{"$schema":"nativecad-dfm-pack/1","id":"aerospace","title":"Aerospace -- drone frames, motor mounts, payload rails and airframe hardware","sector":"aerospace","version":"2026-09-03","summary":"Multirotor frame and motor-mount dimensions, flight-controller and battery-bay standards, payload rails, fixed-wing basics, aerospace fastener locking, weight/CG budgeting and the environmental tests a small UAS airframe is held to.","aliases":["drone","quadcopter","uav","multirotor","aircraft","airframe","motor mount","prop","propeller","payload rail","fpv","wing","aerospace bracket"],"crossSector":false,"size":"core","sources":[{"id":"faa-14cfr107","title":"FAA 14 CFR Part 107 -- Small Unmanned Aircraft Systems","url":"https://www.ecfr.gov/current/title-14/chapter-I/subchapter-F/part-107","accessed":"2026-09-03"},{"id":"tmotor-mn-series","title":"T-Motor MN-series brushless motor mechanical drawings (bolt pattern, shaft, thread)","url":"https://store.tmotor.com/","accessed":"2026-09-03"},{"id":"iflight-xing-motor","title":"iFlight XING-series brushless motor mechanical drawings","url":"https://shop.iflight.com/","accessed":"2026-09-03"},{"id":"oscar-liang-frame-guide","title":"Oscar Liang FPV quadcopter frame size and build guides","url":"https://oscarliang.com/category/frame/","accessed":"2026-09-03"},{"id":"sandia-isogrid-handbook","title":"Sandia National Laboratories / NASA isogrid design handbook (Meyer et al., triangular rib-pattern structures)","url":"https://www.osti.gov/biblio/5117252","accessed":"2026-09-03"},{"id":"matweb-materials","title":"MatWeb Material Property Data (aerospace aluminium, composites, engineering plastics)","url":"https://www.matweb.com/","accessed":"2026-09-03"},{"id":"asme-b1-1-unc","title":"ASME B1.1 Unified Inch Screw Threads (UN and UNR Thread Form)","url":"https://www.asme.org/codes-standards/find-codes-standards/b1-1-unified-inch-screw-threads-un-unr-thread-form","accessed":"2026-09-03"},{"id":"ardupilot-pixhawk-standard","title":"ArduPilot/PX4 standard flight-controller mounting patterns (30.5mm and 20x20mm)","url":"https://ardupilot.org/copter/docs/common-autopilots.html","accessed":"2026-09-03"}],"entries":[{"id":"frame-plate-thickness","kind":"dimension","tier":1,"title":"CF plate thickness for drone frame arms and center plates","summary":"Drone frame arms and center plates are cut from carbon-fiber/epoxy plate at 2, 3 or 4 mm -- 2mm for small whoops and non-structural covers, 3mm for 5-7in racing arms, 4mm for 10in+ or load-bearing center plates.","applies":["frame","arm","center plate","quadcopter"],"value":{"options":[2,3,4],"unit":"mm"},"basis":"Common FPV frame-manufacturer plate-thickness convention scaled to arm/plate span and prop torque","sources":["oscar-liang-frame-guide"],"tags":["frame","plate","carbon-fiber","thickness"]},{"id":"frame-tube-diameter","kind":"dimension","tier":1,"title":"CF tube diameter and wall for round drone arms","summary":"Round carbon-fiber arm tubes run 16, 20, 25 or 30mm OD at a 1mm wall -- larger diameter for bigger motors and props, the 1mm wall standard across sizes because that is what pultruded CF tube is stocked at.","applies":["arm","tube frame","quadcopter"],"value":{"table":[{"odMm":16,"wallMm":1},{"odMm":20,"wallMm":1},{"odMm":25,"wallMm":1},{"odMm":30,"wallMm":1}],"unit":"mm"},"basis":"Standard pultruded CF tube stock sizes used by FPV frame manufacturers","sources":["oscar-liang-frame-guide"],"tags":["frame","tube","carbon-fiber","arm"]},{"id":"arm-length-vs-prop-size","kind":"dimension","tier":1,"title":"Motor-to-motor diagonal by propeller