Tesla Motors
 

https://www.teslamotors.com/

The cover comes off tonight after Midnight + a few time zones . . .

Preview . . .

https://blog.wired.com/teslacar/

repost. JK. I was waiting for this for a couple of weeks now. It's an electric roadster. It will be expensive though.

Looks like they did a better than typical job on the motor design.

They should of spent more time on the interior. The exterior is nice.

Interior is typically a big piece of plastic and adds nothing to the performance of the car plus casting something that big is expensive - I think they used all standard car components so that they are easy to repair - except for the big stuff of course like extruded aluminum chassis. Looks pretty impressive and FINALLY someone has a manual transmission that shifts automatically.

Govenator takes a ride
 

Photo Compliments of Dave Cutter

Attachment 17

I wonder what he thinks of Hydrogen power now?

Thanks to the terminator the Hummer came out.

how much damnit !
the range kinda sucks...
but not bad all in all ...
over-unity or bust

I've read $80 - $100 K US.

And according to someone who was at the unveiling and who posted on the EVDL, people were writing cheques - not for deposits, but for the full amount.

They will not let them go over-unity:mad:

you over-unity guys need to get real!

I figured if 200-250 miles per charge 100,000 mile battery life = 500-400 cycles nothing new or ground breaking for the battery life.

80-100k ???

holy shnikees
you know how much f'in gas that is...???
hmm

my car is say $3000
a difference of about $87k
thats 29,000 gallons at $3.00/gal
even at 30mpg thats 870,000 miles !!!!!!!
PAAAAALEEEEEEZEEE!!!

thats so uncool
thats stupid
i'd shoot anyone i see driving one
f'in idiot

[quote=molecule]80-100k ???

holy shnikees
you know how much f'in gas that is...???
hmm

my car is say $3000
a difference of about $87k
thats 29,000 gallons at $3.00/gal
even at 30mpg thats 870,000 miles !!!!!!!
PAAAAALEEEEEEZEEE!!!

thats so uncool
thats stupid
i'd shoot anyone i see driving one
f'in idiot[/quoteoy]You tell em!

it doesn't burn gas
which is worth something
but not my entire careers worth of driving mileage up front
what sense do all these efficient cars make relatively...
$$$$

ahhhh there in lies the problem as Toecutter was saying make a high performance vehicle . . . they did and thus the cost goes up . . . you think engineers and CEO's work for three years for nothing? When was the last time you built a high performance vehicle? Carbon fiber body - Lithium battery probably their cost $23,000 plus battery management and assembly. $1,000 for electric energy to go 100,000 miles no maintenance cost.

80-100k. HAHAHAHAHA No thanks.

If you want a $10k electric car, there's always the Zap Zebra in the US, or the REVA in England.

https://www.coolbuzz.org/images/r_zapzebra.jpg

https://www.sunvee.com/Images/reva.jpe

:)

Looks like I'm in the wrong business

I'd reserve judgment on that feeling for a couple of years ;)

Just wait until alot of people start pluging in and the grid go's down.

I practically creamed my pants looking at that body. God damn, if that were a woman, I'd hit it!

Ok, in all seriousness, this was the proper route to go. Tesla does not have the capability to mass produce. That would take $200+ million in machine tools and crash tests. Only the major automakers have that money(as we know, the major automakers refuse to mass produce electric cars).

No one is going to pay $80k for a 5-seater family car that does 0-60 in 9 seconds, when they can buy a Corolla for $15k, even if that $80k car were electric.

Will they pay $80k for a 2-seater supercar that does 0-60 mph in 4 seconds? Yes.

Tesla has the right strategy.

The technology is there to mass produce an electric car with 200+ miles range, 0-60 mph in < 9 seconds, 110 mph top speed, and ability to seat 5 adults. It's been there for a decade. BUT, that requires mass production. The big automakers are the only ones who can mass produce, and they refuse to make electric cars. Period. Tesla motors cannot yet mass produce. They would do it if they had the economies of scale, believe me. So would AC Propulsion, Commuter Cars, and others.

Same range as many gas cars, really.

a) It's a sports car, not a family car or errand runner. It's not made to save money.
b) That gas car is ~$.03-.08/mile in maintenance depending on what it is(Hondas and Toyotas at the lower end, Ford or GM at the upper). Even factoring in the battery pack, this car is certainly cheaper to run than a Corvette or similar sports car.

