deturbulated std cirrus flies against Diana 1

For the latest parallel flight of my deturbulated Standard Cirrus vs. a
modern glider, go to
http://sinhatech.com/SinhaFCSD-Progr...08.asp#article .

20 minutes of parallel flying should be enough to make the point.

Download and replay the logs in SeeYou, or what have you.

Jim Hendrix
Oxford Aero Equipment, LLC
417 N. 11th Street
Oxford, MS 38655

662-234-0492 voice
662-234-2195 fax

www.oxaero.com

On Jun 9, 2:58*pm, Jim Hendrix wrote:
For the latest parallel flight of my deturbulated Standard Cirrus vs. a
modern glider, go tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#article.

20 minutes of parallel flying should be enough to make the point.

Download and replay the logs in SeeYou, or what have you.

Jim Hendrix
Oxford Aero Equipment, LLC
417 N. 11th Street
Oxford, MS 38655

662-234-0492 voice
662-234-2195 fax


Jim,

How narrow is the airspeed "sweet spot" for achieving these
performance gains? From the looks of the presentations on the
website, it seems like it might be rather small. Are there any
handling characteristics that are affected by the modifications such
as stall, slow speed, thermalling, etc.?


Dave

At 20:39 09 June 2008, wrote:
On Jun 9, 2:58=A0pm, Jim Hendrix wrote:
For the latest parallel flight of my deturbulated Standard Cirrus vs.
a
modern glider, go
tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#a=
rticle.

20 minutes of parallel flying should be enough to make the point.

Download and replay the logs in SeeYou, or what have you.

Jim Hendrix
Oxford Aero Equipment, LLC
417 N. 11th Street
Oxford, MS 38655

662-234-0492 voice
662-234-2195 fax


Jim,

How narrow is the airspeed "sweet spot" for achieving these
performance gains? From the looks of the presentations on the
website, it seems like it might be rather small. Are there any
handling characteristics that are affected by the modifications such
as stall, slow speed, thermalling, etc.?


Dave

Dave,

The narrowness of the extreme performance peak near 50 KIA is seen in the
third graph on page http://sinhatech.com/SinhaFCSD-Progress-12012007.asp .
The two neighboring speed points are 2.5 kts on either side, or 5 kts
apart. That I was not accounting for my additional weight and was flying
too slow at 50 KIA is seen in the 47.5 point being higher than the 52.5
KIA point. I believe that is the reason that my extreme performance
flight on 12/1/07 only reached 70:1 whereas Johnson's a year earlier
reached over 100:1. This is confirmed by my second 50 run on 12/1/07 in
which excessive pitch momentum arriving at the magic speed made the AOA
and deturbulator performance "hunt" each other such that the performance
swung between Johnson's performance at the top and baseline at the bottom
(Click Extreme Performance powerpoint link and scroll to the bottom for
that graph.).

It is interesting that if, as it appears, my ship was matching a 45:1
glider, that is about the performance level between the neighboring speed
points I used to define the performance peak width. So, the polar from
12/1/08 closely matches the Diana performance I saw last Saturday.

Stall speed is not affected significantly. Neither is handline, though
there are a number of interesting effects from flying with wings that
change moment to moment. Lately I've been experimenting with instantly
improving performance by pulling up to nearly a stall and slowly settling
down to 51 KIA. It seems that often this gives me a quick performance
boost.

JEH

On Jun 9, 4:13*pm, Jim Hendrix wrote:
At 20:39 09 June 2008, wrote:



On Jun 9, 2:58=A0pm, Jim Hendrix *wrote:
For the latest parallel flight of my deturbulated Standard Cirrus vs.
a
modern glider, go
tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#a=
rticle.

20 minutes of parallel flying should be enough to make the point.

Download and replay the logs in SeeYou, or what have you.

Jim Hendrix
Oxford Aero Equipment, LLC
417 N. 11th Street
Oxford, MS 38655

662-234-0492 voice
662-234-2195 fax


Jim,

How narrow is the airspeed "sweet spot" for achieving these
performance gains? *From the looks of the presentations on the
website, it seems like it might be rather small. Are there any
handling characteristics that are affected by the modifications such
as stall, slow speed, thermalling, etc.?

