Detonation - cylinder destroyed

[PT20J]

3 hours ago, A64Pilot said:

Pretty close I think, I know I was surprised to find that an IO-540’s peak EGT was significantly lower than the lower compression O-540.

‘I can’t prove it, but I suspicion the higher compression engine is more efficient and the lower EGT is from more heat being extracted, these things are heat engines, develop power from expanding air from heat, they don’t get power from “explosions”

Exactly. But, it's not just the air in the cylinders that is heated and expanded to do work; it's the heating and expanding of all the molecules of "substance" (primarily unburned fuel and combustion products) in the cylinder. This is why the maximum power is generated at slightly richer mixtures than stoichiometric. The dissociation at high temperatures frees up oxygen and so more fuel can be added and partially burned. This increases the number of molecules in the combustion chamber. It is the combined force of all the molecules jiggling around due to heating and hitting the piston that creates the force to move the piston down. 

Skip

[jaylw314]

4 hours ago, A64Pilot said:

Pretty close I think, I know I was surprised to find that an IO-540’s peak EGT was significantly lower than the lower compression O-540.

‘I can’t prove it, but I suspicion the higher compression engine is more efficient and the lower EGT is from more heat being extracted, these things are heat engines, develop power from expanding air from heat, they don’t get power from “explosions”

LOL, thanks, I accidentally deleted my post and couldn't be bothered to repost.  They were just toilet seat ruminations anyways 

Edited September 7, 2022 by jaylw314

[carusoam]

Note for Torrey…

There are things we can avoid using the engine monitor…. (Red box)

Things we can see with the monitor… (High CHTs)

The one thing we can’t see, that we are trying to avoid…. (Pre-ignition, detonation, or ping)

Our pistons are made of aluminum…  and melt around 1200°F…

Amazingly are EGTs are a bit more than that… around 1500°F depending on where we are measuring…

Our pistons keep from melting by using a small boundary layer of cool fuel/air mixture….

 

When there is pre-ignition and ping… this boundary layer isn’t enough… EGTs probably don’t change much… CHTs will begin rising…

The CHT rise probably will be buried unless an alarm goes off….

When this occurs… the piston crowns melt within minutes…

The pilot generally gets to traffic pattern altitude  before the piston stops working….

This is similar to having Jet fuel instead of 100LL…

Melted pistons = no power….. oil gets pushed out of the case….

We have seen a Long Body get mis-fueled… Landed safely off the end of the runway… out over the ocean…

 

Essentially, it happens so quickly… at a time where changes are occurring rapidly, normally….

Plan A, land straight ahead…

Plan B, with enough altitude… declare emergency as you turn back…. Avoid the temptations of the fatal 180….

 

Pp thoughts only, not a CFI…

Best regards,

-a-

[T. Peterson]

On 9/8/2022 at 12:58 AM, carusoam said:

Note for Torrey…

There are things we can avoid using the engine monitor…. (Red box)

Things we can see with the monitor… (High CHTs)

The one thing we can’t see, that we are trying to avoid…. (Pre-ignition, detonation, or ping)

Our pistons are made of aluminum…  and melt around 1200°F…

Amazingly are EGTs are a bit more than that… around 1500°F depending on where we are measuring…

Our pistons keep from melting by using a small boundary layer of cool fuel/air mixture….

 

When there is pre-ignition and ping… this boundary layer isn’t enough… EGTs probably don’t change much… CHTs will begin rising…

The CHT rise probably will be buried unless an alarm goes off….

When this occurs… the piston crowns melt within minutes…

The pilot generally gets to traffic pattern altitude  before the piston stops working….

This is similar to having Jet fuel instead of 100LL…

Melted pistons = no power….. oil gets pushed out of the case….

We have seen a Long Body get mis-fueled… Landed safely off the end of the runway… out over the ocean…

 

Essentially, it happens so quickly… at a time where changes are occurring rapidly, normally….

Plan A, land straight ahead…

Plan B, with enough altitude… declare emergency as you turn back…. Avoid the temptations of the fatal 180….

 

Pp thoughts only, not a CFI…

Best regards,

-a-

Thank you Anthony!

 I know I really sound ignorant now, but what is the red box? Is that the high power while very lean regime of which A64 often warns?

Torrey

[Will.iam]

10 minutes ago, T. Peterson said:

Thank you Anthony!

 I know I really sound ignorant now, but what is the red box? Is that the high power while very lean regime of which A64 often warns?

Torrey

Red box starts at approximately 66% power and grows until it’s maximum size at 100% power. We use extra fuel to avoid the red box. We could go extra lean but power would be reduced and the fuel injectors would have to be very well balanced which is hard to obtain. With your engine even at 65% power which is safe at any mixture for the pistons and cylinders, the turbo will be running very close to your TIT limit where the red box would start which is approximately 50 degrees ROP. Either go towards 100 ROP or go toward Peak into LOP. 

[carusoam]

Red box is the lingo used by the Gami people…(?)

Often called red fin by other organizations…

Going to the Savvy website is probably the best place to read a few paragraphs about it…

 

Its all about when to lean, how to lean, and what not to do…

and, with NA engines… at what altitude it can’t be a problem…

With a TC’d engine… see Will’s notes above… select the %BHP that avoids the red box… as PIC you still get to avoid other redlines as well…

Best regards,

-a-

[Will.iam]

Torrey here is your homework assignment for When you need a break from studying your cbt’s.
 https://resources.savvyaviation.com//wp-content/uploads/articles_eaa/EAA_2012-12_red-box-red-fin.pdf

it explains the red box red fin in greater detail. 
 

when you get a free day call me and I’ll fly down and we can get that hamburger. Did you get your plane back from annual yet?

[carusoam]

Nice work Will!

Thanks for sharing the link!

+1 for @Mike_Busch and Savvy… (Mike actually stopped by one day…  )

Best regards,

-a-

[Will.iam]

8 minutes ago, carusoam said:

Nice work Will!

Thanks for sharing the link!

+1 for @Mike_Busch and Savvy… (Mike actually stopped by one day…  )

Best regards,

-a-

Mike also goes on to say that once you find your LOP settings you can go straight there so as to not linger in the red box trying to find peak egt. Which i agree with. He even talks about using the cht personal limit as your leaning boundary but you have to use that method with common sense. I. E. 380 cht in summer is way less power than 380 cht in winter. 

[T. Peterson]

12 hours ago, Will.iam said:

Red box starts at approximately 66% power and grows until it’s maximum size at 100% power. We use extra fuel to avoid the red box. We could go extra lean but power would be reduced and the fuel injectors would have to be very well balanced which is hard to obtain. With your engine even at 65% power which is safe at any mixture for the pistons and cylinders, the turbo will be running very close to your TIT limit where the red box would start which is approximately 50 degrees ROP. Either go towards 100 ROP or go toward Peak into LOP. 

Thanks, Will! You numbah wun smart fella!….for a brand x pilot! Just funnin!!

[Will.iam]

2 hours ago, T. Peterson said:

Thanks, Will! You numbah wun smart fella!….for a brand x pilot! Just funnin!!

I’m just repeating what i learned from mooneyspace archives, John Deakins, and mike busch. They did all the research and data collecting to backup their claims.