Perfect loop

More_Flaps wrote in news:3d5df584-796e-4cfd-96a5-
:

On Jun 5, 9:51*am, Bertie the Bunyip wrote:
More_Flaps wrote in news:12a345a9-5ce8-4938-
9b3e-
:







On Jun 5, 9:18*am, Bertie the Bunyip wrote:
More_Flaps wrote in news:7d7074a7-c7bc-4a8b-
9fe8-
:

My aerobatic traing is going very well, I'm having all the fun I
thought it should provide. So far I haven't messed up a manouver
but
I'm nagged by the thought: How can I tell if my loops are
perfect
circles? At present I go to full power at the vertical phase and
over
the top but then throttle back a lot as I go vertical again .My
wings
are level when inverted. I'm pulling 3.5 G as I pull up and
level
out
again. I hit my wake every time but I wonder how much I should
throttle back on the descent phase. Should I just try to keep
rpm
constant? Any ifeas BtB or Dudley or other aerobatic pilot?

Dudley's the guy, but the only really reliable way I know of to
tell
until you become experienced enough to know by feel is to get an
outside
observer, or, better yet, a tripod mounted recording of them.
Into the wind helps a lot BTW, but "L" shaped or "granny" loops
are
pretty much standard at this stage of your game!

OK but it's not practical for me to have a ground camera. Should
rpm
be constant at all stages? What do you use in your Citabria? Could
I
try counting through verticals to give me an indication? With a 3.5
G
entry I'm puliing about 0.5 G at the top is that going to give me a
near circular loop?

Mine's stil not flying! Aaaargh! More delays now. I'm going on a
fairly
rusty memory now, so take it al with a grain of salt, but just get a
friend to take a quick snip of you from a distance if you can. The
other
option is a good ground observer, preferably with a viewing glass for
the loops ( something clear with a circle on it so he can hold it up
against your figure to compare)
Max poser as soon as it will take it all the way up

Love that typo!!!!! Max poser indeed!!!!!!!!!!!!!!!


Heh heh. Stay well away form showing off for those on the ground though!


Bertie

More_Flaps wrote:
On Jun 5, 9:40 am, Dudley Henriques wrote:
More_Flaps wrote:
My aerobatic traing is going very well, I'm having all the fun I
thought it should provide. So far I haven't messed up a manouver but
I'm nagged by the thought: How can I tell if my loops are perfect
circles? At present I go to full power at the vertical phase and over
the top but then throttle back a lot as I go vertical again .My wings
are level when inverted. I'm pulling 3.5 G as I pull up and level out
again. I hit my wake every time but I wonder how much I should
throttle back on the descent phase. Should I just try to keep rpm
constant? Any ifeas BtB or Dudley or other aerobatic pilot?
Cheers
Constant speed prop or fixed pitch? Makes a difference.

Basically, what you're doing in a loop is controlling energy by varying
g and airspeed. The main error pilots make that causes egg shaped loops
is in not easing off the g through the high apex. If you don't ease off
the g through the top you pull the nose down and spoil the circumference
of the maneuver.
As for power control, if you are using a constant speed prop, leave it
alone and use MP (if at all) to control airspeed. In most trainers like
the Decathlon for example, you can just set the airplane up power and
prop wise and fly the loop starting with the suggested entry airspeed
and vary the g to control the shape of the maneuver without touching the
engine controls at all. With a fixed pitch prop, you can increase power
on the way up the vertical line (watch the redline) and decrease it on
the backside (watch the redline). Be especially watchful for overspeed
with the fixed pitch prop.
Generally your g profiule sounds about right 3.5 to 4.0 are good
profiles for the average trainer using about 140 for your entry.

Hitting the wake is a good sign. Sounds like you're doing ok to me.


Thanks D, my entry is 140 as you suggest and i'm exiting close to that
speed. Its a fixed pitch plane and I am trottling well back on the
dive (2000 rpm) and my G at the top is dropping to about 0.5, I'm
easing the stick only slightly as I go over. Any other ideas that I
can use to evaluate my circularity (or lack thereof?).