Dave

Dave,

The narrowness of the extreme performance peak near 50 KIA is seen in the
third graph on pagehttp://sinhatech.com/SinhaFCSD-Progress-12012007.asp.
*The two neighboring speed points are 2.5 kts on either side, or 5 kts
apart. *That I was not accounting for my additional weight and was flying
too slow at 50 KIA is seen in the 47.5 point being higher than the 52.5
KIA point. *I believe that is the reason that my extreme performance
flight on 12/1/07 only reached 70:1 whereas Johnson's a year earlier
reached over 100:1. *This is confirmed by my second 50 run on 12/1/07 in
which excessive pitch momentum arriving at the magic speed made the AOA
and deturbulator performance "hunt" each other such that the performance
swung between Johnson's performance at the top and baseline at the bottom
(Click Extreme Performance powerpoint link and scroll to the bottom for
that graph.).

It is interesting that if, as it appears, my ship was matching a 45:1
glider, that is about the performance level between the neighboring speed
points I used to define the performance peak width. *So, the polar from
12/1/08 closely matches the Diana performance I saw last Saturday.

Stall speed is not affected significantly. *Neither is handline, though
there are a number of interesting effects from flying with wings that
change moment to moment. *Lately I've been experimenting with instantly
improving performance by pulling up to nearly a stall and slowly settling
down to 51 KIA. *It seems that often this gives me a quick performance
boost.

JEH- Hide quoted text -

- Show quoted text -

Jim,

Thanks for the info. Some additional questions for you. What do you
"feel" in the aircraft when this "AOA
and deturbulator performance hunt" is going on? Is there some kind of
noticable oscillation going on? What are some of the other
"interesting effects"?


Dave

At 21:30 09 June 2008, wrote:
On Jun 9, 4:13=A0pm, Jim Hendrix wrote:
At 20:39 09 June 2008, wrote:



On Jun 9, 2:58=3DA0pm, Jim Hendrix =A0wrote:
For the latest parallel flight of my deturbulated Standard Cirrus
vs.
a
modern glider, go
tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#a=3D
rticle.

20 minutes of parallel flying should be enough to make the point.

Download and replay the logs in SeeYou, or what have you.

Jim Hendrix
Oxford Aero Equipment, LLC
417 N. 11th Street
Oxford, MS 38655

662-234-0492 voice
662-234-2195 fax


Jim,

How narrow is the airspeed "sweet spot" for achieving these
performance gains? =A0From the looks of the presentations on the
website, it seems like it might be rather small. Are there any
handling characteristics that are affected by the modifications such
as stall, slow speed, thermalling, etc.?

Dave

Dave,

The narrowness of the extreme performance peak near 50 KIA is seen in
the
third graph on
pagehttp://sinhatech.com/SinhaFCSD-Progress-12012007.asp.
=A0The two neighboring speed points are 2.5 kts on either side, or 5
kts
apart. =A0That I was not accounting for my additional weight and was
flyin=
g
too slow at 50 KIA is seen in the 47.5 point being higher than the
52.5
KIA point. =A0I believe that is the reason that my extreme performance
flight on 12/1/07 only reached 70:1 whereas Johnson's a year earlier
reached over 100:1. =A0This is confirmed by my second 50 run on
12/1/07
in=

which excessive pitch momentum arriving at the magic speed made the
AOA
and deturbulator performance "hunt" each other such that the
performance
swung between Johnson's performance at the top and baseline at the
bottom
(Click Extreme Performance powerpoint link and scroll to the bottom
for
that graph.).

It is interesting that if, as it appears, my ship was matching a 45:1
glider, that is about the performance level between the neighboring
speed
points I used to define the performance peak width. =A0So, the polar
from
12/1/08 closely matches the Diana performance I saw last Saturday.

Stall speed is not affected significantly. =A0Neither is handline,
though
there are a number of interesting effects from flying with wings that
change moment to moment. =A0Lately I've been experimenting with
instantly
improving performance by pulling up to nearly a stall and slowly
settling
down to 51 KIA. =A0It seems that often this gives me a quick
performance
boost.

