Index
Every page on the site, in the groups the menus use, with a line on what each one is for.
Sizing
- Sheet 01Wing SizingWork out wing loading, cube loading, stall speed and Reynolds number for an RC plane or small UAV. Enter your dimensions, get a scale planform and plain-English guidance.
- Sheet 05Weight BudgetBuild up the all-up weight of a model aircraft or small UAV group by group: structure, propulsion, battery, avionics, payload and contingency.
- Sheet 06Constraint DiagramPlot wing loading against power loading for a model aircraft or small UAV. Stall, cruise, climb, launch and turn on one chart, with the design point.
Aerodynamics
- Sheet 02Airfoil MatrixPick a wing section for an RC plane or small UAV by Reynolds number, mission and build method. 27 airfoils with honest notes on stall and buildability.
- Sheet 07Drag Build-UpBuild the parasite drag of a model aircraft or small UAV component by component: wetted area, skin friction, form factors, and the gear that dominates.
Stability & control
- Sheet 03Balance & TailNeutral point, centre of gravity range, tail volume coefficients and trim tail load for an RC plane, flying wing or small UAV.
- Sheet 11Controls & ServosHinge moments and the servo torque they demand, for ailerons, elevator and rudder, plus the roll rate your ailerons actually deliver. For model aircraft and small UAVs.
- Sheet 12Lateral StabilityWeathercock stability and dihedral effect for a model aircraft or small UAV: fin volume against fuselage, dihedral against wing position, and the balance between them that decides whether it tracks straight.
Propulsion
- Sheet 08Propeller MatchingMatch a propeller to a model aircraft or small UAV: advance ratio, pitch speed and slip, tip Mach number, static thrust, cruise and climb efficiency.
- Sheet 09Battery SystemSize a flight pack properly: current draw, C rate, voltage sag under load, resistance losses, usable capacity and endurance for a model aircraft.
Structures
- Sheet 10StructuresV-n diagram, manoeuvre and gust loads, root bending moment and spar cap sizing for a model aircraft or small UAV. What the wing has to survive, and what will carry it.
- Sheet 15Landing GearTricycle against taildragger geometry for a model aircraft or small UAV: wheel loads, tip-back and nose-over angles, turnover angle, propeller clearance and wheel size against the surface you fly from.
Performance
- Sheet 04Power & EnduranceDrag polar, power required curve, motor sizing, battery pack and endurance for an RC plane or small UAV.
- Sheet 13Field PerformanceGround roll, distance over an obstacle and landing roll for a model aircraft or small UAV, on the surface and in the wind you actually fly in. Will it get off your field, and will it stop on it.
- Sheet 14Glide & Sink PolarSink rate against airspeed for a model aircraft or small UAV: best glide ratio and the speed for it, minimum sink, the speed to fly into wind, and what circling costs.
- Sheet 16Mission EnergySegment by segment energy for a model aircraft or small UAV: climb, cruise, loiter and reserve against the pack you have, and the payload you give up to stay out longer.
Tools
- AtmosphereAir density, pressure, temperature, density altitude, speed of sound and viscosity for any elevation, temperature and humidity. The atmosphere every sheet on this site uses.
- ReynoldsReynolds number for every part of a model aircraft or small UAV, with skin friction, boundary layer thickness and the speed each chord needs to escape the low-Reynolds bands.
- UnitsEvery unit pair the Saqr design sheets use: millimetres and inches, grams and ounces, wing loading in g/dm² and oz/ft², servo torque in kg·cm and oz·in, thrust, power, pressure and pack energy.
Learn
- How to use the sheetsA short guide to the Saqr design sheets: where to start, the order to work them in, how your figures travel between sheets, and how to read what a sheet tells you.
- Design checklistA one-page design checklist for the workshop wall: what to have settled at each stage of a model aircraft or small UAV design, and which Saqr sheet settles it.
- Worked studiesFour aircraft run end to end through all sixteen Saqr design sheets: a club trainer, an FPV platform, a long-endurance survey UAV and a thermal glider, with every number as the sheets produced it.
- Exercises23 aircraft design exercises with worked answers, mapped to a typical course. Every one is a link that loads its own aeroplane into the sheet that solves it, and every published answer is captured from a run of that sheet.
- Design reportLoad the design file the sheets write and read the whole study back as one document: the aircraft, what each sheet worked out, everything the sheets flagged, and which sheets you have not run yet. Nothing is computed here and nothing is uploaded.
- MethodsEvery formula the Saqr design sheets use, with its source, its constants, and where it stops being valid. The half that says where a method breaks down is the half that makes it checkable.
- GlossarySeventy-three terms the Saqr design sheets use, defined plainly and each linked to the sheet where it matters: angle of attack, static margin, Reynolds number, tail volume, sag, washout and the rest.
- SymbolsEvery symbol used on the Saqr design sheets, with its unit, and every sign convention stated plainly: what a negative pitching moment, tail load, dihedral effect or load factor actually means.
- SourcesEvery source behind the Saqr design sheets: the UIUC low-speed airfoil volumes, the NACA reports, the Sandia data, Timmer and Laitone, with what each one covers, where it stops, and how to get it.
- MaterialsBalsa, basswood, spruce, pine, ply, glass and carbon with strength, stiffness and density, plus specific strength and stiffness; foam densities and covering weights; and finished-structure areal densities for six build methods.
- ChangelogWhat changed in each revision of the Saqr Consulting design sheets, and why. Corrections are applied to the current revision and recorded here.
Blog
- All postsArticles from Saqr Consulting on designing model aircraft and small unmanned aircraft: the reasoning behind the design sheets, worked examples, and the mistakes the numbers catch.
Saqr Consulting
- Cover: the sheet indexSixteen free calculation sheets for model aircraft and small UAVs: weight budget, wing sizing, airfoil choice, balance, drag, power, propeller and battery.
- AboutHow the Saqr Consulting design sheets are built: the published methods behind them, the compiled-not-measured convention, and how the sixteen sheets check each other.
- ChangelogWhat changed in each revision of the Saqr Consulting design sheets, and why. Corrections are applied to the current revision and recorded here.
- SearchSearch every figure the Saqr sheets work out, every field you can enter, every glossary term and every symbol — 1433 entries across 35 pages, indexed by what each page answers rather than by what it mentions.
- PrivacySaqr Consulting collects nothing you type: no accounts, no cookies and no third-party scripts. Every calculation runs in your browser.
- Terms of useTerms of use for the Saqr Consulting design sheets: free to use, no warranty, not an airworthiness determination, and what remains your responsibility.