Hill Helicopters HX50
From the video's description, the announcement appears to be that they're working on three prototypes that they expect to test sometime in 2022. I remain skeptical but hopeful.
It's like Boris's promises of sunlit uplands - hype with some glossy bits and catchphrases.
This is like being asked for your bank details by a scammer promising you an unbelievable return on your investment.
This is like being asked for your bank details by a scammer promising you an unbelievable return on your investment.
Originally Posted by [email protected]
It's like Boris's promises of sunlit uplands - hype with some glossy bits and catchphrases.
This is like being asked for your bank details by a scammer promising you an unbelievable return on your investment.
This is like being asked for your bank details by a scammer promising you an unbelievable return on your investment.
Originally Posted by Bravo73
And the announcement is… (drumroll, please)…
’WE’RE GETTING CLOSER.’
🤣
’WE’RE GETTING CLOSER.’
🤣
There seem to be a lot of companies that have very good cgi and marketing, but with claims that are hard to believe.
Slight thread drift, but I haven’t seen anything on PPRuNe about the Vertical VA-X4, a proposed 4-passenger, commercially certified and piloted VTOL air-taxi vehicle - Hill Helicopters do not seem to be the only ones with some pretty impressive claims.
https://vertical-aerospace.com/investors/
While they obviously have a lot of investment, and a highly qualified design team, a lot of their claims seem just about unbelievable to me.
“We have consistently developed our plans based on a piloted aircraft, as we expect that passengers and regulators alike will require a pilot in their vehicle for at least the next decade. With a pilot on board, we expect to need at least four passengers to make the economics work, meaning the aircraft will have to be at least 2,500 kilos or 5,000 lbs.”
Their design is for a 1 pilot plus 4 passenger seat aircraft. As they suggest they “expect to need at least four passengers to make the economics work”, this seems to imply that they will have to have the aircraft at least full, if not more than full, for every trip . . .
“This readily available technology, coupled with our unique business model and partnership ecosystem, means that we are now able to build and operate our aircraft at an estimated cost of one dollar per passenger mile. At this level, we believe eVTOL will clearly be a mass market proposition, not a niche opportunity”
Will it really be a “mass market proposition”? If it was, would the airspace system cope? Can a commercially piloted $1.6m aircraft really be operated profitably at $1/passenger mile?
“The VA-X4 is going to be 100x quieter than a helicopter, 100x safer than a helicopter, zero carbon, and of course it’s going to be a fraction of the cost.” Elsewhere it quotes 1/5 the cost of an equivalent helicopter, so with a price per aircraft of $1.6m I presume they must mean operating costs, as it certainly is not equivalent to an $8m helicopter.
In fact, with a 100 mile range, I am not sure what their “equivalent helicopter” might be.
Elsewhere they say “15 dBa quieter” than an equivalent helicopter - I am not very good on dB - is that consistent with “100x quieter” ?
“For key shorter missions, such as linking airports to city centres, the high vehicle efficiency means that we use only a small fraction of the battery energy, enabling rapid charging in ten minutes or less” If this is true, why hasn’t the electric car industry managed this yet?
“On pilot training, the inherent benefits of electrically powered aircraft combined with our partnership with Honeywell provides a major advantage. Leveraging Honeywell’s ‘Simplified Vehicle Operations’ capabilities in flight controls and avionics (or cockpit displays), the VA-X4 will be incredibly simple and safe to fly and operate. All of this results in a pilot workload for standard FAA defined tasks that is reduced by 80% compared to existing commercial aircraft.”
So this is going to be incredibly simple to fly and operate, only 20% of the workload of a normal aircraft? Do they imply that pilots will be quicker and easier (and cheaper) to train and certify. Will there be a new category of licence for this simplified form of flying . . .
And as for “100x safer” than a helicopter - in an aircraft with 4 x tilting rotor/propellers and 4 x folding rotors, an endurance to empty batteries of about 30-40 minutes (based on their claim of 100mile range at 200mph), what could possibly go wrong! What about weather/icing/air traffic delays etc.
They certainly seem to have a lot of investment (Microsoft/ American Airlines/Honeywell/Rolls Royce) and claim “up to” 1000 pre-orders (although I think “up to” can mean the same as ≤ , which includes 0 )
There seem to be quite a few of this type of design around - the Lilium 7-seater has a mere 36 ducted fans.
I wonder if any of them will ever become successful.
Every 3 dB is a doubling of actual volume. So 15 dB quieter means 3% of the original volume. But that sounds hard to believe since even electric propellers are very loud, and small ones are louder than large ones due to the necessarily higher RPM. But for sure it would be much quieter than a helicopter.
eVTOL sounds dubious to me but there are a lot of major companies pursuing it so there must be merit to it. I believe they have no auto-rotation capability though.
eVTOL sounds dubious to me but there are a lot of major companies pursuing it so there must be merit to it. I believe they have no auto-rotation capability though.
