Rotors

[lllazar]

Mr. Anderson, that opinion may as well be fact. I don't see what else it could mean. And yes, everything bends when force is applied to it.

[illusionist]

Right, I just wanted to see what your opinions would be about that. I inferred they were talking about the specially designed VP props. Thanks

[carneyf1d]

film covered rotor blades vs solid balsa rotor blades. Thoughts or comments on which is better?

[lllazar]

I prefer using film covered just because im used to it, and its a lot easier to make for me. How does that effect time? Well that requires experimentation.

[Balsa Man]

A quick question for Jeff (and anyone else that wants to chime in, of course)

On covering rotors - spar & rib construction, curved (airfoil x-section) ribs; in your experieence, is the extra weight of covering both top and bottom sides likely to be worth the (presumed) improved drag/lift?
Thanks,

[jander14indoor]

Almost NO feature is worth added weight on flying devices. I'm actually tempted to drop the 'Almost'.

Challenge is to implement the feature WITHOUT weight gain. All other things being equal, the lighter copter/plane will ALWAYS win.

OK, more direct answer, look at Wright Stuff experience. With the old 7.0 gm budget there was plenty of weight budget to double cover wings and still hit 7.0 gm. No one did it, though some tried. MANY years of experience in indoor freefllight, and much creativity. Even in the min weight classes, let alone the unlimited classes, you never see double covered wings. I strongly suspect the same results in Helicopter. Its only in the comparatively high speed outdoor freeflight planes that you start seeing wings with bottom covering and they are much higher camber.

Something to keep in mind about the wing surfaces commonly used in Free Flight. We talk about the camber of the curve used in the rib as if that's all the camber in the airfoil. Simple, convenient, but TOTALLY wrong. The camber INCLUDES the front and rear spar. Think of the wing as a gently curved surface with a big leading edge droop and a big drooping flap at the trailing edge. Covering the lower side changes the shape of the airfoil drastically, probably providing much less lift along with that reduced drag. And its the balance that's important.

One opinion,

Jeff Anderson
Livonia, MI

[Danny Smith]

So i was unsure what catagory to put this in. But i have a problem that i have not yet experienced with any of my previous helicopters. About 8 seconds into flight, the helicopter turns over and propels itself crashing into the ground. It goes up, flips, and comes straight back down. I have one free rotor at the top and one fixed rotor about half way down the motor stick. What is causing the helicopter to flip, and how would i go about fixing that?

[Balsa Man]

Thanks, Jeff; think that answers my question.

Danny, on your.....flipper copter- a possibility (not from expertise, or extensive experience); actually from the "supplemental instructions" from a Parlor Copter kit- discussing refining the kit design to 2011 S-O specs; suggests 1) moving the bottom fixed rotor as far down the motor stick as possible, 2) depending on where you're at weight-wise- using a really light stick to extend stabilizing vane on the bottom end of the motor stick down further. The first may fix your little stability problem, if not second may be worth trying.

[lllazar]

Yes i think Balsaman may have a point Danny, try moving the fixed rotor to the opposite end of the body of the copter, that allows for for more stability.

[illusionist]

I can agree from experience that moving it further down = greater stability