Hey Dudley, detailed analysis of these?

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

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:


Didn't see the T6 roll on these links, but I think I remember the
crash. The 6 has a lousy roll rate and loses energy like a brick
when rolling and doing 2 in a row while down in the weeds can bite
you in the butt dishing out. More than one guy's lost a T6 this way.

Yeah, gave you the wrong one the sifrst time and couldn't get it when
I replied. Youtube seemed to be down or something. Still is. He just
did a single roll. It's pretty obvious from the get go that he hasn't
got a chance. By the time he's 90 deg left the nose is well down on
the horizon and he's commited to some major thrashinbg around on the
elevators and rudder to keep the thing goin which degenerates into
dishing out of the bottom in a big way towards the end. I am
surprised about your comments on it losing energy, though..
The Cobra; his best chance would have been to anticipate the torque
roll carrying all that MP and throttle back to idle before it
torqued out on him, then rolling to the nearest horizon after a
mistake like he made on the way up. In certain conditions you just
don't get a second chance in prop fighters.


OK, that makes sense. I get the feeling he was a bit surprised by the
time he reached the 3/8ths point of the loop and had no real plan
out. They do teach this nowadays, right? I was quizzed mercilessly
about escape routes from all sorts of fjukkups (all of which I had a
good answer for) by the FAA inspector that signed my waiver. Do
inspectors even do those anymore? Evrythng else seems to be done by
someone else these days.





Bertie


The Cobra was a perfect example of something every pilot who flies
these hot prop fighters in demonstrations should be told on the very
first day a check pilot works with them.
First thing you learn is that if you have to think about it, you
shouldn't be doing it...period! The second thing you learn is that
money and horsepower don't necessarily equate.
All of these guys have egos. If they didn't, they wouldn't be
demonstrating a prop fighter at low altitude. Ego is fine, but you
leave that on the ground or sooner or later it dies with you in these
airplanes. The first thing you do when you work with these pilots is
take away that ego and replace it with a deep respect for the
airplane. Trust me, those things can kill you quicker than a
rattlesnake strike. Complacency will kill you in prop fighters. The
only way you can demonstrate a prop fighter at low altitude and live
to retire and talk about it is to develop a keen respect for the
airplane even more keen than any airplane you have ever flown or ever
will fly. The next thing is consistency. Bob Hoover is alive today
because of consistency. Every maneuver he does is like it was cut out
of a template. His g profiles in his pulls and his top gate parameters
are as consistent as a finely tuned swiss watch. He seldom varies more
than a few feet in altitude and a few knots in airspeed, and his
application of g is totally predictable.
Predictability is the key to survival when demonstrating an airplane
like a Mustang, Spitfire, or a King Cobra.
There is a killer up there and it rides with you all the time. Neglect
it for only an instant and you're history. It's a game that has to be
played right the first time....every time....period!

You have an issue with these high powered prop fighters that you don't
have in any other kind of airplane when it comes to demonstration
flying at low altitude. This issue concerns what happens when these
airplanes get too slow, have too much angle of attack on the wing, and
are carrying high amounts of manifold pressure.
Just to give you some idea of exactly how powerful these airplanes
are, consider for a moment that a P51 will actually jump it's wheel
chocks at 40 inches. You can't hold it!
Now, put one of the fighters on top approaching a critical low
altitude top gate after losing all your maneuvering airspeed to
positive g on the way up there; now throw in a high power setting and
a mushing nose rate as an 11 foot prop disk rotates through the air in
pitch and what do you get? You get a King Cobra severely being
impacted by torque in roll, severe P Factor with the prop sensing a
relative wind; and as the prop disk rotates; gyroscopic precession 90
degrees to the pitch axis. As if all this wasn't enough, with the high
power setting, he had spiraling slipstream forces acting on the
airplane in yaw as well. As the man says, "this just ain't no place
for a sane person to be"

The Cobra had all these things in play, and it really messed him up
badly from what I saw. He had all this mess going on at the same time.

