Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:


OK, the first one should have been the T6 slow roll where he dished
out
in the end.(orange one in south america?)
Looks like he had nothing even beginning the roll and had completely
lost the plot by the time he reached even 45 degrees and should have
just thrown it away at that point.
To me, the KC accident looked like the result of a way too low
energy
state going through the top gate. He should have had at least 150
indicated inverted on top but it looked like he lost his energy to
drag going up the up line by pulling too much g. He was practically
dead in the water on top but apparently at fairly high power. This
looked like it torqued him in roll pretty good and he lost it coming
through the gate. He recovered as the angle of attack narrowed back
into the work range but by then he was committed way too nose low
and
had no radial g available to affect the recovery.
The guy in the T6, rolling right, judging from the clip, never made
the
rudder switch from left to right rudder as he passed through inverted.
His held in left rudder became bottom rudder as he passed through
inverted then yawed him hard as he reached the second knife edge. Add
to
this he didn't have enough forward stick in either as he went through
inverted. The combination of the two errors caused the nose to come
down
as he rolled into the 3rd quarter.

You just don't do this in a low altitude roll and survive. To me it
looked like bad control coordination beginning at inverted and held
through impact . The first half of the roll looked good BTW. He just
blew it on the second half.
His airspeed looked fine for a T6 going into the roll set so energy
wasn't the issue here.



Hmm, yes, OK. Looked at it again a few times. I still think he's a bit
nose low at the first 90 point which would have exacerbated the nose
down inverted, though. I usually looked for the side of the cowl to be
resting on the horizon at the 90 before commiting to inverted.
I think you're right about the rudder coming through inverted, he got
so absorbed in that problem his rudder control went astray and it
degenerated into just panic thrashing and pulling and hoping for the
best.


Bertie

The best technique to use in low altitude roll entries is to use adverse
yaw to your advantage as you enter the roll. You need top rudder anyway
and that's the way the nose will go if you don't use rolling rudder into
the roll to coordinate the entry. I just allow the yaw and follow it
closely with top rudder as the roll stabilizes.

A lot of these guys doing low altitude rolls will use inside rudder with
aileron entering the roll because it's the "natural" thing to do. If the
rudder isn't switched immediately to opposite rudder as the roll
initiates, this will naturally be bottom rudder and pull the nose down.
At low altitude, this can get you killed.


--
Dudley Henriques