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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/tiltrotor-and-compound-rotorcraft-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Patent Landscape · Rotorcraft TechnologyTiltrotor and Compound Rotorcraft Patents: Who Holds the Proprotor Claims
- 90.0% of all 1,807 records sit with just five assignees — this field is one of the most concentrated corners of aerospace patenting.
- Filings fell 78% from 188 in 2021 to 42 in 2024, the last year the data can be treated as complete.
- B64D aircraft equipment covers 33.7% of records, while gearing (F16H) and vibration damping (F16F) each sit under 6% — signalling where claim space is still thin.
1,807
Published Records
90%
Top-5 Share of All Records
-78%
Filing Growth 2021→2024
US
Leading Jurisdiction
Filing growth compares 2021 (188 records) with 2024 (42) — 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 1,807 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Field Overview
What this landscape covers
Tiltrotor and compound rotorcraft patenting sits at the intersection of fixed-wing and rotary-wing engineering: proprotor hub design, nacelle tilt actuation, whirl flutter suppression and the conversion corridor between helicopter and airplane modes. This landscape draws on 1,807 patent records published between 2015 and mid-2026, filtered on tiltrotor and compound-helicopter terminology cross-referenced against the mechanical signatures that separate this field from conventional rotorcraft — proprotor architecture, nacelle tilt actuation, lift-offset rotor and rotor download effects.
The result is a narrow, technically demanding field rather than a broad one. Filing activity concentrates around a small number of legacy aerospace programmes and a handful of newer eVTOL entrants, and the classification spread shows most of the claim activity still sits in core airframe and equipment categories rather than in electronics or control software.
Filing activity by year, 2015–2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
The Data
Filing trends and technology composition
The two views below track when this field was built out and which mechanical subsystems carry the claim density. Publication lags filing by roughly 18 months, so the most recent one to two years in the trend will always look thinner than they will eventually turn out to be.
Filings peaked in 2017 and have not returned
Annual filings peaked at 352 in 2017. By 2021 the field was still active at 188 filings; by 2024 — the last year in the trend that can be treated as complete — that had dropped to 42, a 78% decline over that three-year span. Read this as consolidation around fewer, better-capitalised programmes rather than as the technology going quiet: the underlying engineering problems have not gone away, but who is willing to file on them has narrowed.
Claim density concentrates in airframe and equipment classes
B64C (aeroplanes and helicopters) appears on 80.2% of the 1,807 records in scope, confirming this is fundamentally an airframe-architecture field. B64D (aircraft equipment) follows at 33.7%. Everything else — UAV integration at 8.2%, ground installations and gearing each at 5.8%, control systems at 4.4%, vibration damping at 4.0% and bearings/couplings at 3.9% — sits in single digits, which is where a search for open claim space should start rather than in the crowded airframe classes.
Shares are the percentage of the 1,807 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
Go deeper on Tiltrotor and Compound Rotorcraft with Eureka
This page is one run against one query. Ask Eureka your own question about tiltrotor and compound rotorcraft and every answer comes back with the patent numbers behind it.
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The documents that anchor this field
Representative Filing
Proprotor Systems for Tiltrotor Aircraft (US20180162526A1)
TEXTRON INNOVATIONS INC.
A proprotor system for tiltrotor aircraft having a helicopter mode and an airplane mode. The proprotor system includes a hub and a plurality of proprotor blades coupled to the hub such that each proprotor blade is operable to independently flap relative to the hub about a flapping axis and independently change pitch about a pitch change axis. The proprotor blades have a first in-plane frequency less than 1.0/rev.Filed by Textron Innovations Inc., published 2018-06-14 — chosen here as representative of how the leading assignee frames proprotor blade dynamics rather than as the field's single most-cited document.
Most-cited records in the dataset
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5765783A | Vertically launchable and recoverable winged aircraft | 205 |
| 2 | US5054716A | Drive system for tiltrotor aircraft | 181 |
| 3 | US20180002011A1 | Aircraft with Selectively Attachable Passenger Pod Assembly | 174 |
| 4 | US5094412A | Flaperon system for tilt rotor wings | 135 |
| 5 | US20180002026A1 | Aircraft having a Versatile Propulsion System | 132 |
| 6 | US9963228B2 | Aircraft with selectively attachable passenger pod assembly | 126 |
| 7 | US5046684A | Airplane with braced wings and pivoting propulsion devices | 123 |
| 8 | US20100193644A1 | Aircraft with Integrated Lift and Propulsion System | 111 |
| 9 | US6227492B1 | Redundant ice management system for aircraft | 108 |
| 10 | US6641365B2 | Optimum speed tilt rotor | 105 |
Citation counts reward older documents simply for having been in circulation longer; treat them as a signal of influence within this corpus, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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What the numbers mean for a filing decision
Three patterns recur across the dataset and each has a direct bearing on where a new filing is likely to clear prior art versus where it will collide with an incumbent's portfolio.
Concentration
90.0% of 1,807 records
held by five assignees
The field has an unusually narrow top
Five assignees hold 90.0% of all 1,807 records in scope, and the top ten extend that to 95.4%. That is a steeper concentration curve than most mechanical-engineering fields show, and it means freedom-to-operate work here is really a small-set clearance exercise against a handful of portfolios rather than a broad landscape scan.