Cheers

Many display pilots (myself included) will develop a set reference plane
for vertical maneuvers in the interest of establishing a continuity of
visual cues.

Basically what this means is that referencing the same side for your
visuals can result in the establishment of a continuity reference wise
that is a great help with energy management and timing. Eventually,you
will be "matching" what the airplane is telling you audibly and through
the controls, with the visual cues you are receiving on the horizon and
wingtip.

My reference sequencing for Loops, Immelmanns , and Cubans was the nose
initially in the pull, then the left wingtip through 120 degrees, then
the nose again.

--
Dudley Henriques

Viperdoc wrote:
However, it's important to remember that the technique needs to vary with
the plane and amount of energy going into the loop. From the front in the
Decathlon/Citabria, after the initial pull, the back of the lift strut
should carve a small circle around the horizon. It is pretty easy to get a
sense if the loop is pinched at the top. Unfortunately, without a sight
gauge it is somewhat harder (in my opinion) to get a sense of flying over
the top and knowing when to ease up on the pull.

In the Extra, on the other hand, it generally takes around a 6.5-7G pull to
get a good looking loop, since entry speed is generally around 160-180k, and
the pull needs to be harder to get the loop at around the same size. Pulling
only 3-4g will get a giant loop, but doesn't present well. Because of the
greater energy going into the loop in an Extra or equivalent plane, there is
less need to ease off and float over the top.

If you really want a challenge in energy management, try flying a loop with
an entry speed of around 100 or even 80k. It is a great drill in learning
how to manage your energy for any given situation.

The best way to accurately assess your loop is to get a ground critique,
which is also true of any other figure. Without this, you could do the same
figure over and over but have it wrong and never know. (at least this was my
excuse during competitions).

Flying acro is a great flying experience and confidence builder- it will
never get boring and will always present new challenges. Just be sure to get
good spin recognition and recovery training (for both upright and inverted
spins). In this vein, I think most instructors are not a big fan of the
Beggs-Mueller method of 1. power off, 2. let go of the stick, and 3. rudder
opposite the yaw (not direction of spin).

This is the topic for a whole thread in itself.

Best of luck and have fun!


Respectfully as I know you own and fly an Extra :-)

1. Sensing a loop profile through the float is not especially hard to
accomplish without a sight gauge.

2. 6.5 to 7.0 g's even in the Extra is an extremely aggressive loop
entry and totally unnecessary for any pilot flying normal aerobatics.
A 170 entry speed using 4g's will get you a nice even looking loop in a
Pitts S1S, and this is for demonstration.
But what you said is interesting. Patty Wagstaff is a friend and flies
her Extra in extremely aggressive displays; in fact, some of the best
and most aggressive flying I've ever seen. I'll email her tonight and
ask her what she uses for loop entry in her displays. I'll be surprised
if she uses 6.5 to 7 but I could be wrong. She's EXTREMELY aggressive
acrobatically.

--
Dudley Henriques

More_Flaps wrote:
How can I tell if my loops are perfect
circles?

Ask Dudley for technique, but as for the physics: a perfect loop would
have a constant acceleration. Just take an accelerometer with you and
see how consistent you are (preferably one that can discount the Earth's
gravity, and one that you can download the data from, so that you don't
have to stare at it while in flight).

TheSmokingGnu

"Viperdoc" wrote in
:

Let me know what she says- I've spoken with her a number of times, at
OSH as well as St. Augustine (I doubt she would remember, but I have
the photos). I flew with Phil Knight in some of my intro flights in
the Extra, as well as Nicolai Timofeev on several occasions for
instruction. Phil was much more aggressive, but he had me pulling on
looping maneuvers (full, half, and quarter pulls to vertical) pretty
hard, just to where the stick pressure got "soft" at the edge of a
stall, in all of the looping maneuvers. With a reasonable pull, this
was around 6-7G, as were the pulls to vertical, after doing a bump to
load the G. In general, my impression of the same figures in the Extra
were around 2-3G more than the Super Decathlon I flew prior to getting
the Extra.

