Outflow forces for the ten sources of the PILS Cygnus survey over their envelope mass. The outflow forces are plotted using colored rectangles covering the range of possible results for the different inclination correction factors. Plotted in the same figure are, Class 0 sources from Yildiz et al. (2015) in red triangles, Class I sources from Yildiz et al. (2015) in blue triangles, Class 0 sources from Mottram et al. (2017) in red circles, Class I sources from Mottram et al. (2017) in blue circles, Class I sources from van der Marel et al. (2013) in blue stars, intermediate-mass sources from van Kempen et al. (2009) in dark gray diamonds and high mass sources from Maud et al. (2015b) in light gray squares. The blue dashed line shows the best fit as found in van der Marel et al. (2013) for CO J = 3–2 observations of a low mass protostellar sample.