JEH- Hide quoted text -

- Show quoted text -

Jim,

Thanks for the info. Some additional questions for you. What do you
"feel" in the aircraft when this "AOA
and deturbulator performance hunt" is going on? Is there some kind of
noticable oscillation going on? What are some of the other
"interesting effects"?


Dave

Dave,

I measured this only once. I felt nothing that I recall, but was a bit
perturbed that the vario was not as steady as for the first 50 kt run in
that flight. Of course, at the time I had no idea what was going on. My
thinking is that when it was hunting, it was sweping back and forth past
the "magic" airspeed that I didn't realize should have been around 51
KIA.

JEH

If both gliders were flying at about 51 kts, doesn't this give the Cirrus
an advantage? 51 kts probably gives best l/d for the Cirrus, but it will
be well below best l/d for the diana.

At 22:28 09 June 2008, Mark Dickson wrote:
If both gliders were flying at about 51 kts, doesn't this give the
Cirrus
an advantage? 51 kts probably gives best l/d for the Cirrus, but it
will
be well below best l/d for the diana.

Mark,

That is a good question and one that I have not taken the time to look
deeply into.

According to the polar Johnson measured, the Diana 1 has a sink rate dip
at 53 kts calibrated that gives it 45:1. We were trying to fly 51 KIA on
my ship which is about 51.25 calibrated, or 1.75 kts slower than the Diana
likes. At that speed Johnson gives the Diana about 115 fpm sink rate for
an L/D of 44.1. This would still be 10.6 points higher than my ship
measured. However, especially on the cloud-street run, both ships were
flying though turbulence that bounced the airspeed all over the range that
covered my performance peak and the Diana’s too. So, we’re dealing with
ball park numbers here.

JEH

On Jun 9, 5:13*pm, Jim Hendrix wrote:
At 22:28 09 June 2008, Mark Dickson wrote:If both gliders were flying at about 51 kts, doesn't this give the
Cirrus
an advantage? *51 kts probably gives best l/d for the Cirrus, but it
will
be well below best l/d for the diana.

Mark,

That is a good question and one that I have not taken the time to look
deeply into.

According to the polar Johnson measured, the Diana 1 has a sink rate dip
at 53 kts calibrated that gives it 45:1. *We were trying to fly 51 KIA on
my ship which is about 51.25 calibrated, or 1.75 kts slower than the Diana
likes. *At that speed Johnson gives the Diana about 115 fpm sink rate for
an L/D of 44.1. *This would still be 10.6 points higher than my ship
measured. *However, especially on the cloud-street run, both ships were
flying though turbulence that bounced the airspeed all over the range that
covered my performance peak and the Diana’s too. *So, we’re dealing with
ball park numbers here.

JEH

Looks like the results speak for themselves and it sounds promissing.
But why does it take so long to turn it into production? According to
the web site the experiments started at 2003 and so far it was only
tested on a standard cirrus. How longer will it take until I can have
it on my 27?

Ramy

Umm...

What happened to the wind tunnel testing that was underway over four
years ago? This is where experimentation that requires such tight
control of parameters and is so sensitive to humidity, turbulence,
etc. should be conducted. If this research looked so promising and
was funded by NASA, they have rather lovely tunnels you could put the
whole Cirrus into if you wished. I would think that performance
questions could be answered in a matter of a month or two. What went
wrong there?

I am the first to consider that new breakthroughs are almost always
met with significant criticism, so I like to fall back on the facts
whenever possible. As a sanity check, lets look at the latest
comparison flight between the Cirrus @ the claimed 33.5:1 glide ratio
and the Dana 1 at 45:1 On one leg that was graphed, the flight lasted
8 minutes with the two aircraft flying side by side at about 51
knots. It looks like the Cirrus kept up quite nicely with the Dana!

