What was the longest NHL Winning streak?

Answer 1

The longest winning streak in NHL history is held by the 1992-1993 Pittsburgh Penguins at 17 games to end the season (though, their last game was a 6-6 tie which would have been win number 18).

The Pens also own the record for most consecutive playoff wins with 11 wins straight in 1991-1992 where they won three straight to end the series with the New York Rangers, swept the Bruins and then swept the Blackhawks to win their second straight Stanley Cup. Their streak actually stands at 14 games however, since the next year in the 1992-1993 playoffs the Pens won three more straight to open those playoffs.
Of additional note, the 1979-1980 Philadelphia Flyers (a.k.a the "Broad Street Bullies") hold the longest undefeated streak (games without a loss) with 35 straight games where they either won or tied. That is a North American professional sports record.