This is at least the second folded wing on a Summa that I've heard of. One of my flying buddies lost one of these to the same fate. I flew that bird a couple of times and was thoroughly unimpressed.
The turning performance was lacking in my opinion. I didn't measure the dihedral angles on the plane, but they seemed low. RnR is trying to make a competition RES plane and may have reduced the effective dihedral angle too much, effecting the turning performance. I suspect that the rudder design may also be a culprit. The rudder has a huge amount of rake to it. Rake reduces rudder effectiveness. I was surprised with RnR's selection of the Eppler 387 airfoil for the plane. This seems to be a questionable selection on a molded plane. The 387 was long ago found to benefit from roughened surfaces or turbulator strips. Kind of like its sibling, the 214. Brian Agnew had success with his designs that used the 387, but that was a decade ago. The aeronautics of airfoil design have advanced well beyond the 387. For current fliers of this craft, you may want to try tubulator strips (full span) at about 20 to 30 percent chord and see if there is an improvement. The prior knowledge suggests that it will. The selection of the 387 may have also been due to the slightly elevated wing loading. This plane probably needs the extra camber (and resulting lift coefficient) to gets it sink speed down to acceptable limits. The folded wings on these ships is unacceptable. For a molded plane that is touted as being strong enough to take a full-on winch launch, it doesn't seem to live up to the billing. Another area that seemed to be a problem on the plane was the tail boom. My friend had cracking on his boom. All of this seems to suggest that RnR strugled with this design. They may have sought to keep the plane light, but may have done so in less than ideal places. A couple more tweaks in the structural and aerodynamic design may be all that is needed to make this plane a good performer. Martin Brungard Tallahassee, FL _________________________________________________________________ Join the world’s largest e-mail service with MSN Hotmail. http://www.hotmail.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
