Frame Geometry - Stretch X vs Tight X

Table of Contents:
00:59 - DISCLAIMER!
02:58 - Disk interaction isue
03:25 - Solution to the issue
05:49 - Performance result of solution
07:39 - X frame recommendation
10:15 - Z frame geometry
11:20 - Acro frame geometry and AUW
12:58 - Hyperlow designs
13:50 - Issue with low batt/gopro
My best race frame design yet:
Hyperlow designs:
My favorite Hyperlow design:
Hyperlow YouTube:
The blue canopy for the Floss 2:
Summary:
Disclaimer:
Having any particular geometry does NOT mean you will or will not be able to fly well. Anyone can fly anything. It's purely a matter of preference.
The issue and solution:
The front props will always interfere with the rear props when in fast forward flight. Whatever is happening, the solution to the issue is to somehow get more fresh air to the rear props. The easiest way to do this is to either elongate the front to back dimension or lift the rear props above the plane of the front props. The latter is known as a Z or Step geometry. (I believe the Z has not caught on likely due to complexity of design, need for added weight and potential structural integrity issues.)
X frame recommendatoin:
If you want to use an X frame, it's recommended to use a larger stance X such that you get a longer front to back dimension such that the disk interaction is reduced. It is very common to run 5" props on a 6" size frame for this reason.
Stretch X dilemma:
Many want a true X because they feel the quad responds weirdly when it's not symmetrical. While this is true, I have found in my testing that the longer dimension typically rotates faster than the shorter dimension. This can easily be compensated by increasing/decreasing the appropriate rate by a small increment. Usually around 0.01 on the super expo depending on the quads dimensions.
The one limitation of a stretch X that cannot be accounted for is the slightly reduced yaw performance. I do not see this as an issue because typically race rates are lower and the ever so slightly lacking yaw response is pretty much never an issue.
My personal preference:
I like the stretch X because I haven't found the larger true X to have any substantial difference or benefits in comparison. I prefer a tighter frame so I hit less things, therefore, I feel stretch X is the optimal solution for me and is what I recommend to others. This geometry also often results in shorter arms that are lighter and more difficult to break. Finally, the longer body allows me to easily put my battery on top, normal way, how I like it :-)
If you wanna learn what a Custom mix is:
Tips?
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