How to impress your neighbors now that everyone has a Tesla

[A64Pilot]

7 minutes ago, Pinecone said:

But my airplane does 62% power (136 HP) on 10 GPH.  So 13.6 HP-hour per gallon.

Which means 30% efficiency with your number.

But I am trying to figure out how a Telsa does 300 miles at say 50 MPH, so 6 hours, using 67 HP-hour.  So Telsa cruises on 11 HP?

I don’t know, math isn’t my strong point, I attached a couple of charts, in particular I think the watt hours per mile will help, noe remember we are in Fl and the AC is pretty much always on and I have it set to between 68 and 70, with the seat heater on because tgat feels good on my back, so we aren’t trying to conserve, this is normal driving, we tend to accelerate much harder than normal, because the car can, and does so noiselessly with no gear shifts etc.

‘Oh, and honestly I haven’t tried to see what it’s range really is, I’ll attach another Tesla fi chart that may help.

Edited August 4, 2023 by A64Pilot

[A64Pilot]

Our theoretical rated range has dropped from 260 when new to 238 I think now. This isn’t perfect as I can reset the BMS and “recover” range, the reported range is pessimistic. 

There is a really stupid amount of data you can pull from this car

Blue is our car, green the “fleet” at least those that are Tesla Fi members and there are a lot of those

Edited August 4, 2023 by A64Pilot

[N201MKTurbo]

18 minutes ago, Pinecone said:

But my airplane does 62% power (136 HP) on 10 GPH.  So 13.6 HP-hour per gallon.

Which means 30% efficiency with your number.

But I am trying to figure out how a Telsa does 300 miles at say 50 MPH, so 6 hours, using 67 HP-hour.  So Telsa cruises on 11 HP?

I can believe a Tesla can cruise along on 11 HP. I would think most high MPG cars can do that. 

 

As far as the 30% efficiency is concerned, the laws of thermodynamics predict that the best a heat engine can do is about 30% efficiency. All Carnot engines have about the same efficiency from internal combustion engines to giant steam power plants.  

https://energyeducation.ca/encyclopedia/Carnot_efficiency

[A64Pilot]

From the chart I posted we spend the majority of the time consuming about 210 WH per mile, if you take 50,000 and div it by 210 you get about 240 or so, and our actual of 210 wh per mile is actual, running the AC and starting and stopping, sitting at lights etc., not the theoretical test.

I wonder if it counts the time we keep the car in “dog mode” which keeps the car at set temp while we are eating out and shopping etc., the little dog goes everywhere with us.

Someone smarter with math than me could convert 210 WH per mile to HP. 1 HP is I think 748 Watts?

That would give us HP used at 45 MPH or so, which is where we spend the majority of our driving as I suspect most do.

Edited August 5, 2023 by A64Pilot

[A64Pilot]

1 hour ago, N201MKTurbo said:

I can believe a Tesla can cruise along on 11 HP. I would think most high MPG cars can do that. 

 

As far as the 30% efficiency is concerned, the laws of thermodynamics predict that the best a heat engine can do is about 30% efficiency. All Carnot engines have about the same efficiency from internal combustion engines to giant steam power plants.  

Actually 30% is much better than the average auto is capable of, it’s pretty darn good. In truth our old fashioned non electronic aircraft engines are awfully efficient due to largely very narrow RPM ranges and throttle openings.

This quote from the attached link

https://en.wikipedia.org/wiki/Fuel_efficiency#:~:text=Passenger car diesel engines have,gallon for an efficient turbodiesel.

Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%. A common margin is 25% more miles per gallon for an efficient turbodiesel.

One thing it doesn’t address is that one reason for a Diesels greater milage is the fuel has a lot more BTU / KWH per unit volume

 

Edited August 5, 2023 by A64Pilot

[aviatoreb]

7 hours ago, A64Pilot said:

Couple of statements, first I think short trips of less than 10 min isn’t really viable, but then your statement of then they recharge between trips.

OK so where do they recharge? Do they only fly to chargers or do they fly from a charger to you, then to your destination and from there to a charger? How long does a recharge take? Time interval between recharges, IE how do you dissipate the heat, because anyone who has ever repetitively recharged any kind of battery rapidly will tell you that they get hot, quick and heat is battery enemy #1, so you have to deal with that heat, and that adds quite a bit of weight, Tesla does it with copper tubes filled with antifreeze and a heat pump to cool the battery, run the car hard and when you stop you can hear the heat pump and fans running hard, which takes power of course as well as weight.

