Vertiport regs for windspeeds

[GregLocock]

I don't suppose it is much news to say that I'm thoroughly opposed to eVTOL taxis , purely from the noise issue, but here is the FAA looking at something I didn't think about, the downwash and radial wind speeds under a rotorcraft as it lands and takes off. These are high enough that my nightmare of these things commonly landing in city streets is untenable. https://aviationweek.com/aerospace/...es-evtol-downwash-challenge-vertiport-design?

 

[Sparweb]

Landing a copter on city streets? Never going to happen. Legally. It's already illegal for regular helicopters to do so.
Landing a eVTOL on city streets? Never going to happen. Legally. For the exact same reason as helicopters.

The police, fire, ambulance and other rescue services do it with waivers, special provisions in the law, plus special crew training and equipment on board.

Joby confirms that it participated in the surveys. The magnitudes of the outwash for the Joby S4 and Robinson R44 light helicopter are similar, the company said in a presentation on the testing to the Vertical Flight Society’s Forum 80 in May 2024. “The Joby S4 has a higher per-propeller disk loading than the R44 and approximately twice the overall weight,” the company noted.

So basically a JOBY can land anywhere a R44 can land. That's probably just fine for you and me. Not sure if the truth of that has sunk into the heads of the Joby investors, yet. The investors in Joby, and the folks who are eagerly lining up to be passengers, are probably expecting that they can land in Greg Locock's back garden. Whenever they please.

...the report notes that instantaneous winds can be more upsetting for people than sustained winds due to the startle response.

Startle response? The thing is so noisy everyone heard it coming a few minutes ago. No, the upsetting thing with rotor downwash is that it is UPSETTING. As in: human body displaced sideways and inverted by turbulent rotorwash exceeding 100mph.

"The resulting data shows that the Joby aircraft’s outwash does not present an increased risk relative to traditional light helicopters and is acceptable within established safety areas for heliports of all sizes.”

Good, the FAA is all geared up to permit these EVTOLs to use heliports and airports, just like the rest of them. Perfect.

Can't wait to see how they figure out the separation rules between EVTOLs and other aircraft. That won't be a simple thing, either. And probably require several more near-collisions (or some fatalities) before they get it right.

 

[WKTaylor]

FYI related... UK seems to be ahead of us...

UKCAA CAP 722 Unmanned Aircraft System Operations in UK Airspace – Operating Safety Cases
UKCAA CAP 1616 Environmental Assessment Requirements and Guidance for Airspace Change Proposals
UKCAA CAP 1724 Flying Display Pilot Authorisation and Evaluation: Requirements and Guidance
UKCAA CAP 1900 Social Licence to Operate: Concept Guide for New Technologies
UKCAA CAP 1949 Innovation Case Study: Volocopter
UKCAA CAP 2289 Guide for Innovators: On the Path to Certification
UKCAA CAP 2290 Guide for Innovators: Getting Your Prototype off the Ground
UKCAA CAP 2296 CAA Response to 2021 Government Consultation on the Future of Transport Regulatory Review: Future of Flight
UKCAA CAP 2530 Airspace Fundamentals and the Future of Flight
UKCAA CAP 2505 Emerging Technologies: The Effects of eVTOL Aircraft Noise on Humans
UKCAA CAP 2506 Noise Measurements From eVTOL Aircraft: A Review of Available Data
UKCAA CAP 2522 Future Flight Aircraft Capabilities Exploring the Requirements of Next-Generation Aircraft
UKCAA CAP 2536 UK National Aviation Safety Roadmap - Implementing the National Aviation Safety Plan 2022/2024
UKCAA CAP 2537 UK CAA Certification of EVTOL Aircraft
UKCAA CAP 2539Guide to Applying the Civil Aviation Authority’s (CAA) Consumer Principles to the Advanced Air Mobility (AAM) Industry
UKCAA CAP 2576 Understanding the Downwash/Outwash Characteristics of eVTOL Aircraft
UKCAA CAP 2600 Airspace Modernisation – 2023 Progress Report
UKCAA CAP 2962 The Effects of Emerging Technology Aviation Noise on Humans
UKCAA CAP 3019 CAA’s Strategy for AI - AI in Aviation: A Technology Outlook CAA Horizon Scanning and Insight
UKCAA CAP 3038 Delivering Scalable UAS BVLOS in the Specific Category
UKCAA CAP 3066 Revision of Special Visual Flight Rules (SVFR) Weather Minima Criteria for Operations Within the London & London City CTRs

FYI for related 'technical'... SAE & ASTM...

SAE R-462 Fundamentals of Electric Aircraft
SAE T-135 Electric Flight Technology: The Unfolding of a New Future

ASTM F3060 Standard Terminology for Aircraft
ASTM F3341 Standard Terminology for Unmanned Aircraft Systems
ASTM F3367 Standard Practice for Simplified Methods for Addressing High-Intensity Radiated Fields (HIRF) and Indirect Effects of Lightning on Aircraft
ASTM F3423 Standard Specification for Vertiport Design
ASTM F3457 Standard Guide for Aircraft Certification Education Standards for Engineers and Professionals in Aerospace Industry

/NOTE/ With eVTOL... VS engine-powered VTOL... Acft at least the ENGINE noise, heat and exhaust gas-flow/pollutants... and fixed-based refueling systems/equipment/infrastructure/hazards for turbine, compressed/liquified/etc fuels... are pretty much eliminated... by 'rapid charging stations'.

 

[verymadmac]

A quick google suggests that Joby S4 (~9.4 lb/ft^2) is a bit more than the disc loading of a CH-47 (8.8 lb /FT^2).
In practical terms a CH47 downwash isn't remotely the same as an R44.

CH-47 downwash

Its still a long way from a V-22 at 26.68 lb/ft^2

Watch This CV-22 Osprey's Rotor Downwash Absolutely Demolish A Hospital's Helipad

The Osprey's beastly rotor blast is notoriously powerful, as is showcased in this crazy video clip.

www.twz.com

Really its just yet another reason why eVTOL dead in the water for all but the smallest niche.

 

[FrederickSinclair]

Good point! Addressing downwash challenges could improve eVTOL feasibility.

 

[WKTaylor]

This might also help... specific references/rules for designing heliports for rotor/down wash... very serious stuff...

ICAO 9261 - Heliport Manual