{"id":849,"date":"2025-06-05T15:59:52","date_gmt":"2025-06-05T12:59:52","guid":{"rendered":"https:\/\/ft.systems\/product\/heavy-line-f421-frame\/"},"modified":"2026-09-08T16:05:08","modified_gmt":"2026-09-08T13:05:08","slug":"heavy-line-f421-frame","status":"publish","type":"product","link":"https:\/\/ft.systems\/en\/heavy-line-f421-frame\/","title":{"rendered":"Heavy Line F421 21\u201d Carbon Fiber FPV Drone Frame"},"content":{"rendered":"

The Heavy Line F421 21\u201d carbon fiber FPV drone frame is engineered for large-scale builds using propellers up to 21 inches<\/strong>. An 830mm<\/strong> wheelbase paired with a 4-arm True-X<\/strong> layout forms the foundation for a high-power FPV platform.<\/p>\n

The structural core is manufactured from 3K carbon fiber, featuring full-length reinforced arms. An arm thickness of 10 mm<\/strong> combined with robust carbon profiling handles extreme torque and thrust forces from heavy-duty motors and oversized props.<\/p>\n

Reinforced arms preserve structural geometry during high vibrations and sudden load fluctuations. Carbon motor mounts prevent arm flex during aggressive maneuvers, minimizing the risk of propeller-to-frame strike.<\/p>\n

The central section is also reinforced with an expanded surface area of 180 \u00d7 180 mm<\/strong>. It serves as a mounting deck for main power components, battery packs, or specialized payloads. With assembled dimensions of 630 \u00d7 630 \u00d7 65 mm<\/strong>, the frame provides ample working room. Total frame weight is 1100 g<\/strong>, a crucial consideration during component selection.<\/p>\n

The Heavy Line F421 carbon frame is tailored for surveillance platforms, radio communications relays, and signal repeaters requiring extended hover endurance. Additionally, it suits long-range delivery drones capable of carrying payloads up to 8 kg.<\/p>\n

Flight stack mounting uses a standard 30.5 \u00d7 30.5 mm<\/strong> (M3) pattern. The frame is designed for 42xx and 60xx size motors, with motor installation secured via a \u00d825\u2013\u00d832 mm<\/strong> pattern with four M4 screws.<\/p>\n

Package Includes:<\/strong><\/h3>\n
    \n
  • Top plate IP27 F415-F421, 3 mm \u2014 1 pc.<\/li>\n
  • Bottom plate IP27 F415-F421, 3 mm \u2014 1 pc.<\/li>\n
  • Cover plate F421, 3 mm \u2014 1 pc.<\/li>\n
  • Bottom X-brace F421, 5 mm (with press nuts) \u2014 1 pc.<\/li>\n
  • Top X-brace F421, 5 mm (with press nuts) \u2014 1 pc.<\/li>\n
  • X-brace F421, 5 mm \u2014 2 pcs.<\/li>\n
  • Arm F421 21\u2033, 10 mm \u2014 4 pcs.<\/li>\n
  • Plate with press nut, 3 mm \u2014 4 pcs.<\/li>\n
  • Spacer shim, 10 mm \u2014 4 pcs.<\/li>\n
  • M3\u00d78 Flat head screw \u2014 8 pcs.<\/li>\n
  • M3\u00d78 Button head screw \u2014 2 pcs.<\/li>\n
  • M3\u00d78 Socket head cap screw \u2014 2 pcs.<\/li>\n
  • M3\u00d710 Button head screw \u2014 4 pcs.<\/li>\n
  • M3\u00d726 Socket head cap screw \u2014 1 pc.<\/li>\n
  • M3\u00d730 Socket head cap screw \u2014 4 pcs.<\/li>\n
  • M4\u00d730 Socket head cap screw \u2014 4 pcs.<\/li>\n
  • M4\u00d725 Socket head cap screw \u2014 20 pcs.<\/li>\n
  • M3\u00d750 Socket head cap screw \u2014 4 pcs.<\/li>\n
  • M2.5\u00d76 Button head screw \u2014 2 pcs.<\/li>\n
  • M2\u00d74 Button head screw \u2014 4 pcs.<\/li>\n
  • M2\u00d78 Button head screw \u2014 2 pcs.<\/li>\n
  • M3\u00d714 Button head screw \u2014 2 pcs.<\/li>\n
  • M3\u00d718 Socket head cap screw \u2014 2 pcs.<\/li>\n
  • M3 DIN934 Nylon lock nut \u2014 12 pcs.<\/li>\n
  • DIN934 Metal nut \u2014 4 pcs.<\/li>\n
  • Black aluminum standoff, 20 mm \u2014 4 pcs.<\/li>\n
  • Black aluminum standoff, 32 mm \u2014 6 pcs.<\/li>\n
  • Video Transmitter (VTX) Bracket \u2014 1 pc.<\/li>\n
  • Quick-release VTX Mount \u2014 1 pc.<\/li>\n
  • Left Camera Front Standoff \u2014 1 pc.<\/li>\n
  • Right Camera Front Standoff \u2014 1 pc.<\/li>\n
  • Left Camera Damper \u2014 1 pc.<\/li>\n
  • Right Camera Damper \u2014 1 pc.<\/li>\n
  • Left Control Antenna Mount \u2014 1 pc.<\/li>\n
  • Right Control Antenna Mount \u2014 1 pc.<\/li>\n
  • Rubber Pad Set \u2014 1 set<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

    Heavy Line F421 carbon fiber frame designed for 21-inch FPV drone systems. Manufactured from 3K carbon fiber with heavy-duty 10mm thick arms. Features a standard 30.5 \u00d7 30.5 mm stack mounting pattern. Comes complete with a camera and video transmitter mounting kit.<\/p>\n","protected":false},"featured_media":1987,"template":"","meta":{"_acf_changed":false},"product_brand":[],"product_cat":[123,122],"product_tag":[],"class_list":["post-849","product","type-product","status-publish","has-post-thumbnail","product_cat-all-frames","product_cat-carbon-frames-for-drones","first","instock","shipping-taxable","purchasable","product-type-simple"],"acf":[],"yoast_head":"\nHeavy Line F421 21\u2033 Carbon Fiber FPV Frame | FT Systems<\/title>\n<meta name=\"description\" content=\"Ultra-heavy Heavy Line F421 (830mm) carbon frame for FPV & X8 platforms up to 21\u2033 props. 3K carbon, 10\u201312mm arms, 6\u201312S support. 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