Let me explain it.
Module research points and plane research points are not the same. One unlocks modules, the other unlocks planes/tanks, and they're not interchangible. What Aseaheru means is that the amount of module RP you get is the same as the amount of Plane RP, before modifiers.
You can research only 1 tank or 1 plane at the same time. As the matchmaking uses the highest BR (battle Rating) amongst your planes, I suggest researching planes of equal battle rating and moving your way up.
Convertible (or free RP, as it was called a few updates ago, is useless.) Unless you convert it, you get nothing. ((Btw, don't convert them. If you want to spend Eagles, buy a premium plane or Talisman instead. More RP for your money)). Speaking of which, some (short) tutorials award you Golden Eagles (premium currency), so you should do those.
Now, I mentioned modifiers earlier. Mostly, these are ignorable. Using a Rank X plane means that you get 100% RP for Rank [X-1 to rank X+1] planes. For the next Rank difference, it's 90%, and afterwards I think only 50%. As such, try to limit the rank spread between your craft, and the one you're trying to research. Using the preferred research plane (Ie, the one in the rank below researches at 110%).
Also, you can't research planes by flying tanks or vice-versa, but the 2X daily bonus is shared. (So if you get a tank victory, the bonus is used up and you can't use it for a plane match)