← back to the build document · the rack for the lengthwise layout · the build order · the roof frame · the two joints · the cut pattern · what to buy · making it · what to measure first
The front fairing
The rack lifts the panels about 10 in off the roof, and at highway speed that gap is a scoop. The fairing is one flat aluminium plate across the front of the rack, leaning back, that closes the scoop at the leading edge and leaves the sides and rear open. This page is the plate drawn to scale, the two joints that hold it, the shape to cut, and the parts to buy.
82.5 × 18.4 infinished plate at 45°, from an 84 × 20 in blank · 84 × 15 in blank at 70°
3 + 4three bent tabs on the panel-rail ends, four stays under crossbar C0
~20 lball aluminium at 45° · ~16 lb at 70° · hardware estimated at 1.5 lb of that
What is still assumedThe roof ahead of the rack has not been measured, so the angle is not chosen yet: 45° needs 8.2 in of roof ahead of the rack envelope, 70° needs 2.9 in. The roof curve under the bottom edge is the same assumed profile as the rack section, so the bottom edge is scribed on the van and never cut from this page. The 82.5 in width comes from the assumed 86 in gutter-to-gutter. What to measure first lists each one.
What it looks like, to scale
two side views at the van centreline and one front view · heights from the stud base, same stack as the rack section
Which angle45° sheds air more cleanly and is the first choice. 70° is the fallback if there is less than about 9 in of usable roof ahead of the rack. Both use the same parts; only the blank height, the bend angles and the stay length change.
The A/C sits behind the curb-side halfThe Velit 3000R is 8 in behind the front of the rack on the curb side. Which way its condenser draws air has not been checked against the manual. If it draws from the front, the curb-side half of the plate needs a louvred or cut-back section, and that changes the pattern below.
The two joints
side views at a panel rail and at a stay, both angles · every part numbered F1–F9, matching the table below
What drawing it to scale changedThe first parts list, sent in chat, put five hinges on top of crossbar C0. Drawn to scale that does not work: a plate hung from C0's top runs straight through the three panel-rail ends, at 45° and at 70°. So the top mounts moved to the panel-rail ends, three of them, and C0 takes only the stays, from underneath, through the back slots it already has. The Unistrut P1843 hinge went as well: its knuckle would stand through the plate, and its catalog sheet does not dimension the knuckle, so the joint could not be drawn honestly. A bent tab can.
- The tab's channel nut sits 2.4 in back from the rail end, which is 1.6 in behind the rack's own crossing bolt inside the same rail. It is reached with a socket from above, through the slot between the plate and panel P1.
- The nyloc behind the tab's upper hole clears the rail end by 0.90 in at 45° and 0.39 in at 70°. That is why the two tab holes are 1.3 and 2.5 in down the tab's leg and no higher.
- Nothing is drilled in the rack. The tabs use the rail slots, the stays use C0's back slots. Every drilled hole is in the fairing's own parts.
This is the one fabricated item on the roofThe rack pages say catalog parts only, and that still holds for everything that carries the panels. The fairing is the exception because the universal catalog deflectors found top out around 52 in wide and this one is 82.5. It carries no panel load. Nothing on this page is load-rated: as a rough figure only, a plate this size sees on the order of 100 lb of wind at 75 mph in still air and about 175 lb into a 25 mph headwind.
The shape to cut
flat pattern, looking at the front face, driver side on the left · the plate is flat so there is no bend allowance
Not a cut templateThe bottom edge on this drawing is the assumed roof profile. Cut the top edge and the two ends from the numbers; take the bottom edge from a cardboard template made on the van. Hole positions are nominal too — mark them through the tabs with the plate clamped in place.
