Will a Gallon make a Big Difference?

[Missile=Awesome]

55 minutes ago, Niko182 said:

The fuel flow comes down to 22.8 because the prop gets pulled from 2700 to 2550 and the MAP gets pulled to 25 in.

Do doesnt climb at full power. He climbs at 25^2.

Is THIS how you climb your Eagle?

[Missile=Awesome]

On 8/18/2020 at 5:16 PM, gsxrpilot said:

What RPM are you using in the climb? I'd try more fuel and less RPM. I've found that a reduction of 50 to 80 RPM in the climb makes a difference in temps.

 

This is what Paul recommended early in the thread...I just have NEVER done this (RPM reduction in climb)...Hmmmmm....

[Niko182]

8 minutes ago, Missile=Awesome said:

Is THIS how you climb your Eagle?

No. Some people have the belief that its nicer on the engine to climb at 25 squared. I have no clue if thats true, but I have always climbed WOT and 2550RPM. Lean as you climb. Keep the CHT's below 380. It's something less to deal with. I don't want to be playing with the throttle as im climbing. It's kind of like taking off with flaps. On a long runway why do so. It's one more thing to forget. Just my personal opinion however.

[Missile=Awesome]

Mike says it’s O.K...That’s how I’m doing it...

[Missile=Awesome]

10 minutes ago, Niko182 said:

No. Some people have the belief that its nicer on the engine to climb at 25 squared. I have no clue if thats true, but I have always climbed WOT and 2550RPM. Lean as you climb. Keep the CHT's below 380. It's something less to deal with. I don't want to be playing with the throttle as im climbing. It's kind of like taking off with flaps. On a long runway why do so. It's one more thing to forget. Just my personal opinion however.

I will try lowering RPM to 2550 at 1k’...I would LOVE to see ALL cylinder temps at or below 380 in the climb.

[carusoam]

Signs of CHT problems show up over time...

It is a balance of rate of heating vs the rate of cooling...
 

Our rate of cooling doesn’t change very much...

• attitude can affect the cooling rate...
• airspeed can affect the cooling rate... (IO550(g)s are rpm limited to 2500... while WOT)
• Excess FF, or °F ROP can greatly affect the cooling rate...

Max heating rate is at 100%bhp... @peak...

If your CHTs are too hot, you get a couple of choices...

• increase FF
• increase IAS / Change the deck angle
• Open the mythical cowl flaps more...
• Cut back on the rate of heating

Looking at the rate of heating... we can adjust it with a coarse or fine approach... We have...

• MP
• RPM
• Mixture/EGT gauge... climbing in the 200 - 300°F ROP range...

Many IO550s use The mixture knob to adjust ROP as MP changes in the climb....

If the engine can’t achieve 300°F ROP... during the climb... it runs out of choices for cooling...

To increase cooling further... reduce the rate of heating... MP and RPM reductions are the only choices left...
 

That is all from inside the cockpit...

From outside the cockpit... increasing max FF is a Mechanic’s job...

Prove to yourself that you want one more gallon...

Because the IO550 is capable of climbing out at 100%bhp... air cooling is going to be a limiting factor... getting the CHTs lower is going to require additional FF...

How much FF do you want... this is a bracketing effort... keeping all things steady... what does 1gph do to your CHTs... you have the flexibility to take away 1gph... how much do the CHTs rise?

An ordinary PP has the skills of getting incredible amounts of useable data...

One of the best resources for the IO550 is the guy that wrote the 310hp STC...  

Not sure why you want to go to anyone else... other than second opinions...

No disrespect meant towards Mike... his input is great... See if he has specific details for the 10550(A)...

See if he can tell you what FF you should be using...

It might take being a member of Savvy... it would be worth it...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Missile=Awesome]

11 hours ago, carusoam said:

Signs of CHT problems show up over time...

It is a balance of rate of heating vs the rate of cooling...
 

Our rate of cooling doesn’t change very much...

