It sounds like the name of a vehicle in some sci-fi tale, but that fiction is only a short leap from reality. Light Rider is, in fact, an electric motorcycle with a 3D printed frame that resembles an organic structure more than a machine.
Designed by the Airbus subsidiary [APWorks], the largely hollow frame was devised to minimize weight while maintaining its integrity and facilitating the integration of cables within the structure. The frame is printed by melting a sea aluminium alloy particles together into thousands of layers 30 microns thick. Overall, Light Rider’s frame weighs 30% less than similar bikes; its net weight — including motor — barely tips the scales at 35 kg. Its 6 kW motor is capable of propelling its rider to 45 km/h in three seconds with a top speed of 80 km/h, and a range of approximately 60 km — not too shabby for a prototype!
An initial production run of 50 has long since sold out, so we hope this will spur others to invest in lightweight, clean-running transportation.
If you have an electric bike already and are looking to extend its range, we got you covered.
[via Urdesign]
Very beautiful design.
The problem with highly optimized structures is that they can’t take a dent or a bit of rust. One would imagine it takes a single small fracture and the whole structure starts to unravel very quickly. Hopefully not at 80 kph.
http://holyjoe.org/poetry/holmes1.htm
That is not entirely true because it depends on how fine grained the force transfer network is, they can in fact be stronger as they do not favour fracture propagation in the same way solid masses do.
I believe Dax was refering to the fact that the structure is designed to only withstand the design load that it was optimised with. Load sharing through the ‘members’ (or web?) can be comprimesed when one is damaged.
But im sure they had a fairly good safety factor.
Usually in these prototype demos the safety factor isn’t a factor more so than the cool factor. They’re simply not designed for use 20 years down the road; especially aluminium tends to crack at the seams and this thing has dozens of welds across the structure if you look closely where the 3D printer parts have been joined together.
Over-optimization is already an issue with rust-proofing new cars where structural members are made out of thin high-strenght steel. Where previously you had 2-3 millimeters of steel to rust through, now you have 0.8mm and the same rate of corrosion will make the structure unsafe very rapidly. So then, you have to add extra galvanization and coats of paint on your critical parts which largely negates the optimization you’ve done – or you don’t and get cars that break down as soon as the warranty is over.
Stainless steel?
“Stainless steel?”
Welding stainless steel is a problem because the additives that make it stainless start to migrate due to the heat. Heat treatments like annealing don’t work so well for the same reason, so drawing and forming stainless steel parts is more difficult.
And it’s bloody expensive.
Even the Delorean DMC-12 didn’t have full stainless bodywork. Just the outer panels were stainless steel, and the inner frame was regular steel with fiberglass.
Other manufacturing issues with stainless you can find by googling around:
“Stainless is easy to weld but very difficult to keep flat, the coefficient of linear expansion is 1.7 times that of mild steel.”
“Paint will not adhere to un-etched or otherwise un-prepped SS. That adds to the cost.”
“welding SS panels with conventional mild steel techniques leads to crystallization on the backside of the weld, giving a weaker joint that is much more susceptible to fatigue than a mild steel weld.”
Etc. etc. it’s a world of trouble trying to make a car chassis out of stainless, and even then it’s not really rust-proof. It’s just more corrosion -resistant- than mild steel – except of course at the places where the working and the heating of the metal has changed the alloy.
To be fair, the term “stainless steel” covers a lot of ground, and one selects which alloy one uses based on the service, the geometry, and the fabrication techniques being used, and as one can guess, this is almost always a set of compromises. Nevertheless, given the spectrum of materials now available, it is not really useful to make sweeping statements about the properties of “stainless steel.”
Dax id usually right, except for when Dax is wrong, then somebody else points out the error, we all learn from it and move on.
“they can in fact be stronger as they do not favour fracture propagation in the same way solid masses do.”
While that’s true, consider what happens when you put a hole through a sheet of metal. Instead of two edges for fractures to start, you now have four edges. The more holes you punch, the more stress concentration points you create and while the cracks won’t propagate from one to the other, you still get a cascade failure when one link fails and the load is transferred to the remaining links.
A structure like this undergoing various vibrations and flexing that the designers’ model didn’t account for – maybe you fell down and bent some of the members slightly – will develop metal fatigue in multiple places and won’t be able to handle the transfer of stress when something eventually fails. It will be like the Deacon’s Masterpiece that develops problems all over silently until something goes, and then everything goes.
That’s pretty convincing.
Somewhere in my head it went “but… organic structures look a bit like this. There must be an advantage in doing it like that”.
Until I realized that organic structures are dynamic: the feeling of pain gives the system an immediate feedback on what loads to avoid (so the system can have a short term reaction to a partial failure as you describe them), and for a longer term reaction there’s healing. Bones are known to adapt their local density to load. And so on.
It’s nice things “look” organic, but even better when they “behave” so :-)
So much hacking to do!