A quick look on the "recent registrations" on G-INFO and it shows that Hill Helicopters Ltd. have registered G-DIAS, G-GELB, G-ODDB, and G-OISY as Hill Helicopters HX50 S/N PP02-PP05 respectively. Hopefully we see a working, flying prototype soon.
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Elsewhere they say “15 dBa quieter” than an equivalent helicopter - I am not very good on dB - is that consistent with “100x quieter” ?
To go from linear to decibels when measuring power the equation is x (in dB) = 10log(y).
Still worse is that because of the way humans (not machines) perceive sound, each factor of 10 equates to twice as loud or half as loud, depending on which direction the calculation is going. Hence something that is a factor of 10 (10dB) less is half as loud (2 times quieter), and a factor of 100 (20dB) less is a quarter loud (4 times quieter). Thus if this wonderful aircraft is 15dB quieter than a helicopter it is somewhere around 3 times quieter as the human ear perceives things. So very much not even close to "100x quieter"!
Then there is the subtlety of the fact that they use the sound pressure level "A weighted" scale. That's where the "a" on "dBa" comes in. But at this point it's not worth quibbling about how much crazier their numbers are
Originally Posted by aa777888
For power (not voltage) the conversion from decibels (dB) to linear is y = 10^(x/10) where x is the value in dB. Thus for x = 15dB then y = 31.6. So, no, not even close to "100x quieter".
To go from linear to decibels when measuring power the equation is x (in dB) = 10log(y).
Still worse is that because of the way humans (not machines) perceive sound, each factor of 10 equates to twice as loud or half as loud, depending on which direction the calculation is going. Hence something that is a factor of 10 (10dB) less is half as loud (2 times quieter), and a factor of 100 (20dB) less is a quarter loud (4 times quieter). Thus if this wonderful aircraft is 15dB quieter than a helicopter it is somewhere around 3 times quieter as the human ear perceives things. So very much not even close to "100x quieter"!
Then there is the subtlety of the fact that they use the sound pressure level "A weighted" scale. That's where the "a" on "dBa" comes in. But at this point it's not worth quibbling about how much crazier their numbers are
To go from linear to decibels when measuring power the equation is x (in dB) = 10log(y).
Still worse is that because of the way humans (not machines) perceive sound, each factor of 10 equates to twice as loud or half as loud, depending on which direction the calculation is going. Hence something that is a factor of 10 (10dB) less is half as loud (2 times quieter), and a factor of 100 (20dB) less is a quarter loud (4 times quieter). Thus if this wonderful aircraft is 15dB quieter than a helicopter it is somewhere around 3 times quieter as the human ear perceives things. So very much not even close to "100x quieter"!
Then there is the subtlety of the fact that they use the sound pressure level "A weighted" scale. That's where the "a" on "dBa" comes in. But at this point it's not worth quibbling about how much crazier their numbers are
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Certainly is a smart website and pdf download. But 100 x safer than a helicopter? With only a 30-minute endurance. And I can't see how 4 tail-rotor-size props and 4 teensy 4-bladed props all screaming away to lift 5 pax, the craft and their baggage will be quieter than a real rotorcraft.
To be fair, electric cars are much quieter inside the cabin than equivalent gas cars, especially when accelerating or on surface streets. (On the highway they're somewhat similar.)
Regarding the Hill registrations, Mischa Gelb and Ruben Dias are doing sales/marketing for the company, so those two registrations were clearly named after them, which is pretty neat.
Regarding the Hill registrations, Mischa Gelb and Ruben Dias are doing sales/marketing for the company, so those two registrations were clearly named after them, which is pretty neat.
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Originally Posted by Ant T
Thanks for that (and thanks to CGameProgrammerr as well). So as I thought, their claim to be “near silent when in flight” might be a bit economical with the truth, and very unlikely to be “100x quieter”. I’m sure there will still be a lot of prop noise! It’s a bit like people thinking that electric cars are “silent” - they might be at very slow speeds, but at cruising speed they are barely any quieter than combustion engined cars as most of what you hear is road noise.
If truly "V" TOL then they're just as likely to be as noisy in the hover.
They certainly seem to have a lot of investment (Microsoft/ American Airlines/Honeywell/Rolls Royce)
Originally Posted by ETOPS
Still wondering about the buyers of the private version having to participate in actually building their machine at the factory...........
CRAN
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Originally Posted by toptobottom
I wonder how much cheaper the skid version will be over the (much more expensive) retractable gear version?! 
