Hi all
With regard to the Cessnas and rocket firing, the weapons were 37mm Matras and were fired from a smaller version of the 68mm pod fitted to the Fougas and Marchettis.They were meant to be used both as explosive ordnance and as target-marker rockets, for artillery spotting.The firing kit consisted of a gunsight, braced to the top of the panel, the firing panel and the airspeed arming switch on the underside of the wing(the floppy aluminium strip.have a close look).The gunsight was basically an illuminated concentric circle and was crude.American pilots in Vietnam used the same sight, firing the same rockets, from 0-1 Bird-Dogs.Half the time, the sight was discarded and the pilots would aim by eye, with chinagraph marks on the side window to illustrate dive angles.
As for the alleged loss of airspeed, I was told by one old Don pilot that the "wash" from the departing rocket would temporarily affect the airflow over the pitot-head, hence the momentary flick of the airspeed needle.
The pods and remaining rockets were scrapped, as the pods were corroding and the rockets were time-expired and were blown up by EOD.I saw a memo to this effect in the Don before I left in '95.
The armed Cessnas will feature in a forthcoming book by Jan Forsgren and two American writers in a forthcoming book about Military Cessna 172s.
regards
GttC