I need to know where to set the CG chysalis?

I purchased a used chrysalis from a fellow club member as my first HLG. I would describe my skills a solid beginner. [I don't bring planes home in a bag anymore! ;-) ] I need to know where to set the CG. The plane weighs 11.4 oz (including some nose weight) and the CG is currently set 3/16 inches behind the spar. Any suggestions?

From : Don Stackhouse

Thanks for the feedback!

That C/G location is just behind the forwrd C/G limit shown on the plans. Measuring aft from the back face of F2 (the bulkhead at the leading edge of the wing), the specified range is at 2.75" to 3.4" . Your present C/G is at about 2.8". This should result in GOBS of pitch stability. The Chrysalis has lots of stability in general, and a C/G location near the forward limit gives almost too much. Take a close look at the wing saddle, and the tail where it's mounted to the fuselage. See any shims or other incidence adjustments? With the C/G that far forward, it's going to need either some extra up incidence on the wing leading edge, some shims under the trailing edge of the stabilizer, or else the elevator will need to be rigged a little bit "up".

A forward C/G gives more stability in general, but it also means you'll need to work the elevator more going in and out of a turn. The airplane wll tend to pick up speed in a turn, and "balloon" as you level out after the turn (if you didn't feed in enough "up" during the turn to keep it from picking up speed). A more aft C/G reduces these effects. General behavior in a turn is also better with a more aft C/G. I'd recommend flying it with the C/G where it is, but be ready to feed in some up trim if necessary. If you can keep up mentally with the airplane at that C/G, try moving the C/G aft about 3/32" to 1/8" at a time, till you find the C/G that's the furthest aft it can be without making the airplane uncomfortable for you to fly. I suspect you'll find that after a few flights, a more aft C/G will actually be easier for you to handle than the present one, because of the smoother handling going in and out of turns. Lots of stability is fine for a beginner who still has trouble just keeping the airplane level, but once you're past that stage, that much stability often just gets in the way.

I personally like to set the C/G on my Chrysalis at about 1/8" to 1/16" ahead of the aft limit. Stability is still adequate, but the airplane is more responsive, and it also holds itsdelf in a thermal turn significantly better.

One other tip: Some folks have complained about not being able to get any performance out of their Chrysalis. This is almost always either too much washout in the wing (check it regularly, it can change with weather and temperature; it should be about 3/32" on each inboard panel and zero on the outboard panels), or trying to fly too slowly. If the tail is flying noticeably low, you're mushing, and that will brutally murder your L/D and sink rate. Your control response will also be very soggy (in fact, sloppy turns and poor control response is one of the first indications that you're flying too slowly).

The airfoils on the Chrysalis, as with most of the modern airfoils for HLG's, like to be allowed to "run". Concentrate on keeping the fuselage nearly level with the ground at all times. It only takes a few degrees of change in pitch attitude to go from high-speed penetrating to low speed thermalling. If you try to push those limits by trying to hang it on the edge of a stall while thermalling, you're going to be rewarded with VERY short flights! Keep the fuselage level, and the airspeed up, and the plane will fly much better.

Don Stackhouse
DJ Aerotech