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  1. Heliano

    Prandtl lift distribution for conventional configurations?

    I want to add a few comments to this very interesting thread: 1 - If the idea is an aircraft with fuselage, be careful with spanwise lift distribution methods, be it Prandtl's lifting line, Schrenk, CFD or whatever: the fuselage has an important effect: a drop in lift in the center portion...
  2. Heliano

    How old can you be to start a new aeroplane project ?

    Speedboat100: it is never too late. Have a look at the book written by William Randolph entitled "Flight of a Lifetime" - about his 27000-mile solo flight around the world on an airplane built by himself, when he was 76. Or the book entitled "the propeller under the bed" about Arnold Ebneter...
  3. Heliano

    Looking for info on controlling airfoil shape in moldless composite wing

    The critical step is using the strip as template to laminate the 90-degree flange (strip has the inner surface covered with two layers of fiberglass - same as on the inner surface of the skin plates); laminate two layers of fiberglass on the skin plate's inner surface (plate remains flexible as...
  4. Heliano

    Looking for info on controlling airfoil shape in moldless composite wing

    Interesting discussion. I agree with BoKu: for "normal" airfoils the first 10-15% are critical, and a lot less critical behind that. The wing of my plane is moldless glass/foam, but the idea of dozens and dozens of hours of sanding terrifies me. So we´ve developed a method - you can get the idea...
  5. Heliano

    Liquid cooling

    Exactly as you say, Charlie: flaps can be designed to close or to open with air load simply by changing the flap shape or relocating the pivot axis. As for fat "lips", yes, fat lips prevent flow detachment and the resulting loss of efficiency. The turbofan installations are an example: at high...
  6. Heliano

    Liquid cooling

    These postings are most interesting and those participating are clearly knowledgeable on the subject. And it affects me directly because I am in the process of designing the engine installation in my aircraft which is about 70% complete by now. - the engine is a converted Honda Fit engine...
  7. Heliano

    Static Margin too low (4.5%). What to do?

    The gut impression by looking at your three-view is that the horizontal tail is OK at least for CG's up tp 30%. I do not know the computation method you are using. But bear in mind that static margin depends on things like downwash at the tail and fuselage interference, which are difficult to...
  8. Heliano

    IFR capable plane with auto conversion

    Chances of engine failing at night are no different from chances of failing during daytime. But the chances of preforming a successful forced landing are different.
  9. Heliano

    IFR capable plane with auto conversion

    Aircraft certified piston engines' IFSD (rate of unintentional inflight shutdown) is roughly one every 8000-10000 hours. Therefore an inflight engine failure is a real possibility. If one flies IFR at night with a piston single engine he is running an important risk. Turboprops do much better: a...
  10. Heliano

    Two cylinder gear-less twin aircraft

    David, you are right. It was the Hindenburg. There was another factor too: at that time not much was known about static discharging and how to do it effectively. My mixup was in part because the Graf Zeppelin made several trips to South America. There is still a huge (when I say huge I mean it)...
  11. Heliano

    Two cylinder gear-less twin aircraft

    Having a single motor with two independent sources of electricity is certainly feasible. However to know if it is convenient or not, one has to evaluate the reliability of such setup. If the source of electricity is highly reliable, then there is no need for two of them. Additionally, if the...
  12. Heliano

    Two cylinder gear-less twin aircraft

    As it stands today, 100% electric aircraft are viable in some niches only, such as flight schools, glider towing, motorgliders, etc. There is a long way to go to make electric aircraft viable for widespread use including cross country. It all boils down to one parameter: energy density. However...
  13. Heliano

    Two cylinder gear-less twin aircraft

    I came across this thread out of curiosity. Niels knows what he is talking about. There are two positive facts about electric propulsion: 1 - Reliability. A Rotax 912 IFSD (rate of inadvertend inflight shutdowns) is around 7000 hours; an asynchronous electric motor has a IFSD at least ten times...
  14. Heliano

    Load Test Question

    Proppastie, it seems by looking at the pictures that you are loading the wing by hanging the ballast bags. Why don't you turn the wing upside down and simply lay the ballast bags on the wing? Aerodynamic loads are distributed loads by nature, not loads that act on a single point. You could do...
  15. Heliano

    Elevator balancing for tube and fabric tail

    Interesting subject. Aeroelasticity is no simple matter: it is a complex combination of aerodynamic loads, loose connections and several vibration modes. The tail boom may be a factor, but control cable elasticity may also contribute, and many other things. One thing I can say: be careful when...
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