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  1. Eduardo Fadul

    Bigger spinners !?

    Sure that almost the whole propeller generate thrust, I do not know if I could not explain well. What I am saying is that the percentage that the center third is small enough to neglected the area of the spinner, if we see the whole prop. This is the result of the example 14-18 of the book...
  2. Eduardo Fadul

    Bigger spinners !?

    Almost the center 1/3 of the prop is dead (no thrust generated) so you can make the spinner as big as practical/beautiful you want. You will not get any kind of truly advantage if the smaller was right sized.
  3. Eduardo Fadul

    CL/CM - α charts for tube "airfoil" tails?

    Hi everyone I am working with a plane that owns a tail like the RANS s12, however I do not have any kind of chart for those "airfoils" made of bended tube. Does any one have or knows how to calculate de CL and CM Vs Alpha charts for those "airfoils"? Best regards
  4. Eduardo Fadul

    How to "capture" shape for a custom rib?

    The easy (and hardest) way could be with a "jig" a plumb an a ruler. Some time ago we have to obtain the points of the airfoil that no-one knows which was it was, so we made a jig with wood a couple of rulers and one plumb. We take several measures until the point when we "feel kind of...
  5. Eduardo Fadul

    Naca airfoil performance in fabric wings

    The problem is that after all the possible tricks, the wing becomes 185ft^2 quite large for this kind of planes (40% more). kind regards to all
  6. Eduardo Fadul

    Book ‘Aircraft design-A systems engineering approach’

    Hi Pierre, I have been following it with some caution. In amazon it only has 4 reviews, 2 5-stars (with a few credibility for me), and 2 1-stars one complaining for an old version and one from Raymer complaining for the similar name (really a bad choice for the name). So, when I have to uses...
  7. Eduardo Fadul

    Question: The lift of a swept wing

    You always have to take into consideration the correction factor regardless the flight speed. Do not think to much in this, always that you see CL you have to correct it. So even for the spanwise lift distribution you can utilize the lifting line theory.
  8. Eduardo Fadul

    Naca airfoil performance in fabric wings

    I made a fast (and wrong) analysis and you are complete right. The general numbers shows that the Cm of the wing comes to almost twice its original value. I am a little worried about the increase of the wing's weight. However, that is something easy to handle. However, I would like...
  9. Eduardo Fadul

    Naca airfoil performance in fabric wings

    Comes to almost twice the size. With a single slot I comes achieve (theoretical) up to 2.1, however with a clean wing I only could achieve something around 1.1 S= (2*Wto)/(ro*(Vstall^2)*CL) S= (2*1320)/(0.0023769*(70^2)*1.1)=206 ft^2 S= (2*1320)/(0.0023769*(70^2)*1.9)=119 ft^2 S=...
  10. Eduardo Fadul

    Question: The lift of a swept wing

    If I do know the desirable stall speed I just would size the wing area mixing the two upper equations, getting the other two. The first one if you know the stall speed to achieve and the cl of the airfoil, and the second equation if you know the area and want to know the stall speed. regards
  11. Eduardo Fadul

    Naca airfoil performance in fabric wings

    I have been trying to size the wings to fulfill with the stall speed parameter of no flaps, however I always ends with some huge wings, regardless if they are composites/metal/fabric. I knew that the requirements says What if the minimum flaps set is (aprox) 10° to fulfill with LSA...
  12. Eduardo Fadul

    Naca airfoil performance in fabric wings

    Thank you very much for all your answer, really give a better understand. The plane that i have in mind is something really basic where safety and economy are the main goals. It will be something like a far prettily Rans S12. i will be sharing more info as soon as i get something more mature.
  13. Eduardo Fadul

    Naca airfoil performance in fabric wings

    Hi all, I have been looking for information/charts about fabric wings (CL,CD, CM), however I couldn't find any kind of paper/document. I am thinking in airfoils such as NACA 4415 or so, so nothing laminar just something pretty conventional. How does they perform compared with conventional...
  14. Eduardo Fadul

    Rotec engines.

    Hi all Thanks for all your inputs. Over the last two months I was talking with the personnel at Rotec and they are very friendly people. Despite the fact that they do not have a performance chart for their 3600 engine I heard a lot of great comments from many people all over the world. Best...
  15. Eduardo Fadul

    Rotec engines.

    Good afternoon to all I would like to know the experiences and general opinion about the Rotec engines. We are working in a plane and the owner wants to use the Rotec 3600, I contact Rotec asking for the performance charts of the engine, and what a surprise I get when they told me that they...
  16. Eduardo Fadul

    IO-470VO Injection Fuel Pump

    Hi Jay, thanks for your answer. kind regards
  17. Eduardo Fadul

    IO-470VO Injection Fuel Pump

    Hi all I'm doing a little research about the Injection Fuel Pump of the IO-470 VO, I need to know the range of revolutions per minute and the torque of this fuel pump (I think is the 638154). I did a research using every single manual that i could get, however I couldn't find this specs...
  18. Eduardo Fadul

    MAC and Y mac for double tapered wing

    Good morning to all I'm evaluating a collegue Thesis and I have a question. She was trying to determinated the MAC and Y Mac according to USAF - Datcom (Double-delta and cranked Wing page 2.2.2-4) however the values doesn't fit. Doing the math it gives: Mac of the whole wing = 7.8841 ft Y...
  19. Eduardo Fadul

    New agricultural aircraft

    The big problem with the pusher is the prop wash, as well if you extend the spray bars them will be in the area of the wing vortices, so you will lose a great amount of products. There is a way to get a higly maneuver aircraft even with large AR (around 9) for the aircraft ;)
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