There are huge problems to solve, current Government promised to spend Billions on electric car chargers, which I’m also against, but where are all these chargers? I haven’t seen any, have you? How many chargers would air-taxis need, and where would these things land and takeoff from? Only thing I can see is roof tops, so then the building is going to have to get a cut of the money.

The expense of point to point air transport would be prohibitively expensive for the average Joe I think, yet I wouldn’t be surprised if his taxes aren’t what will pay for it, just like the current subsidies.

Solid State batteries have been around for longer than fuel cells have and have the same problem, that is unless your NASA they aren’t affordable, and it doesn’t look like they will be in the foreseeable future. Fuel cells were what was promised decades ago to Government agencies to get them to drop the electric car because the major manufacturers didn’t want to have to completely re-tool etc to build something new, more money in continuing with ICE technology.

Solid State is in the group of “magic batteries” when or if the magic battery becomes viable, then sure lots of things will become possible, but I wouldn’t hold my breath

That's exactly what I imagine - and I have said this for several years already - a fleet of Uber-like quadcopter things sitting on top of buildings at their charger stations waiting to swoop down and pick up their customers when on demand.

Cooling is a matter of a large enough fleet - if each vehicle needs 10 minutes or 20 minutes of downtime between each 3 or 5 mi runs then that just means the fleet needs to be bigger.

Getting the infrastructure all in place - clearly a legal and economic headache - I agree! - to imagine how that all happens but I imagine it could happen.  And clearly whether cars and or air vehicles the general over all grid would need to super size.

solid state magic batteries.  Can't wait!  Someday....  I Agee - I know its not around the corner but I will be shocked if it is not eventually practical and cheap and available.  Meanwhile a few days ago I read a nice article in no other than my favorite bicycle magazine of a Swiss company playing around with them - and the ceo did say to when will it be marketed - years away.  https://velo.outsideonline.com/ebike/stromer-solid-state-battery-e-bike/

[Pinecone]

12 hours ago, N201MKTurbo said:

I can believe a Tesla can cruise along on 11 HP. I would think most high MPG cars can do that. 

 

As far as the 30% efficiency is concerned, the laws of thermodynamics predict that the best a heat engine can do is about 30% efficiency. All Carnot engines have about the same efficiency from internal combustion engines to giant steam power plants.  

https://energyeducation.ca/encyclopedia/Carnot_efficiency

Except for Formula 1 engines.  

"To achieve the necessary power and efficiency, F1 engines achieve a peak thermal efficiency above 50 percent, significantly higher than a modern passenger car's 35 percent thermal efficiency. "

Cruising at 11 HP sounds low, for highway speeds.  My M3 gets 28 MPG on the highway, which at 85 MPH is about 40 HP.  My Fiat 500 Abarth does 70 MPH on about 27 HP.

 

"Let's take the vanilla car out on a highway cruise, at 65 mph or 30m/s. At that speed, P_air = 14.6 kW = 19.5HP."

"People find it difficult to believe that their car only needs about twenty horsepower to cruise along at a steady 65 mph."

[A64Pilot]

Model 3 Tesla had I believe the lowest CD of any mass produced car at introduction of .23, so that helps especially at higher speeds.

Now if this math works, 210 WH per mile at 45 MPH means a current draw of 9450 Watts, which if divided by 748 Watts is 12.6 HP.

If anyone is interested you should be able to calculate HP required at other speeds from the chart I posted, except that in truth the power consumed doesn’t correlate into HP for a couple of reasons. first parasitic loads are included like AC etc and of course the motor isn’t 100% efficient. The parasitic loads aren’t trivial, only reason I can explain why going slower than 40-45 MPH uses more power is because of increased time the parasitic loads are running, can anyone else come up with another reason? 

Tesla heat pump is BIG, it can draw at max load as much as 7,000W, but it’s heating / cooling the car interior, the battery, the computer(s) and the drive train and I think normally pulls a lot less, but it’s not a trivial load.

If you back out the unknown parasitic loads and the motor efficiency I believe the actual HP required is significantly less than 12.6, my Swag based solely on how much going slower increases power consumption per mile is that it’s probably well less than 10 HP.

So to extrapolate this out, I think it’s not unlikely that even inefficient SUV’s etc are driving around usually not using more than twice the HP of a Model 3, say 20 ish HP. Maybe less, probably less I think.

