If the formula you created for the plane's motion doesn't keep the plane on the screen the whole time, you may want to create a sub-VI the verifies that the plane is on the screen.
SubVI inputs:
1. Circle dimensions: Center X, Center Y, Radius (either separately or in a cluster).
2. Position cluster from the formula calculating the plane's position).
SubVIs output:
Boolean showing whether or not the plane is in the specified circle.
The sub-VI can use Pythagorean's Principle to calculate the distance from the center of the circle to plane. If the distance is less than or equal to the radius of the circle, the plane is within the circle: make the output TRUE. If the distance is greater than the radius of the circle, the plane is outside of the circle: make the output FALSE.
Using Pythagorean's Principle, distance of the plane to the center of the circle = the square root of ((position X - center X) squared + (position y - center y) squared).
You'll calculate the circle dimensions (radius and center x and y) using a property node of the radar screen indicator. Center x =left + width/2; Center y = top + height/2. If the indicator is a circle, the radius of the circle = width/2 = height/2.
Calculate the circle dimensions once before you start your loop. For easier wiring, bundle them into a cluster and make the subVI's input a cluster.
On each property node you're using to set a plane's position, right-click and select Add Element. Right-click on the new element that was just added and select Properties >> Visible. Place an instance of your new subVI close to the property node, wire the desired position and the circle's dimensions to the subVI. Wire its boolean output to the Visible property you just added to the property node. Add the visible property and the subVI for the property node for each plane.
This way, when the plane reaches the edge of the radar screen, the plane will disappear. It will appear back on the screen as soon as the formula puts it back within the radius of the circle. Depending on the formula, it may never come back on the screen, but that's a legitimate case: a plane flying through and continuing will be on the radar screen as it passes through, and then it's gone.
Double check your formula for calculating the position of EK 781. In the Position cluster to the property node, the top element is Left; the bottom element is Top. For EK 781, you're calculating its Left based on the Top and Height of the radar screen. You're calculating its Top based on the Left of the radar screen. Your formula for EK 781 Top = radar screen left + (2 / radar screen left). I don't think any of that is what you intend to do. What is this formula supposed to do?
For BM 110, you use the radar screen Left in the calculation for BM 110 Left and BM 110 Top.
I would expect that the plane's left is based on the radar screen left and the plane's top is based on the radar screen top.