**** that. $10k for a hand-built golf cart?

If you want an eelctric car for $10k, build it. You could get much better results that way, 0-60 mph ~5-6 seconds, 130+ top speed, and 60-80+ miles range is doable for that amount of money. But only if you build it yourself.

Most charging is going to be done when the car is not in use, usually at night. When the grid is not seeing peak use, it tends to have 40-60% of capacity freed up. We could handle many tens of millions of pure electric cars charging during those times without a problem.

As to the amount of electricity consumed, according to the CIA World Fact Book, the U.S. consumes about 3.7*10^12 kWh of electricity per year from the outlet. A midsize electric car sized and shaped like a Ford Taurus or a small SUV like a RAV4, with no attention to aerodynamic efficiency, will use about .3 kWh per mile from the batteries, about .4 kWh/mile from the outlet. Typical car in America sees 12,000 miles/year of use. America has 220 million cars.

Do a little number crunching on how much electricity consumption would go up if all cars were electric.

With a grid that often has lots of available capacity during off peak, wouldn't even make a dent.

Now recrunch the numbers for a full size EV with low drag coefficient around .16, say, sized like a Ford Crown Vic and needing .2 kWh/mile from the outlet, or .15 kWh/mile from the batteries.

From ETLIST:

"The roadster is designed and built by Lotus in the UK and will be sold in California, Chicago, New York and Miami starting next year, with prices reported to be in the $80,000-$120,000 range. Hot on the heels of the ?Who killed the electric car?? documentary, as well as the recent launch of the electric Smart For Two, interest in electric cars is once again rising."

No manufacturing??

And I thought it looks like a Ferrari - it's a Lotus! DUH!

I could be wrong, but isn't the chassis is produced by Lotus, and not the entire car and drive components itself(The latter by Tesla Motors)?

Tesla Motors itself has said that it would love to sell a $50k four door car(likely a sort of luxury sedan), dependent upon the success of the Tesla Roadster to raise the funds.

If Lotus has 100% of the say in control, design, and manufacturing, they'd be able to do it already.

Probably a little easier to mass produce a $80,000 car than a $6000 Vectrix motor scooter. And since they are only 3 years old they should not have wasted all the raised capitol like Vectrix did over the past 9? years?

https://video.google.com/videoplay?do...85113933785378

Interesting commentary about where the money GOES....

"...all free cashflow goes completely into driving the technology to lower costs and make it more available..."

Yep. They'd like to get a mas market EV on the road for common folk. It can be done. Someone willing to do it just needs the money.

I'm kinda dissappointed they didn't make it smaller, 250miles@70mph woulda been nice. I wonder how many people will get stranded because the range drops to ~150miles@75mph?

Even given that aerodynamic drag varies as a square of velocity, the change in range from 70 mph to 75 mph wouldn't be that dramatic. If it gets 250 miles at 70 mph, it would get around 220 miles at 75 mph. This of course neglects cross winds and such.

The designers really didn't pay much attention to aero. The drag coefficient of the Tesla probably isn't drastically better than the Elise it shares many traits with. I'd guess around .30 for the Tesla, while the Elise has a published .36. But it looks damn good.

With a 55 kWh Li Ion pack and 250 miles range, that's 220 Wh/mile consumed. The GM EV1, weighing 500 pounds more than the Tesla, with a .19 drag coefficient, only needed 140 Wh/mile. If this car would have been done in the body of say, an Opel Eco Speedster, with its .20 drag coefficient and 16 square foot frontal area, while keeping the 2,500 pound weight, range would be 400-450 miles with that pack.

omgwtfbyobbq, do you happen to be a member of peakoil.com forums by chance?(Another member there has your same name) I lurk there, quit posting there when college and in-progress EV took too much time, will again resume posting there shortly.

Yeah, I have a few names and frequent more than a few boards. And I've been browsing bbs' a bit much since I'll probably have to wait until the end of August before I start work. For the comparison I was refering to the roadster's ~250 miles epa highway rating, which is at ~48mph, so range should be *~150miles@75mph, which will probably result in a couple strandings due to extended high speed highway driving. The 250miles@70mph is what I think they should've built, but something that looked too small and too streamlined probably wouldn't have appealed to their target as much as a sportscar looking vehicle that's still faster and more efficient than anything in it's price range. They may have to move away from people's perceptions of EVs, but they can't run from physics forever! :D
Speaking of your EV project, hows it coming?

