Can I finish the fuselage tail boom with a thinned wiped on coat of clear water-based polyurethane (as I did my Crysallis hlg), or does an iron-on covering add needed strength?

From : Don Stackhouse

If you're expecting to do a lot of contest-style "lawn-dart" landings, I'd recommend the film. You can get away with the lightweight film on the fuselage to save some weight. Quite honestly, unless you use too much glue, the 2M Chrysalis is already very light, and the small amount you save from a Varathane finish on the fuselage really isn't that significant. However, if you usually do gentle landings in grass, AND you are looking for every possible bit of weight savings for some really weak lift capability, AND you know how to do a REALLY lightweight Varathane finish (anything worse than that will probably be heavier than lightweight film), then you might save some weight in the tail by that approach. Of course that means you have to be careful not to sand too much off the tail boom when rounding the corners of the fuselage, since you won't be getting any help from film to carry the loads from the fuselage sides into the longerons, so that eats up a little more of your possible weight savings.

I Varathaned the fuselage and tail on the first two prototypes, and used film on my latest ones. When it's all said and done, there doesn't seem to be much effect on weight either way.

Don Stackhouse
DJ Aerotech