My big foam Viper jet has always had a problem dropping the front landing gear. Everything from progressively more blue locktite, cranking down the screws, and lots of field-side engineering consultations couldn’t seem to solve the problem. Finally it was noticed that the screw bearing surface that the center langin gear leg mounts on was slightly tapered towards the end. Today I re-ground the surface to taper slightly towards the base and re-mounted the gear. Hopefully this is the end of the nose-dragger landings.