I think the average Auto spends the majority of its life developing 10% or less of its max HP.

One reason we just can’t correlate a car motor to our aircraft motor, and the steady high power required to fly vs the low power to drive is one reason why an electric car works, but an electric flying machine just can’t.

Edited August 5, 2023 by A64Pilot

[AH-1 Cobra Pilot]

4 hours ago, A64Pilot said:

The parasitic loads aren’t trivial, only reason I can explain why going slower than 40-45 MPH uses more power is because of increased time the parasitic loads are running, can anyone else come up with another reason?

Sure, tire rigidity, for one.

[AH-1 Cobra Pilot]

4 hours ago, A64Pilot said:

Model 3 Tesla had I believe the lowest CD of any mass produced car at introduction of .23, so that helps especially at higher speeds.

The planform area also matters.

[A64Pilot]

Tire rigidity I don’t think is going to make much difference, they are Pilot Sport’s and are inflated to 42 PSI, and the centripetal force at 40 ish MPH isn’t much

CD is CD isn’t it ?Why would planform matter, yes I know it could change CD, but CD is set it’s not a variable with speed.

‘Either way excepting for the fact that parasitic loads are the same, but cut speed in half they are double per mile is the difference, but then above the 40 to 45 MPH additional power required for higher speed to overcome drag exceeds the loss of consumption of the AC from decreased run time.

I think with AC off we would see the slower I go the less watt hour per mil.

[Fly Boomer]

2 minutes ago, A64Pilot said:

CD is CD isn’t it ?Why would planform matter, yes I know it could change CD, but CD is set it’s not a variable with speed.

One would think, but I was looking for a list of coefficients for various cars this morning, and on at least one of the charts they showed Cd as well as CdA which is Cd times frontal area (flat plate ??).  You would think frontal area would be baked in when considering Cd, but apparently CdA adds something to the measurement.

[A64Pilot]

I think flat plate drag can be broken out of CD but is as you say is a part of CD, but then I’m no car guy, not to that extent anyway.

But to explain really significant increase in power consumption per mike to drive 20 ish MPH as opposed to 40 ish MPH is tough to do. Logic says within reason the slower you go the less power required over unit distance.

Only thing I can come up with is something has a significant power draw and by going half as fast it’s drawing power for twice as long per distance, and I think that something is the heat pump

Edited August 6, 2023 by A64Pilot

[EricJ]

Cd is just a metric for how streamlined an item is and does not reflect its size.   A tiny thing with a particular Cd requires much less power to move than the same thing scaled up 1000x.   The frontal area, A, reflects how large the item is, regardless of Cd, so that together drag is proportional to Cd*A.   The force required to move something through the air also takes account of the density of the medium (air, which takes into account temperature, pressure, etc.), and the square of the velocity through the medium.

So Cd is only a part of the story, but certainly a marketer will emphasize Cd if it's good within the industry rather than Cd*A if that's worse.   Sports cars and performance cars tend to have narrow roof lines (i.e., the side windows tilt in) and low roof lines in order to help minimize A.

This is the same reason a Mooney has a small frontal area by having a fuselage with a short vertical dimension.    That taller cabin in a Bonanza costs drag, even if the airframes had a similar Cd otherwise.   It's also why GA cabins are about the same width,  to minimize A, and why airplanes that provide that extra width, like a Commander 112, are slower. 

[AH-1 Cobra Pilot]

1 hour ago, A64Pilot said:

Tire rigidity I don’t think is going to make much difference, they are Pilot Sport’s and are inflated to 42 PSI, and the centripetal force at 40 ish MPH isn’t much

Well, at 40 mph, the acceleration on the rim of a 27" diameter disk will be over 3000 ft/s², and at 20 mph it will be 1/4 of that, so without figuring the mass of the tire tread in contact with the road, I would still call that a significant difference.

[Pinecone]

I have a Fiat 500 Abarth.  I switch between summer tires (P Zero Nero) and winter tires (Pirelli All Season).

The difference is about 3 MPH difference.  All Seasons get around 36 MPG, summer tires are around 33.

[A64Pilot]

3 hours ago, AH-1 Cobra Pilot said:

Well, at 40 mph, the acceleration on the rim of a 27" diameter disk will be over 3000 ft/s², and at 20 mph it will be 1/4 of that, so without figuring the mass of the tire tread in contact with the road, I would still call that a significant difference.

Even parked there isn’t much sag in the tires, and we are talking primarily about the energy lost in flexing the tires I assume?

