Now this is a puzzle that I've been really excited about getting for quite some time now. It is my first puzzle by the mysterious 'Roger' (RD), a German puzzle maker who is well known for making very high quality puzzles that also tend to be really hard to get hold of. This particular puzzle is called 'Propeller':
The Propeller essentially only has two main visible parts, these are the propeller itself which is at the front (this includes the circular plate that is actually attached to it) and the main body which it is attached to. There are three Allen key bolts that can be seen in the photo, one of them holds the propeller onto the main body of the puzzle and the other two bolts are firmly screwed into the top of the main body. The propeller will rattle around a bit but it will only move <1mm in either direction.
One thing about puzzles designed by Roger is that not only do they not come with the solution, but they also don't come with the objective. After playing around with it for a little bit I worked out what I thought was the objective, and after working that out I accidentally managed to solve it a few minutes later! After I solved it, it immediately went back to it's unsolved state and I had no idea what I had done. It took me many more attempts and quite a bit of imagination before I worked out how to repeat my feat reliably, and you do have to pay attention otherwise it will lock itself back up again.
I really do love this puzzle, and I definitely intend to add as many of Roger's puzzles to my collection that I can. Unfortunately it now seems that Roger will no longer be producing any more puzzles, so his current ones are becoming highly collectible.
I got hold of this Roger puzzle and one other (Wasserhahn) from another puzzle collector who happened to have duplicates of these puzzles that he was generously willing to sell to me. Sadly you are unlikely to find any of these puzzles for sale from any source other than other puzzle collectors, so if you are interested keep an eye on some of the puzzle auction sites such as Cubic Dissection and hopefully you may get lucky.
Also, take a look on Rob's Puzzle Page to see plenty more of Roger's puzzles.