AboutKen Myers Expertise I can answer beginning, advanced and expert questions about electrically
powered R/C model aircraft, and many questions about R/C model aircraft of
all types, except helicopters. I`ve been building, flying and designing R/C
model aircraft for 40 years.
Experience I have been building and flying radio controlled model aircraft since 1960. I'm the president of the Electric Flyers Only, Inc., located in southeasten Michigan. I'm a past president of the National Electric Aircraft Council. I'm vice-president of the Midwest R/C Society. I was president and main founder of the UFO (Union Lake Flying Organization). I've built and flown most types of model aircraft except helicopters.
Question Hi Ken..
I have the Hyperion Extra 300, that normally uses a 400 engine.. I did put an EFlite 480 on it, with a 2200 battery, which makes the A/C heavier..
Now, when i use 70 degrees bank turn, it goes ok, but if i pull some G s in the turn, the aircraft rolls over, and bank on the other side of the turn..It oes the same effect on a right or left turn.. My beleive is that with the high wing loading (added by the extra weight), the outside wing might High speed stall, and that would cause the A/C to roll on the other side.. What do you think of the cause of the Rollover?
Answer While it could be high speed stall, the few times I've seen it happen on some others models, the model drops. If it didn't have sufficient altitude to recover, it crashed. High wing loadings can cause high speed stall, but I don't believe that you've increased your loading to that point. I think you need to check the CG to start with. Also, it sounds more like "Dutch Roll". Here is one source for what Dutch Roll is: http://en.wikipedia.org/wiki/Dutch_roll
I'm sure that Hyperion has designed the plane well for the intended power system, but you might need to add a bit more vertical fin area to reduce the roll, just as they had to do on the original B-17. If you look at the prototype B-17 and first models you can see that there was no dorsal fin and the vertical fin and rudder were smaller than on the more familiar G model.
Also, if you can get any of the gear or battery lower in the fuselage, that should help too.
Until you come up with a fix, I'd recommend that you avoid pulling any high G maneuvers near the ground, just incase it is the high speed stall affect.
One other thing I noticed, that might help as well, use a smaller capacity battery pack as that will reduce some of the mass as well. In general, a 2200mAh pack is "pretty big" physically for use on a 480 powered plane.
