In the video attached I did a comparison of two flying wings that are similar in almost every way except weight and airfoil type. The white one uses KFm-2 and the red one uses KFm-4.
The videos shown side by side was shot within a few minutes on the same day so weather conditions was similar for both flights.
My conclusion is that the KFm-4 seems to be a lot more stable under the same conditions. This is just my opinion and may or may not be true for other types of planes, builds, setups or pilots.
So based on my own experience, my tip for any potential FPV49 builders would be to go for the KFm-4 instead of the KFm-2 if you want to have smooth and stable FPV video :)
Good tip thanks
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AsI'm sure you realize, the weight differnece alone can make a big difference, and there's benefits to both a lighter and heavier weight. A heavier plane will penetrate and handle more wind or turbulance, but a lighter plane will glide better in smooth air.
Looks like you've found a real difference, as long as the weight difference isn't too great.
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You may be right.
The weight of the KFm-2 plane was 1450grams
The weight of the KFm-4 plane was 1850grams
The main reason for the weight difference is that the KFm-4 plane was flying with 2 x 2650mAh 3cell batteries while the KFm-2 only had one. Also the motor and servos are slightly heavier on the KFm-4 plane.
I have flown the KFm-2 with dual batteries as well, but it still feels like it bounces a little more in the air. The KFm-4 wing feels like it flies on rails compared.
Keep in mind that these are scratch built planes and there are many potential sources of errors in my test.
Best Regards
Trond
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