Yep. Why haul an extra 50 pounds of skeleton inside you when you can simply repair the damage continuously.
That’s why I find humanoid robots and “androids” unconvincing. They’re bound to be incredibly fragile, or inefficient heavy lumbering beasts.
That bike is really awesome!
However you could go a bit more into the design, since the organic form was shaped by topology optimization algorithms which rely on on organic grow paths. Or the material, Scalmalloy, which was developed by APworks too and has a strength similar to pure Titanium.
But yeah, thanks for the article, I like seeing it on Hackaday too!
Those disc brakes and front fork seem very small to me… It looks more like electric bike (bicycle) than motorcycle.
Looks like they used downhill mountain bike parts for the front end. That’s probably sturdy enough but I do wonder about heat on that front rotor. It also looks weird because the rear brake is the same size as the front. Not what you typically see on a motorcycle, because of the huge difference in braking force balance front to rear.
If your body weight is greater than the weight of the bike, you can use your body to bias the weight to provide more stopping power to the rear wheel. Can’t do that when the bike weighs two or three (or more) times than you do.
Deceleration causing your center of gravity to move forward of your center of mass makes for a losing battle with trying to bias your weight towards the rear, as the front wheel becomes a fulcrum for your forward momentum and lifts the weight from your rear causing a loss of traction that tends to make your rear want to come around the front to one side or the other. It’s actually worse when the bikes lighter because your center of mass is much higher.
Great if you want to do power slides on your Schwinn Stingray or your Big Wheel, but disastrous for motorcyclists who are not accomplished stunt riders. An 80/20 force ratio front to rear is accepted for controlled upright deceleration in most cases. I find myself rarely using the rear, if at all during normal riding. The exception is the occasional “too hot into the turn” miscalculation, where the extreme lateral forces and lean angle call for very light and more even application of both brakes balanced carefully against lean angle. I find this usually tends to happen in “bullet time” where I’m acutely aware of every detail, including the extreme negative pressure forcing the seat vinyl into my posterior.
It would probably make a good trials bike, if it had some sort of clutch to control the low end torque, but I wouldn’t trust those baby brakes at any but the lowest of road speeds.
Well you could do that if the bike was 5 meters long!
It doesn’t really matter that much where you put your body because the front tire is forced *into* the ground with breaking while the back is forced *away* from the ground during breaking.
The ratio may include your body mass but because your moving and you have momentum, the force vector from your mass is more forward than down.
I used to race motorcycles and in heavy breaking I tended to move down closer to the seat and tank or to one side when cornering rather than forward or back. I probably moved slightly forward as the front breaks are more efficient. When heavily breaking into a corner you treat the back as if the back wheel was missing and you keep all the forces in balance on the front tire.
unless you found a magic place where you can always go downhill, the brake only need to be able take out what the motor can put in
Yes the front forks are rokshox – mountain bike parts.
The disks, sproket and chain also look like bike parts.
Which is all fine for the design parameters.
I’d be happy riding it – 80km on push bike parts is quiet acceptable.
Going down a good hill id be getting close to 80km with only rubber pads on the rim to slow me down
interesting how it appears to be “printed” in segments and then welded together.
it’s weight is more comparable to an electric bike than a motorcycle…it doesn’t need to stop an extra 200kg. And it is a prototype.
The brake size would need to be scales to account for mass times velocity, so with a much lighter bike it could be less and still shed enough energy as heat in order to get the velocity down to the required level.
All nice but why does it still has a gas tank, albeit a fake one?
I am going to go out in a limb and guess that the batteries live in there. I don’t see any other place to put them.
I want one! Now! Seriously, it looks great and we be fantastic for getting around the local area…
– and in reply to the above, I think the gas tank is a battery..
I like But like everyone else I do have a problem with the front end. I know they probably made it small for the weight claim. But for me know way.
Still I love it just change the front end And I’ll take it.
OH Wait I live in Canada.
Its illegal to drive a electric motorcycle here.
You have to drop the speed down to 32km a hour add blinkers, head light, bicycle peddles and a kick stand.
There we go now all set for Canada. (WIMP country)
There’s nothing in the Transport Canada definition of a motorcycle that prohibits an electric drivetrain. It would have to include the same kinds of safety features (lighting etc.) as on a gas powered motorcycle of course.
example – you use to be able to get a mountain motor cycle and add blinkers and a head light and brake lite. then have it inspected, And away you go. Unless the manufacturer has installed these additions you are all set.
Now in a non combustion vehicle there are different rules for them to be on the road.
I was looking at having my electric moped turn into a electric motorcycle but the ministry said unless it comes from the manufacturer the right way I cant. you are not allowed to add these devices yourself to try to make it street legal easly.
I am just saying what I had tried to do. I did it by calling and emailing. That was last year. Because I wanted to get rid of the pedals because I believe they are a danger when they are on and in order to drive it they have to be on.
Nothing but stupid.
