Compared to the other HLGs, Chrysalis's rudder area is a little narrow, I think. And the elevator is a little extensive.

Therefore, I'd like to add some to the rudder and to cut the elevator. Do you recommend it?
If you would, how much can I add and cut on the rudder and the elevator?

From : Don Stackhouse

Hiro, it's very difficult to compare tail sizes for different models. There are all sorts of things to consider, such as chords, areas and Reynolds numbers of wing and tail surfaces, mass distribution along the wing's span and in the fuselage, dihedral setup, dutch roll vs. spiral stability balance, desired handling, control response and stability, the flying skills of typical pilots expected to be flying it, and a host of other considerations.

In the case of the Chrysalis, the fin is relatively small in part because the tail moment arm is proportionately long compared to the wing span. On the other hand, because of the large wing area, the wing chord is fairly large for an R/C HLG, so the stabilizer and elevator are also relatively large, even with the long tail moment.

You do have the option, as shown on the plans, for shortening the span of the stabilizer and elevator if you are an experienced flier. The stabilizer halves as supplied are the correct size for a V-tail. If you are building the conventional tail version, those stabilizer halves don't have to provide yaw stability anymore, they are only responsible for pitch stability. For this reason they can be smaller by an amount equal to the area of the vertical tail assembly. The lines on the plans show just how much to cut off to achieve this. Of course, if you are a beginner and want some extra pitch stability from a larger horizontal tail, you can leave them the original size.

Be careful. We spent a lot of time, effort and testing on getting the tail of the Chrysalis just the right size. It was carefully tuned to match the needs of that specific design. Whether or not it looks similar to or different from any other R/C HLG is pure coincidence. You cannot make any firm conclusions about the tail size based on that alone. If it would be better at a different size, we would have made it a different size. Other than the option for reducing the size of the stabilizer as shown on the plans, I'd recommend building the tail as designed. It wasn't just guessed at, it's that size for a specific reason. If you go making changes in any basic parameters like the tail size, wing dihedral, tail moment, washout, etc., you're probably going to hurt the aircraft's handling.

If you build and fly it as designed and THEN decide to experiment with different tail sizes, that's fine. Just be prepared to go through a lot of work and testing before you find something to your liking. There's a lot more to sizing a tail than most people realize!

Don Stackhouse
DJ Aerotech