stall speed

[erman152]

Hi I just need to Calculate the stall speed (no flap) at maximum take off weight of a Cessna 172 also has a span of 36 ft 1 inch and a wing area of 174 ft2. The MTOW for the Cessna 172 is 2,450 lb. Base your initial Reynolds Number calculation on ISA sea level conditions and a nominal flight speed of 70 KTAS. Standard roughness of wing surfaces should be assumed.



I have the formula

V= sqrt ( 2 W n / P S Cl max)

where W = weight 2450lbs
P = air density at sea level
S = wing area 174ft ^2
Cl Max = 1.2 got that from the graph



I just cant work out what I have to do for "n"

I have the formula n= 1 / cos ᵠ

But I dont know how to use it

If someone could help me I would greatly appreciate it :)

[Genghis the Engineer]

If you are an aero-eng student past your first month, you may fail your degree! If you aren't, I've no idea why you're doing this..

n = the amount of g being pulled, normally 1 in this calculation. The symbol you have is for bank angle, which again should normally be zero.

I would strongly recommend working in SI units, use of fps units is fraught unless you are very used to using them.

G

[erman152]

I am an aero eng student and I am in my first month..this is why I didnt know what the n standed for. Thank you for your help.

[Genghis the Engineer]

Fair enough.

N = Nz = normal acceleration, commonly called "g".

You and I are (I assume) currently sat at Nz=1.

Nx = acceleration along the longitudinal axis, Ny is acceleration along the wingtip to wingtip axis.

G