More aeronautical physics

Instead of picking and grinning I just fiddle with bits and fiddle with fiddles

Ps = (Thrust - Drag)/Weight * Velocity -- Boyds formula for energy excess or deficiency

Cd (coefficient of drag)

Cd = D/(r times A times.5 times V^2)
where r is air density
A is Area
D is Drag
V is Velocity

Typical Cd of Flat plate 1.28

Induced drag

Cdi = (Cl^2)/(pi * AR * e)
where Cl is lift coefficient
AR aspect ratio of wing (wing_span squared/wing_area)
e is efficiency factor (typically 0.7)

Lift Coefficient

L = (1/2)d v^2 s Cl
L is lift
d is air density
v is velocity (FPS)
s wing area in square feet
Cl coefficient of lift (related to angle of attack coming later)

angle of attack / Cl
0 0.2
2 0.3
4 0.48
6 0.61
8 0.8
10 0.97
12 1.1
14 1.25
16 1.41
18 1.55
20 1.4 i.e stall starting to occur

Density altitude
0 .002377
1000 .002308
3000 .002175
5000 .002048
7000 .001927
9000 .001811
10000 .001755
15000 .001496
20000 .001266
25000 .001065
30000 .000889
35000 .000737
40000 .000585
45000 .000460
50000 .000362
55000 .000285