Activity for KlausG
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KlausG posted a comment on discussion Open Discussion
Thanks, Stefan! At the moment I take the average CL over the span and insert it into the Lift-formula (CL * ro/2 * A * v2). I just wondered, because alle the values are there, would be easy to implement it! By the way, for my planned aluminium-fuselage I have safety factor 1,5. But you never kow :-) regards, Klaus
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Short version: For a defined plane: Where can I see the total lift (in Newton) separately for main wing and elevator for different OP-Points?
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-mounted-elevator: The lower the AOA of the mainwing...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The lower the AOA of the mainwing, the higher the AOA of the upsidedown-elvator and the more downward lift is generated...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of board+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The faster, the more downward lift is generated by the elevator. Because the sum of all lift-forces must always equal...
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Maybe a stupid question and/or often asked, but I could not find an answer in this forum: My hydrofoil consists of Mainwing and Elevator. Analysis with fixed lift, because the lift of the complete plane must always compensate the weight of baord+rider. For all Wingfoil-hydrofoils the elevator is mounted "upside down" and therefore generating negative lift for nearly all Op-Points. The faster, the more downward lift is generated by the elevator. Because the sum of all lift-forces must always equal...
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Forgot to mention, that a backwing-offset of z=10mm makes a huge difference: The VLM1 and VLM2 - curves (e.g. CL/CD vs alpha) are now nearly indentical, whereas before with z=0 they differed a lot! Looks good now!
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Good morning Stefan, thank you very much for your tips! I think I learnt a lot for my next calculations with XFLR5, which is such a great tool! Of course I will try all your tips! Many thanks for your support!!!!!!!!!!!!!!! best regards, Klaus
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Unfortunately my onboard-graphics does not support newer versions of XFLR5...
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In this similar project all CL/CD-polars look perfect!
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Finally I have my project file for you with strange outcome! In my opinion only one polar is the "bad guy": Modell: "1) KG Foil EW=1,0/-2,8" Analysis: "T2-VLM1" dark yellow best regards, Klaus
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Hi Stefan, I made a new project with different models for the different angles to make it clear for you and it turned out, that I cannot reproduce my problems. Everything is exactly as you wrote!!! Now its up to me to apologize and to check my original project again to find out the reasons for my strange outcomings... Once again: Many thanks for your support and sorry for the inconvenience!
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I meant "different CL/CD-Maxima" or "best glide"
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Hi Stefan, many thanks for your fast reply! What do you mean with "decalage"? To be clear: With "Angle of Incidence AOI" or "Einstellwinkeldifferenz EWD" I mean the fixed or "built in" angle difference between main wing and elevator. In my example this angle is always 3°. In my XFLR5-calculations I only vary the distribution between main and elevator, eg. 3° Main/ 0° Elevator, 2° Main/ -1° Elevator, 1°Main/-2°Elevator, but in total it is always 3° AOI. Why should this lead to different CL/CDs?
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Additionally, the distance between VLM1 and VLM2-results also vary with the distribution of the given AOI. By the way: Hydrofoil, AR=6, Span=81cm, Mass=85kg: Would you recommend VLM1 or VLM2? Sometimes the results are quite similar, sometimes they differ a lot...
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Given Wing, given elevator, given AOI (Angle of Incidence) e.g. 3°, no fin, no body If I only shift the distribution of my given AOI, e.g. +3/0, +2/-1, +1/-2, I am getting different Maxima for CL/CD! In my opinion, the polar (x = Alpha, y = CL/CD) should always look the same, only shifting "horizontal" depending on the distribution of the fixed AOI between main wing and elevator. The MAX (CL/CD) cannot be affected!
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