*75^2/50^2=~2.25, which will probably be less than half, but I'm giving rolling losses the benfit of the doubt. ;)

Lets estimate the amount of power it needs to maintain various speeds. The following parameters are estimates(guesses):

Weight(W): 2,500 pounds
Drag Coefficient(Cd): .30
Frontal Area(A): 18 square feet
Rolling Resistance Coefficient(Cr): .012 (Assumes sticky, non LRR tires)
Transmission Efficiency(TE): .90 (Assumes wheel bearing losses and other stuff are counted, which is outside the realm of the transmission itself)
Motor Efficiency(ME): .91 (assumes inverter losses as well)
Battery Capacity(C): 55 kWh

Velocity(V): expressed in mph
Force Drag(FD): expressed in pounds
Force Rolling(FR): expressed in pounds
Wheel Power(WP): expressed in horsepower
Motor Power(MP): expressed in horsepower
Battery Power(P): expressed in kW
Range(R): expressed in miles per charge

I will use the following equations to estimate how the car will behave:

Equations used:

FD = .002558 * Cd * A * V^2
FR = Cr * W

WP = (FD + FR) * V / 375
MP = WP / TE
P = MP / ME / 1.35

R = C / P * V

Results:

At 48 mph:

FD = 31.83
FR = 30
WP = 7.91
MP = 8.79
P = 7.16
R = 369

At 70 mph:

FD = 67.68
FR = 30
WP = 18.23
MP = 20.26
P = 16.49
R = 233


So range at 48 mph is estimated at a very high 369 miles. Way over the EPA cycle. Obviously, my calculated result is incorrect, as Tesla or the EPA did not claim such high range. Thus one or more of the following explanations may be correct:

a) The EPA highway cycle isn't a constant speed of 48 mph, and thus energy taken for repeated accelerations and the limited recovery of energy while braking eats into range significantly
b) The electric motor is operating at a less efficient level at these low speeds
c) The range Tesla/EPA claims was obtained with accessories running, such as heat or a/c, or obtained with the top down where aero drag would be highest

The above may or may not be true. I'd need to know the gear ratios to figure out 'b'(Motor/inverter efficiency data available on AC Propulsion's website), and the driving cycle for 'a' can probably be found on the EPA website.

The estimate at 70 mph makes much more sense.


If the 250 mile range is really obtained at a steady 48 mph, this car would be consuming 220 Wh/mile at 48 mph. This is astronomically high consumption for an EV. I know of 5,200 pound pickup truck conversions with no aero mods that consume 225-250 Wh/mile at a steady 50 mph, around 350-400 Wh/mile at 60 mph. For a small sports car to match a pickup in energy consumption, a pickup with over double the weight and far higher frontal area, would be almost laughable.

But hey, stranger things have happened. Failing explanations 'a', 'b', and 'c', maybe the Tesla Roadster has a high .65 drag coefficient. It sure doesn't appear that way and there is talk of it being more aerodynamic than the Elise(.36 Cd), but who knows?

Looking at it from a mathematical standpoint, it would probably need to be going a bit above 60 mph to get under 250 miles range. Lithium batteries are unaffected by Peukert's losses, so no significant(in regard to range) diminished capacity with increased draw.

The EPA highway test schedule is in fact ~48.3mph average with one stop at the end.
https://www.cleanmpg.com/photos/data/..._Histogram.gif
While the tesla site may be down, iirc range was using the EPA's highway cycle. I went over the calcs again and I'm pretty sure they're using the Lotus Elise' (~17.5ft^2) reference area with a Cd of ~.23.

The force in newtons require to move the car at 48.3mph is roughly, W*Crr+.5(ro)V^2(CdA), without sliding friction. But, it's not much in most expression I've seen (~20N), so we can leave it. W=2500lbs, Crr=.015 (sticky, sticky tires), CdA=4.1ft^2, V=48.3mph and ro=.075lb/ft^3 (sea level), so we get...
Rolling friction~40N
Fluid friction~360N
So total drag is ~400N. Now we're going 48.3mph~21.6m/s, so power is 8.64kw. If this vehicle has a range of 250miles@48.3mph then it takes 5.17hours to travel this distance. So we're left with ~45kwh required at the wheels, but we have drivetrain losses as you suggested, and ~18% seems *reasonable. 45kwh/.82=~55kwh of battery and everything seems to match up. I have to say, you lost me after that 375 showed up, I have no clue where that came from! :confused:


*They stated the motor was ~90% efficient iirc, so as long as bearing losses are ~10%, you're spot on.

