Giff:

Good moves all.

Additionally, I think in the early days, guys didn't consciously realize how much AOA increases with bank angle.  Flying square corners in a pattern, especially in the base to final turn, can stall the plane way too close to the ground to do anything about it.

That is why HPAT recommends flying a 1500 foot pattern, and a roundish arc from down wind to final, rather than square corners from down wind to base, then base to final.

John Hafen


On Jun 29, 2011, at 8:26 AM, Giffen Marr wrote:

Before I started to build my IV-P, I reviewed the accident history of the IV.What I found was a significant number of stall spin accidents in the IV. Why a higher rate then other aircraft? From my analysis, I felt there were two reasons, one,the aircraft tended to have an aft CG, and two, the tail became blanketed in the spin, causing difficulty in recovery. My un-flown solution was to move as much weight forward as I could, add stall strips, add the ventral fin and add about 48 square inches of area to the rudder trailing edge. You must also remember that when you retract the gear, the cg moves aft about 2 inches. With an aft CG, the aircraft will tend to go flat in the spin, which makes recovery difficult.

Giff Marr
N229GM
1st engine run before AirVenture.
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