It looked like he tried to salvage it, but instead of cutting the
power and rolling to the nearest horizon throttled back as he should
have done, then repositioning, continuing his routine by recapturing
the show line and continuing, he tried to stay with it and ride it
out. The result was a rolling yawing motion almost surely behind the
max CL curve with a lot of mush on the airplane. Naturally this worked
itself out for him as the wing recovered some workable angle of attack
but by then it was way too late. He had no g available that would
recover the airplane on the front side of a high speed stall before
impacting the ground; a classic coffin corner vertical recovery
failure.


OK, that all makes sense. I've never flown anything this powerful, but
if an immelman was going badly for me I would just transform it into a
half cuban rather than try to roll level with too little speed. With the
power available torque was still and issue, but it wasn't the bomb that
it is on these contraptions, obviously. It's amazing to watch the
difficulty they have regaining a bit of grip once it;s gone..


Bertie

Dudley Henriques wrote in
:

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.



OK, that's the way I always did it. Rudder into roll until the adverse yaw
is no longer a problem at say about 30 deg. Swiftly to top rudder then. I
found, in most of the draggy things I flew, that if you didn;t, you lost
the point. With the roll rates I'd be dealing with a large aileron input
was required (max aileron, to get even a 2.5 to 3 second roll) and adverse
yaw could be fierce. rudder required was only light though and I was fully
mindful of the consequences of not getting top rudder in quickly! I'm
having trouble remembering how I did a lot of things though since at the
end of the day I just kept the point in place and did the neccesary to keep
it there. I'll have to re-educate myself procedurally, though.


Bertie

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:
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.



OK, that's the way I always did it. Rudder into roll until the adverse yaw
is no longer a problem at say about 30 deg. Swiftly to top rudder then. I
found, in most of the draggy things I flew, that if you didn;t, you lost
the point. With the roll rates I'd be dealing with a large aileron input
was required (max aileron, to get even a 2.5 to 3 second roll) and adverse
yaw could be fierce. rudder required was only light though and I was fully
mindful of the consequences of not getting top rudder in quickly! I'm
having trouble remembering how I did a lot of things though since at the
end of the day I just kept the point in place and did the neccesary to keep
it there. I'll have to re-educate myself procedurally, though.


Bertie
Coordinated rudder into the roll followed by the switch as you indicate
is indeed the normal way to enter a slow roll. At low altitude however,
as a safety margin for airplanes like a T6 or a 51, I like using the
adverse yaw to negate the switch and give me just that little extra of
nose up in case something "unusual" happens like a bird strike for
example. You can't really see the difference from the ground unless it's
excessive so the roll axis still looks smooth and precise.
In other words, at low altitude you need that nose pointing up at all
times. The Blue Angels use nose down trim for the same reason. Inverted
they have a slight "edge" in case they are distracted for a nano-second
by something unexpected happening with the airplane.
Unless you are doing low altitude work, using coordinated rudder into
the roll entry then switching to top rudder is just fine.

--
Dudley Henriques

On Nov 18, 5:22 pm, "Viperdoc" wrote:

Congrats on your performance at the nationals.

Hey, thanks. I managed to achieve several personal bests at that
contest - highest % score in a glider flight, highest % in a free
style, highest % overall for the contest. Didn't win, but, hey, if I
keep achieving personal bests, sooner or later I have to win, right?
At least that's what I tell my kids. ;-) I'd have done a lot better
except for a brain fart in the middle of the Unknown sequence where I
turned the wrong way and didn't realize it till after I landed.
Actually, I didn't realize it even then - I had to be told. ;-)

I do confess to working really hard at this. Over 160 practice
flights this year. It DOES make a difference.

K l e i n

Viperdoc wrote:
Great work! Saw your photo in the IAC mag. There was a while when I was
going up at least five days a week, and twice a day practicing on the
weekends. However, it soon stopped being fun, and started feeling like a
responsibility.

Then, a bunch of us were going to hire a coach to come up and critique, and
I suddenly realized that it was getting too intense, and the fun aspect of
flying acro was going away- it had become a second job.

