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Motorcycle Wind Management Design

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    Motorcycle Wind Management Design

    Motorcycle Wind Management Design --

    (Just some casual thoughts by an amature; new comments highlighted with blue font)

    My K1200RS iABS

    The K1200RS bikes have poor to moderate wind management.

    The '98 version was very poor.

    There was improvement with the '02 version but still a lot to be desired.

    My '02 has near perfect management due to:

    1. Double windshield.

    2. A 30 degree OEM windshield attitude (in the lower position).

    3. Lower bar clip-ons (from my '98)

    4. Lower winglets trailing each ''pod''.

    Turbulence/wind buffeting still occurs at over 70 mph with ambient traffic and cross winds. But this is subtle and remains enough to remind me that I'm on a motorcycle and not inside a cage.

    Although further improvement may be possible, it's time to ride. Additional modifications will have to wait until next season.


    Elements of wind management.

    Helmet Design

    Safety First

    Helmets are primarily designed for crash protection.

    Noise reduction is a secondary factor and is usually addressed by helmet aerodynamics design.

    Little has been done to introduce noise dampening materials into the helmet structure.

    See this article, "Lowering the Volume for Motorcyclists" for a good discussion of this: http://physicsbuzz.physicscentral.co...rcyclists.html

    Style.

    How the bike look on the showroom floor often dominates other elements as if you can't sell it, it's a bad design.

    Cost.

    Some designs and materials are clearly more expensive than others.

    Structure.

    How does the overall structural engineering of the bike support the structures for wind management.

    Aerodynamics Theory.

    What does the engineering and aerodynamics literature, say.

    Testing (wind tunnel).

    Only sometimes done and possibly not well.

    For example, hitting air straight on is different than when riding with a 30 mph cross wind on when at speed and sitting in the turbulence of a semitrailer truck.

    And air flow can change with luggage and passenger or with adjustable mirror positions.

    Safety.

    Basically this deals with how the windshield and supporting structures will behave in a a crash or bird strike and the associated rider protection risk.

    Top Speed Aerodynamics

    Bike stability at higher speeds is a safety concern that is necessarily addressed.

    While this may result in stability at top end speed, and perhaps even good wind management at that velocity, the required aerodynamics may result in excessive wind noise and buffeting when riding at more usual speeds.

    Note that an aerodynamic tuck is assumed with very high speeds.

    In general, wind noise and buffeting increase as speed increases, at least at legal speeds.

    With the addition of "aerodynamic wings" to fairings, there is yet another factor to consider.
    Last edited by wildbears; 4 weeks ago.

    #2
    Wildbears, I've been thinking about this a lot lately. I am thinking of buying a completely naked bike, the Triumph Speed Twin. What I want more than about anything, is smooth air hitting my helmet and upper torso. Chattering wind in those area is simply too aggravating to put up with. Surprisingly, a fair number of bikes with fairings share this flaw.

    Comment


    • wildbears
      wildbears commented
      Editing a comment
      In my limited experience, even some unfaired bikes have excessive wind noise and buffeting.

      Make sure you get in a good test ride before purchasing.

      The original Indian Chief Vintage had the best wind management of any bike I had ridden when they came out in 2013 (2014 model year).

      Riding two up on the expressway at 70-80 mph, my wife and I could carry on a conversation. without raising our voices. This was with full face helmets with the face shields up and with the stock windshield.

      Unfortunately, Indian screwed that up recently when they went to a steeper front end and windshield attifude. I'm thinking the bean counters were responsible because they starting using the same front end from their Springfield model on the Vintage.

      Triumph had a good configuration on their Thunderbird LT but that model was dropped years ago.

      The Yamaha XSR 900 has smooth air flow.. I was seriously getting ready to get one until I took a second test ride and found the suspension to be uncomfortably stiff for pleasure riding (probably good for the track). That could be fixed for a grand or so. The engine also emitted a high pitched whirling sound which might have been normal but sounded like a bad bearing somewhere. May have just been a problem with the demo bike.
      Last edited by wildbears; 05-17-2020, 06:50 PM.

    #3
    BUMP

    Original Post edited with additional comment in blue font.
    Last edited by wildbears; 06-02-2020, 06:56 AM.

    Comment


    • 955i
      955i commented
      Editing a comment
      Wild,
      Interesting observations. Thanks for the update. Wind management, no wind elimination, is the goal I seek when messing around with this stuff. Sounds like you do the same.
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