I am preparing to build one of the Early 2-Meter Chrysalis kits. Are there are any changes or modifications that I should be aware of, before I begin?

I have read most of the questions and answers on the web site. Your consideration is very much appreciated.

From : Don Stackhouse

I presume you mean that yours is one of the first Chrysalis 2-meters we produced. The biggest difference between those and the later ones is the reinforcement of the spar caps at the center section. We found out that the woven 1" fiberglass tape was not quite as strong as we had originally believed, so we added two pieces of 1" wide x 2" long unidirectional "S" glass to bridge across both the upper and lower spar caps at the center section. Sand the tops of the spars a little where you add the strips to make sure there isn't any sap residue, etc. on the wood surface to interfere with the bond strength. Some carbon uni would work there as well. Send us your snail mail address if you need us to send you a pair of "S" glass strips.

The wing of the Chrysalis is plenty strong compared to the other economical built-up wooden 2-meters on the market, over 5 times more than some of the most popular alternatives. However, they're also stiffer. It turns out that folks were relying on the amount of wing flex to tell them when they were overstressing the wing, and the Chrysalis wing just doesn't flex as much. In addition, a winch and winch line is much stiffer (i.e.: less stretchy) than the hi-starts typically used by the sport fliers the Chrysalis was originally intended for, and therefore generates much higher loads in response to wind gusts. If you're planning to winch launch your Chrysalis, we strongly recommend that you add some .014" x 1/2" carbon to the top of the upper inboard main spar caps, and .007" x 1/2" carbon to the bottom of the lower inboard main spar caps. I believe you can get this carbon/epoxy strip from CST, among others. The rear spars and the spars in the outer panels are OK as is. The cleanest way to do this is to sand the bottoms of the notches in the ribs deeper by the thickness of the carbon you're adding, so the carbon comes out flush with the outer edges of the ribs. The best way to do that is to make a small sanding tool.

For winch launching it's not a bad idea to reinforce the stabs with a strip of glass tape or .007" x 1/4" carbon (split some of the 1/2" carbon down the middle) on both the top and bottom surfaces, running from the leading edge at the root to the end of the basswood at the hinge line at the tip. It does add a little weight, but greatly increases the torsional and bending strength and stiffness of the tail.

I know of at least one case where the pilot was getting too heavy-footed on the winch pedal, actually causing the wing to overcome the rubber bands and lift up out of the saddle and shift aft a little, which also resulted in reducing the wing incidence! Nothing that a generous dose of added "up" trim couldn't overcome, but still an indication of just how strong that wing is and how much lift it could make. Yes, he did eventually break that wing (no added carbon, and before we added the "S" glass patches), flying off of a winch in a very gusty 15 knot wind. With the added carbon, it would probably have survived that incident. BTW, he loved the airplane so much that he immediately bought another one. However, the point is that while you're beefing up the wing with carbon, you might also need to consider going to a bolt-on attachment system, or at least using more rubber bands (he was using six!).

Probably the easiest bolt-on system that doesn't weaken the wing is to mount 1/8" plywood plates (grain spanwise) in the fuselage just below the wing (remember to set them low enough to allow a little clearance for the dihedral in the wing's underside), and mount some 1/8" lite-ply plates in the wing (grain fore-an-aft) in the space bounded by the main spars, the leading edges, and ribs "A" and "B". Make sure they're securely bonded to the leading edge dowels and the A-B shear webs (you can let the aft edges of these ply plates sit on top of the lower spar caps and butted up against the front of the A-B shear webs). Fill in the space between the ply wing plates and the upper surface balsa sheeting for about 1/2" to 3/4" aft of the leading edge with scrap balsa (it's best to fit and install the ply plates and fit and install the balsa filler blocks before you apply the center section upper surface balsa sheeting ahead of the main spars). Put an extra patch of glass tape on the wing upper surface at the trailing edge. Clamp the wing exactly in place on the fuselage and drill two holes down through the wing about 5/16" aft of the leading edge and into the ply fuselage plate, about 3/4" out from the centerline on both sides, and another hole perpendicular to the wing's upper surface about 1/2" ahead of the trailing edge on the wing centerline. Open up the holes in the wing for clearance for some 10-32 nylon bolts, and tap 10-32 threads in the holes in the ply plates in the fuselage. Counter-bore the balsa in the tops of the holes in the wing leading edges so the bolt heads have a flat place to sit.

The spoiler linkage shown on the plans works fine, but it's a lot of work to build, adjust and maintain. At the time we designed the model, servos were still relatively bulky and expensive. Today I'd recommend simply installing an ultra-micro servo at each spoiler. The Hitec HS-50 or HS-55, or the GWS "Pico" servos or their clones should all be fine for this job. Make a 1/16" balsa platform at the upper surface of the wing and run a short pushrod from the servo mounted to the underside of the platform to the horn on the spoiler. Run a "Y" connector from the center section out to both servos. If you're not planning to fly your Chrysalis in competition and you have a programmable transmitter, it is possible to run the servos to separate channels and mix them with the rudder channel to assist with roll control. However, this is illegal for RES competition, and the roll response of the Chrysalis 2-meter is already excellent with just rudder alone, so it's probably not worth the trouble to rig the spoilers for independent differential motion.

Make sure you have the tubes for the tail pushrods well tied-down, and that the unsupported lengths of the pushrods at the front adn back ends are as short as possible. There have been some reports of tail flutter, and virtually ALL of them have been traced to slp and/or flex in the control linkages.

All of the above mods are optional, other than the "S" glass or carbon patches at the center section. The rest are mainly for ease of construction and use (the servos for the spoilers) or for more serious contest flying. Most of them will add a little weight, but not enough to significantly change the plane's low speed performance.

Don Stackhouse
DJ Aerotech