size","summary":"Frame diagonal (motor shaft to motor shaft) scales with prop size: about 210mm for 5in props, 300mm for 7in, 450mm for 10in -- undersize it and adjacent props overlap or strike the frame.","applies":["prop","frame","arm length","quadcopter"],"value":{"table":[{"propIn":5,"diagonalMm":210},{"propIn":7,"diagonalMm":300},{"propIn":10,"diagonalMm":450}],"unit":"mm"},"basis":"Common FPV frame-sizing convention relating motor-to-motor diagonal to propeller diameter","sources":["oscar-liang-frame-guide"],"tags":["frame","arm-length","prop-size"]},{"id":"prop-clearance-rule","kind":"rule","tier":1,"title":"Propeller tip clearance: prop-to-prop and prop-to-frame","summary":"Keep tip-to-tip clearance between adjacent propellers, and between any prop tip and the frame or canopy, at least 10-15% of the propeller diameter -- e.g. >=13-19mm clear on a 5in (127mm) prop -- or vibration and yaw authority both suffer.","applies":["prop","frame","arm","quadcopter"],"value":{"min":10,"max":15,"unit":"%"},"basis":"Common FPV/multirotor prop-clearance design rule expressed as a percentage of prop diameter","sources":["oscar-liang-frame-guide"],"tags":["prop","clearance","rule"]},{"id":"motor-bolt-circle-patterns","kind":"dimension","tier":1,"title":"Motor bolt-circle (square-pattern) sizes by stator frame","summary":"Brushless motor 4-hole mount squares scale with stator size: 22xx square12mm M2 or square16mm M3, 28xx square19mm M3, 4108/5008 square25mm M3/M4, 6215+ square30mm M4 -- read the actual motor's back plate, the 4-digit code only bounds the stator, not the hole spacing.","applies":["motor mount","motor","bldc","quadcopter"],"value":{"table":[{"frame":"22xx","squareMm":12,"bolt":"M2"},{"frame":"22xx","squareMm":16,"bolt":"M3"},{"frame":"28xx","squareMm":19,"bolt":"M3"},{"frame":"4108/5008","squareMm":25,"bolt":"M3/M4"},{"frame":"6215+","squareMm":30,"bolt":"M4"}],"unit":"mm"},"basis":"Common outrunner BLDC motor back-plate bolt-square conventions across drone motor vendors","sources":["tmotor-mn-series","iflight-xing-motor"],"tags":["motor mount","bolt-circle","bldc"]},{"id":"motor-shaft-prop-adapter","kind":"dimension","tier":1,"title":"Motor shaft and prop-adapter thread","summary":"Multirotor motor shafts are dia5mm with an M5 threaded tip for a prop nut or collet-style prop adapter -- the near-universal size across 22xx through 4108-class motors.","applies":["motor","prop adapter","prop nut","quadcopter"],"value":{"table":[{"field":"shaftDia","value":5},{"field":"threadSize","value":"M5"}],"unit":"mm"},"basis":"T-Motor/iFlight mechanical drawings for 22xx-4108 class multirotor motors","sources":["tmotor-mn-series","iflight-xing-motor"],"tags":["motor","shaft","prop-adapter"]},{"id":"standoff-sizes","kind":"fastener","tier":1,"title":"M3 standoff lengths for a stacked FC/ESC deck","summary":"Nylon or aluminium M3 standoffs at 20, 25, 30 or 35mm space a stacked flight-controller/ESC/VTX deck off the frame -- pick the length by stack height plus a few mm of clearance for wiring underneath.","applies":["standoff","flight controller","esc stack","quadcopter"],"value":{"options":[20,25,30,35],"unit":"mm"},"basis":"Common FPV stack-mounting standoff length series sold across frame kits","sources":["oscar-liang-frame-guide"],"tags":["standoff","m3","stack"]},{"id":"fc-mount-pattern-30-5","kind":"dimension","tier":1,"title":"Flight controller 30.5x30.5mm mounting pattern","summary":"The dominant FPV/mini-quad flight-controller mount is four M3 holes on a 30.5x30.5mm square -- match this before any other FC footprint, it is the de facto standard