Tail Rotor and Anti-Torque Patents: Leaders & Filing Trends 2026
- Concentrated at the top. The five leading assignees hold 52.3% of all 128 records in scope, and the top ten hold 73.4% — a small group of filers controls most of the documented claim space.
- Filing accelerated sharply. Filings rose 89% between 2021 (9) and 2024 (17), the peak year on record, before the most recent two years (still filling in due to publication lag).
- One design core dominates. B64C (aeroplanes & helicopters) touches 78.9% of records, while control-systems classes like G05D (19.5%) and navigation class G01C (11.7%) mark where electronic yaw control is being layered on.
Filing growth compares 2021 (9 records) with 2024 (17) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 128 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Tail rotor and anti-torque patenting spans mechanical duct and blade geometry, electronic yaw-control logic, and the sensing needed to keep a helicopter or VTOL aircraft in controlled flight when yaw authority is marginal. The 128 records in scope were pulled using claim and abstract language tied to tail rotor effectiveness, duct lip separation, unequal blade spacing, and pedal control gradient — a targeted slice of rotorcraft flight-control patenting rather than the whole helicopter field.
Filing offices skew heavily to the United States (47 records) and Europe (26 at the EPO, plus 6 in Germany and 5 in Austria), with WIPO PCT filings (21) suggesting a meaningful share of applicants are pursuing multi-jurisdiction protection rather than filing purely domestically.
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Filing trend and technology composition
Two views of the same 128-record dataset: how filing volume moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend
Filings climbed from 9 in 2021 to a peak of 17 in 2024, an 89% increase over that span. The two most recent years are undercounted because publication typically lags filing by around 18 months, so 2025 and 2026 should not be read as a slowdown.
Technology composition by IPC subclass
B64C (aeroplanes & helicopters) appears in 78.9% of the 128 records, confirming this is fundamentally airframe and rotor-mechanics territory. B64D (aircraft equipment, 21.1%) and G05D (non-electric variable control, 19.5%) show where flight-control electronics are layered on top of that mechanical core, while B64U (drones, 9.4%) and G08G (traffic control, 9.4%) mark the smaller but growing overlap with unmanned and urban air mobility use cases. Since a single record can carry multiple classes, these shares sum to well over 100% and should be read individually against the 128-record total, not against each other.
Shares are the percentage of the 128 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Tail Rotor and Anti Torque Systems with Eureka
This page is one run against one query. Ask Eureka your own question about tail rotor and anti torque systems and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US11801936B2 — Preventing helicopter loss of tail rotor effectiveness
A flight control system that translates pilot pedal input into an actuator command while applying yaw rate limits tied to a vortex ring state envelope for the tail rotor, using an electronically controlled tail rotor actuator to keep commanded yaw within a safe operating envelope.Filed by Textron Innovations Inc., published 2023-10-31.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US8800912B2 | Three wing, six-tilt propulsion unit, VTOL aircraft | 206 |
| 2 | US20110315809A1 | Three wing, six-tilt propulsion unit, VTOL aircraft | 192 |
| 3 | US20110168835A1 | Three Wing, Six Tilt-Propulsion Units, VTOL Aircraft | 189 |
| 4 | US20110303795A1 | Three-wing, six tilt-propulsion unit, VTOL aircraft | 118 |
| 5 | US8616492B2 | Three wing, six tilt-propulsion units, VTOL aircraft | 99 |
| 6 | US20110006165A1 | Application of conformal sub boundary layer vortex generators to a foil or aero/ hydrodynamic surface | 86 |
| 7 | US6929215B2 | Rotor system for helicopters | 74 |
| 8 | US6466888B1 | Neural network system for estimation of aircraft flight data | 69 |
| 9 | US8708273B2 | Three-wing, six tilt-propulsion unit, VTOL aircraft | 68 |
| 10 | US20160280369A1 | rotorcraft | 64 |
Citation counts inside a searched corpus favour older filings by construction, so treat this table as a signal of influence on later art, not a ranking of current technical importance.
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Browse MCP servers →What the numbers mean for a filing decision
Three findings that shape where a new filing is likely to run into prior art, and where it is not.
A small group controls most of the claim space
The five leading assignees combine for 52.3% of all 128 records, and the top ten reach 73.4%. That leaves a long tail of single- and few-filing entrants competing for the remaining share, which is where freedom-to-operate work needs the most care since the tail is fragmented rather than absent.
Filing activity nearly doubled in three years
Volume rose from 9 records in 2021 to a 2024 peak of 17, an 89% increase. Recent-year momentum by individual assignee shows several leaders flat or down year-on-year in the most current data, but that reading is unreliable this close to the cut-off given the roughly 18-month publication lag.
