If the answer is in the book, I'll say fair enough; but if not...
I took notice of:
Issue: 497 Section: Technical Features 9 September, 2008
The Patent Files: Pneumatic Aerofoils!
Blowing air over wings to give extra downforce!
A VW flat 4 disgorges approximately 1000cfm at 5 psi of engine cooling air. If the boattail rear of a car was as #38 in the patent, how many square feet of cross-section area could be supported pneumatically with that amount of air?