Edit-Forgot to convert lbf to N, ack, .454 would've helped a bit! Can't mix and match units in any case... ;)

I think you goofed your units on calculating drag at that speed. It is nowhere near 400N at 48 mph.

Your rolling force for instance, .015 * 2,500 pounds gives you 37.5 pounds rolling force, which is 166.8 Newtons. Way different than the 40 N you post.

As for aero drag, .5(ro)V^2(CdA)
= .5 * .075 lb/ft^3 * 21.6 m/s * 21.6 m/s * 17.5 ft^2 * .23
= 70.4214 lb/ft * m^2/s^2
= 31.9589 kg/ft * m^2/s^2
= 104.85203 kg/m * m^2/s^2
= 104.85 kg*m/s^2
= 104.85 N

So 105 N aero + 167N rolling = 272 N of drag, way less than the 400 you post.

I think you screwed your units up. :p



If I do it in horsepower, feet, mph, ect., and even plug it into Uve's EV Calculator(https://www.geocities.com/hempev/EVCalculator.html), my numbers end up working out very close to what I had posted earlier insofar as power requirements.

Lets try this in metric working with metric from the start.

I'll use the Cd*A reference you provide and the 18% transmission loss, the rho value(~1.25kg/m^3), and 20N sliding friction.

Mass(W): 1,135 kilograms
Drag Coefficient(Cd): .23
Frontal Area(A): 1.63 square meters
Rolling Resistance Coefficient(Cr): .015
Transmission Efficiency(TE): .82
Motor Efficiency(ME): .90
Battery Capacity(C): 55,000 Wh

Velocity(V): expressed in meters per second
Force Drag(FD): expressed in newtons
Force Rolling(FR): expressed in newtons
Force Sliding(FS): 20 newtons
Wheel Power(WP): expressed in watts
Motor Power(MP): expressed in watts
Battery Power(P): expressed in watts
Run Time(T): expressed in hours

Air Density(Rho): 1.25 kg/m^3
Gravitational Constant(G): 9.8 N/kg


Equations used:

FD = .5 * Rho * Cd * A * V^2
FR = Cr * W * G

WP = (FD + FR + FS) * V
MP = WP / TE
P = MP / ME

T = C / P

Results:

At 21.6 m/s(48 mph):

FD = 109
FR = 167
FS = 20
WP = 6,397
MP = 7,801
P = 8,668
T= 6.34

At 31.3 m/s(70 mph):

FD = 230
FR = 167
FS = 20
WP = 13,052
MP = 15,917
P = 17,686
T= 3.11


So at 48 mph, we get 6.34 hours of run time, or 304 miles range. At 70 mph, we get 3.11 hours of run time, or 218 miles range.

Check the units, they work out.

The results I arrive at are quite a bit different from the 250 mile range at the EPA cycle, are they not?

Heh, dammit... I did the entire thing in english and forgot to convert the force to metric! :o :D
So, going backwards again, assuming a 55kwh pack and 82% efficiency, we're using 45kwh at the wheels. We'll keep this in metric since last time I f'd it up, 45kwh/5.17h=8.7kw, 8.7kw/21.6m/s=403N. So, since W*Crr=1134kgm/s^2*.015=17N, then fluid friction must be 403N-17N=386N. So... Like you said, at 75mph~33.5m/s, all of this makes sense since 386N=.5(1.2)(33.5^2)(1.65(Cd), which yields a Cd of ~.35. Which sounds exactly like a stock lotus elise... I wonder what the actual CdA is?

My best educated guess is a Cd of .30 and a frontal area of 18 feet square. The Elise has a .36 Cd, and Tesla claims to have made the car more aerodynamic.

I'd think on level ground at 60-65 mph, it would achieve 250 miles range, assuming little to no stops or slowdowns. This would correspnd to 220 Wh/mile at that speed, which makes a lot more sense, as that's more typical of small EV sportscars with only mild attention paid to aerodynamics(By comparison, the GM EV1 got 140 Wh/mile, AC Propulsion TZero 150 Wh/mile, at that speed).

