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  1. DaveD

    Articles / Blog - Ultralight Design Concepts

    I probably should have held off on the glass of wine until after I gave it a proof read! Thanks for pointing that out Percy, I'll fix it when I get home from work (and I promise I do know my four-times-table... on a good day!). It really does show the value of a fresh pair of eyes, I must have...
  2. DaveD

    Articles / Blog - Ultralight Design Concepts

    It's taken me a couple of weeks, and more than a few, "Why am I doing this to myself?!" moments, but the first bite at Tensors is ready to go. I've tried really hard to make it accessible, let me know if I succeeded! Composites Part 3 - Nervous Strain Makes You Tense, But Engineering Strain...
  3. DaveD

    Articles / Blog - Ultralight Design Concepts

    Ok, there's no easy way to put this, it's time for some mathematics... Composites Part 2 - The-Matrix
  4. DaveD

    Articles / Blog - Ultralight Design Concepts

    Thanks, I hope you find it useful!
  5. DaveD

    Articles / Blog - Ultralight Design Concepts

    ...and then 10 months went by without me doing anything! But now I'm back, and I'm taking on the composites topic. Composites Part 1 - Composing Composites I haven't posted the full index for a while so to save you digging back through this thread: Introduction - In The Beginning...
  6. DaveD

    My library is complete! What am I missing?

    Aircraft Structures - David J. Peery (the Dover 2011 Reprint or the 1950 original) is definitely worth having.
  7. DaveD

    Jim's 7/8th Scale Nieuport 11 Finished and Flying

    Great Job. Congratulations!
  8. DaveD

    Mechanics of Composite Plates, Beams, and Bigger Structures

    Thanks for that Billski. It corresponds fairly closely to how I approached the problem. Right up to the "Converting from Plates to Beams" part. I was a bit doubtful about treating the whole beam as a super-thick plate especially as the web (and therefore web laminations) are at 90deg to the...
  9. DaveD

    Need help from Raymer’s book

    This might be helpful. The man is to scale, so you can print and cut out...
  10. DaveD

    Workshop lighting

    I bought a 50m string of white LED's off ebay. They were about A$50 from memory. Hung them around the roof of the shop to give distributed lighting (fills in the the areas of shadow created by the floro tubes). As an added bonus I can unhook them to get light wherever I need it, especially areas...
  11. DaveD

    Beam Theory Explained - How Spars Work

    These will be to do with buckling. The thin sheet nature of a spar web means it will likely fail through instability (buckling) long before exceeding it's material shear strength. By breaking the web down into smaller panels with stiffeners the buckling strength is improved. Depending on the...
  12. DaveD

    Beam Theory Explained - How Spars Work

    I don’t think this really got answered so I’ll chip in. Firstly, just to clarify, there is shear load, shear stress and shear strain: Shear load – The load (force) acting perpendicular to the axis of the beam. This is the lift when considering the vertical forces acting on a wing spar...
  13. DaveD

    Articles / Blog - Ultralight Design Concepts

    That's All Folks! The last article from my back catalogue "Into the Vortex" is now posted: Here I'll post the full index to this thread in the next couple of days for easy reference. I hope you enjoyed them, and thanks for all the "likes"! Cheers Dave P.S. If I find the time (and the...
  14. DaveD

    Less than 100 % Static Balance

    Going all the way back to ANC-12 (Published in 1948):- For airplanes with limit diving speeds below 260kn (300mph) equivalent airspeed, complete static balance is not often necessary. The allowable amount of unbalance is often determined by comparison with previous aircraft or by calculations...
  15. DaveD

    Articles / Blog - Ultralight Design Concepts

    One More: V-Tails - To 'V' or not to 'V'
  16. DaveD

    Bending-beam spar carry through schemes

    Something along these lines? (Drawing is still not one of my strong points!)
  17. DaveD

    Plywood fuselage design methods

    It depends on your definition of "negligible" but I think your ring frames will see some loading prior to skin buckling. If the fuselage is acting as a beam, then bending loads will attempt to distort the cross section. For example landing gear loads attempting to bend the fuselage in the...
  18. DaveD

    Articles / Blog - Ultralight Design Concepts

    Here's the next batch: Article Index Riveted Joints - Riveting Stuff Fatigue - Chronic Fatigue Designing For Fatigue - Battle Fatigue Enjoy
  19. DaveD

    Articles / Blog - Ultralight Design Concepts

    A few more updates are in: Article Index Back into the structural end of things I'm looking a joint design: General Joint Design - Keeping It Together Bonded Joints - Stick With It Bolted Joints - A Bolt From The Blue Bolts in Shear - Shear Excitement Enjoy Dave
  20. DaveD

    Articles / Blog - Ultralight Design Concepts

    You're right, and my previous post was poorly worded! Slats mostly push up the stalling aoa rather than significanly increase lift at a fixed aoa. So the concern from an asymmetric deployment is presumably having one wing stall at a lower aoa than the other and causing an asymmetric stall (in...