# Winglets

> Do winglets reduce drag?

- Category: Aircraft design › Wing features
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/winglets/ · JSON: https://xemstudio.com/api/geometry?object=winglets · Plain text: https://xemstudio.com/objects/winglets/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

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

## Notes

- Whitcomb's NASA winglets move the tip vortex away from the wing rather than weakening it; he predicted about 20% less induced drag and 6-9% better L/D, and KC-135 tests measured 20% and 7% (NASA Spinoff; ERAU).
- Leishman models a winglet as an effective aspect ratio gain AR_eff = AR(1 + K h/s), with K = 1 for a classic winglet (ERAU). Winglets avoid the wing strengthening a span extension needs (NASA).
- On NASA's canard model, enlarged winglets substantially increased directional stability (NASA TP-2623).
- Used on: KC-135, Boeing 747-400, MD-11, Boeing 737-700.
- The file is a reference example built by Xem Studio from the numbers above. Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

## Sizes

| parameter | value or range | source |
|---|---|---|
| Induced drag reduction (KC-135) | 20% predicted and measured | NASA Spinoff 2010 |
| L/D increase | 6-9% predicted, 7% measured | NASA Spinoff 2010 |
| KC-135 winglet height | 9 ft | NASA Spinoff 2010 |
| Effective AR | AR(1 + K h/s), K = 1 classic winglet | ERAU (Leishman) |
| 737 MAX AT winglet fuel saving (claimed) | up to 1% | ERAU |
| Reference build | tapered wing with 60 mm winglets | illustrative |

## Where the files are

- NASA Spinoff 2010: [Winglets Save Billions of Dollars in Fuel Costs](https://ntrs.nasa.gov/api/citations/20110000748/downloads/20110000748.pdf) — web — Publisher's page; dimensions are facts
- Embry-Riddle (Leishman), Introduction to Aerospace Flight Vehicles: [Wing Shapes and Nomenclature](https://eaglepubs.erau.edu/introductiontoaerospaceflightvehicles/chapter/wing-shapes-and-nomenclature/) — web — Publisher's page; dimensions are facts
- NASA Langley (D. Satran): [Wind-Tunnel Investigation of the Flight Characteristics of a Canard General-Aviation Airplane Configuration, NASA TP-2623 (1986)](https://ntrs.nasa.gov/api/citations/19870000606/downloads/19870000606.pdf) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/winglets/index.json · license: https://xemstudio.com/files/hardware/winglets/LICENSE.md

- winglets-wing: [STEP](https://xemstudio.com/files/hardware/winglets/winglets-wing.step) · [STL](https://xemstudio.com/files/hardware/winglets/winglets-wing.stl) — tapered planform: span 1000, root 220, tip 99 mm, LE sweep 0°, dihedral 3°, NACA 2412

## Questions

**Do winglets help small RC planes?**

The physics is the same: they act like extra span (AR_eff = AR(1+K h/s), ERAU), but Whitcomb's numbers are for transports.

## Fits with

- [Plain flap](https://xemstudio.com/objects/plain-flap/)
- [Split flap](https://xemstudio.com/objects/split-flap/)
- [Slotted flap](https://xemstudio.com/objects/slotted-flap/)
- [Fowler flap](https://xemstudio.com/objects/fowler-flap/)
- [Leading-edge slat and fixed slot](https://xemstudio.com/objects/leading-edge-slat-slot/)
- [Gurney flap](https://xemstudio.com/objects/gurney-flap/)