Upper deck pressure

Let'sgoflying!

Touchdown! Greaser!
Joined
Feb 23, 2005
Messages
20,261
Location
west Texas
Display Name

Display name:
Dave Taylor
Just for curiosity I am trying to get a feel for how much pressure (or force) is on those rubber connecting hoses attaching the large metal tubes of the induction system of a TSIO-550.

The turbos generate 38.5" MP. At sea level the outside pressure is 30".
How much is that in psi?
It is as easy as 38.5 minus 30 = 8.5psi (edit this should be mmHg) and google says that is 4 psi?

If so does that also mean at fl180 (if the turbos can still do 38.5psi) where the ambient pressure is 15" the diff is 23.5" or 11.5psi?

I have heard of these hoses letting go and causing a boom, I just wondered if it was a 'boom' or a 'BOOM!'.
 
Last edited:
Just for curiosity I am trying to get a feel for how much pressure (or force) is on those rubber connecting hoses attaching the large metal tubes of the induction system of a TSIO-550.

The turbos generate 38.5" MP. At sea level the outside pressure is 30".
How much is that in psi?
It is as easy as 38.5 minus 30 = 8.5psi and google says that is 4 psi?

If so does that also mean at fl180 (if the turbos can still do 38.5psi) where the ambient pressure is 15" the diff is 23.5" or 11.5psi?

I have heard of these hoses letting go and causing a boom, I just wondered if it was a 'boom' or a 'BOOM!'.

Your car cooling system has rubber connecting hoses maintaining 16 pounds circulating coolant over 170F. Have many failures? Rubber hoses don’t fail often under low pressure
.
 
Last edited:
Just for curiosity I am trying to get a feel for how much pressure (or force) is on those rubber connecting hoses attaching the large metal tubes of the induction system of a TSIO-550.

The turbos generate 38.5" MP. At sea level the outside pressure is 30".
How much is that in psi?
It is as easy as 38.5 minus 30 = 8.5psi and google says that is 4 psi?

If so does that also mean at fl180 (if the turbos can still do 38.5psi) where the ambient pressure is 15" the diff is 23.5" or 11.5psi?

I have heard of these hoses letting go and causing a boom, I just wondered if it was a 'boom' or a 'BOOM!'.
Nope....the math doesn't work that way. Here's a link to the conversion.

the delta P between 38.5" and 30" is....3.8 psi
 
Your car cooling system has rubber connecting hoses maintaining 16 pounds circulating coolant over 170F. Have many failures? Rubber hoses don’t fail often under low pressure
.

That's another question I had, how hot is the compressor discharge?
And I know they bust - have talked to pilots experiencing it. Yes, maybe rare but they do. Probably due to mx inattention.
 
What did I say, 4 psi? This is just an approximation!
well...you were subtracting inches of Hg and noting it as 8.5 psi....that doesn't compute. :D


the "Boom" you speak of comes from a greater pressure differential "at" altitude pressures. 30" is a sea level pressure.
 
What about the temperature?
I know there are some practicing Thermodynamacists here!

incoming air 10C
pressure change +4psi
losses and other factors
typical (approximate!) resulting temp?

Probably easy enough to find a calculator on google.

Right after that, you know I'm going to ask T after passing through the intercooler, be ready!
 
Reading accident and incident reports (sick hobby) I will note that most "turbo failures" appear to be nothing more than a hose popping off due to poor clamping. I've not found one that has burst (though I've seen one, but that was due to a backfire!) If you read Peter Garrison's blog (http://www.melmoth2.com/texts/Progress.htm) he notes the pressure on his soon-to-be-installed modified intercooler will try to blow off the ends with about 350 lbs. of force.
 
Back
Top