Now, a bunch of us use the box, and we go out and have fun, and frequently
hook up on those summer evenings and fly formation. Afterwards, we go to one
of our hangars and cook out, have a few beers, and tell stories.

So, I realize how much work and effort go into all of your practice
sessions, and it obviously did pay off! Congrats again, and best wishes in
the future.

Good luck next year!
JN


You'll never know how much I both envy and respect you new guys. You're
flying equipment that we in our time only dreamed about, and you're
doing things with these airplanes we envisioned but didn't have the
planes available to us to make it happen.
I never flew competition acro as military stuff was basically my venue
but I got a piece of what you guys can do today in the Pitts.
It was what made flying fun then, and I'm sure you guys feel the same
way today.


--
Dudley Henriques

On Nov 18, 9:01 pm, Dudley Henriques wrote:
Viperdoc wrote:
Great work! Saw your photo in the IAC mag. There was a while when I was
going up at least five days a week, and twice a day practicing on the
weekends. However, it soon stopped being fun, and started feeling like a
responsibility.

Then, a bunch of us were going to hire a coach to come up and critique, and
I suddenly realized that it was getting too intense, and the fun aspect of
flying acro was going away- it had become a second job.

Now, a bunch of us use the box, and we go out and have fun, and frequently
hook up on those summer evenings and fly formation. Afterwards, we go to one
of our hangars and cook out, have a few beers, and tell stories.

So, I realize how much work and effort go into all of your practice
sessions, and it obviously did pay off! Congrats again, and best wishes in
the future.

Good luck next year!
JN

You'll never know how much I both envy and respect you new guys.

Hehe. I should have mentioned that I also won the "Old Buzzard Award"
which goes to the highest % scoring pilot, power or glider, who is 65
or older. ;-) Nevertheless, I am only an egg.

K l e i n

"Dudley Henriques" wrote in message
Unless you are doing low altitude work, using coordinated rudder into the
roll entry then switching to top rudder is just fine.

I took (a little) aerobatic instruction from Ken Hadden and he would call
out "kick the sky! kick the sky!"
as a way to coach you to switch to the top rudder input as the airplane
rolled.

Regards
Todd

K l e i n wrote:
On Nov 18, 9:01 pm, Dudley Henriques wrote:
Viperdoc wrote:
Great work! Saw your photo in the IAC mag. There was a while when I was
going up at least five days a week, and twice a day practicing on the
weekends. However, it soon stopped being fun, and started feeling like a
responsibility.
Then, a bunch of us were going to hire a coach to come up and critique, and
I suddenly realized that it was getting too intense, and the fun aspect of
flying acro was going away- it had become a second job.
Now, a bunch of us use the box, and we go out and have fun, and frequently
hook up on those summer evenings and fly formation. Afterwards, we go to one
of our hangars and cook out, have a few beers, and tell stories.
So, I realize how much work and effort go into all of your practice
sessions, and it obviously did pay off! Congrats again, and best wishes in
the future.
Good luck next year!
JN
You'll never know how much I both envy and respect you new guys.

Hehe. I should have mentioned that I also won the "Old Buzzard Award"
which goes to the highest % scoring pilot, power or glider, who is 65
or older. ;-) Nevertheless, I am only an egg.

K l e i n
Hey...congratulations anyway. In this case I should simply say;
"We "older folk" have to stick together" :-))

--
Dudley Henriques

Todd W. Deckard wrote:
"Dudley Henriques" wrote in message
Unless you are doing low altitude work, using coordinated rudder into the
roll entry then switching to top rudder is just fine.

I took (a little) aerobatic instruction from Ken Hadden and he would call
out "kick the sky! kick the sky!"
as a way to coach you to switch to the top rudder input as the airplane
rolled.

Regards
Todd


Each acro instructor will pick up little subtle ways of getting
something through to a student that can be easily remembered under
pressure. "Kick the sky" seems to be a good method of presentation for
your instructor.


--
Dudley Henriques