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  1. D

    CAM 04 - Schrenk's lift distribution

    Hi all, I'm currently looking for a copy of CAM 04 (Civil Aeronautics Manual), which apparently has a detailed explanation of Schrenk's method for estimating the spanwise lift distribution for the wing. Anyone knows where I can get it please? Thanks in advance.
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    Is there a way to calculate the lift curve slope vs aspect ratio?

    General Aviation Aircraft Design by Snorri Gudmundsson has a short section in Chapter 9 listing various methods for estimating wing lift-curve slope. Inbox me if you want screenshots.
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    lift curve slope vs span?

    As Billski metioned, a lift slope of 9.68 is unrealistic high for both "per radians" and "per degrees". For two-dimensional lift slope, I normally use the DATCOM method, which depends on the airfoil thickness-to-chord ratio, trailing edge angle, Reynolds number and an approximate location for...
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    Control surface hinge moment

    What is your go-to method for estimating control surface hinge moment? E.g. the elevator. I’ve tried using the Datcom method, which calculates the derivatives needed for the hinge moment coefficient based on the airfoil geometry and flow condition. This method requires reading several charts...
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    Calculating Oswald Efficiency

    Thank you for your insight! I think that perhaps I've been overthinking about this factor. The reason why I was asking initially is because I'm attempting to write an optimization code to quickly compare configurations within the design space during the conceptual phase. And that involves 50 or...
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    Calculating Oswald Efficiency

    Yes, this is the paper that I was referring to. What if you are comparing two or more different wing planforms in order to get an initial idea of which one will produce less total drag at a given lift coefficient? Will you use the same oswald efficiency for all the wing planforms?
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    Helpful CAD airfoil smoothing tutorial

    Another way to do it is to simply re-panel the airfoil in XFOIL by adding more points using the "ppar" command and save it as a new airfoil.
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    Calculating Oswald Efficiency

    What is your go-to method for estimating the Oswald efficiency factor (e) used for calculating the Induced drag? Raymer suggests an empirical model for a straight-wing aircraft, which is a function of the Aspect Ratio only. As for a swept-wing aircraft, it's a function of Aspect Ratio and...
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    T-tail on a powered sailplane

    Thanks a lot for the replies, guys! Really appreciate it!
  10. D

    T-tail on a powered sailplane

    I'm curious in knowing why a T-tail is used on most powered sailplanes, with a propulsion arrangement similar to the picture attached. In the example provided, the horizontal tail (HT) lies straight in the wake of the propeller, hence in disturbed airflow which will increase drag. My first...
  11. D

    SURFACES - Aircraft Design Software

    Hey guys, Hope you're all doing well. Just wanted to check if any of you have used the following software before for complementing your conceptual and preliminary design calculations: http://www.flightlevelengineering.com/surfaces
  12. D

    Effect of wind on the drag value during cruise

    Random question: Does the drag on an airplane change due to headwind? Some of the texts I read state that drag is calculated based on airspeed. When flying in a headwind, the groundspeed will reduce. Therefore, to increase the groundspeed, one has to increase the airspeed, which in turns...
  13. D

    Basic question about torsional load calculation along the span

    Thank you all for your replies! Much appreciated! I'll try to work with what Birdman100 wrote and see the results.
  14. D

    Basic question about torsional load calculation along the span

    I thought a bit more about it. I'm not sure if my understanding about it is correct, so please correct me if I'm wrong or point me in the right direction. Just for clarification, I'm calculating the torsional load due to the lift only. Basically, I have several span stations. Lets say the wing...
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    Basic question about torsional load calculation along the span

    But isn't the twisting moments calculated about the aerodynamic center? Which means that it won't change at any AOA. I'm not exactly sure of the effect of aileron deflection on the position of the aerodynamic center. I'll try to look into it. My main confusion is if I use only one spar placed...
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    Basic question about torsional load calculation along the span

    Hi all, This is probably a silly question, so please bear with me. Regarding the torsional load calculation along the span of a wing; by dividing the wing into several sections/stations, one typically computes the local torsion (at one station) about a spar by the product of lift at that...
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    Composite wing without ribs

    It's an unmanned aerial vehicle.
  18. D

    Composite wing without ribs

    Thanks for the advice, Billski! I did some quick calculations for a foam core wing and graphite skin using some of the materials that I have at my disposal a few weeks ago and got some numbers that were far from ideal, mostly because of the high density of structural foam that I have (~8...
  19. D

    Composite wing without ribs

    Email sent. Thanks!
  20. D

    Composite wing without ribs

    I meant sandwich skin with hollow core and spars, as shown in the link in the original post. Airfoil is about 10cm thick at the root and 5cm thick at the tip.
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