The MJ-77 is a 75% scale plans built replica of the most famous American fighter of WWII, the mighty P-51 Mustang.  The plans show details for duplicating several different variants of the Mustang which all include tandem two place seating.  Two versions can be built from the same plans; standard (2860 lbs. gross, 200-400 hp) or reinforced (3300 lbs. gross, 400-650 hp).  Horsepower will dictate the performance of the aircraft. The airframe was designed for positive six and negative four G loading.  Average construction time is between five to eight thousand hours.  Like all Jurca designs the MJ-77 Mustang has been professionally stress analyzed.

Basic structure consist of a 4130 steel tubular fuselage frame with aluminum bulkheads, stringers and skin.  The wings main spar is built as a one piece laminated box spar structure.  The wings, and tail group are covered with a thin plywood veneer and surfaced with a fiberglass cloth.  All other components such as the cowlings, wing fillets, gear doors, gun fairings, etc. are built with fiberglass.  All fuselage formers and wing ribs are shown full scale on the plans so they can be traced directly onto the material for easy cut-out.