IS there some odd trick I'm missing in trying ot complete the "Introduction to soaring" mission in FSX?  The voice-over says to trim to fly at 80, but the only way I can stay at 80 is when I'm losing altitude fairly quickly. Then, when I get to the thermal, and try to circle, either airspeed drops or I "pop out..."
Can anyone share any advice? Thanks!

I'm typically circling hard, far from level..maybe banked too far? I must have to stay closer to level than I do...Seems like if I don't turn hard, I fly out of the thermal?

takes practice and a good thermal    I found one that I was at about a 75 degre bank angle and climbing furiously      was not the mission though 

I have't flown this mission, but I have played around with DG 808 a bit in free flight. If they are telling you to "trim for 80" they must be talking about km/h and not knots.  80 km/h would be very close to 46 knots which is the listed MINIMUM SINK speed for the 808.  Now that IS the speed that you would want to fly at while a thermal.  Once you leave the thermal and start the search for another one, you would want to trim for appx 57 knots/105 km/h, which is the MAX L/D speed.  Max L/D will give you a bit higher sink rate, but you will cover a LOT more ground, which is what you want to do in between thermals.

Another thing to check for is your flap setting.  I know that if I use an aero tow, the flaps are set NEGATIVE, and that will definately give you a high rate of sink.  Make sure that they are at 0 for normal flying.

It's interesting that these airspeeds are very close to what I used in a RL Grob G-103 that I flew some years back.  It's also interesting that the same numbers in MPH work for the Schweitzer 1-26, 2-22, and 2-33.

Another thing to know is that once you are in the pattern, you want to fly somewhere in the neighborhood of 65 knots.  This gives you a bit of a 'cushion', and you should always have to use the spoilers to get you on the ground once you are over the threshold.  You have to remember that you don't have the 'noisemaker' in front, and go arounds are definately a no no in a saiplane.