Twinsarus:
The JP5/167 was not weak in either longitudinal static or dynamic stability. As I said, the stakes were said to make the erect spin less oscillatory in yaw.
It was designed as a trainer and weak longitudinal stability would have made it difficult to fly in close formation. The short period mode was very well damped but at high altitude (high TAS) it did exhibit (like many aeroplanes) the long period phugoid. It was. however, neutral in roll.
I was fortunate enough to win three aerobatic competitions, one of them international, in a 5 and in my view an aeroplane needed the right qualities
to perform an accurate Derry turn. The 5 certainly did. Structurally the fin post was its' weakest point, and lots of rudder above 150 KIAS was not a place to go.
Spoff:
Where did you fly the Strikemaster and when? I might know you.
JP