Scimitar, GR, and Brooklyn all had drag brakes with pneumatic cylinders. They were reliable, although they took up a lot of space. In Scimitar and GR the brake was under the driver's chin, which made for good braking, albeit without any steering! The downside was the size and inconvenience of the tank and cylinder, coupled with the fact that braking while turning pretty much guaranteed a spin (not that most calipers seem to do better in that). The benefit was that you never brake on your wheels, so flat spots from capes were not a problem. We were able to keep the same set of practice tires for most of a season.