across brands.","applies":["flight controller","fc","quadcopter"],"value":{"table":[{"field":"pattern","value":"30.5x30.5"},{"field":"boltSize","value":"M3"}],"unit":"mm"},"basis":"Industry-standard FPV flight-controller mounting square used across ArduPilot/PX4-compatible boards","sources":["ardupilot-pixhawk-standard"],"tags":["flight controller","mount","30.5mm"]},{"id":"battery-bay-sizes","kind":"dimension","tier":1,"title":"LiPo battery bay envelope by common pack size","summary":"Size the battery bay to the pack: 4S 1500mAh about 35x34x75mm, 6S 1300mAh about 36x34x70mm, 3S 2200mAh about 105x35x25mm, 6S 5000mAh about 155x48x40mm (W x H x L) -- add 1-2mm clearance per side for the strap and heat-shrink wrap.","applies":["battery","lipo","battery bay","quadcopter"],"value":{"table":[{"pack":"4S 1500mAh","wMm":35,"hMm":34,"lMm":75},{"pack":"6S 1300mAh","wMm":36,"hMm":34,"lMm":70},{"pack":"3S 2200mAh","wMm":105,"hMm":35,"lMm":25},{"pack":"6S 5000mAh","wMm":155,"hMm":48,"lMm":40}],"unit":"mm"},"basis":"Common LiPo pack envelope dimensions across major hobby battery vendors (Tattu/CNHL-class packs)","sources":["oscar-liang-frame-guide"],"tags":["battery","lipo","bay","dimension"]},{"id":"camera-thread-1-4-20","kind":"fastener","tier":1,"title":"1/4-20 UNC camera mounting thread","summary":"Action/FPV cameras and gimbal quick-release plates use a 1/4-20 UNC thread (0.25in major dia, 20 threads per inch) -- the universal tripod/camera mount standard; an M6 tapped hole is only a rough geometric substitute, do not call it equivalent on a drawing.","applies":["camera mount","gimbal","tripod thread","payload rail"],"value":{"value":"1/4-20 UNC","unit":"in"},"basis":"ASME B1.1 Unified inch screw thread series; 1/4-20 is the de facto universal camera-mount thread","sources":["asme-b1-1-unc"],"tags":["camera","1/4-20","unc","thread"]},{"id":"thrust-to-weight-ratio","kind":"rule","tier":1,"title":"Minimum thrust-to-weight ratio for stable hover","summary":"Target thrust-to-weight >=2:1 at full throttle for stable, controllable hover with headroom for wind and maneuvering -- a 1:1 airframe can only just hover with zero control authority left over.","applies":["motor","prop","weight budget","quadcopter"],"value":{"min":2,"unit":"ratio"},"basis":"Common multirotor propulsion-sizing rule of thumb for hover stability and control margin","sources":["oscar-liang-frame-guide"],"tags":["thrust","weight","hover","rule"]},{"id":"cg-tolerance","kind":"tolerance","tier":1,"title":"CG offset from the prop-plane centroid","summary":"Keep the airframe's center of gravity within +-5mm of the geometric centroid of the motor/prop plane -- beyond that the flight controller trims out a persistent tilt at the cost of thrust margin and battery life.","applies":["cg","weight budget","frame","quadcopter"],"value":{"max":5,"unit":"mm"},"basis":"Common multirotor CG-balance tolerance relative to the prop-plane centroid","sources":["oscar-liang-frame-guide"],"tags":["cg","balance","tolerance"]},{"id":"lightening-hole-rule","kind":"rule","tier":1,"title":"Lightening-hole and web sizing on a pocketed structural plate","summary":"On a pocketed aluminium or CF plate, leave webs at least 1.5x plate thickness wide, round pocket corners to >=3mm radius, and keep any lightening-hole diameter <=60% of the flange width -- undersize these and the pocket becomes the fatigue-crack origin.","applies":["bracket","lightening hole","pocket","airframe"],"value":{"table":[{"param":"minWebMultiplier","value":1.5},{"param":"cornerRadiusMm","value":3},{"param":"maxHoleFractionPct","value":60}]},"basis":"Sandia/NASA