Saqr ConsultingDesign sheets
Saqr Consulting

Design Checklist

What to have settled before you cut anything, stage by stage
Checklist

Print it, pin it up, tick it off. Each line is something the design should have an answer to before the next stage starts, and the sheet that gives the answer is named beside it. A line you cannot tick is the sheet to open next.

Requirements

  • The all-up weight you are designing to, payload included, written down — Sheet 05
  • The slowest you need to land and the field you will land on — Sheet 06, Sheet 13
  • How long it must stay up, and with what reserve — Sheet 16
  • The day you will fly it: elevation and the hottest temperature you expect — Atmosphere

Sizing

  • Wing loading and cube loading in the band for the kind of model it is — Sheet 01
  • A stall speed you are comfortable landing at, on the hot day, not the standard one — Sheet 01
  • A design point inside every constraint, and you know which one binds — Sheet 06
  • The weight Sheet 05 builds up agrees with the weight Sheet 01 assumed — Sheet 05

Aerodynamics

  • A section whose measured Reynolds range covers your wing and your tail — Sheet 02, Reynolds
  • A parasite drag figure built up part by part, not picked from a category — Sheet 07

Stability and control

  • The balance point, measured from the leading edge of the mean aerodynamic chord, with its static margin — Sheet 03
  • Tail volumes in the band, horizontal and vertical — Sheet 03, Sheet 12
  • Servos chosen against the hinge moment at the fastest speed it will fly, with margin — Sheet 11
  • Dihedral and fin enough that it comes back level and tracks straight — Sheet 12

Propulsion

  • A propeller that is efficient at cruise and does not stall at climb — Sheet 08
  • A pack that delivers the climb current within its C rating, and an ESC with headroom over it — Sheet 09
  • Enough power in hand to climb at the rate you asked for on the hot day — Sheet 04

Structures

  • A spar sized for the manoeuvre and gust loads of its envelope, with the factor you chose — Sheet 10
  • Gear that does not tip over or nose over, and carries the landing — Sheet 15

Before the first flight

  • Balance checked on the real aeroplane, at the point Sheet 03 gave, with the flight pack in — Sheet 03
  • Endurance and the landing voltage from the pack you will actually fly — Sheet 09, Sheet 16
  • The design file saved, so the numbers you flew are the numbers you can come back to — Design report

Every line is a question the sheets answer; none of them replaces checking the built aeroplane. Balance, control throws and the airframe itself are checked on the real thing before it flies.