Klein G, who is on the board of the IAC and frequents this NG, also
owns an Extra, and may have a different opinion.

In an early contest after getting the Extra, I flew it in sportsman
with around the same pulls as with the Decathlon (4.5-4.5G), and the
figures were of course a lot bigger due to the higher speed, but
didn't present well. It seems that with a high performance monoplane
it takes more g to keep the figures tight and present better.

However, I'm far from an expert, and now I fly acro for fun- it's just
as enjoyable, without the compulsion to make everything perfect. It
had started to get to be too much of an obsession, and the fun factor
decreased. At this point I figured that if I was looking for stress I
could park the plane and go back to work!

I would be interested in Patty's comments, but my guess is that
looking at the tight corners she pulls that they're at least 7G,
particularly when entered with a lot of energy.




Oh my God. I'm getting a headache just reading this! I suppose it;s not
so bad when you're semi reclined, but still. I've rarely been over five
even in square loops.

Bertie

Viperdoc wrote:

In an early contest after getting the Extra, I flew it in sportsman with
around the same pulls as with the Decathlon (4.5-4.5G), and the figures were
of course a lot bigger due to the higher speed, but didn't present well. It
seems that with a high performance monoplane it takes more g to keep the
figures tight and present better.

However, I'm far from an expert, and now I fly acro for fun- it's just as
enjoyable, without the compulsion to make everything perfect. It had started
to get to be too much of an obsession, and the fun factor decreased. At this
point I figured that if I was looking for stress I could park the plane and
go back to work!

I would be interested in Patty's comments, but my guess is that looking at
the tight corners she pulls that they're at least 7G, particularly when
entered with a lot of energy.



I've never flown competition having mostly done demonstration flying in
military prop fighters, the AT6, Decathlons and the Pitts, but I agree
totally with you that 3 to 4 wouldn't present well in an Extra routine
being judged from the ground.

The problem I see with 6+ to 7 is snatch factor (no pun intended :-). At
that much positive g into the pull you are really close to alpha crit
and could easily slide the airplane deep into drag rise or into
accelerated stall from the high aoa delta (rates). In your airplane
could be done however with a steady hand :-)
Of course having a 10g spread both ways can be helpful :-)

I emailed Patty already. Don't know where she is today but she said
something a few days ago about showing her horse. She usually answers
when she gets a few moments.
We work together on a display flying workgroup. She's a great person and
is deeply invlved as I am in the human factors involved in display
flight safety issues.
If I hear back from her I'll post a ping for you.

The question as I put it to her was for her entry g profile for a single
loop during her demonstration in the 300S. I specified single maneuver
realizing her entry speed and g would be higher for a sequence starting
with a loop.
--
Dudley Henriques

Bertie the Bunyip wrote:
"Viperdoc" wrote in
:

I would be interested in Patty's comments, but my guess is that
looking at the tight corners she pulls that they're at least 7G,
particularly when entered with a lot of energy.




Oh my God. I'm getting a headache just reading this! I suppose it;s not
so bad when you're semi reclined, but still. I've rarely been over five
even in square loops.

Bertie

You and I BOTH get a headache :-))

I don't think I've ever seen anyone work a routine more aggressively
than Wags. She works out physically constantly to stay in shape and I
know for certain she uses most of the 10g's she has available in her 300S.
I'll tell you this much. I flew acro most of my life and I never even
came close to doing with an airplane what Patty does in her Extra
display routine.
MAN..that woman can fly!!! :-))
--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
"Viperdoc" wrote in
:

I would be interested in Patty's comments, but my guess is that
looking at the tight corners she pulls that they're at least 7G,
particularly when entered with a lot of energy.




Oh my God. I'm getting a headache just reading this! I suppose it;s
not so bad when you're semi reclined, but still. I've rarely been
over five even in square loops.

