Thanks for the webinar. It appears that the effect of adding unsprung weight is worse with lighter vehicles. The Aptera is about the same weight as the Lotus Elise, so the ratio of sprung to unsprung weight would be about 3 for the Aptera, which seems pretty dramatic, and they will need some serious dampening to mellow secondary modes (wheelhop). But at least in the videos provided by Aptera it didn’t seem so bad. Having a relatively small wheel, hub motor, brake and tire might be similar to slapping on some big 20″ cast wheels and wide tires.
Loved the video and the paper on the Focus experiments. I remain concerned about the unsprung weight in such a light car because not all roads are as nice as the test tracks! The highways in Arizona are a good example. The pothole tests in the video were only conducted at 50kph but at over twice that speed (typical of highways here) the effects would be simply dramatic. Add to that the increased difficulty of avoiding road hazards with the center positioned third wheel. I think Aptera can do a good job mitigating *some* of this problem but a stigma of “bad ride” on rough roads could be fatal to a car’s appeal. Aptera cannot afford the fate of the AMC Pacer – great innovations plagued by emotion killing problems. I love the low RPM of hub motors and if these could be inboarded with a half-shaft, that would solve the problem (and take torque stress off of the front suspension, allowing simplification). I LOVE this car but it is critical that it gets past any self-defeating quirks.