On Aug 24, 11:33*am, Andreas Maurer wrote:
On Tue, 24 Aug 2010 11:09:01 -0700 (PDT), Ramy
wrote:

Seems like many pilots are using multiple complicated methods to
determine their final glides. Most are using MC settings for that
purpose. Is it just me who never use MC setting to determine arrival,
but using bug factor instead? Following the KISS principal, this is
the simplest way. No need to compare L/D, guesstimate MC, disconnect
the vario or ignore the MC speed to fly, etc. Just set your bug factor
to degrade your polar to something you are comfortable with (I found
70-75% to work fine most of the time), set your MC to zero and watch
your arrival altitude. Once you are comfortable with the arrival
altitude just keep maintain the same number by either speeding up or
slowing down. Works perfect for me.

... but is neither accurate, nor fast, not safer.

Most pilots don't want to waste time (or simply don't have the
weather) to climb extremely high in the last thermal, hence they
follow McCready's advice that has been proven for the last 50 years:
Set the average climb rate of the last thermal as MC setting, add the
bug factor, and leave the thermal once the arrival altitude is to your
liking. Works like a charm, and is extremely easy to use.
To be honest, I have difficulties to find an explanation why something
different (your settings, for example) should be less complicated.

What you are doing is simply to abandon the performance of your 56:1
ship and fly it like a 30:1 Ka-6. Works, but is far, far away from the
optimum.

Cheers
Andreas

Nope. We both are going to leave the thermal at the same time and
glide at the same speed.
In my case the MC will be zero and the bug factor 75%, in your case
MC=3 and bug factor = 95-100%.
However you will need to ignore the speed to fly as John suggested
unless you are willing to risk landout to save couple of minutes
(which may make sense only in contest).
Using the last average climb in the thermal is often meaningless in my
opinion. In many places I fly (Truckee, Hollister, Byron), the last
average thermal is maybe 5 knots but the next is zero since this was
the last thermal. This is true for many soaring sites which are in the
valley and not on the top of the montain range you just left, as well
as long XC flight where the likelyhood to find another thermal late in
the day is small. So using the method of dialing MC = last average
climb and then follow STF is guaranty landout, and a very silly one...
So my recomendation to all non contest XC pilots will be to degrade
your performance using bug factor 70-75%, which will give you enough
buffer for unexpected sink or head wind (which can also be very
different from the wind measured in your last turn) and fly MC=0 until
you are comfrtable with your arrival altitude and then speed up if
your arrival altitude start increasing. This will usually result in
slower glide speed at the beginning of the final glide, gradually
increasing as you get closer, much safer than the other way around.

Ramy