I have been building for a while now and I still have some difficulty with terms.
Regarding terms for the fin edges.
Leading/forward edge I get
Trailing/rear edge I get
To me, both Root and Base edge BOTH refer to the part that sticks to the rocket. I call this the Root edge.
Is there a standard term for the Lateral Edge (maybe it IS just called “Lateral Edge”)?
I did a search and found this
https://www.rocketryforum.com/threads/fin-surface-nomenclature.10393/
But still didnt answer my question
Also the drawing post 3 has the sweep angle wrong, it should be from leading edge to root.
Also not sure why #6 is labeled “Semi Span” instead of just span
If you paper fins and the fins are perfect square or perfect diamond shapes, make sure to keep track of the grain direction, a few light pencil marks on the paper do the trick and are easily covered by paint. Don’t use pen, it may bleed through paint.
Square edge fins (no rounding or tapering) are certainly not aerodynamic, but for sport rockets they work great and often look very stylish (see Estes FlutterBye). Papering is easy, just leave edges that fold over. Leaves you with no raw balsa edges to seal or finish or taper or round or anything.
One trick for getting your paper clean to the root edge but not over it: Oversize the span/width of your fin when you cut it, so maybe 1/8 “ or 1/4” extra at the root. Paper all the way to the root. When dry put your normal (non-supersize) template on the fin and mark in pencil where the Root edge should be. Use knife and metal ruler and cut here. You will have a perfectly glued clean paper/balsa edge. As a plus, if you extend that edge 1/4”, after you paper it you have an extra bit of room you can put a couple of clothes pins on which won’t contact your final finished edge. You can use the pins as handles (keep those gluey fingers off the paper!), even use the pins as stands to allow the fin to dry. Again, once dry pull the clothes pins off and cut the Root Edge line at the correct spot.