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Side skirts (ground-effect sealing)

What do side skirts do on a ground-effect race car? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: side skirts, sliding skirts, ground effect skirts, skirt seal, rocker panel skirts, side skirt aero, lotus 78 skirts, venturi skirts, underbody seal, rc side skirts

Exact dimensions. True size, with no printing tolerance added.

sizes
5 in table

Notes

  • Side skirts seal the gap between the car's sides and the road so that low pressure built under the floor is not destroyed by air leaking in from the sides (Wikipedia, Ground effect (cars)).
  • Lotus sealed inverted-aerofoil sidepods to the ground with flexible skirts on the Lotus 78 (1977) and 79 (1978); the advantage was so large that sliding skirts and then ground-effect floors were banned, with flat bottoms mandatory from 1983.
  • Used on: Lotus 78, Lotus 79, Chaparral 2J.
  • The file is a reference example built by Xem Studio from the numbers above (Dimensions illustrative; no skirt-gap figure in source.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

Side skirts size chart

parametervalue or rangesource
Lotus 78 season1977, five winsWikipedia
Lotus 791978, six wins and the drivers' titleWikipedia
Chaparral 2J (fans + skirts)end of 1970; led to movable-aero banWikipedia
Flat-bottom rulemandatory from 1983Wikipedia
Ground effect returns to F12022Wikipedia

Where the files are

Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.

WikipediaGround effect (cars)webPublisher's page; dimensions are facts

Free files

★ Free files 1 parts. Xem Studio design: free to use, print and sell things from; not to be republished as files. Xem Studio Design License. index.json

side-skirts-side-skirtSide skirt 2000 mm long with a horizontal flange (illustrative section)STEP · STL
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Plain text: sheet.txt · JSON: /api/geometry?object=side-skirts

Side skirts (ground-effect sealing), isometric render of a generated part
Render of side-skirts-side-skirt from the free STEP; not to scale.

Fits with

Single-element rear wing (race car), isometric render of a generated part
Single-element rear wing (race car)7 sizes★ 1 file
Dual-element (two-element) rear wing, isometric render of a generated part
Dual-element (two-element) rear wing9 sizes★ 1 file
Swan-neck rear wing mount, isometric render of a generated part
Swan-neck rear wing mount5 sizes★ 1 file
Gurney flap / wickerbill, isometric render of a generated part
Gurney flap / wickerbill7 sizes★ 1 file
Wing endplates / side dams, isometric render of a generated part
Wing endplates / side dams6 sizes★ 1 file
Front splitter, isometric render of a generated part
Front splitter8 sizes★ 1 file

Questions

Are road-car side skirts the same?

Styling skirts follow the shape but rarely seal to the ground; the race-car function described here relies on a minimal gap to the road (Wikipedia).