This seems likely, but then how do you explain such low sink rates with such small surfaces, knowing that the part of lift is minor for a glide ratio of 0.66 (1:1.5), and zero in its absence?
No coefficient is mentioned on the documents and pages linked to my comment.
I tried to deduce them from the sink rates, the given loads, and the projected areas which I deduced arbitrarily. That said large Cd about 3 were tested.
But I think you are right. I had noted in particular:
About the “enormous Cd of 2,727 mentioned here”:
There may be a relationship between the coefficients and the load-to-area ratio, Reynolds number and scale.
I found the thrust and drag coefficients very high, as well as the lift coefficients for steerable rescues.
I would like to know more about this topic.