Recent content by erobz

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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    @berkeman I'm in the grey shirt. This is Mt. Creek Bike Park in New Jersey. This is me coming off of a pretty nice sized drop. And landing! We are all in our 40's and 50's. I only get out to do this 1 to 2 times annually. Otherwise we prefer to ride technical XC (Enduro).
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    To me personally it feels like you are initiating pedaling (in a high gear), while leaning back simultaneously. It puts a "smooth" tension in your arms.
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    I don't have youtube for videos, but maybe I can get some still frames. :smile:
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    Usually we don't do this unless the drop landing in not developed (or underdeveloped). For instance if you are jumping from the top of a rock to a flat landing, it's a slow-moving technique. Not the set up I'm pondering.
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    I'm getting ## \omega = \frac{L^2 mg}{(mL^2 + I)v } ## otherwise ( the factor of ##2## )we align on the approximation. Never mind. I see we have more time for the applied torque than I accounted for. You are correct.
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    The thing is you want to do less of this as the drops get large. You want to get the speed correct and let the physics do the rest for you...ideally. I don't ride this intensity, but that video gives you some scope of the drops that can be encountered and may point you to why I posed the...
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    Basically that is what I was hoping for. Ignoring the actual bike geometry (treating it as a point), that the tangent of the landing profile matches the angle of rotation of the bike at that point of landing so we aren't landing nose or rear heavy over a range of reasonable takeoff velocities...
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    Undergrad DH Mt Bike - Optimizing Drop Landing Ramp Profile

    I do downhill Mt Biking - and this question popped into my head; Is there a kind of "optimal" landing profile mathematically for a drop feature that is not obvious in the sense that it is not what we "intuitively design" for landings on these features? My idea is that the bike leaves the top...
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    Measuring Deer Antler Volume

    I don't hunt for trophy, but a trophy I'll take! The entire encounter lasted about 5-10 seconds on this last one...so I'm not sitting in the tree stand freezing my ass off saying - is it symmetric? - is it going to score well?... As its 80+ yards away walking quickly through thick brush...
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    Measuring Deer Antler Volume

    I never assumed the females had a preference. As far as I can tell it is the competition of males that makes the losers fearful of approaching receptive females while the champion is around. If a female in heat is left in unattended, smaller (defeated) competitors will also breed them while the...
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    Measuring Deer Antler Volume

    Portable, just to see if it gains any traction as "objective measurement" Maybe supplement. Whitetail ( sp[ecifically midwest )could still require a pretty large tank ( maybe 1m by 1 m), but not "moose large" If we just measure volume and assume a common density, I don't think it would be an...
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    Measuring Deer Antler Volume

    I'm just looking at White Tail sized antlers.
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    Measuring Deer Antler Volume

    I wasn't really thinking about weight(although it could be argued to be just as genetically of interest) ). The reason for all this is that the most genetically gifted trophy white tail are usually the largest volume of antler on the head...its naturally most impressive. They assert their...
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    Bernoulli vs real life experiment

    In a real system with viscous losses I wouldn’t be able to tell until I had some real system/fluid properties to fiddle with computationally.
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    Bernoulli vs real life experiment

    This system has a static pressure pre charge of 200 kPa. Turning on the pump will accelerate flow through the pump via pressure differential across it until the viscous losses in the loop grow to match the differential. It’s more complicated than this considering the actual response of the...