James Dyson and the Harrier.

[Al R]

Not sure it had a carbon fibre wing back in the 60s though..

http://www.bbc.co.uk/news/technology-36257643

[thunderbird7]

Composite technology came with the re-design as the AV8B in the early 80s so he's wrong, it wasn't around in the 60s.

[CoffmanStarter]

... I'm still trying to work out what Dyson means when it says it uses 'Digital Electric Motors' :rolleyes:

[POBJOY]

I seem to recall that the advent of major composite airframe parts then caused a rethink in how it stood up to battle damage in the field; as what was a 'hole' punched into metal originally became a more serious problem when it shattered a composite component.

[PDR1]

Dyson is a scroat with a tendency to marketing B/S to justify inflated prices.

His famed "digital motor" is simply a brushless DC motor - nothing that clever or unique. They are manufactured in the millions all over the world for uses ranging from robots and UAVs to radio-controlled toys. Every quadcopter "drone" has at least four of them...

PDR

[Nige321]

... I'm still trying to work out what Dyson means when it says it uses 'Digital Electric Motors'

Bushless DC motor, uses a switching speed controller.
Smaller, more efficient, runs cooler...

[rugmuncher]

Dyson is a scroat with a tendency to marketing B/S to justify inflated prices.

His famed "digital motor" is simply a brushless DC motor - nothing that clever or unique. They are manufactured in the millions all over the world for uses ranging from robots and UAVs to radio-controlled toys. Every quadcopter "drone" has at least four of them...

PDR
If it has more than four, is it still called a quadcopter?

[Union Jack]

Dyson is a scroat with a tendency to marketing B/S to justify inflated prices. - PDR1

Have just been in touch with James who laughed, and replied that you might like to look up the definition of a "scrote" in the Urban Dictionary.......:E

Jack

[John Farley]

I first flew the plastic wing in 1979.

[CoffmanStarter]

Nige ...

That's my point ... The physical motor is no more than a bog standard DC Brushless Electric Motor ... How you generate the field in the stator coil is another matter.

Marketing 'Hype' ... Pure and simple. The word 'Digital' has been/is being overused by the advertising industry IMHO.

Sorry for thread drift ...

[NutLoose]

Is that a digital thread drift, or simply an analogue one? On important issues like this, we need to know.

[CoffmanStarter]

Nutty ...

01000100 01101001 01100111 01101001 01110100 01100001 01101100

Go figure :p

[PDR1]

If it has more than four, is it still called a quadcopter?

No, it can be called a hexcopter, octocopter or the catch-all multicoptor/multi-rotor term that is also used. For those with *fewer* than four it is far more common to hear them descibed as "multirotors" than "tricopters".

Well you did ask...

:)

PDR

[PDR1]

I first flew the plastic wing in 1979.

Just typical - how are we supposed to have a typical internet rant-fest when you go jumping in with claims based on the simple matter of having been the man who actually did it, John. It's unfair!

:)

Actually I think I have photos of that flight amongst the piles I salvaged from Phil's bin when the Dunsfold photograph dept was closed down.

PDR

[glad rag]

Yee I did smirk at the wing moment :}

[cats_five]

I thought the binary might be more exciting than it was

[PDR1]

Having now viewed the video - his comment about it weighing "five tons" was a bit off as well. I'm sure John can correct me here, but from memory I don't think a Harrier II has a flyable configuration down at 10,000lbs does it? Certainly the original 1127/kestrals had basic weights down there somewhere, but I'm not that sure if even any of the Harrier Is did.

At the other end of the scale I can remember the 34,000lb AUW (or was it 32,000?) clearance trials, but that's a different skillet of trout, of course.

PDR

[Rhino power]

Having now viewed the video - his comment about it weighing "five tons" was a bit off as well. I'm sure John can correct me here, but from memory I don't think a Harrier II has a flyable configuration down at 10,000lbs does it?

I seriously doubt the Harrier in Dyson's company car park is even remotely approaching a 'flyable configuration'! It will have been stripped of it's avionics and other sundry classified/dangerous items at the very least and possibly it's engine too...

-RP

[Nige321]

Coffman

What is slightly unusual is the speed Dyson's motors run at, over 100,000 RPM. I suspect the speed controller is doing some quite clever stuff measuring RPM and governing speed... I do know they get through thousands of prototypes of the airmoving parts....

[PDR1]

There are plenty of electric motors (especially brushless ones) which operate at these sorts of speeds. And the controller will be either a sensored or sensorless brushless controller of the kind made in gazillions al over the world - known technology and nothing particularly clever. With a synthetic commutator (which is how a brushless motor works) you don't need to do anything clever to know and govern speed because you're nailing it in the control function.

