Ok Got the control runs analysed.
And its good - both separate runs with the non aero helmet are very close together!
So the concern about the extra wind in the second trial seems not to be a problem.
Here's the graph:
Certainly the area between 32 and 41 kmh is very similar from both trials.
Will get to analysing the other two aero helmets soon, but probably not today.
The process is a bit tedious and if I'm gunna do more of this I think I might write a program to do the analysis. 5am swim training .... :unsure: :sleepy: