<Dale.Clay@mdhelicopters.com> schrieb:
> In the aero world it is 7 degrees, but porkpie say 6 degrees for autos
> (don't know why it would be different.
>
> Dale C.
>
>
Hi Dale,
I'm surprised that you remember my comment - I like that, there is someone out
who reads my mails really, wow.
By the way - I got some weeks ago a nice discussion with a guy from the
windtunnel.
I asked him about this different - and where it comes from.
He told me that there is no 100% explanation - but today there is the opinion
that the different comes from the mixture of the ground (road/salt) back
bouncing airflow and the airflow which goes around the side surface of the
vehicle. On an aeroplane the airflow is complete around the plane like a cone,
there is no mixture from rebouncing airflow with the other airflow, the only
desturbing of the air flow comes from the wings, canopy aso.
May be this mixture produce a kind of extra compression or turbulence. It's not
visible, but they hope that once the computer programs are good enough that
shows this effect.
But what they found out - that the 6 degrees is the safe number - depends to
the shape and to the speed it could be up to 6.2 degrees - which is a very
interested point. In the earlier time the equipment was not sensitive enough to
register this different.
If I get more information I will write a mail to the list.
Think fast.....always
Pork Pie
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