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

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