Project Logs

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• First issues

  0xF • 07/06/2016 at 13:08 • 0 comments

  So apparently the radios I bought hate me, and have yet to figure out why. If it's beyond me, I'll order different parts and hope future me is a more knowledgeable person.

  On the mechanical front, updated the plans to reflect design changes in the overall plane, especially the wings. Links below for the (several) papers I've gone through to inform those decisions.

  I figured that stability should be the major concern for the design, seconded by efficiency in flight, which are being addressed respectively by wing design and streamlining the fuselage design.

  There will also be a short sequence of tests I'm preparing to assess the performance of electrical systems; namely

  • static thrust
  • servo response times and jitter
  • battery duration at various thrust profiles

  I've also been having some interesting ideas for the controller design and ergonomics, which I hope to try out as soon as the design is more mature.

  cheers
  

  "The road to wisdom? well it's plain and simple to express: Err and err and err again, but less and less and less" -Piet Hein
  

• <Updates Furiously>

  0xF • 06/29/2016 at 23:00 • 0 comments

  Added two scaled drawings of the fuselage-to-be, after adapting the earlier referred to plans and mashing some other stuff in.

  Will probably still modify if, it is by no means a finished design.

  In the electronics front, will order a motor (BLDC, 12v, 2200 Krpm per volt) + 30 A rated ESC from our good friends from shenzen or nearby.

  Battery will probably be sourced from cell phones or the like.

  Will start (and hopefully finish) building the actual aircraft in the next week(s)

  Soldered enough of the main boards of the plane and controller to start testing the radios and control protocols. Coding ensues.
  

• Delicious data

  0xF • 06/27/2016 at 23:34 • 1 comment

  Data(very rough numbers)
  

  XPS foam density (fuselage) - 28 to 45 Kg/m3 (lets say 35)

  thrust (expected) - 800 to 1200g

  electronics weight - about 250g

  • 70g motor
  • 100g batteries
  • 50g servos
  • 30g everything else (wires, boards)

  estimated from the design files:

  • empty fuselage weight - 500g
  • main wing area - 0.21 m2
  • rear wing area - 0.04 m2
  • bottom area - 0.04m2
  • total lifting area - 0.29m2

  Design targets
  

  • wing loading - 1500g/m2
  • weight - 800 to 1000g

  we're ate:

  • 250g max payload which is OK
  • 2760 to 3500 g/m2 wing load which needs addressing
  • 0.8 to 1.2 TWR which is so-so

• Research - pt1

  0xF • 06/27/2016 at 19:32 • 0 comments

  For the airplane body, I want to select early on a fuselage design to adapt to the project. The requirements are malleable right now, but I do want some payload capability and easy handling characteristics.

  carrying capacity depends on the wing loading and thrust , and interferes with the center of gravity, so a design with a large(r) wing surface is necessary. thrust depends on the motor which feeds from the batteries which requires further analysis to find the optimal setup (diminishing returns and all that).

  With all that in mind, I've selected the STS seaplane (minus the seaplane) from user WaterDog at
  

  http://www.rcgroups.com/forums/showthread.php?t=372857
  

  as a primary choice. it is a simple design, doesn't require fussing too much and the plans are comprehensible. plus since the wings are a simple shape, they can be extended to support heavier craft and moved forwards and backwards to adjust the center of lift. I also like the way it looks.
  

  As for the motors and ESC, I'm looking into CD-rom motors

  http://hackaday.com/2009/11/17/rc-airplane-motors-from-computer-trash/
  

  I do appreciate any input

  "The bluebird carries the sky on its back"
  

  -Henry David Thoreau
  

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