Or if you go the EPA cycle and factor in all the accelerations and slowdowns, as there still are quite a few to help waste energy. I could try to integrate that curve, and the 250 miles range would then make sense. The graph certaily doesn't show the steady speed that would be more representative of highway driving.

That's something I was thinking about... Range shouldn't drop because of the combined cycle... It should actually increase. Take a diesel and a hybrid, the diesel gets about the same mileage in city driving as it does in highway because it doesn't suffer from pumping losses at lower rpm so engine efficiency is constant, and the hybrid gets better city because the regenerative brakes capture a large portion of energy that would otherwise be lost and allow it to be reused and it also doesn't waste any energy at stops/deceleration. An EV is the best of both worlds, no drop in engine efficiency wrt speed and regenerative braking... city mileage should own highway mileage. Anecdotally, in my diesel bunny I get the same mileage in city driving with a ~30mph average and all that idling/braking as I do on the freeway at ~50-55mph, so I could go off and make a statement like idling/braking wastes as much energy as going 50mph compared to 30mph does. If I had regenerative braking and an EV motor I'd probably get twice the city mileage I do now, even if the brakes only catch ~1/3-1/2 of the energy. Going 55mph compared to 30mph is still ~three times the energy, fluid drag is huge! :D

I sent them an email asking about range, but I doubt they'll respond. I figure they're deliberately understating the range because they'd rather not have people strand themselves if they're cruising along at 85-90mph or something like that. I wonder if they'll have a forum where people can post their distance traveled, conditions, and energy used?

Edit- Here's the EPA's city driving schedule
https://www.fueleconomy.gov/feg/city_histogram.gif
I think the best way to compare would be to take the average speed from each segment then take some fraction of the energy at the top speed of each segment for regenerative braking. Not sure how much energy it would capture, but we should be able to figure out the average consumption and range from that. It'd be very wishy washy and all that since the time intervals aren't well defined, but it's something. I wonder if we could contact the EPA and get better info?

Regenerative braking will only recover 10-30% of lost kinetic energy. Further, AC motors/inverters do not see increased efficiciency with increased load like internal combustion engines do.

The lower aero drag seen at lower speeds will only be noticed if the speed is kept constant. Frequent and repeated acceleration/deceleration is actually one of the EV's least efficient operating points, and why so many attempt regen just to gain an extra 10% of so of range. Steady cruising is its most efficient. The EPA cycle, if you look at the time taken for each acceleration/deceleration, the car isn't coasting down to speed, it's actually braking, wasting lots of kinetic energy(although regen helps some). To drive an EV efficiently, you must coast.

Wait.. a sec. Time to bust out some more of my four year old community college physniks! ;)

Cruising at *25mph~11.17m/s, rolling friction is still the same 1123(.015)=17N, .5(1.2)(11.17^2)(1.65)(.35)=43N, so we use 60N to go 25mph. But it isn't just 60N, we also need to include the force used to accelerate the vehicle and apply the range of energy captured by the regen brakes. At rest this vehicle has zero kinetic energy, and at 25mph is has (.5)(116kg)(11.17^2)=7236W which, at an average of 11.17m/s is a total of 648N. So... Almost 700N, a lot of energy, of course the peak speed is higher, but then again we regain a fraction of the energy required in regen braking... Can anyone who's still in the know verify this?

*Since there are some stops, the ~20mph average isn't quite right. But there aren't that many stops, so it's in motion ~80-90% of the time with an average of maybe 25mph.

Lets examine the energy lost slowing down and stopping in that 48 mph highway cycle for a minute.

I'm going to assume 50% of lost kinetic energy is recovered during the slow downs through regen. I'm going to neglect aero losses.

We have the following major speed drops from the EPA highway cycle graph:

-36 mph to 35 mph
-49 mph to 40 mph
-49 mph to 42 mph
-45 mph to 43 mph
-44 mph to 40 mph
-50 mph to 30 mph
-59 mph to 57 mph
-57 mph to 56 mph
-57 mph to 56 mph
-60 mph to 58 mph
-58 mph to 54 mph
-55 mph to 45 mph
-45 mph to 42 mph
-56 mph to 47 mph
-50 mph to 48 mph
-60 mph to 0 mph

I'm going to convert all of these to meters per second, and determine the total kinetic energy lost in joules assuming the 50% recaptured by regen and neglecting aero losses during acceleration/deceleration. It will be presented in a chart.

