Calculated Industries Hot Rod Calc 8703, User Manual

Page: 23 / 70

H
OT
R
OD
C
ALC
™ — 21
conditions are an unseasonably chilly 33° F, absolute pressure of
28.77 in Hg, and a relative humidity of 64% at 8:30 a.m.
Calculate the Air Density Index (ADI) and Density Altitude for this
example.
KEYSTROKES DISPLAY
 0.
1. Enter current local measured weather conditions:
   TEMP S 33. °F

(Absolute Pressure)
P-ABS S 28.77 INHG
  
(Moisture/Relative Humidity)
RH% S 64. %
2. Calculate ADI and density altitude:

ELEV S 0.
 ADI 101.002 %
 D-ALT - 341.909 F
While these weather conditions at Firebird International Raceway
are unlikely, this example demonstrates an ADI value of over 100%
which is certainly a possible situation. As stated previously, air
density is typically over 100% when temperatures are well below
60 °F.
Calculating ADI and Density Altitude
Using Elevation
For this example, you are at Top Gun Raceway in Fallon, Nev.,
and only have access to air temperature and humidity data.
However, you know the track’s elevation is about 3,963 feet
above sea-level. With these three variables — air temperature,
humidity, and elevation — you can still calculate ADI and Density
Altitude. The current weather conditions are posted as 51° F and
5% relative humidity at 9 a.m.