Concentration figures, assignee ranking
Momentum
-78% (2021→2024)
filing decline, complete years only
Volume is down, but not evenly across assignees
Total filings fell from 188 in 2021 to 42 in 2024. Recent-year momentum data shows several named assignees at zero filings in the latest year, including entities that were active as recently as a few years prior — a sign of programme pauses or strategic shifts rather than a field-wide retreat.
Filing trend, recent-year momentum
Composition
80.2% vs. under 6%
B64C share vs. gearing/damping classes
Claim density sits in airframe, not in subsystems
B64C carries 80.2% of the 1,807 records, while F16H gearing and F16F vibration damping each sit at only 5.8% and 4.0% respectively. Mechanical subsystem claims — transmission paths, damping architectures, bearing arrangements — are comparatively thin next to the crowded airframe-architecture classes.
IPC subclass shares
Eureka AI Agent
Looking for what nobody has claimed yet?
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to tiltrotor and compound rotorcraft, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Who's Filing
The assignee landscape
The ranked list covers 92 companies, all counted by patent family. It is not a top-50 or top-100 cut — it is the entire ranking the dataset returns, and the leader alone accounts for the majority of records in scope.
Leader
779 records
single largest assignee
One programme dominates the record count
The leading assignee's 779 records sit well above fifth place at 29 and tenth place at 12 — a gap wide enough that most competitive filings are really responding to one incumbent's portfolio rather than to a distributed field.
Assignee ranking
Long tail
92 ranked companies
vs. five holding 90.0%
A long tail of single- and few-filing entrants
Beyond the top ten, filing activity drops off sharply. Newer eVTOL-oriented entrants and specialist suppliers appear in the ranking with small counts, suggesting the field is still open to focused entrants even though it is dominated at the top.
Concentration figures
Collaboration
10 co-assignee pairs
strongest pair: 11 shared filings
Inventor-assignee pairings cluster around one team
The strongest co-assignee pairing in the dataset appears 11 times, and the next two strongest both involve the same corporate assignee — evidence of a stable core engineering team rather than broad cross-company collaboration.
Co-assignee pairs
Recent-year filing momentum by assignee
| Assignee | Recent year | YoY |
|---|---|---|
| Textron Innovations Inc. | 2 | -67% |
| Bell Helicopter Textron Inc. | 0 | — |
| UNMANNED AEROSPACE LLC | 0 | -100% |
| Overair Inc. | 0 | — |
| RESPONSE TECHNOLOGIES LLC | 0 | -100% |
| KAREM ABE | 0 | — |
| Goodrich Corp. | 0 | — |
| The Boeing Co. | 0 | — |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's Next
Where to take this analysis
The dataset points to specific next steps rather than a general monitoring exercise.
Run freedom-to-operate against the top five
With 90.0% of records held by five assignees, a targeted clearance search against those portfolios covers most of the risk in this field far more efficiently than a broad novelty search.
Explore assignee portfolios in EurekaDraft into the thin IPC classes
Gearing, damping and bearing subclasses each sit under 6% of records, well below the airframe classes — a more defensible starting point for new claims than crowded B64C territory.
Map white space in EurekaTrack the momentum shift, not just the volume drop
Several named assignees show zero filings in the latest year after being active a few years earlier. Watching which specific programmes restart filing is more informative than watching the aggregate trend line.
Set up assignee alerts in EurekaSource: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions about tiltrotor patents
One assignee holds 779 of the 1,807 records in this dataset, far ahead of fifth place at 29 and tenth place at 12. That gap means a large share of the field's core proprotor, nacelle-tilt and conversion-corridor claims trace back to a single corporate portfolio built up over decades of tiltrotor programme work. Anyone assessing freedom to operate in this space should start with that portfolio before looking at the long tail of smaller filers.
Filings peaked in 2017 at 352 and declined to 42 by 2024, a 78% drop from the 2021 level of 188 filings over that three-year span. 2024 is the most recent year the data treats as complete, since publication typically lags filing by around 18 months. The decline reflects consolidation around fewer, better-resourced programmes rather than a collapse in engineering activity.
A proprotor is the rotor system on a tiltrotor aircraft that acts as a helicopter rotor in vertical flight and rotates into a forward-thrust propeller for airplane-mode flight. It is the mechanical core of tiltrotor patenting: hub design, blade flapping and pitch-change axes, and in-plane frequency tuning all appear repeatedly in the highest-value filings in this dataset, including the representative filing highlighted on this page. Most whirl-flutter and conversion-corridor claims are built around proprotor geometry.
B64C, covering aeroplanes and helicopters, appears on 80.2% of the 1,807 records in scope and is the dominant classification for this field. B64D, aircraft equipment, follows at 33.7%. Supporting classes — UAV integration, ground installations, gearing, control systems, vibration damping and bearings — each cover under 10% of records, marking them as comparatively under-claimed relative to the core airframe categories.
The classification data points to gearing and transmission systems, vibration damping architectures, and control logic for lift-offset rotors as areas with comparatively low claim density relative to the dominant airframe classes. These subsystem-level classes each sit under 6% of the 1,807 records, well below the 80.2% carried by core airframe claims. That gap does not guarantee an easy filing, but it does mean less prior art per claim in those specific mechanical areas.
Answers are grounded in the same dataset. Derived from a Patsnap search on Tiltrotor and Compound Rotorcraft covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Research Tiltrotor and Compound Rotorcraft in depth with Eureka
Go past this page: query the whole tiltrotor and compound rotorcraft corpus yourself, in your own scope.
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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.