Bertie

You and I BOTH get a headache :-))

I don't think I've ever seen anyone work a routine more aggressively
than Wags. She works out physically constantly to stay in shape and I
know for certain she uses most of the 10g's she has available in her
300S. I'll tell you this much. I flew acro most of my life and I never
even came close to doing with an airplane what Patty does in her Extra
display routine.
MAN..that woman can fly!!! :-))

Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I
would not have cared for that much punishment. i doubt it ver would have
appealed, but then again, I never did any aerobatics in an airplane with
a semi reclined position though and that should be a huge help. I still
can't see how anyone can do 10 Gs regularly even for a short time. in
any case, that's over a 300% increase in stall speed! Yipes!


Bertie

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
"Viperdoc" wrote in
:
I would be interested in Patty's comments, but my guess is that
looking at the tight corners she pulls that they're at least 7G,
particularly when entered with a lot of energy.



Oh my God. I'm getting a headache just reading this! I suppose it;s
not so bad when you're semi reclined, but still. I've rarely been
over five even in square loops.

Bertie
You and I BOTH get a headache :-))

I don't think I've ever seen anyone work a routine more aggressively
than Wags. She works out physically constantly to stay in shape and I
know for certain she uses most of the 10g's she has available in her
300S. I'll tell you this much. I flew acro most of my life and I never
even came close to doing with an airplane what Patty does in her Extra
display routine.
MAN..that woman can fly!!! :-))

Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I
would not have cared for that much punishment. i doubt it ver would have
appealed, but then again, I never did any aerobatics in an airplane with
a semi reclined position though and that should be a huge help. I still
can't see how anyone can do 10 Gs regularly even for a short time. in
any case, that's over a 300% increase in stall speed! Yipes!


Bertie

I've pulled high g in the Pitts doing multiple snap entries for example
but those, as well as Patty's, are instantaneous with quick release.
Most I ever pulled sustained was 9 in the F14 doing some ACM as a
"guest" of the Navy and I can tell you that actually hurt! :-)
Typical display in the Mustang was 4 or under.

--
Dudley Henriques

Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
Dudley Henriques wrote in
:

Bertie the Bunyip wrote:
"Viperdoc" wrote in
:
I would be interested in Patty's comments, but my guess is that
looking at the tight corners she pulls that they're at least 7G,
particularly when entered with a lot of energy.



Oh my God. I'm getting a headache just reading this! I suppose it;s
not so bad when you're semi reclined, but still. I've rarely been
over five even in square loops.

Bertie
You and I BOTH get a headache :-))

I don't think I've ever seen anyone work a routine more aggressively
than Wags. She works out physically constantly to stay in shape and
I know for certain she uses most of the 10g's she has available in
her 300S. I'll tell you this much. I flew acro most of my life and I
never even came close to doing with an airplane what Patty does in
her Extra display routine.
MAN..that woman can fly!!! :-))

Mmm, yes, absolutely. I'm pretty sure tha even at 20 and very fit I
would not have cared for that much punishment. i doubt it ver would
have appealed, but then again, I never did any aerobatics in an
airplane with a semi reclined position though and that should be a
huge help. I still can't see how anyone can do 10 Gs regularly even
for a short time. in any case, that's over a 300% increase in stall
speed! Yipes!


Bertie

I've pulled high g in the Pitts doing multiple snap entries for
example but those, as well as Patty's, are instantaneous with quick
release. Most I ever pulled sustained was 9 in the F14 doing some ACM
as a "guest" of the Navy and I can tell you that actually hurt! :-)
Typical display in the Mustang was 4 or under.


I rarely did more than four displaying and I found five in the Decathlon
or Lakes was punishing, but of course neither lasted for long because
the speed evaporatd very quickly from those sorts of Gs anyway. I
couldn't hardly take more than three outside and avoided doing much of
that anyway! Got a good excuse to stay away from them with the new
airpane anyway..



Bertie



Bertie