Can you point me to a collection of tips for lightening the design?

From : Don Stackhouse

Well, first of all, it comes out plenty light as it is if you build it stock from the kit. Use micro radio gear, with the V-tail and narrow fuselage option. I'd suggest you start by going through everything in the Building, Finishing, Hand Launch and Chrysalis departments in the "Ask Joe and Don" section of our website.

Use Varathane on the fuselage and tail, and put on extremely thin coats. This is discussed in some of the articles in AJ&D.

Some folks have used 1/32" sheet for the fuselage in the tailcone area, with bands of 3/4 oz. glass cloth around the tailcone every few inches to keep it from splitting too easily.

Use 30 guage wire for your radio antenna (you can find it at Radio Shack), or use .020 music wire in the nylon sheath from the thin Sullivan cables for your pushrods, and use one of the pushrods for an antenna. There's an article in AJ&D about this one too.

A stock per-the-plans Chrysalis can come out around 8.0 to 8.5 ounces or less if built well. I know of one in California that came out under 7 ounces using "heroic measures", including lightweight covering on the wing (NOT recommended due to flutter concerns!). With 411 square inches of wing, that's a wing loading slightly higher than a dandelion seed. BTW, increased weight in the Chrysalis seems to definitely hurt the launch height, so it pays to keep it light. Just don't sacrifice flutter resistance in the process, flutter also hurts launch height!

Second, can you suggest additional tips for avoiding flutter demise?

See above. If you have a really good arm and this is a major concern, I'd suggest using 1/64" ply with the grain running +/- 45 degrees to the spar caps for the shear webs. Put shear webs on BOTH sides of the spar caps all the way out to the poly break at rib K1. Also, use Weldbond or Titebond to glue them on rather than cyanoacrylate.

Cover it with transparent Monokote, it's slightly stiffer but slightly lighter than the regular weight Ultracoat. Make sure the covering is tight but not buckling the ends of the ribs (cover both sides before shrinking, and shrink it gradually and carefully; stick it to the ribs after shrinking out the initial slack but before you shrink it fully tight).

Don Stackhouse @ DJ Aerotech
djarotec@bright.net
http://www.bright.net/~djwerks/