isogrid and aerospace lightweighting design-handbook pocket/web sizing conventions","sources":["sandia-isogrid-handbook"],"tags":["lightening hole","pocket","web","bracket"]},{"id":"aluminium-7075-t6","kind":"material","tier":1,"title":"7075-T6 aluminium for high-strength brackets and mounts","summary":"7075-T6 (yield about 503 MPa, density 2.81 g/cm3) is the go-to aerospace aluminium for highly-loaded brackets, arms and motor mounts where strength-to-weight matters most; it welds poorly compared with 6061, so use it for machined/CNC parts, not fabricated weldments.","applies":["bracket","motor mount","arm"],"value":{"table":[{"property":"yield","value":503,"unit":"MPa"},{"property":"density","value":2.81,"unit":"g/cm3"}]},"basis":"MatWeb 7075-T6 aluminium property data, the standard high-strength aerospace bracket alloy","sources":["matweb-materials"],"tags":["material","aluminium","7075-t6"]},{"id":"aluminium-6061-t6","kind":"material","tier":1,"title":"6061-T6 aluminium for general airframe fittings","summary":"6061-T6 (yield about 276 MPa, density 2.70 g/cm3) trades some strength for weldability and machinability versus 7075-T6 -- the default for landing gear, standoffs and fittings that do not need 7075's peak strength.","applies":["fitting","landing gear","standoff"],"value":{"table":[{"property":"yield","value":276,"unit":"MPa"},{"property":"density","value":2.7,"unit":"g/cm3"}]},"basis":"MatWeb 6061-T6 aluminium property data, the general-purpose aerospace/airframe fitting alloy","sources":["matweb-materials"],"tags":["material","aluminium","6061-t6"]},{"id":"cf-epoxy-plate","kind":"material","tier":1,"title":"Carbon-fiber/epoxy plate for frame arms and plates","summary":"3K/12K woven CF/epoxy plate (density about 1.55 g/cm3, in-plane tensile about 550 MPa) is the default drone-frame material: stiff, light and machinable by CNC router or laser, but it splinters at a drilled edge without a pilot hole and chamfer.","applies":["frame","arm","center plate"],"value":{"table":[{"property":"density","value":1.55,"unit":"g/cm3"},{"property":"tensile","value":550,"unit":"MPa"}]},"basis":"MatWeb woven CF/epoxy laminate property data, typical drone-frame plate/tube layup","sources":["matweb-materials"],"tags":["material","carbon-fiber","cf-epoxy"]},{"id":"tolerance-frame-hole-position","kind":"tolerance","tier":1,"title":"Frame hole-position tolerance by process","summary":"Hold general frame/arm hole positions to +-0.05mm on a CNC-machined or laser-cut CF/aluminium part, versus +-0.2mm on a 3D-printed part -- the same CNC-vs-FDM capability gap seen across every sector in this knowledge base.","applies":["frame","arm","hole position"],"value":{"table":[{"process":"CNC","toleranceMm":0.05},{"process":"printed","toleranceMm":0.2}]},"basis":"Common CNC vs FDM positional-tolerance capability gap applied to drone frame hole patterns","sources":["oscar-liang-frame-guide"],"tags":["tolerance","frame","hole-position"]},{"id":"test-drop-handheld","kind":"test","tier":1,"title":"Handheld-drone drop test","summary":"Drop a handheld-launch drone from 500-1000mm onto a hard level surface in landing orientation and on one corner; the frame, arms and prop guards should show no crack propagation past a single layer of skin -- 1000mm is a common small-UAS reference height.","applies":["frame","arm","prop guard","test"],"value":{"min":500,"max":1000,"unit":"mm"},"basis":"Common small-UAS handheld drop-test height, aligned to typical launch/landing mishap heights","sources":["faa-14cfr107"],"tags":["test","drop","handheld"]}]}