Bruno, your XC videos are exceptionally fine as they are. For pretty
pictures for non-glider-pilots outside cameras are fun but for for me
what is really interesting in XC flight videos is watching from the
pilot's point of view and seeing ahead to the land, sky and
instruments.

John Galloway

At 22:15 03 January 2015, wrote:
I knew I could catch a smart fish with that bait. Thanks! I try not
to
fl=
y around too much at 60 knots but cruise more in the summer
months around
8=
5+ knots...I said try. =20

Please check my math and reasoning on this: I went to an online
calculator
=
and it said 85 knots at 15k alt is ~24.4 lbs/sq ft. Therefore, about
2.5
l=
bs of drag. Looking at the polar of a 27 at 85 knots, you are about
39/1
at=
that weight and speed...I think. So you would then be 36.5/1
with one
cam=
era or a drop in performance of around 6.5%.

I was seriously considering a camera on the tail and one on the
wing. If
b=
oth together add up to at 13% penalty, that is pretty harsh to
impose upon
=
yourself when attempting longer 750km - 1000km flights. If these
calcs
are=
correct, looks like the external cameras will be for the soft
weather
loca=
l flying days only.

Thanks!
Bruno - B4


=20
Very roughly: at 48:1 flying at 1000 lbs, total drag is 20.8 lbs.
At 60
k=
nots, dynamic pressure is 12.2 lbs/sq ft. Camera is roughly .1 sq
ft,
addin=
g 1.2 lbs drag, increasing your total to 22 and reducing L/D to
45.5. That
=
is probably pretty worst case (drag coefficient probably less than
1, not
i=
n free stream, etc.). A tiny bit of streamlining on it could improve
that
a=
great deal I would think.