And Insurance thats a big #$%^&$%##$%&#$%&#$%#$%&^#$&^ mess as well……
and yea its all most 3am forgive the messed up writing but I hope you get the idea.
I’d expect you’ll find that requiring max 32kmh pedals and a kickstand is if you want it to be classified as an electric bicycle i.e. no type approval, no license plates, no motorcycle license
is this a real thing or a nice 3D rendering? I want to see some video of someone riding it.
Serviceability is all about ease of access to internal components, for testing and possible replacement.
There seem to be a lot of small finger-catching (not to mention dirt and stick catching) holes in that frame.
Apart from that and the woefully undersize front brakes, it’s an interesting build.
Why do we always rely on plastics, Why are we not focused on organic construction programmable bone growth with acceleration built using bio-waste for Housing a vehicles car or bike gets damaged patch it let it regrow back together.
There is a simple reason, even before we get to technical questions like how practical it is to actually make a biostructure like that to survive the environments we tend to leave cars in. Plastic is cheap, meat is expensive. I mean, artificial meat is thousands of dollars per pound. I can buy a lot of plastic for a pound of that. And you’d need artificial meat production methods to grow them, you can’t just graft fenders to cows.
Going more into technical details, all sorts of chemicals and solvents are used around and in cars constantly. The biostructure would have to be designed to work with and compensate for them, while it would also need to be programmed to grow an organ perfectly suited to mount an engine and drivetrain to (for our purposes, ICE and electrical motors are far superior to muscle and biostructures here), which would also need to remain the proper size indefinitely. You would need to engineer it to grow rapidly to a defined size and shape, while not exceeding this later in it’s life cycle, otherwise it is inferior to the plastic parts.
Then you need to make sure it grows a proper circulatory system, feed it, and deal with a lot of other baggage that an inorganic design doesn’t need. If it gets sick, you’ll have to put down your car. Rather than replacing a part and being done with it overnight, a car might need weeks to heal.
Biotech is a massive mess from an engineering standpoint, because it is unpredictable. I can’t take a sample and put it on a hardness tester and be sure that all the other parts are within a margin of error. A biotech structure also requires energy to maintain itself, because the activity inside it that allows it to repair itself also burns energy, and cells are constantly damaged and dying in normal conditions.
It’s far easier to design repairable composites and concretes, as well as engineering structures for longevity rather than trying to grow a car. I can mix concrete that will patch cracks, and indeed, the romans did so. I can make composite structures that on being activated by a chemical or electromagnetic trigger (Or indeed, ultrasonics or a number of other methods), release a binder or resin previously held inert in the matrix to seal cracks. I can weld a piece of metal to another. You can do some of that with biostructures, but we modeled that after reactions like clotting and healing. And we improved on it. What would take hours for a body to restore to nominal strength can be put right in seconds.
If it were practical, we would try it. We’ve got tons of tinkers, experimenters, engineers. Billions and billions of dollars and thousands if not millions of man-hours are thrown into research, design, and refinement every year. And in all of that, have you heard of any success with tailoring a brand new organism to do anything at the macro scale? Sure, kittens can glow and pigs can have human cells growing in them now, but have we designed a cow-mato? You ask for something far harder than we’ve managed so far. And perhaps we’ll eventually get there. But I don’t think the future is promising to be wet and squishy.
What does the writer mean by,
“melting a sea aluminium alloy particles”?
Yeah this is ambiguous. It could mean that it was a corrosion resistant marine alloy such as 5000-series that was used for the frame. Or it could mean a “sea of aluminium alloy particles”, i.e. a powder bed manufacturing technique.
“melting a sea *OF* aluminium alloy particles”
It’s Selective Laser Sinter (SLS) printed.
The alloy is probably a low content Magnesium / Aluminium alloy so that it doesn’t combust while SLS printed.
I would have expected, that this is done under inert gas anyway. I think even Al powder without any Mg in it would combust when laser sintered in an oxygen containing atmosphere.
The process is not called sintering because the powder particles are fully melted. Selective Laser Melting (SLM) or Laser Beam Melting (LBM) are the correct english terms for that process.
The alloy they used for that bike is Scalmalloy (Aluminium with Magnesium, Scandium and some other elements) which is melted under Nitrogen or Argon atmosphere.
3D printing has come a long way. Maybe we can create one-offs of almost anything.
I day not see why so many people have a problem with the forks and brakes from a bicycle. The bike is a lightweight low powered vehicle mountain bikes are designed to take an absolute flogging and generally hold up very well.
The braking power of those disks is very good – this isn’t a 200+ kg bike with 100s of KW’s pushing it along at 200km/h
Need to keep the equipment in perspective to the performance and expectations.
There are eletric scooters selling for less than 10k, with 60km or more autonomy and top speed of 110km/h! I’ve tested one… Oh and it weights between 100-200kg!
I dont see any special specs here! I like the bike, but somtehing on the batery/controller is not optimized.