VBA User Form help

[misterminis]

I'm creating a user form to calculate the lift force of a helicopter and the user form always returns a value of 0. Here is my code.
Private Sub calculatelift_Click()
Dim density As Double, velocity As Double, area As Double, lift As Double
'Choosing units for the air density
If kgperm3 Then
p = density
Else
p = density * 2.204622 / 3.2808 / 3.2808 / 3.2808
End If
'Choosing units for the blade velocity
If mpers Then
v = velocity
Else
v = velocity * 0.000621371 / 0.0002778
End If
'Choosing units for the referance area
If m2 Then
a = area
Else
a = area / 3.28 / 3.28
End If
'messaging the force of the lift
forcelift = (0.5 * p * (v ^ 2)) * a * 0.08
MsgBox ("The Force of lift is = " & FormatNumber(forcelift, 1) & "N")

It always reports 0 as the answer.
Thanks

 

[PHV]

You may try this:
FormatNumber(forcelift, 10)

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[combo]

Have you tested p, v and a values just before calculation?In your code all variables: density, velocity, area and lift are local. If nowhere set will stay =0. If you have wider scope variables with the same name, they will be overwritten with those you declared in the procedure.

combo

 

[fumei]

Yes, it may the scope of your variables. You have no parameters passed into the Sub (p, a, v etc.), so they have to be global.

Gerry
My paintings and sculpture

 

[SkipVought]

Hi,

When you do not get the expected result, try using BREAK and Step thru your procedure, using the Watch Window to inspect the variables of interest.

Skip,

_[red][/red]

 

[misterminis]

Thanks everyone. I actually got it to work by dimming p, v, and a instead of density, velocity and area. I did figure that out through break mode, so thanks SkipVought and everyone else.