Once purchased, you will receive instructions with material needed for building a working rotocopter. I will give you tech support through the process. A Rotocopter, can be used to lift objects by a single lift rotor, with torque balanced primarily by airfoils beneath the lift rotor. There is no exposed rotor and no tail rotor necessary. It is US Patent Pending. Each paid download grants you one license to make and use one tsvls model of the size downloaded. You may not resell or sell the downloaded model or any that would infringe on the US Pending Patent when issued. More infor at www.tsvls.com, or contact me at medlock_charles@yahoo.com, or 501-993-4384