The contract offered an £18,000 bonus for every knot above 36 knots achieved in trials. Nearly thirty propeller designs were tried in the effort to reach the required performance. High-speed endurance remained short, with the example giving only about six and a quarter hours. The quoted trial speeds and fuel details vary within the account, so they do not establish a single clean consumption figure. Failure to meet the contracted speed brought penalties that reduced the payment to just under £240,000.
Notable Point · 11:33-13:32
Swift's trials expose the cost of extreme speed
Propeller experiments, heavy fuel consumption and contract penalties qualify Swift's impressive speed requirement.