Mechanical rotor and airframe claims still anchor the field
B64C touches close to four in five records, but the presence of G05D (19.5%), G01C (11.7%) and B64U (9.4%) shows a meaningful secondary cluster building around electronic yaw control, navigation-linked stabilisation and drone-scale anti-torque design.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to tail rotor and anti torque systems, with the prior art for and against each one.
Who is filing, and where the field is still open
The ranked leaders sit alongside a long tail of single-patent entrants — universities, individual inventors, and newer VTOL and eVTOL entrants among them.
One filer sits well ahead of the field
The top-ranked assignee holds 19 of the 128 records, notably ahead of the fifth-place holder at 10 and the tenth-place holder at 4 — a steep drop-off that marks this as a field with a genuine leader rather than a tight cluster at the top.
Individual inventors and niche entrants file alongside majors
The ranking includes established aerospace names alongside individual inventors and smaller VTOL ventures, reflecting how anti-torque and tail rotor problems attract both incumbent rotorcraft OEMs and newer eVTOL and drone-adjacent entrants.
Co-filing is rare in this field
Just two co-assignee pairs appear across the dataset, both linking an individual inventor to a related corporate entity rather than two independent companies. That points to a field built on in-house R&D rather than joint development agreements.
| Assignee | Recent year | YoY |
|---|---|---|
| BLR Aerospace LLC | 0 | -100% |
| Honeywell International Inc. | 0 | -100% |
| SKYRYSE INC | 0 | — |
| The University of Queensland | 0 | — |
| OLIVER RICHARD DAVID | 0 | — |
| Textron Innovations Inc. | 0 | — |
| NEISER PAUL | 0 | — |
| IRELAND PETER S | 0 | — |
Where to take this next
The dataset points to where claim space is dense, where it thins out, and which filings are worth reading in full before drafting.
Map freedom-to-operate against the top ten
With 73.4% of records held by ten assignees, a new filing in this space should start by clearing the leading players' claim sets rather than the long tail.
Explore assignee claims in EurekaWatch the electronic yaw-control cluster
The overlap between B64C and G05D/G01C classes marks where mechanical tail rotor design is being paired with control software and sensing — a cluster likely to keep growing as VTOL and drone applications expand.
Track this cluster in EurekaRe-check 2025–2026 data as it fills in
Because publication lags filing by roughly 18 months, the apparent flattening in the most recent years is an artefact of the data cut-off, not a real drop in activity.
Set an alert in EurekaCommon questions about tail rotor and anti-torque patents
One assignee leads with 19 of the 128 records in this dataset, well ahead of the fifth-ranked holder at 10 and the tenth at 4. The top five assignees combined hold 52.3% of all records, and the top ten hold 73.4%, so the field has a genuine leader plus a fragmented long tail rather than a tight cluster of equally sized competitors. Anyone assessing this space should check the leader's portfolio first, since it covers the largest single block of claim space.
Yes — filings rose from 9 in 2021 to a peak of 17 in 2024, an 89% increase over that three-year span. The years after 2024 show lower counts in the raw data, but that reflects the roughly 18-month lag between filing and publication rather than an actual slowdown; 2024 is the most recent year that can be treated as complete. Anyone tracking momentum should wait for later data cuts before concluding the field has cooled.
US11801936B2, assigned to Textron Innovations Inc. and published 2023-10-31, covers a flight control system that translates pilot pedal input into a tail rotor actuator command while applying yaw rate limits tied to a vortex ring state envelope. In practice this means the claim ties electronic actuation of the tail rotor to a specific control-input pathway (pedal input) and a specific limiting condition (avoiding loss of tail rotor effectiveness via VRS limits). Designs that use a different control input path, a different envelope basis, or purely mechanical (non-electronic) actuation sit further from this claim's core.
B64C, the aeroplanes and helicopters class, appears in 78.9% of the 128 records, making core rotor and airframe mechanics the densest area by far. Control and sensing classes are thinner but present: G05D (control of non-electric variables) at 19.5% and G01C (navigation and gyroscopes) at 11.7%. Drone-specific class B64U sits at just 9.4%, suggesting anti-torque solutions purpose-built for unmanned platforms remain comparatively under-claimed relative to manned rotorcraft mechanics.
The United States leads with 47 records as a receiving office, followed by the EPO with 26, then WIPO PCT filings at 21, Germany at 6, Austria at 5 and Australia at 5. The relatively high PCT count alongside strong US and EPO activity suggests a meaningful portion of applicants are seeking protection across multiple jurisdictions rather than filing only at home, which is typical for aerospace hardware with global supply chains and certification requirements.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.