1.5 pounds of batteries? Your teacher really doesn't know anything about RC. Seriously, you should suggest that the teacher talk with someone who flies RC planes to get some perspective on the project. I did a little bit of math for you, and found that using sub-c 3000mah cells a 1.5 pound battery pack would provide 68 volts. Even going up to 5000mah packs comes out to 46 volts, which is still way more than a typical RC system has. Even allowing that the solder tabs and such are going to cost you some weight and therefore won't allow you to run as many cells, you're still talking about a power system that is not appropriate for RC gear.
And the fuse idea is just foolish. A wattmeter will accomplish the same goal of keeping the contest fair without the negative of having a fuse blow and causing the planes to crash. Fuses are for keeping things from burning up in the event of a failure when you'd rather have the equipment shut down than be damaged. No RC pilot in his right mind would put one in his main power system. If the parameters are correct that you've given us, there won't be a single plane in the class that will make it even once around those pylons if they even get off the ground at all. The amp limit is too low, the electrical system engineering is flawed, and the battery parameters are all wrong, not to mention that it sounds like you are also supposed to design a plane to work with this power system that may or may not be a viable flying machine itself.
It may be an exercise in futility, but I'd be willing to talk with your teacher about designing a project that will be appropriate for beginners, practical, and give a decent chance for success. Feel free to share my user name here and have him get in touch.