How come there are not more frames similar to the vortex, in that they have the battery and arms on same level ? Wouldn't that make it a better flying machine compared to being above or below the arms? Why not design a frame around the battery? Or does it not really matter? What are your thoughts/experience?

There are Look at catalyst machineworks speed addictt frame. Oscar reviewed one here: https://oscarliang.com/speed-addict-210-frame/

What you want is a balanced quad, so it actually doesn't matter where you put yor battery, as long as the centre of gravity COG is in the middle of the craft, in line with the props. Since the battery is the only thing that is not fixed on a quad, the placement will decide the COG. normally, you are only able to move weight backwards or forwards.
If you take a quad with battery attached, hold it in two of the props. Then you can see if it is balanced, top heavy or bottom heavy.
Next try to balance the quad on the frame right between the motors and move the battery untill it is balanced.

From my experience, a top mounted battery is what gives the best COG and not necessarily a lowered top plate. A whole lot of a racing quads weight is placed under your props (bottom plate, arms, motors, PDB etc). My lisam LS210 is quite balanced (a tiny bit top heavy) with a 1300mah 4s battery even though it doesn't look like it.

As I mentioned, I have a quad with top mounted battery, but also got a quad with bottom mounted battery, and another thing I have noticed is that the battery is better protected when put on the top. when I crash, I tend to crash more with the bottom side of the quad, which makes the battery more vulnerable.



There are a whole bunch of frames on banggood with lowered top plate:

http://www.banggood.com/Lantian-LTX-HEX4...55199.html

http://www.banggood.com/Diatone-Tyrant-2...51744.html

http://www.banggood.com/RC180-V2-186mm-C...21110.html

http://www.banggood.com/X220-220mm-Carbo...59493.html

http://www.banggood.com/Q210W-210mm-Carb...60042.html


Edit: I forgot an important part here, Moment of inertia. You actually want to keep most of the mass as close to the COG. This way, the moment of inertia will be less so your motors doesn't have to work that much when doing flips and rolls

Something I have noticed (not scientifically confirmed or anything), is "true x" frames with the bottom mounted battery and usually a big stack of electronics on top will not fly as locked/solidly in as older style frames with a top mounted battery, and no big stack of electronics.

While they both might have a perfect vertical cg, I think that the distribution of the weight plays a part in the flight characteristics

(13-Aug-2016, 12:09 PM)Gryffin Cook Wrote: Something I have noticed (not scientifically confirmed or anything), is "true x" frames with the bottom mounted battery and usually a big stack of electronics on top will not fly as locked/solidly in as older style frames with a top mounted battery, and no big stack of electronics.

While they both might have a perfect vertical cg, I think that the distribution of the weight plays a part in the flight characteristics

I have to agree with you. I have a Martian 3 220 X frame with undermounted battery and I don't think it flies as good as my lisam ls210. I have tested with the same fc, escs and motors on both of them, but as you say, the lisam feels much more locked in. I believe this has to do with the COG and moment of inertia

My take on it is that the conventional box style quads are better suited to battery on top, so long as you can, as oyvinla states Keep the COG happy.

That said I also have a couple of True X frame quads, the Armattan F1 5acro and 4acro, and of course the only place to mount a lipo is underneath, which gives a kind of pendulum effect on the quad.

The true X quads fly great, very fast indeed, able to do insanely extreme tight turns but do as others have mentioned, suffer from that "all round locked in feeling"

I also have the Catalyst Speed addict 210R with the lipo mounted on top but closer to the level of the motors and it fly's really well, but honestly, no better than a equal spec and sized quad with lipo sitting taller on top.

I think a lot of what we read about the elusive "Perfect" quad is half truths and half fanciful BS.

I always go back to my way of thinking.

"If it fly's good for ME, then that is all I care about, regardless of battery placement, motor type, esc's etc "

Battery on top, or inside, or underneath makes no difference to me so long as the quad fly's to my liking.

I was thinking about our body. We have good center of gravity (most of us, at least, lol) If we carry a backpack on our back, then we have to lean forward. If we have a backpack on our chest, we have to lean back slightly. If the quad is banked during a turn, and the Z axis weight is too high, I think it has a harder time staying "locked in". If the battery was as low as possible (lower than speed addict) without going below the motors, I think it would stay more "locked in" during the turn for example. Also during flips and such. The battery, being the heaviest component, not only has an impact if you move it forward or back, side to side, also matters up and down. Just my take and thinking.

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  Also think about sports cars. Why are they so low to the ground? Lower the center of gravity on the Z axis and it handles better. Wheels/Tires, Chasis, and Motor all lined up as much as possible.

Well, I modified my nighthawk 200 frame for it to sit the battery in line with motors. Feels so much more nimble now. Same PIDs. The roll axis was affected more than the pitch. I'm liking the results so far.