without knowing the details on that carbon joiner tube, its hard to say for sure... but the ultimate strength of the wing is probably greatly reduced from that of the normal wing.

Now, the normal wing is REALLY strong, but an R54 can hit 150 mph, and with that big wing, if you had enough elevator authority to stall the wing, thats probably over 1000 lbs of lift (50 G loop, about 60 ft diameter). The elevator is a pretty small chord with a large fixed stab, so that will limit the pitch rate and thus the G's. (i.e. there is plenty of elevator to stall the wing in landing flare, but not enough to stall it in a high speed loop where it also has to overcome the pitch damping of the fixed stabilizer. A full pivoting tail would not have this inherent safety feature!)

The stock wing is probably good for about 12,000 inch pounds of root bending moment. Thats about 1500 lbs of wing lift, so a nice safety margin.

Looking at your photos, you have about a 1" OD joiner. It depends on how thick the wall is and what kind of layup (mostly unidirectional or woven) etc, but even uni carbon with a .05" wall thickness would only be about half as strong as the normal wing. A woven joiner might only be 1/4 as strong as the basic wing.

So, it would still be good for 15 G's, and thats plenty for "jet like flight" but I would not suggest entering it in the "who can do the tightest high speed loop" contest!

Note, all of these are REALLY rough "back of the envelope, too early on a Saturday morning" number, but they are probably not too far off.

Bob