Cessna 150/152 spin modes
Having long ceased my instructional career I wonder if this forum could provide some theoretical advice on a spin mode I encountered many years ago in the Cessna 152.
The 152 is to say the least reluctant to spin if the entry is done power off and the accepted technique is to use a low power setting around 1500rpm to give more authority to the rudder and elevator. In experimentation I found that if one entered the spin using this technique and then, once the aircraft stabilised, you applied full power and full in-spin aileron deflection the rotation rate was not dissimilar to a Pitts S1. On then taking recovery action of ailerons neutral and power off the nose rose to a flatter attitude and the rotation rate slowed down a bit in a classic flat spin. Full opposite rudder had no effect until the control wheel was pushed forward against the aerodynamic load on the underside of the elevators in a similar fashion to the Chipmunk. The control wheel had to be much further forward than usual before the spin abruptly stopped after perhaps a further three turns. The height lost per turn seemed to be similar to normal but with the considerable increase in the number of turns the total height loss was considerable.
This was repeated on numerous occasions and even demonstrated to a few of my FIC students who enjoyed spinning and they all were of the opinion that they had never come across anything like it.
The aircraft was well within the CofG envelope but, as is usually the case, close to the MTOM.
Any thought please especially since compliance with BCAR Section K was not assured here.
Thanks,
Trapper 69