe levels with airflow and fuel. But if it can’t the power should be reduced. 

Too many variables to put cylinder heath directly related to climb habits.  It might be that a consistent 75% cruise-climb, cruise, and decent is far better on an air cooled engine than a 100/65/50% strategy. Biggest problem IMO is all the engines sitting a decade with less than 10 hrs per year. Do what feels right and makes you (or your instructor if he’s good) happy!

[ArtVandelay]

High horsepower comes from high ICP...it’s the timing of the pressure peaking that is important. The red box seems like an arbitrary limitation, derived from ICP.


Tom

[M20F]

20 hours ago, Hank said:

Reducing power just makes your climb to altitude take longer at a lower airspeed, whuch reduces cooling airflow through the cowl.

It takes longer because you climb less FPM but you should still be climbing at Vy or published cruise climb (IAS) so same airspeed and airflow through the cowl.  Only thing changing is FPM and Groundspeed. 

[M20F]

2 hours ago, Shadrach said:

Instructors have to ride a fine line. Deviation from the POH can appear antiauthority. My POH recommends 26”x2600rpm. 

I dial back to 2600 rpm because it is a lot quieter, I notice no discernible difference in FPM and works for rayjay/prop limitations (26/26 is what I use all the way up till I stop).

Parasitic drag is a real thing, very little gained using 100% versus something less other then burning a lot of gas. 

[Two7Victor]

1 hour ago, M20F said:

I dial back to 2600 rpm because it is a lot quieter, I notice no discernible difference in FPM and works for rayjay/prop limitations (26/26 is what I use all the way up till I stop).

Parasitic drag is a real thing, very little gained using 100% versus something less other then burning a lot of gas. 

Was there a Rajay revision that allows 2600 rpm continuous?  the latest I have for my M20F is 27 x 2500 max continuous between 3500 and 20000 (From Feb 1985)

[Cyril Gibb]

2 hours ago, ArtVandelay said:

...it’s the timing of the pressure peaking that is important...

A true statement that inevitably ends in OWTs.  Although our engines have fixed timing BTDC, we can use the mixture and prop to have at least some control over peak ICP and the desired degrees ATDC for the peak.

Knowing that mixture burn speed essentially peaks at the ideal stochiometric ratio and the burn slows either rich or lean of that is one control (mixture).  Using a higher engine speed to delay the peak or slower engine speed to peak earlier is another (prop).

[Shadrach]

1 hour ago, M20F said:

I dial back to 2600 rpm because it is a lot quieter, I notice no discernible difference in FPM and works for rayjay/prop limitations (26/26 is what I use all the way up till I stop).

Parasitic drag is a real thing, very little gained using 100% versus something less other then burning a lot of gas. 

I appreciate that your rajay requires climbing at 26”.  For the purposes of this discussion, parasitic drag is ralated to speed not power. Furthermore, for a given velocity, drag is less in climb then in it is in level flight at the same velocity.  Climb performance is a function of reserve power. A 10% reduction in rated power is a far greater percentage of reserve power. Using my airplane’s SL 1055fpm book ROC at MGTOW 2740lbs, a 10% power reduction would result in a calculated 22% loss in ROC. A 20% reduction results in a calculated ROC loss of 45%. This stuff is not my opinion, it’s physics. It’s well understood by every columnist from Deakin to Busch to Hirschman.

Edited March 6, 2019 by Shadrach

[David_H]

I'm also in the camp that pulls back to 26 squared after obstacles are clear, flaps are cleaned up for the climb, and the trim is largely settled in.

This seems to be quieter, pulls the prop off the stops, and burns less fuel with very little performance degradation. 

That said, I wouldn't be hesitant at all to climb out with the prop full forward if the situation called for it.

I cannot think of a good reason to start the climb at less that 26 squared.

