Skyhawk 172/Cutlass 172
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 120; Flight Crew Total 5552; Flight Crew Type 250
Aircraft Equipment Problem Critical; Ground Event / Encounter Gear Up Landing
Aircraft Aircraft Damaged; Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition
Aircraft
When extending the landing gear for a training maneuver the main gear extended but the gear unsafe light was illuminated.  The gear was recycled twice with the same result.  Then the operating handbook was used to verify the proper manual gear extension procedure.  This was attempted with no positive result. After that the Tower was notified of the situation and a flyby was performed for the tower to visually observe the gear. They reported both mains down and the nose gear retracted with the gear doors partially open. We then departed to orbit 5 miles north and contacted the flight school by cellphone for any additional advice. Normal and manual extensions were tried again with no positive result. The last attempt was to descend with the gear extended and abruptly pull up just before maneuvering speed was reached hoping that the addition G force may free the nose gear. This was tried 3 times with no positive result. We then notified the Tower that we were returning to land and would like a low pass first to run through the procedures and land on the next pass.  We ended up doing several low passes to allow 3 inbound jets to get on the ground first.  On the final approach the mixture control was pulled to idle/cutoff at 200 feet above the runway hoping that the prop may stop.  It continued to windmill and the landing was made on the main gear as slow as possible. The nose settled very quickly and the aircraft slid straight ahead to a stop. All systems were secured and we exited the aircraft and met at the tail as briefed.
[Report narrative contained no additional information]
C172RG instructor pilot and student reported landing with the nose gear retracted after all efforts to extend it failed.