Of course electric motors are *inherently* speed limited by the nature of the wind and the applied voltage anyway. I have a motor which can develop 1500watts at 8,000rpm into a 22" propeller from a 44v power supply. If I take the prop off and apply full power it turns at a whopping great...

...10,100rpm. That's all.

The effect of back-EMF as expressed in a paramter called the "motor constant" (Kv) means that the motor will never turn more than a certain number of rpm per applied volt of electrickery.

The rest of it is snake oil, of course. And purple plastic - that makes it very high tech!

PDR

[CoffmanStarter]

^^^ Totally agree with our Engineering Member ^^^

[CoffmanStarter]

Now PDR1 ....

Let's be having those pics of John with the 'plastic' wings ;)

Best ...

Coff.

[Tourist]

PDR1

I think you are wrong.
A small bit of google research suggests to me that they are actually quite clever.

Both Ford and Mercedes make cars.
They all have 4 wheels, windows and doors.

Just as other people make "similar" motors to Dyson, there is a difference in the cars.

[Nige321]

PDR 1

Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.

There are plenty of electric motors (especially brushless ones) which operate at these sorts of speeds.
There are, but not many in this application...

the controller will be either a sensored or sensorless brushless controller of the kind made in gazillions al over the world - known technology and nothing particularly clever.
The Dyson motors only have 2 (assymetric) poles, not the 9 to 12 used in 'normal' motors and as you note use Hall Effect sensors to sense armature position.

you don't need to do anything clever to know and govern speed because you're nailing it in the control function.
You don't. But you do need to be clever if you want to go from zero to 100,000 RPM in 0.7s, do it as the battery is dropping in V, and do it with a motor efficiency around 90%.

The rest of it is snake oil, of course. And purple plastic - that makes it very high tech!
Can I suggest you search and read some of Dyson's patents...?

[barnstormer1968]

An interesting thread.
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums :)

[airpolice]

Mrs. Airpolice loves her Dyson. Great for eating the Labrador hair.

[cattletruck]

Small steps first. Before we ditch the mighty Pegasus, would a Dyson vacuum cleaner be able to supercharge my 6 pot piston banger of which there is already a variant but it uses a belt driven Eaton pump.

I think not, but just like the Harrier interior it could easily be kept sparkling clean with such an apparatus.

[PDR1]

PDR 1

Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.
[quote]

So we're talking about a clever application, but Dyson claims it's a clever motor, which it ain't IMHO.

[quote]
There are, but not many in this application...


So you agree there's nothing inherently unique about the motor - it's a shame that Dyson't marketing pretty well all focusses on his "clever" motor, then.


The Dyson motors only have 2 (assymetric) poles, not the 9 to 12 used in 'normal' motors and as you note use Hall Effect sensors to sense armature position.


The two-pole motor config is simply the standard way of getting a high motor constant (high rpm/v number). Most applications for electric moptors are seeking to do the opposite and obtain a low motor constant to get the torque to drive loads without the need for gears - hence the pole counts that go from 8 to as many as 200 poles to get Kv numbers in the more usually useful 2,000 to 100 rpm/v region. This specific application needs the opposite to get a small diameter turbine that will deliver the desired pressure/flow characteristics. It's not unique - even cheap, mass-produced commercial motors like the Mega-16EDF have two-pole configurations for similar reasons. This is not novel. Nor are kevlar/carbon wrapped rotors to provide magnet containment - these concepts have been in series production for over a decade in many places.


You don't. But you do need to be clever if you want to go from zero to 100,000 RPM in 0.7s, do it as the battery is dropping in V, and do it with a motor efficiency around 90%.


Getting the acceleration is simply a matter of motor power and having a controller that can track that sort of a speed ramp. 0.7secs might sound pretty fast when your normal experience is waiting for a big turbofan to respond to a throttle demand, but to a low-inertia electric motor it's quite a while, and to a microcontroller in a speed controller 700,000microseconds is a vast amount of time for doing the simple job of deciding when to switch poles on and off - especially when the chosen microcontroller has been selected to have a clock speed suited to switching poles at a bit under 2,000 times a second. These are not complicated electronic problems.


Can I suggest you search and read some of Dyson's patents...?

Can I suggest you do a little reading-up on the ambient state of the art in BLDC motors, and where it's been for well over a decade?

