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