It’s there just I don’t think it’s real significant is all.

Of course it could be some anomaly as there is a big bump in the curve right at that speed, faster or slower consumes much less energy which doesn’t make sense, not sure why, I can’t explain it.

I’d like to see the current draw of a quad copter thing with a 500 lb useful load. I’m assuming two people and think to make it viable it would have to be able to hover with 500 lbs of people. You have to be able to hover to fly

I honestly don’t think it could be done. I think that’s about all you can get out of a turbocharged IO-360 in a helicopter.

But then ten years ago if you told me that you could land an orbital launch vehicle on a barge out in the Ocean I would have laughed and begun listing reasons why it just wasn’t possible.

[AH-1 Cobra Pilot]

2 hours ago, A64Pilot said:

Even parked there isn’t much sag in the tires, and we are talking primarily about the energy lost in flexing the tires I assume?

Just watch the first few seconds of this clip and the car body rise.  

 

[A64Pilot]

I don’t drive on crinkle wall slicks, I do understand them, been around them in my youth. The front tires on the dragster are more like passenger car tires, how much do they grow?

Many Sport bikes that can run pretty much 200 MPH have only a fingers width or less between the tire and front fender, yet the tire never touches.

It’s called tire growth in the vernacular and I maintain that a passenger car tire is subjected to very little and especially not at 45 MPH.

Next time you have your tires balanced watch how much growth there is on the balancer. I’ve never noticed much if any and I’ve watched.

Rolling resistance is real and significant, moreso than maybe I’m giving it credit for, I believe the biggest reasons trains are so much more efficient is rolling resistance of steel on steel is much less than rubber on pavement. Of course their traction sux though.

With an ICE (internal combustion) higher mileage up to a point is understandable with speed, higher gear ratios and running at the engines “sweet spot” RPM wise etc. But their highest mileage is at speeds much lower than many want to believe

But an EV doesn’t have a transmission so gear ratio is fixed and I don’t think an electric motor’s efficiency changes all that much with RPM, so why is there so much difference in WH per mile between 20-25 and 40-45?

I think maybe one reason my be that those are average speeds, not steady state and the low speed actually has a lot of stop and go and of course continually accelerating from a stop requires energy in excess to steady state. I think that’s likely most of it, longer running time of the AC and rolling resistance play into it, but I think it’s stop / go that’s the biggest contributor as steady state driving at 20 ish MPH isn’t common for us, but steady state at 40 ish is pretty common. 

If so then it’s another lesson in data doesn’t always display all variables, don’t make assumptions.

Electric motors sweet spot is I think not as big as an ICE and is more load dependent than RPM so picking motors for a large quad copter thing won’t be as difficult.

With piston airplanes our engine choices are much more limited, we essentially have two choices big and small and to turbocharge or not, I think most have given up on geared motors except Rotax which has to.

 

Edited August 7, 2023 by A64Pilot

[cliffy]

We will NEVER be able to get rid of dino juice power plants unless we go all nuclear!

We will always need a back up standby power source to take up the slack of sudden demands to the grid

The wind doesn't always blow at night or on cloudy days 

Clouds significantly reduce solar panel outputs

The rest of the world will rely on dino juice and coal for electricity for the next century as THE primary source of power!

Calif shuts off the grid at many times in the summer to prevent fires Where does that leave a one car (Tesla) family? They also tell large areas to not charge there electric cars on certain days as they don;'t have the power available. Wind power per KW is still much more expensive than any thing else even with subsidies. WHY?

Can anyone find how many hours a year each and every wind turbine actually produces viable electricity going to the grid? NO!  I've tried for 10 years with no numbers yet because they are not published by anyone in the wind turbine industry.

Just who is making the money in the wind turbine industry?

How many birds are acceptable to be killed by every wind turbine out there?

Are we ready to kill every living thing (and keep them dead) under a hundreds of square miles of solar farms that are needed to support a total "Green" energy plan?

Going electric with vehicles is only the start of the problems ahead

Now back to the title of this thread  How to impress your neighbors_?

You buy one of these :-)  below

 

[Pinecone]

10 hours ago, cliffy said:

Can anyone find how many hours a year each and every wind turbine actually produces viable electricity going to the grid? NO!  I've tried for 10 years with no numbers yet because they are not published by anyone in the wind turbine industry.