PDR

[PDR1]

An interesting thread.
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums :)

We have a dyson vac - we also had a dyson washing machine until it died a couple of weeks after they declared them "no longer supported" for spares. Both are/were well designed pieces of kit which worked well. His service support system concept is especially effective. I'm not disputing that. I'm just suggesting that the claims in his marketing material about his "digital motor" are rather over-blown.

I do feel his choice of materials in the vacuum cleaner is sub-optimal. Most of the parts are made from a plastic which is hard, but rather brittle and prone to damage in normal use - a tougher plastic would make for a more durable product. Our Dyson vac has had crack-failures several times, and now sports several epoxy-glass and epoxy-carb repair patches (the main clip area where the handle/wand attaches to the chassis cracked several times in normal use and now has a stiffening/reinforcing piece madee from 10 layers of 5-thou UD carbon cloth).

The washing machine was an excellent piece of kit which gave good service for many years. But then it did cost roughly three times the price of the competition (£900 vs £300ish) and I was disappointed when they stopped supplying spares for it - I'm not sure it has lasted long enough to justify the price premium.

Dyson's "novel" vacuum cleaner design is simply the application of industrial particle-separation technology to domestic vacuum cleaners (he even said as much in his appearance on "desert island disks" many years ago). Making it work at this scale is good engineering, but it's not brain science or rocket surgery IMHO - it's good, effective engineering rather than "genius".

PDR

[ORAC]

"Genius is one percent inspiration and ninety-nine per cent perspiration. Accordingly, a 'genius' is often merely a talented person who has done all of his or her homework."

Thomas Edison

[aox]

An interesting thread.
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums

When I read that the most powerful vacuum cleaners were soon to be removed from sale, I thought this might be an opportunity coming up, and we need a new one soon anyway.

I bought a superseded and imported AEG Vampyr model on eBay for £33 including postage. Original price seems to have been about €130-150

Even though it has a 2000W nominal rating, it's adjustable and set to a bit below half scale most of the time

When these limits were imminent, Dyson marketing gleefully pointed out none of its models were affected as they are less powerful. But now they are saying the new rules have drawbacks, and are proposing a new label ...

Apparently, according to Dyson, over 126 million bags and filters end up in landfill each year across the EU. I read a review that suggests that works out to £50 per home per year, though I couldn't see whether Dyson itself said this.

According to official sources there are about 27 million homes in the UK. The EU seems to add up to about 200 million homes.

Maybe Dyson and its fans should leave the brilliant maths to its engineers, rather than the marketing department.

If I spent £300 or so on a new Dyson maybe I could save about £3 a year on bags and electricity, but I already saved over £250 by buying an alternative.

[barnstormer1968]

PDR
I agree about the quality of plastics used on Dyson vacuum cleaners.
My comment about experience in using them referred to people talking about patents or tech wizardry rather than real life experience.
From my own experience Dysons are far more likely to block than any other make of vacuum, and require more engineer visits than other makes.
The particularly small air/dust/dirt intake on upright Dysons is the main reason why they block so easily.
Guaranteeing no loss of suction becomes meaningless when the suction is measured within the vacuum. It has still stopped functioning as a usable tool once the intake is blocked :)

Perhaps the energy saving feature of brushless motors should be featured more in the sales pitch as a 'green' feature. The sales blurb on my cordless power tools always mentions longer battery life with brushless motors compared to conventional motors. It's been that way for several years now.

[Nige321]

Can I suggest you do a little reading-up on the ambient state of the art in BLDC motors, and where it's been for well over a decade?

PDR

Go and find out why the motor runs part time in sensor mode, part time open loop... You may be surprised...

[PDR1]

Go and find me a correctly-sized brushless motor that runs at LESS than 90% efficiency on design load and then explain why Dyson feel this is some discriminator that they can crow about in their marketing snake-oil.

PDR

[Al R]

I considered the Dyson but settled on a Gtech 22V Air Ram. Great quality materials, fast recharge, and efficient and simple to use. Pricy though - fair to say I didn't have budget oversight. All in all though, a great buy that makes housework an breeze.

Having summoned up the courage to post that, shooting myself now by way of contrition is but a small step.

[dragartist]

Good job I don't need one but I could never afford his latest hair drier! (as featured on the BBC news tech feature last week end)


We kept a DC 04 going for years. the DC 54 replacement is rubbish in comparison.

[Chesty Morgan]

I can't believe you blokes are talking about vacuum cleaners and hair driers.

[ORAC]

It's all just a load of hot air.....

[hec7or]

I agree, vacuum cleaners suck!

[Pontius Navigator]

But they have big balls.