A question for Martin about Phoenix aerodynamics

[Dave Soar75]

On 6/1/2016 at 3:33 PM, edwalker said:

I think that aviators may have created a false dichotomy about crabs and slips in landing. In fact, I believe most experience pilots seem to learn a combination of the two and use an intermediate mix of both on landing, constantly adjusting between the two modes as they tune the landing flare and touchdown. There is a risk to extreme adherence to ether method. The slip camp is at risk for banging a wingtip, while the crab group risks side loads to the gear if the kick isn't just right (and it rarely is perfect) as the float down starts to drift. I've had a number of owners remark about laterally asymmetric main tire wear on their planes, and I suspect that this is one of the contributors.

Human learning is about what works. You start with a model and then variations on the theme tend to modify understanding and practice. Motor memory is even more tricky because sometimes you're not even aware that you're learning. Here's where your SV data logger can help. I practice cross wind landing a lot, and I find that what I'm actually doing is wing-level crab on final but it transitions to a slightly upwind-wing low slip during the flare that softens the crab angle allowing for a much more gentle kickout. The basic idea is enough slip/crab combo to stay aligned with the centerline without a too-low wing or a lateral drift. I didn't realize I was unconsciously doing this until I started looking at my SV black box data where you can actually see the roll and heading data. I have to admit that the combo provides a much more gentle and controlled landing than either method alone.

No matter what, Jim is right that you have to get all three wheels solidly on the ground and going in a straight line (preferably the runway centerline). I would also add that gusting conditions and orographic turbulence near the runway make it even more difficult, so having more degrees of freedom by continually tuning the balance of the two styles give more options.

The final thing to remember is that the Phoenix has an amazing thrust to weight ratio, so when it's all going to hell the throttle will bail you out for a go-around.

I agree with this technique.  I find myself doing it even in the Gulfstream I fly.  Seems to be less chaotic throughout the flare and touch down.