The overall numbers I have seen point to 12 - 15% MAXIMU of the data plate rating over a year.  So a 1 megawatt wind turbine generates an average of 150,000 watts over the year.  And it could be less.

The Science Museum in Cleveland has a small wind turbine generator.  They are right on the shore of Lake Erie, known for windy conditions.  Based on the average daily wind speed chart on the exhibit, their small one generates full output for about 4 days per year.  The wind speed needed for full output is 30 knots, IIRC.  And only 4 days per year average 30 knots for the day.

And, so you pointed out, the wind blows when it wants to, not when we want/need the power. 

There is a neat facility on the Susquahanna River near me.  It is a hydroelectric plant.  But where it is located, there is a hill right beside it. So when they have excess power, they pump water up the hill to a manmade lake.  When they need more power generated that the river flow produces, they can augment is with water from the lake at the top of the hill.  So a way to "store power."

https://en.wikipedia.org/wiki/Muddy_Run_Pumped_Storage_Facility

 

[aviatoreb]

11 hours ago, cliffy said:

We will NEVER be able to get rid of dino juice power plants unless we go all nuclear!

We will always need a back up standby power source to take up the slack of sudden demands to the grid

The wind doesn't always blow at night or on cloudy days 

Clouds significantly reduce solar panel outputs

The rest of the world will rely on dino juice and coal for electricity for the next century as THE primary source of power!

Calif shuts off the grid at many times in the summer to prevent fires Where does that leave a one car (Tesla) family? They also tell large areas to not charge there electric cars on certain days as they don;'t have the power available. Wind power per KW is still much more expensive than any thing else even with subsidies. WHY?

Can anyone find how many hours a year each and every wind turbine actually produces viable electricity going to the grid? NO!  I've tried for 10 years with no numbers yet because they are not published by anyone in the wind turbine industry.

Just who is making the money in the wind turbine industry?

How many birds are acceptable to be killed by every wind turbine out there?

Are we ready to kill every living thing (and keep them dead) under a hundreds of square miles of solar farms that are needed to support a total "Green" energy plan?

Going electric with vehicles is only the start of the problems ahead

Now back to the title of this thread  How to impress your neighbors_?

You buy one of these :-)  below

 

Never suggests a very very long time.

There are all sorts of good reasons for and against wind turbines and certainly significant challenges to actually going wind and building that all into the infrastructure - and hidden costs and so forth.

But the bird thing is just not one of them.  It just isnt

Estimated number of birds killed by hazards in the US each year (millions) 
Wind turbines, 2020
1.17
Wind turbines, 2050*
2.22
Communication towers
5
Automobiles
60
Pesticides
67
Buildings
100
Cats

Unless we are going to eliminate cats, buildings, pesticides and automobiles, then wind turbines vs birds is a red Herring (haha birds are a fish).  Its a misplaced argument designed as a gotcha against greenies who are supposed to live every living thing and be called out as hypocritical for allowing a poor baby bird to die at the altar of a mean scary wind turbine.  But really I am good with 1.17 birds per year dying considering I still drive a car and we car drivers contribute to 60 billion birds dying.  

And I eat birds too....!!!!  Yum!

If I am for or against wind turbines its not contingent in the least on this measly small fraction of birds that die for all sorts of reasons.  Silly birds....

 

[cliffy]

"Never" until, as I noted, we are willing to accept nuclear power or some new kind of 24/7 power source

Current technology will not allow us to disconnect from the dino-juice grid ever, and there is no new technology on the horizon that can supply power 24/7 at a moments notice in the amounts needed

Going "green" with renewables is a noble idea but when the rest of the world gives you the finger and proceeds down a path to triple dino-juice power plants as they see the folly in "green" for them, it seems somewhat of a strange juxtaposition

Didn't Germany just do an about face on nuclear power?

 

[Fly Boomer]

16 hours ago, cliffy said:

We will always need a back up standby power source to take up the slack of sudden demands to the grid

It's in the future somewhere, but I have seen proposals for using all the battery powered cars sitting in garages and plugged in as a source for peak demand.  People already have storage batteries in houses with solar panels -- not enough by any means, but an increasing number.

[Pinecone]

18 hours ago, Fly Boomer said:

It's in the future somewhere, but I have seen proposals for using all the battery powered cars sitting in garages and plugged in as a source for peak demand.  People already have storage batteries in houses with solar panels -- not enough by any means, but an increasing number.

Great, have a hot night with ACs running hard and everyone can't go to work because the car no longer is charged.