Weight is higher because I carried more fuel than you assume.
From your text, Chris: " I emptied the left tank and about half of the right one to be as light as possible." For me this gives 14 Kg, not 35 kg
What Cd do you get with the numbers I gave you?
If 200 km/h at weight 500 kg, ie 4900 N, then I find a parasitical drag =
0.33m2
(assumed 397 rrpm, rotor drag = 465 N, propeller thrust = 1070 N)
If 185 km/h at weight 4650 N, then I find a parasitical drag =
0.43m2
(assumed 385r rpm, rotor drag = 460 N, propeller thrust = 1130 N)
Pitch at rest is not the same as in flight because the constraints. RRPM informs on that. How much read you ?
A while ago we did a state-of-the-art CFD calculation of drag at 150 km/h cruise. I must see if I can get these data. Alternatively we can do a dedicated test flight.
Computational
Fluid
Dynamics is very reliable when the flow is not separated from the walls. Unfortunately, on the ass of the pod the flow is largely separed.
So, a flight test dedicated is better, noting carefully rpm, weight, power, atmospheric density.
High sensitivity of the results requires be picky
Jean Claude