The iconic part of the Su17 and the mig-21's were the shock cones. In the early days of jet engines, the air intakes were positioned at the front of the aircraft, directly ahead of the jet engine. The pointed part is the shock cone for when the plane flies toward supersonic so that the shock would not mess with the aerodynamics of the plane especially inside the engine. Despite appearances in this photo, the planes don't actually have tusks and aren't imitating mammoths. One is a pitot tube used to measure the velocity and air for the pilot, and the other is for refuelling mid-air. Yep, these guys don't bother landing to top up their tanks. There's videos on youtube that show just how mad it is that they refuel miles up in the sky!