Giff -

If you want the complete story on the accidents and the "why" for each, contact Jeff Edwards.  He has a complete database ( as part of his profession ) of the accidents.  I have had recur training with him and the complete story leads to an understanding of the numbers and what we can do about it.  In those discussions, the need to look at the training and procedures ( not the airframe) is very evident.  If you stall your IV-P in the pattern, your gonna hit the ground no matter how big the rudder is....  Having said that, the changes you made for CG seem to be a good idea, a lot of people have done everything they can to move the CG forward.

The fact that we have organizations like LOBO and HPAT, and that we are talking about these issues in forums like LML is a great thing, and makes us all safer.  A lot of those early accidents didn't have the advantage that we do now...

Good luck!

Bob R



On Jun 29, 2011, at 10:26 AM, Giffen Marr <gamarr@charter.net> 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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