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Build Plans · № 1

ER Sparrow Mk II — CAD Plan Set

The refined one-hour design from the 1 Minute / 1 Hour / 1 Day build — not the original free hand-measured trainer — drawn up in CAD and turned into a complete printable plan set. True 1:1 templates, no guessing, no missing steps between the cut lines and the first flight.

The full-size plan sheet — every part outline at 1:1 The build guide's cover — the finished 30-inch trainer

Two documents, one plan set

1 · The printable plan sheets — true-1:1 cutting templates from the CAD file, in two formats: 12 tiled Letter pages you print at home (with a 1″ scale check on every sheet, a sheet map, and a trim-lap-tape assembly guide), plus a single full-size 36×48 sheet for print shops.

2 · The build guide — 8 pages:

  • Cover & specs — 30″ span, 8″ chord, 3 channels, ~$5 of foam
  • Everything you need — materials, tools, and the tested electronics combo
  • Two-sheet cut layout — how both 20×30 sheets are used, nothing wasted
  • The wing — dimensioned drawing: fold lines, spar placement, dihedral relief cuts
  • Fuselage & tail — the 21″ flat that folds into a 1½″ box tube, tail seat, hinges, alignment checks
  • Assembly & control setup — wing seat, skewers, servo throws, expo
  • Wiring & radio — the five-part chain, the stand-behind-the-plane reversing test
  • Balance & first flight — CG mark, 30-second preflight, launch, trim, landing

That fuselage is the one technique worth practising before you cut the real thing: folding foam board into a square tube comes down to four fold lines and a pair of 3/16″ channels, and that guide has a marking calculator for any face size you want.

Free hand-measured trainer This CAD plan set — $9
The original beginner build, measured by handA different, refined airframe — the one-hour plane
Free dimensions + one-page cut guideTrue 1:1 templates — tiled for home printers + full-size 36×48 for print shops
Built around the original beginner videoFrom the 1 Minute / 1 Hour / 1 Day build + 8-page build guide
Stays free — you never need this plan set to build itFor exact outlines on paper next to the cutting mat

Plans are optional in general, for that matter — the $1 foam-board plane I built in 30 minutes had none at all, just two folding tricks and a CG checked before launch. A plan set is for when you want the outlines exact instead of improvised.

Modeled on a plane that flew. This airframe is the one-hour plane from the 1 Minute · 1 Hour · 1 Day build, drawn up in CAD and turned into a real plan set. The free build walkthrough isn't going anywhere — the plan set is for people who want exact outlines on paper next to the cutting mat.

The one-hour plane in this video is the airframe this plan set was drawn from. The full build is here: I Built RC Planes in 1 Minute, 1 Hour, and 1 Day.

Everything in the plan set is cut from foam board and held together with glue and skewers, so no printer is required. If you already own one — or are working out which 3D printer is worth buying for RC planes — motor mounts, control horns, and wheels are the usual first parts to print for a build like this.

PDF · Instant download
$9 · plan sheets + build guide · 3 files

Personal-use license: build as many planes from it as you like. Includes free updates if the plan gets a revision — currently rev 3 (Aug 29, 2026).

Get the plan set — $9

Instant download — both plan formats plus the build guide. Checkout by Stripe. Digital product — no refunds, but if a file gives you trouble, email me and I'll fix it.

Not sure yet? Build the free hand-measured trainer first — same 30″ class, simpler airframe — or browse all the free foam-board RC airplane plans. This plan set is the refined one-hour design, drawn in CAD with exact 1:1 outlines.

More Plans Coming

What should I draw up next?

The 30-inch slow flyer and the bigger builds are candidates. Tell me which plane you'd buy plans for and it moves up the list.

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