At the last part of the Flying Machine level in the Goblin Menace, you need to finish assembling the machine by picking up two propellers. The first was found easily, but the second appears to be connected to the ceiling with an unbreakable rope.
There's a flame on the left (not currently activated in the screenshot above), but it's blocked, and I haven't any idea how to cut the rope. The space to the left and underneath the propeller are blocked.
Best Answer
Turns out the fire was a dud - you can't use the fire to burn the rope. Instead, the fire is there to limit the amount of time you can use an item to jam the plank open. Using the other propeller, which is fireproof, I jammed the plank open, then used the thief's explosive arrow to cut the rope.