B 105
Having studied Hoffman's B105 manoeuvre, it occurs to me that he was experiencing a fairly well known handling difficulty that can result during the steep 'wing-over' recovery, especially from an into wind low level, low speed entry.
If the speed is allowed to drop below the transition lift point at the top of the manoeuvre, or even to a zero speed, I have found it is vital to regain translational airflow to obtain full disc authority for the normal recovery.
I hate to admit, that in two instances, (albeit in 1213 displays) I have experienced this 'loss of lift' condition, but fortunately on both occasions I had sufficient height to regain translational lift speed in the descent. It seemed to me that Hoffman did not have that height and during the following steep descent where there was not sufficient forward airspeed to regain the required lift, the 105 simply 'fell' into the ground.
I know that on one of the occasions I experienced the problem was when I failed to achieve the correct 'gate' speed for a 270 degree 'wing-over' following a 'toward the crowdline' level approach into a stiff breeze.
In the second half of the 270 degree heading change - the resultant tailwind significantly slowed the recapture of translation lift. The unexpected loss of immediate cyclic response and loss of height gave me more than a second of concern.
I now don't do 'into wind' display wing overs without an extra margin of 'gate' height and speed for the manoeuvre entry.
Not sure this is totally relevent to the Hoffman accident, but I do recall having a conversation with him on the subject at the 1978 Farnborough display, where he performed the first Bolkow 195 Loop I had seen. He certainly knew of the possible condition then.
Safe flying to all,
Dennis Kenyon.