KE = .5 * M * V^2

KE is kinetic energy expressed in joules
M is mass in kilograms, the car being 1135 kg
V is velocity in m/s

https://img.villagephotos.com/p/2006-...yclelosses.JPG

If you add up all the kinetic energy lost, you get 628,341 J, assuming 50% has been recovered by regen.

To convert J to Wh, divide by 3,600, since 1 Wh is 1 Joule per second times 3,600 seconds.

So total Wh lost due to slowing down is 174.54 neglecting aero losses in acceleration/deceleration.

With aero losses, it would be a bit higher.

So that's at least 174.54 Wh lost over 765 seconds of travel at 48 mph average. At 48 mph, it takes 75 seconds to travel 1 mile.

So on average, every mile 17.11 additional Wh are being lost due to slowing down and stopping, completely neglecting aero losses involved in accelerating the car.

Aero losses in acceleration/deceleration would probably add about 50% to that, making it around 26 Wh/mile lost due to slowing down over that EPA highway cycle.


To put this in perspective regarding range, in theory by the calculations in my previous post had 304 miles range at a steady 48 mph, or 181 Wh/mile consumed at that speed. Add 26 Wh/mile to that consumption. That gives 207 Wh/mile.

Or with a 55 kWh pack, 266 miles range.


I think we found the reason for the descrepency. The other minor difference can be chalked up to things like crosswinds, which I didn't account for in my simulation.

From this, it's reasonable to conclude that the range at a steady 60-65 mph with few accelerations and decelerations would be about the same as the range following the EPA highway cycle.

The car weighs ~1123N and has a mass of 1123N/9.8m/s^2=115kg. To move it to 48mph~21.5m/s requires .5(115kg)21.5m/s(21.5m/s)=26579kg(m^2/s^2) or ~26500J. Now assuming we capture ~30% of the energy via regen braking at the end, we only use 26579J(.7)=18605J. Since this test is ~765s, we use 18605J(1/765s)=24W. Compare this to your tesla glider with a Cda=5.4ft^2~.5m^2 and a Crr of .012, using a certain amount of energy per second. Rolling friction is 1123N(.012)=~14N, and fluid friction at 21.5m/s is .5(1.2kg/m^3)21.5m/s(21.5m/s).5m^2=139N, and a sum of 153N. At 21.5m/s, this glider uses 153N(21.5m/s)=3289W. This is huge when compared to the energy required to get the car to ~48mph.

During the city cycle, lets say the average speed is 25mph~11m/s, so using your glider again we get ~50N, or 550W. Now we have 23 accelerations to ~different speeds, which according to section, in m/s are [15,25,17,14,17,12],[12,12,11,13,15,13,13,13,11,10,13,10],[14,25,17,14,17]. The sum of the change in kinetic energy between a stop and these speeds is ~296522J, when considering regen braking it is ~207565J. The energy expended per second is 207565J/1874s=111W. Which is apparently nothing compared to the energy required to go ~50mph!

At 25m/s highway we use ~3300W, and at 11m/s in the city we use ~660W. Comparing these two in terms of efficiency can't be done unless we factor in speed, so if we were going the same distance per time, we need to use a factor of ~21.5mps/11mps=2.27. To compare the two we know that it'll take ~227% more time in the city, so over the same distance the EV in the city uses ~1500W... Which means that it's still twice as efficient as cruising at ~50mph is, but it's not the ideal situation where we're going half the speed and using a quarter of the energy. Braking in the EPA city cycle wastes at least twice as much energy as cruising does, probably more, which seems reasonable. And says a lot about how much gasoline engine efficiency drops at lower rpm imho... Of course radio, lights, heater, AC, etc... all add load.

Anyone see any problems?

If you search for Tesla Motor's white paper, in the end they list the electricity consumption as being 110wh/km over the combined cycle. Assuming 90% mechanical (motor/bearing/transmission) efficiency, this means the glider requires ~99wh/km. Since we know the weight, and the EPA combined schedule, we can move backwards to isolate the CdA. Anyway, after futzing around I get that CdA=.416, which is very nice.