----- Original Message -----
From: <DJA727@aol.com>
Subject: Europa-List: Long wing CG
> The word is definitely that the CG is too far forward for the long wing.
That
> is what is flies like and that is what Europa found with their
demonstrator
> aircraft. One tidbit of information I gained from talking to Andy was that
if
> elevator authority is questionable, you can gain some authority by not
> trimming to the slow approach speed and holding some back pressure during
the
> approach instead. The trimming out of the speed causes you to lose some
> control authority. I reviewed my video tape from the cockpit and found
that
> the stick position was quite aft for the speed I was flying when touching
> down - main first slightly - too fast. I checked the trim system again and
> found all measurements to be in order. It looks as though if you are going
to
> fly both wings, you need to have a compromise CG to work with the 2 wings.
> Right now, I can say that 59.5 appears to be the forward limit for the
long
> wings, and may actually be 60.0 depending on what is considered an
acceptable
> flight characteristic.
>
> The CG has been adjusted to 60.5 for the next flight. I suspect it will be
> easier to plant the tailwheel on the ground with better pitch authority at
> the slower speeds.
>
> Baby steps!
>
>
> Dave
> A227
> Mini U2
>
Hi Dave
My empty Europa has a Cof G set at 60.63 which seems about perfect. It is
impossible to have too forward a Cof G and the only way to get it out the
aft limit is with full fuel, single pilot and full baggage. If this unusual
scenario is required it would be possible to strap a heavy part of the
baggage in position on the passenger seat. This aft Cof G setting is good
for efficiency in the cruise and helps controllability on take-off/landing
(for monowheel Europas) by placing more load on the tailwheel. Your setting
of 60.5 should be good.
For those still building the following suggestion might be helpful.
To ease setting the Cof G, positioning the battery is the best way unless
you wish to reduce your payload with ballast. To that end I would suggest
that the battery is not finally fixed in position until after the weight and
balance is done. An aft battery position is more likely if a VP prop is
used, a heavy panel is fitted or if the engine is heavier than the standard
Rotax. With the XS the engine was moved slightly further forward so is more
likely to need an aft battery mount than the 'Classic'. If an aft battery
position is required, fitting an external power connection is easily
achieved
with very little weight penalty.
Nigel Charles
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