[laytonl]

10 hours ago, Oldguy said:

In my J, I use WOT, full prop, and V_x climb to 1,000' then nose over and keep a 115-120 kt. climb until it drops to 500 FPM. Then it is whatever speed will maintain 500 FPM until my cruising altitude. During the climb, I start leaning at 3,000' to maintain my takeoff EGTs. Once at cruise, it is nose over, close up cowl flaps, set prop to 2,500 RPM, and lean to my desired EGTs. In flight climb is WOT, 2,600 RPM, enrich fuel, open cowl flaps, and keep 105-110 kt. climb.

Down here in Alabama in the summer, this typically keeps my oil temp below 200 and my hottest CHT is <360 dF.

John, that’s exactly my profile too, lee

[carusoam]

One interesting thing falls out of the ‘my CFI told me to do it this way...’ logic..

Often the CFI is following the house rules, and their logic is very often based on time.... not based on distance flown...

A typical MSer’s flight is based on having someplace distant to get to....   And that... makes all the difference...

When renting a plane, wet... climbing and cruising at WOT for an hour... is going to cut into the standard economics they want to follow...

When flying your own Mooney... climb at the highest ROC that you can while keeping forward speed and CHTs as a priority...

If your Mooney has a 310hp IO550... The FF max standard setting is 27.2gph (?)... people have been known to bump this max FF setting to a higher rate 28, 29, or 30gph depending who you read....

30gph sound terrible... but the ROC has been bumped to about 2k’pm... so you are not in the climb for all that long.....

Keep your eyes on the objective...

• Return to Point A within the hour.... save fuel as much as possible...
• Be at Point B as quickly, efficiently, and safely, as soon as practicable...

We have the skills and the instruments that school planes and student pilots just don’t have...

PP thoughts only, not a CFI...

Best regards,

-a-

[MATTS875]

22 hours ago, Bob_Belville said:

BTTW. 

Above about 3000' lean mixture slightly to ~ 300 ROP EGT. Above about 6000' lean to ~ 200 RoP EGT.

Thanks for the help

[MATTS875]

12 hours ago, Bob - S50 said:

Here are a couple good articles for you to read.  The first one is pretty long but is excellent for learning what is happening in your engine and why.  The next two will address your question.  There are LOTS of other articles there so browse through the list and see what else looks interesting.

Mixture Magic - John Deakin

Takeoff and Initial Climb

Climb

Great information. Thanks

[Hank]

4 hours ago, MIm20c said:

One thing I’m certain of is the io-550 and the o-360 create a lot more heat in the cylinders at 2700 vs 2500. This heat can normally be held to safe levels with airflow and fuel. But if it can’t the power should be reduced. 

Too many variables to put cylinder heath directly related to climb habits.  It might be that a consistent 75% cruise-climb, cruise, and decent is far better on an air cooled engine than a 100/65/50% strategy. Biggest problem IMO is all the engines sitting a decade with less than 10 hrs per year. Do what feels right and makes you (or your instructor if and ’s good) happy!

Why pull power to descend??? I only make two changes from cruise to descent:  push yoke forward to establish 500 fpm descent and trim away forces; periodically reduce throttle and advance mixture to keep cruise MP & EGT settings. Climbs start at 100% power, but that declines as altitude increases, often to ~65%, so Climb is 100-65%; Cruise is 65%; Descent is also at 65%.

[carusoam]

Another interesting topic...

at high rpm... the prop is resting on the stops...

I thought that for a long time...

thinking if my govenor breaks... my O360 is going to hit max rpm and I can fly around at max power and 2700 rpm...

 

Then one day... my gov leaked it’s fluids internally... and max power was well beyond 2700rpm.... in overspeed territory....

Fair enough, i’ll Pull the power back some to keep 2700 rpm with my newly fixed pitch O360...

Pulling the prop back so 2700rpm is maintained, is no where near max power... 

getting the gov’s leak figured out became an immediate top priority...

So don’t expect that your prop’s blades are actually sitting on the mechanical stops...

We can always ask Cody about this detail...

PP thoughts only...

Best regards,

-a-

[M20F]

1 hour ago, Two7Victor said:

Was there a Rajay revision that allows 2600 rpm continuous?  the latest I have for my M20F is 27 x 2500 max continuous between 3500 and 20000 (From Feb 1985)

No there wasn’t