Mailing List flyrotary@lancaironline.net Message #2366
From: Marko Bewersdorff <marko@bewersdorff.com>
Subject: RE: [FlyRotary] Re: Cooling?
Date: Sun, 3 Aug 2003 12:58:36 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

doesn't that formula depend on absolute temperature like kelvin or so? where zero degree is minus 459 degree F or minus 273 Celsius.
the ratio of expansion should be something like:
inlet air: 20 degree Celsius (68F) or 293 Kelvin
outlet air: 50 degree celsius (122F) or 323 Kelvin
then
323 over 293 for a change in temperature gives
then the Volume change of more like 1.2

there is some additional expansion due to the pressure difference.

 

Regards

Marko

I started finally welding my engine mount for my turbo rotary long ez

 
here are a bunch of excel numbers:
 

Inlet temp in degree: Outlet temp in degree: Change in
F C K K C F volume
68 20 293 303 30 86 1.03
68 20 293 313 40 104 1.07
68 20 293 323 50 122 1.10
68 20 293 333 60 140 1.14
68 20 293 343 70 158 1.17
68 20 293 353 80 176 1.20
68 20 293 363 90 194 1.24
68 20 293 373 100 212 1.27
68 20 293 383 110 230 1.31
68 20 293 393 120 248 1.34




-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Al Gietzen



The ratio should be more like 1.6 to 1.8.  Do the math - air expands directly proportional to temp - so in at about 80 F and out at about, say, 130 to 140; gives a ratio of 1.7.

Al

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