by klingbergwing2 » Tue Mar 27, 2018 11:30 pm
Here is my two cents based on my engineering, piloting, and designing background.
Most flex wings have very little adverse yaw (but you can force it to happen dynamically). Flex wings and the Prandtl 4 use approximately the same span-wise lift distribution. The span-wise lift distribution is designed such that the tips are very lightly or even negatively loaded. Al Bowers presents this data in one of his papers that I would post here if I could figure out how to upload it!
The result of this type of lift distribution is that when the glider rolls, proverse yaw is generated.
Also, I can note that if a hang glider does show adverse yaw in a turn, it can be hard to detect because it might be just a few degrees and combined with the "odd" sight line from the pilot (no good reference points), it can be very hard to actually see the adverse yaw. If you were sitting in the middle of the wing sighting over the nose at the horizon, then it would be noticeable.
But, in my personal opinion, if there are no vertical surfaces (winglets, fuselage, etc) adverse yaw does not matter one wit. In a pure flying wing the performance does not vary significantly if the nose is not pointed along the velocity vector. In conventional aircraft adverse yaw is a big performance problem, but not so much on pure flying wings. For flying wings the "problem" is mostly one of pilot preference due to common training methods.
For a pure flying wing I say the following about adverse yaw, "Ignore it and it will go away soon enough" (little engineering joke from a pilot)