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  1. RPM314

    Testing a method for making spar caps inside a sandwich panel

    Hi everybody, After learning that it's possible to purchase carbon pultruded strips from China in 0.3 mm thickness, I wanted to test if it were possible to form a spar cap out of these strips to match the curvature of an airfoil, so that the maximum possible depth of a spar could be achieved. It...
  2. RPM314

    Testing a method for making moldless-ish D tube skins

    Hi everybody, After being inspired by the work of Rol Klingberg on YouTube building his new ultralight glider, I decided to test out and idea that I had for making the D tube skin using the shear web and ribs as a male mold instead of hot wiring a dedicated male mold. This is of course a trade...
  3. RPM314

    Longitudinal Leaf Spring Gear

    Hey, all. A couple weeks ago I read through Bob's HP-24 build log (which was very informative), and among several points I stopped for a while at the landing gear section to make sure I understood everything that was going on, because I am by no means an expert in landing gear design. So looking...
  4. RPM314

    Can a shear web be discontinuous?

    Hi, all. This question is for building an RC aircraft, but I think I'll only get a knowledgeable answer on this forum instead of RCG. Plus, I figure it'd be interesting brain food for the types that lurk around here. So the problem is I'm building with some new kinds of materials (different foam...
  5. RPM314

    Not seeing "edit post" button

    This is probably going to be another instance where I showcase my absent mindedness in the face of an obvious solution, but I haven't been able to edit posts. I'm logged in and all, but the edit button is missing from the bottom right of my posts. Not sure what to do. EDIT: so of course it...
  6. RPM314

    The Effect of Cranked Wings on the Stability and Control of Tailless Aircraft

    Hi all, Nobody probably remembers, but a few months ago I posited that I would conduct an extensive test in XFLR5 to produce some quantifiable information about the effects of cranked tips (aka weltensegler tips, diffuser tips) on stability and control of flying wings in order to fill the gap...
  7. RPM314

    The Art of Argument

    Hi, all. I was browsing the Interubes just now and came across this excellent set of memes called Logical Fallacy Ref. I know a good many threads here on HBA descend into misunderstandings and nastiness because of some of the very things listed there (though we've recently seen a lot of that...
  8. RPM314

    "View First Unread" function

    Hi, just a quick suggestion for streamlining the site. In the subforums and the personal 'subscribed threads with new posts' page, there's a button to skip to the last post of a thread. I've only found it useful when I'm certain that only one new post has been added (and otherwise load through a...
  9. RPM314

    Wing/fuse intersections and BWB's

    Yes yes, I know there's a lot of debate in this area so I'll just stick to the one question: We all know that wing/fuse intersections tend to be big drag producers, and that blended wing bodies are held up as the pinnacle of interference drag reduction. Now, increasing the wing chord at the...
  10. RPM314

    The US education system

    Hi, all. Just starting to get into the thick of things in my 12th grade aeronautics class, and it's amazing that even a propeller head such as myself still can learn a few things yet. Like: -The coanda effect directly causes lift -Air goes faster over the top of a wing because it has farther to...
  11. RPM314

    Gaps in a boundary layer

    Quick question - Is it preferable to have a notch in the wing (associated with a live hinge control surface, like #1) on the top or bottom? The application is a low Re (~10^5) tailless craft, so there is upwards deflection at high alpha. XFLR5 indicates that tripping the boundary layer on the...
  12. RPM314

    Estimating Cdo - Different surfaces

    Hi, all. Continuing my initially Raymer-heavy self education, I want to make better estimates of the zero-lift drag for less than conventional planes. Raymer just uses the total wetted area times some skin friction value, but not all flight surfaces are created equal. Wings are probably...
  13. RPM314

    Design iterations

    Hi, all. I picked up "Simplified Aircraft Design for Homebuilders" by Dan Raymer a couple weeks ago at the suggestion of the good mr.Topaz, and started running through the calculations to try my hand at it. I went through a few ideas before I settled on a concept I'd like to explore and do some...
  14. RPM314

    Fuselages with an (approximately) circular section

    Hi, all. I doodled a glider fuselage in SketchUp a few days ago, and since the program is incapable of compound curves (or any curves, really, but whatever) I modeled a round fuselage as having an octagonal cross-section. After reading about composite/foam board construction, I realized this...
  15. RPM314


    Will wonders never cease? All those people really thought flying there would be a good idea? :tired: Can't imagine what it's like from the full scale pilot's perspectives.
  16. RPM314

    Sin^3(x) lift distribution - am I on the right track?

    Hi, all. I've been trying to work out the bending stresses caused by a BSLD, and I think I've got it but would like confirmation from someone with more experience. So the lift distribution (right wing shown only, 1/2 span is pi/2) is sin^3, like this: Then the bending moment each point in the...
  17. RPM314

    XFLR5 problems

    Hi, all. I just got the program yesterday and have only had success with the 2d airfoil part. I can make a 2-d foil (though not from a DAT file, all the sites I go to open the file in a web page instead of downloading it) and run a batch analysis, then define a wing. It says the foils are in the...
  18. RPM314

    Concerning a novel covering material

    Hi, all. I'm from an r/c modelling background and I want to start planning out a Horten-esque sailplane to build sometime in the future when I have the resources. Such a plane would likely require reflex, and from what I've heard, cloth under tension has trouble following negative curves. I just...
  19. RPM314


    Colin Hamilton, from Brooklyn NY. Currently 16 yrs old and in high school. R/C scratchbuilder and pilot, with minimal full scale experience. Looking to acquaint myself with design and construction of man carrying craft early on and start planning my glider, so when someday I finally have the...
  20. RPM314

    Horten Ho. Xc project

    (NOTE - as of this post my current number of posts has been multiplied by infinity) Hi, all. I'm not actually a proper full scale pilot; I design, build, and fly (and crash) r/c model aircraft. Someday when I'm out of school and have steady income I want to get into hang gliding or something...