MAD incorporates a concept called stations. This is simply the location of the ribs along the span of the wing.
For example: if you create a wing with a 30″ (half) span and wanted 3″ rib spacing your stations would be:
0, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30.
Notice this gives you 11 ribs including the root and tip ribs. It’s as easy as that!
Automatic Station Generation
MAD has an “Assist me” menu function to automatically generate evenly spaced stations for your wing. 10 seconds and you are done.
Custom Station Positions
You may not want regular spaced ribs. Perhaps you would like to have extra ribs near the root for additional structure. Maybe you want to move or add ribs to anchor the two ends of an exactly sized aileron or flap. It is very easy to add, remove, and move your stations (rib positions) simply by editing the list of station locations. For example:
0 1 2 4 6 9 12 15 18 20 23 26 28.5 30
This would place ribs at the above positions along the span of the wing. It concentrates more ribs near the root. And perhaps you wish a built up aileron to start at station 18 and extend to station 28.5, so we have stations defined at those locations.
As a designer/engineer you can adjust rib positions to achieve the structure/strength you require along with creating the spacing you need for other structures. It may take a little bit of thought to make everything work out evenly, but that’s half the fun of a new design.
Notice that stations can be any whole or fractional number. 28.5 is allowed, 14.33333 is fine too. Use whatever decimal precision you need to make your design work out the way you want.
Also notice that when it comes time to add other wing features, they don’t have to extend the entire span of the wing. You can specify starting and ending stations for any feature. Thus you may wish to put some thought into your exact station positions as your design evolves.