question about overboosting NA engines in extreme cold

[aviatoreb]

Yesterday morning at -25F we were getting density altitude of -6500!

 

No I didnt go flying...I got that from a call to the ATIS from the comfort of my own home - for gawking factor.

[carusoam]

1" MP for every 1k'..?

6k' = 6" of additional MP

29.92 0r 30" is normal atmospheric pressure...

6/30X100= 16% increase in HP...

This would equate to about a 50HP addition to a 310HP engine...

Byron and I pegged the sustained 2,000' fpm climb rate the other day with the OAT around freezing.

That equates to a huge chunk of 'excess' power!

Hope I did the math correctly...

Gawking along,

-a-

[aviatoreb]

1" MP for every 1k'..?

6k' = 6" of additional MP

29.92 0r 30" is normal atmospheric pressure...

6/30X100= 16% increase in HP...

This would equate to about a 50HP addition to a 310HP engine...

Byron and I pegged the sustained 2,000' fpm climb rate the other day with the OAT around freezing.

That equates to a huge chunk of 'excess' power!

Hope I did the math correctly...

Gawking along,

-a-

 

Aint it sweet to see your VSI pegged on max >2000fpm?  :-)  I am not sure why those southerners are complaining about winter?  On a white and bright day with still air, blue sky, bright sun and a blanket of sun everywhere - it is gorgeous and fun to fly.

 

So 50hp extra for my 305hp engine is ... Um....maybe over spec?  or said otherwise, my engine produces 38'' at at max certified map in my application.  So effectively 38+6=44.  Yikes!  As I said I keep my little fingers between the black knob and the firewall on arctic days that limits MP by about 3 to 4''.

 

Taking this to a thought experiment for fun - In the movie March of the Penguins I remember that on occasion those poor penguins would get to enjoy -110F temps in their Antarctic winters.  = -78C -> That makes -14,000ft density altitude.  Then 14/30x100=46% increase HP - so that's about 135 extra HP.  That makes my 305hp engine go 440HP which is more like a turboprop-like performer.  Who's in - let's do a winter fly-to Antarctica!

[Houman]

Aint it sweet to see your VSI pegged on max >2000fpm?  :-)  I am not sure why those southerners are complaining about winter?  On a white and bright day with still air, blue sky, bright sun and a blanket of sun everywhere - it is gorgeous and fun to fly.

 

So 50hp extra for my 305hp engine is ... Um....maybe over spec?  or said otherwise, my engine produces 38'' at at max certified map in my application.  So effectively 38+6=44.  Yikes!  As I said I keep my little fingers between the black knob and the firewall on arctic days that limits MP by about 3 to 4''.

 

Taking this to a thought experiment for fun - In the movie March of the Penguins I remember that on occasion those poor penguins would get to enjoy -110F temps in their Antarctic winters.  = -78C -> That makes -14,000ft density altitude.  Then 14/30x100=46% increase HP - so that's about 135 extra HP.  That makes my 305hp engine go 440HP which is more like a turboprop-like performer.  Who's in - let's do a winter fly-to Antarctica!

Erik, I hope you don't mind if we don't join you in your Antarctica experiment, but I would love to see the video after, providing the video, plane and pilot make's it back... lol

[aviatoreb]

Erik, I hope you don't mind if we don't join you in your Antarctica experiment, but I would love to see the video after, providing the video, plane and pilot make's it back... lol

 

But I thought you were tough - I thought you were Canadian MAN!  :-)

[Houman]

But I thought you were tough - I thought you were Canadian MAN!  :-)

Yeah, but I like it warm, already have had enough of this cold weather for this year... looking forward to spring and all summer long flying...

[aviatoreb]

Yeah, but I like it warm, already have had enough of this cold weather for this year... looking forward to spring and all summer long flying...

 

Snow bird. :-O

 

I've still got half a block of arctic hard green wax for my skis.  I Can survive this winter as long as my block lasts.