My advisor has developed an idea earlier in his career. While this idea is not particularly bad, he always tries to force all his students to apply it to almost all research topics we encounter. Many of them are, in my opinion, obviously not suitable to apply this idea onto, and have resulted in no research output, but he still insists on making the application of this idea work. This takes away our time to try more sound ideas and makes us work much less efficiently. What should I (and other students) do to stop this?
One suggestion is to use a kind of "red herring" strategy: Work on two directions in parallel.
The one direction is the idea that your supervisor wants you to follow, and that you will mainly discuss in meetings, thus giving him the impression that you buy into his game.
The other direction is the idea that you think will actually lead to results. The time to first mention this direction is when you have made some substantial results - you may then calmly announce that you plan to submit them to a specific publication venue.
Run. Seriously, run from this adviser if you can. Eventually, when your adviser's ideas fail to produce any meaningful output, he might try to portray this as purely your fault. Even if he doesn't blame this on you, wasting precious time is not a good idea either. "Red herring" strategy might work or it might backfire spectacularly. If your idea somehow fails, then you might run into serious trouble with your adviser. He will most likely claim that because you were sidetracked/distracted by your own idea, you didn't put all the effort into his idea and that's why it failed, too. Besides, your adviser is supposed to help you develop your ideas and if you have to hide your ideas from him, that's not a sign of a good adviser-student relationship.
You and your supervisor are scientists. Academia is supposed to be a place to share ideas and to discuss science freely.
If you think that other methods are better suitable to tackle the issues you are facing in the research, it is your duty to discuss it with your supervisor and share the solutions with your group. You should not be afraid of having your own voice as researcher.
I know that in some groups the ambient is not propitious for discussing different views, but you should at least try to discuss things with your supervisor before thinking about tricks to avoid him. And if you reached the point of avoiding him, maybe the best option is changing supervisor.