Easiest way to figure out if the fan is AC or DC is to turn it on. Then, simply unplug the camper electric cord from shore power. If the fan keep running, its DC (provided you have a battery hooked up on your camper). If it stops, it's AC.
Here's one way to do it. If the motor is perfectly fine and it's only the blades that are broken, then do some good measurements and purchase a new fan from Lowe's or Home Depot, or somewhere like that. Then, use the blades from the new fan, toss out the rest of the new fan, and save parts from the new one for some other project.
IF you cannot find a fan replacement, this might be the easier way to accomplish the mission! (Use parts from a new one on the old one).