On Sunday, May 6, 2007, at 01:29 PM, Rman wrote:
>
> It has also resulted in more float, during landing, which I attribute
> to reduced stall speeds. I say reduced stall speeds, because, by
> reducing my final approach from 65 kph to 60 kph, across the numbers,
> Baby Blue lands like she used to.
>
> It is not truly a pressure seal, but is sufficient to direct the air
> under the flap and not up, into the closeout. My guess is that it
> also deflects the air, under the flaps, even with the flaps deployed,
> as there is a definite lack of drag. If you do this mod, be prepared
> to re-learn your approaches and it wouldn't hurt to have a good bit of
> runway on the first few attempts...
Jeff...Thanks for your very clear explanation of your installation.
There are no doubt folks on this list w/ more knowledge of aerodynamics
than I, but I believe that the Europa flap design is such that when
deployed, some portion of the increased lift is the result of air
flowing over the top of the flap as the flap drops and moves to the
rear when deployed.
Of course even when the flap is retracted, some air will find its way
up thru the gap between the leading edge of the flap and the vertical
face of the wing closeout, and it is this airflow which one wants to
eliminate in order to enhance cruise efficiency.
If this is so, it would seem that another way to get this increase in
cruise efficiency might be to install a compressible strip which would
close the gap when flaps are retracted but allow airflow over the flaps
when they are deployed, thus maintaining the short field
characteristics of the aircraft which, if I understand you correctly,
have been changed.
Keep us posted on your testing,
Fred
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