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Sinha Deturbulator Progress Reports

Progress Articles
9/17/2003 First successful test of Sinha deturbulator on a glider
10/18/2003 Further drag reductions on Standard Cirrus wing
  Baseline polar for performance testing
2/8/2004 Progress Report: SSA Convention in Atlanta
2/28/2004 First outer-span test
5/27/2004 Wind tunnel goes into operation
8/31/2004 Stereolithography used for wind tunnel wing sections
12/3/2004 First success on upper surface of Standard Cirrus wing
12/12/2004 More success on upper surface of Standard Cirrus wing
2/18/2005 First Sink-Rate Measurement
(revised 3/13/2005)
2/26/2005 Second Sink-Rate Measurement: Some Encouraging Data
3/19/2005 First Parallel Flight - vs. ASW-28
3/19/2005 Measurements with Full Top Surface Deturbulation
9/12/2005 A Performance Endurance Issue
10/29/2005 It’s Deturbulation Time Again
1/9/2006 Paper Presented at AAIA Annual Conference
2/3/2006 Talk Presented at SSA Annual Convention
5/6/2006 Paper Presented at AAIA Flow Control Conference
7/1/2006 Notes on Endurance and the Temperature/Humidity Issue
10/21/2006 Measurements Show 20% Improvement!
(revised 1/3/07)
12/13/2006 Deturbulator Performance Confirmed!
1/2/2007 Calibrated Airspeeds
12/13/2006 Summary of Johnson Flight Test
(revised 2/10/2007)
12/13/2006 Details of Johnson Flight Test
(revised 12/26/2007)
12/01/2007 Johnson Effect Confirmed
(revised 12/26/2007)
06/7/2008 Third Parallel Flight - vs. Diana 1
(revised 8/3/2008)

Publications and Presentations
1/2006 Sailplane Performance Improvement Using a Flexible Composite Surface Deturbulator - Sinha
(PDF, 1174 KB)
6/2006 Drag Reduction of Natural Laminar Flow Airfoils with a Flexible Surface Deturbulator - Sinha
(PDF, 757 KB)
2/2007 Wing Surface Deturbulators - Johnson
(PowerPoint, 2140 KB)
2/2007 Revolutionary Aerodynamics - Sinha
(PDF, 856 KB)
6/2007 Optimizing Wing Lift to Drag Ratio Enhancement with Flexible-Wall Turbulence Control - Sinha
(PDF, 588 KB)
8/2007 Improving Automotive Fuel Efficiency with Deturbulator Tape - Sinha
(PDF, 1368 KB)

A Performance Endurance Issue (9/12/2005)

Figure 37. Degradation of Performance with Time.

It's been six months since I posted a progress report. I would like to say that we have punched through and are on the way to market with this new technology. However, we have encountered yet another problem that has to be solved first. Over a four month period we have witnessed the initial impressive performance improvements ebb away before our eyes. Changing the usual configuration parameters that we were accustomed to tweaking has not helped.

You can see this problem illustrated in Fig. 37. We were taking crude polars of performance as we progressively deturbulated the wings of Standard Cirrus #60. Fig. 37 is a plot of best polar sink rate improvements (negative values) versus time. When these data were collected, we were experimenting with various configurations to control oddities in the polars. This accounts for the scatter in the data. Plotting the data against time brought this disturbing trend into view.

Without revealing too much detail, I can say that we think we have a handle on the issue and are on our way to solving the problem. Presently, we are reviewing all design parameters, looking at their individual and combined effects to find a fixed configuration that works well over the normal range of flight dynamics and atmospheric conditions. This is taking an enormous amount of time, partly because of the number of variables involved and partly because our flight testing must be done 2.5 hours from home and in summer conditions that are not conducive to flight testing.

Although we have not yet solved the problem it's been six months since our last report and we wanted you to know that the work has not stopped. So, we're issuing this "non-progress" report. On the bright side, we learn something important from every problem we solve. Stay tuned.

Jim Hendrix
Oxford Aero Equipment


© Copyright 2003-2008 Jim Hendrix