• attitude can affect the cooling rate...
• airspeed can affect the cooling rate... (IO550(g)s are rpm limited to 2500... while WOT)
• Excess FF, or °F ROP can greatly affect the cooling rate...

Max heating rate is at 100%bhp... @peak...

If your CHTs are too hot, you get a couple of choices...

• increase FF
• increase IAS / Change the deck angle
• Open the mythical cowl flaps more...
• Cut back on the rate of heating

Looking at the rate of heating... we can adjust it with a coarse or fine approach... We have...

• MP
• RPM
• Mixture/EGT gauge... climbing in the 200 - 300°F ROP range...

Many IO550s use The mixture knob to adjust ROP as MP changes in the climb....

If the engine can’t achieve 300°F ROP... during the climb... it runs out of choices for cooling...

To increase cooling further... reduce the rate of heating... MP and RPM reductions are the only choices left...
 

That is all from inside the cockpit...

From outside the cockpit... increasing max FF is a Mechanic’s job...

Prove to yourself that you want one more gallon...

Because the IO550 is capable of climbing out at 100%bhp... air cooling is going to be a limiting factor... getting the CHTs lower is going to require additional FF...

How much FF do you want... this is a bracketing effort... keeping all things steady... what does 1gph do to your CHTs... you have the flexibility to take away 1gph... how much do the CHTs rise?

An ordinary PP has the skills of getting incredible amounts of useable data...

One of the best resources for the IO550 is the guy that wrote the 310hp STC...  

Not sure why you want to go to anyone else... other than second opinions...

No disrespect meant towards Mike... his input is great... See if he has specific details for the 10550(A)...

See if he can tell you what FF you should be using...

It might take being a member of Savvy... it would be worth it...

PP thoughts only, not a mechanic...

Best regards,

-a-

I have learned a lot about the Missile  engine and cowl as well as operating the engine Safely and properly. We have no cowl flaps. Other owners are communicating their fuel flow as 27.5 minimum at takeoff. We are a gallon below that and experiencing temps over 400f in climb. No desire to experiment with less fuel flow. Do want to experiment with 2550rpm when climbing above 1k. 

[carusoam]

Expect to see the following...
 

The challenge with 2550 is essentially the same...

It will be cooler than 2700... (Typical O3 max climb)

Not as cool as 2500... (Typical O1 max climb)

Specifically because the Rate of cooling will be the same for your plane, but...

The rate of heating will be directly proportional to the FF being converted to heat...

FF is automatically changed with the RPM...
 

As you bring the rpm back, so goes the FF... and the climb rate...
 

The hunt for excess fuel, used for cooling, continues...

That’s the 1 gph (or more) adjustment that we have been discussing.... not available from inside the cockpit... I don’t believe...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

[Missile=Awesome]

8 hours ago, carusoam said:

Expect to see the following...
 

The challenge with 2550 is essentially the same...

It will be cooler than 2700... (Typical O3 max climb)

Not as cool as 2500... (Typical O1 max climb)

Specifically because the Rate of cooling will be the same for your plane, but...

The rate of heating will be directly proportional to the FF being converted to heat...

FF is automatically changed with the RPM...
 

As you bring the rpm back, so goes the FF... and the climb rate...
 

The hunt for excess fuel, used for cooling, continues...

That’s the 1 gph (or more) adjustment that we have been discussing.... not available from inside the cockpit... I don’t believe...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

Yes -a-our annual is this month and both the high and low fuel circuits will be adjusted and flight testing completed.  The modification of RPM is a “band aid” to remedy high temps.  The summer heat and high density are also likely “gone” for a year as well.  THAT will also help.  I have zero problem with a more shallow climb to achieve lower cylinder temps.  The missile covers a LOT of ground while climbing at only 500fpm vs. 1500-1000...BUT I am not going to accept high cylinder temps AND a shallow climb...THAT is not “A Missile”

We will get “it” sorted and I will report back post annual.  Thanks to everyone for their input here.  I hope other future Missile owners can also gain some wisdom from the Mooneyspace knowledge base.