Amen to thegolfpimp. If they have included it in the material, learn it, after all it is called the motivation paper for a reason ;-) Although there was only 3 or 4 questions on them in my stage 1 paper, still 3 or 4 easy marks if you ask me
This question does get asked an awful lot, if i were in your shoes try to categorise them all into different classes of aircraft and then at least you'll know what size aircraft you're dealing with in the paper.
Best of luck anyway.