What to buy
quantities for the drawings above, either angle · none of this has been priced yet
| # | Part | Qty | Where it goes | Source |
|---|---|---|---|---|
| A · Aluminium | ||||
| F1 | 5052-H32 aluminium sheet, ⅛ in (0.125) | 1 blank 84 × 20 in at 45° 84 × 15 in at 70° | The plate. A metal supplier shears the blank; otherwise it comes out of a 4 × 8 ft sheet, and the offcut makes the strip for F4 and F8 | metal supplier |
| F2 | Aluminium angle, ¾ × ¾ × ⅛ in, 6063 | 1 × 82½ in one 8 ft length | Top stiffener, on the rear face along the top edge | metal supplier or hardware store |
| F3 | Aluminium angle, 1 × 1 × ⅛ in, 6063 | 1 × 82½ in one 8 ft length | Lower stiffener, on the rear face, 9.75 in down at 45° or 7.34 in at 70°. The stays bolt to its standing leg | metal supplier or hardware store |
| F4 | Top tabs — ⅛ × 1½ in strip | 3 × 6.6 in at 45° 3 × 6.8 in at 70° | One on each panel-rail end. One bend, ¼ in inside radius | strips cut from the F1 offcut, or one 6 ft length of 6063 flat bar. Not 6061-T6 — it cracks on a bend this tight |
| F8 | Stays — ⅛ × 1½ in strip | 4 × 8.0 in at 45° 4 × 5.1 in at 70° | Lower stiffener to C0's underside, at x = 14, 32, 54 and 72 in from the driver-side gutter line, moved to the nearest back slot. Two bends each | |
| B · Fasteners — stainless | ||||
| F5 | Unistrut P1010 ½-13 channel nut with spring | 3 | In each panel rail's slot, 2.4 in back from the rail end. Same nut as rack line 7 | with the rack order |
| F6 | ½-13 × 1 in hex bolt, flat washer, lock washer | 3 | Tab to panel rail. Same bolt as rack line 8 | with the rack order |
| F7 | ¼-20 × ¾ in button-head screw, 2 flat washers, nyloc nut | 10 | Six hold the tabs to the plate, head on the front face. Four hold the stays to the lower stiffener | hardware store |
| F9 | ½-13 × 1¼ in hex bolt, 2 flat washers, nyloc nut | 4 | Stay to C0: up through C0's back slot, washer and nut inside the channel | hardware store |
| F10 | 3/16 in blind rivets, aluminium, grip range covering ¼ in | 22 a box of 50 | Eleven per stiffener, first one 1.25 in from each end, then 8 in pitch | hardware store |
| C · Edge | ||||
| F11 | Push-on EPDM edge trim for a ⅛ in edge | 8 ft | Along the bottom edge, so aluminium never touches the roof | hardware or auto-parts store |
Lighter option for F13 mm aluminium composite panel (the sign-shop sheet, sold as ACM or Dibond) is roughly half the plate's weight and cuts with a jigsaw. It is less rigid around bolt holes, so use fender washers under every F7. ABS is out: it chalks and goes brittle in sun unless it is painted.
Tools. Cardboard and a marker for the roof template, a jigsaw with a metal blade, a file, a rivet gun, a vise for the bends, and 3/16, 9/32 and 9/16 in drill bits.
Making it, in this order
after the rack is up and the panels are down — it is the last thing on the roof
- Measure the roof and pick the angle. The three numbers in the next section. Nothing gets bought before this.
- Make the roof template. Hold a strip of cardboard across the roof where the bottom edge will land — 8.2 in ahead of the rack at 45°, 2.9 in at 70° — lean it at the plate's angle, and scribe the roof curve onto it.
- Cut the plate. Top edge and both ends from the pattern, bottom edge from the template, ¾ in short of the roof. File every edge.
- Rivet the two stiffeners to the rear face. Drill plate and angle together, 3/16 in, eleven rivets each.
- Cut and bend three tabs and four stays. Bend in a vise over a ¼ in radius. Tab: one bend of 45° or 70°. Stay: 74° and 29° at 45°, 82° and 62° at 70°. Bend one stay first and offer it up before bending the other three.
- Tabs onto the rail ends, finger-tight. Channel nut in the slot, 2.4 in back from the rail end.
- Clamp the plate to the tabs with its top edge level with the top of the glass and its bottom edge ¾ in off the roof. Mark the six tab holes through the tabs, take the plate down, drill 9/32 in, bolt up.
- Stays. Bolt each stay to C0's underside at the nearest back slot, mark the stiffener's standing leg through the stay, drill, bolt.
- Edge trim on the bottom edge, then tighten everything. Check it again after the first loaded highway miles, with the rack's own re-torque.
What to measure first
three measurements on the van, and what each one moves
- Usable roof ahead of the front of the rack. Picks the angle. 45° needs 8.2 in plus room for the edge trim; 70° needs 2.9 in. It also says whether the roof is still the same shape that far forward.
- Gutter line to gutter line. The plate is that number minus 3½ in: two 1⅝ in uprights and ⅛ in each side. On the assumed 86 in it is 82.5 in. Moves F1, F2 and F3.
- Roof crown above the stud base. Assumed 3.7 in, same as the rack. Every inch of extra crown takes an inch off the plate's height over the crown. Moves F1's blank height.
Not verifiedThe roof shape ahead of the rack. The Velit's condenser intake direction. Prices. And the rack itself is still drawn on an assumed envelope, so anything that moves crossbar C0 or the panel-rail ends on the rack page moves this page with it — the drawings are generated from the same numbers.
Status: drawn to scale from the rack's own constants, both angles, not yet measured against the van and not load-rated. Replaces line 21 on the rack's parts list. Drawn and written by Maple, 2026-09-28.