But lets take a closer look. At 51 knots, that's about 5164 ft/minute
forward, and for the Dana, about 114 ft/minute sink in still air.
Over the course of the 8 minutes, the Dana should sink 918 ft, and the
Cirrus, 1233 ft, so the expected difference in altitude is about 315
ft after 8 minutes of flying. From the trace, both aircraft only sink
about 100 feet over this time, and are flying through sink and lift
the whole time of strengths up to 4 knots. So one could say that the
variation in altitude contributed by the still air sink rate of the
gliders is only about 25% of the total. The other 75% is due to
flying through rising and sinking air. Given that the gliders were
flying side by side through slightly different air, is it possible
that any performance variations (good or bad) were completely masked
by minor variances in this more dominant variable of moving air
masses? It would take an average difference of only 0.37 knots of
lift/sink over the flight to account for this.

I would like to think it's all true, but so far have little basis
other than hope. Get back in the wind tunnel, or show me a 40 minute
final glide at 7:am in still air.

Matt

At 04:04 10 June 2008, Ramy wrote:
On Jun 9, 5:13=A0pm, Jim Hendrix wrote:
...
Looks like the results speak for themselves and it sounds promissing.
But why does it take so long to turn it into production? According to
the web site the experiments started at 2003 and so far it was only
tested on a standard cirrus. How longer will it take until I can have
it on my 27?

Ramy

Ramy,

To be brutally frank, it’s taking a long time to develop this technology
because neither Sumon nor I are very disciplined in our methods and a
great deal of hard work remains to fully understand both the flow-surface
interaction of the deturbulator device and the overall wing aerodynamics
we are achieving with it.

Sumon knows what he wants to achieve, but we are dealing with subtleties
that extend well beyond his original concept, which were close enough to
work but not really on target. I’ve watched his concepts morph over time
regarding both the flow-surface interaction and the wing aerodynamics
model. We now have a third person loosely associated with the project to
model the flow-surface interaction using his LINFLOW software package,
Jari Hyvärinen of ANKER-ZEMER Engineering AB in Norway.

The slowness comes down to manpower issues. Sumon is almost completely
committed to developing a deturbulator product for semi tractor trailer
rigs. As he makes improvements in the trucking device, I occasionally
divert his attention long enough to upgrade the deturbulators on my
glider. Thus, for example, we now seem to have something that sometimes
works even in the summer months, if the humidity is not too great. So the
main thrust of his attention is directed toward a, technically easier and
more lucrative, market. For my part, I have higher priorities, so the
deturbulator sort of fills in the cracks. Also, I don’t have the
aerodynamics background for the fundamental work that needs to be done;
that will wait until the aerodynamics community sees the light and begins
doing the work, or large corporations pony up the funds for R&D projects.
Like me, Jari Hyvärinen needs to make a living with his normal engineering
consulting work, so for him too this is not a main priority.

Add to that the enormous amount of research and engineering that remains
to be done to fully understand the modes of flow-surface interaction that
can occur, those can be exploited for specific aims and those that must be
avoided (both are well demonstrated in Johnson’s 2006 test flights-
http://sinhatech.com/SinhaFCSD-Progr...on-Details.asp) and you can
see that we have a bottle neck that is restricting progress. The sooner
the aerodynamics community takes this seriously, the sooner we will get
there. For my part, I intend to keep collecting data until the sheer
weight of it becomes undeniable. At this point in time, I am only
interested in demonstrating the concept. Producing a viable product for
use in aviation is a long term proposition, requiring real, disciplined
R&D work and funding.

The problem with treating other glider wings is that each wing is a unique
problem that has to be studied, then tested iteratively, making adjustments
to the configuration to arrive at something what works. The process was
started with Greg Cole’s Sparrowhawk, but the first attempt failed due
largely to poor quality control of the deturbulator itself (a problem that
I think will be solved with the next application on my glider) and the
project was not pursued to the point of success. My own experience, after
Johnson tested my glider in December 2006, was two failures before the
present application. And even this application was not up to par and had
to be studied with oil flow visualizations to see what the problem was. I
finally had to remove some intermediate tapes that were needed for the
Johnson deturbulators and also smooth the sharp leading edge of the new
deturbulators with (get this) Scotch tape. Finally, the first flight
after those modifications essentially reproduced Johnson’s remarkable
third flight in 2006. Bottom line, it takes a lot of work and persistence
to realize success and there is too little Sinha to go around...he’s a
bottle neck.

Sorry, but reality is reality!
JEH