The AAR probe was very handy during trials of the first RAF variant, saved us having to build our own instrumentation probe.
Have also done a long range test with ferry tanks fitted (pre-production model, so 4 main tanks and 2 ferry tanks, slightly more fuel than the Merlin with 5 tanks plus 1 ferry tank), and was airborne for just over 8 hours.
For that much time, they really need to put a toilet in as well.
