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Rear spoiler (vs rear wing)

Name: Rear spoiler (vs rear wing) dimension sheet
Creator: Xem Studio
License: https://creativecommons.org/licenses/by/4.0/

What is the difference between a rear spoiler and a rear wing? · Standard part · basis: Design rules and figures from the cited sources; example geometry by Xem Studio

Also called: spoiler vs wing, rear spoiler, ducktail spoiler, lip spoiler, trunk spoiler, difference between spoiler and wing, boot spoiler, Gurney spoiler car, rc car spoiler, NASCAR spoiler, wing or spoiler

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

sizes: 5 in table

Notes

A spoiler is a lip or dam on the body's trailing edge that 'spoils' unfavourable flow over the body (Sportwing); a wing is a separate airfoil with air passing over both surfaces, creating a pressure difference (CompetitionX).
Spoilers have lower aerodynamic efficiency than wings (Garry & Le Good, cited in SAE 2018-01-0725), although a NASCAR PIV study found a spoiler made more downforce than a wing because it deflects more flow.
On a 35% DrivAer racing model, spoiler downforce rose with angle from 20 to 60 deg, with the optimum between 40 and 60 deg; 60 deg cost 8.2% more drag than 40 deg for only 3.5% more downforce.
Used on: NASCAR stock cars (spoiler vs wing study).

Rear spoiler size chart

parameter	value or range	source
Spoiler lengths tested (35% model)	40, 80, 120 mm	Cranfield / SAE 2018-01-0725
Spoiler angles tested	20, 40, 60 deg; optimum between 40 and 60 deg	Cranfield / SAE 2018-01-0725
Downforce ratio at peak ride height	1.61 (20 deg), 1.89 (40 deg), 1.95 (60 deg)	Cranfield / SAE 2018-01-0725
60 vs 40 deg	+3.5% downforce, +8.2% drag	Cranfield / SAE 2018-01-0725
1/12 RC pan car spoiler limit	max 25 mm high, 35 mm long	EFRA

Where the files are

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

Cranfield University / SAE	On the Aerodynamics of an Enclosed-Wheel Racing Car (Soares et al., SAE 2018-01-0725)	web	Publisher's page; dimensions are facts
Sportwing	Rear Spoiler vs Rear Wing: What's the Difference?	web	Publisher's page; dimensions are facts
CompetitionX	RC Wings Explained	web	Publisher's page; dimensions are facts
EFRA	EFRA Handbook 2010, Appendix 3: Electric Cars	web	Publisher's page; dimensions are facts

Xem scan

File coming

No downloadable true-size file yet: the published figures do not fix the whole shape, and Xem never guesses a number. A measured scan is planned; request it and it moves up.

Let your AI pull this. Add https://xemstudio.com/mcp to Claude, ChatGPT, Cursor or any MCP client (free, no account, one minute) and it can look up exact sizes, mating fits and free STEP/STL from every chat.

Set it up →

Plain text: sheet.txt · JSON: /api/geometry?object=rear-spoiler

Schematic, not to scale.