Hmm..... no diagonal ribs in the ailerons on mine. You're saying some have them and some do not? Weird. I have seven gallons or more of gasoline through mine. That is probably 40-50 flights I suppose. I have experienced no flutter. I used klett plastic hinges when building this one. Mine is an ARC.

-Cheech

http://www.devino.org/mark/airplanepics/dp330l.htm