[JulianEdgar]

Initial measurement - it's looking very good indeed.

I decided to mount the pitot tube above the car - that's legal here whereas in front of the car wouldn't be. It's 2.2 metres above the ground.

Using the pitot tube as the static reference, the stagnation pressure on front numberplate measured 1.2 inches of water (300 Pa). That compares with the calculated stagnation pressure (see cr45's post above) of 308 Pa.

The reading also does not drift as it does when using the sealed vessel as the reference (it's impossible to keep temps exactly constant, so the volume expands/contracts a bit).

So well done cr45 for the great idea.

Now I need to do all the measurements - and revise the data I showed previously!