Would you purchase a electric plane kit with the following specs?

Discussion in 'Hangar Flying' started by annerajb, Jul 24, 2016.

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  1. Jul 29, 2016 #41

    DangerZone

    DangerZone

    DangerZone

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    It might be wise to make a difference between the grid distribution and the power terminal. Households have (most often) a three phase power cable setup coming into the house, and then every phase is distributed to a monophase wiring scheme (three-phase current is actually three monophase currents, with 120 degree phases apart). Since electric distributers mostly charge the electricity price by the maximum power a subscriber/consumer can use, households have only monophase sockets and electric aparatus inside the house. Thus three-phase power is coming into the house/workshop but is distributed as three monophase wirings. What prevents you from using three phase electricty is the lack of the three-phase terminal (three-phase counter/panel, breaker/fuse, larger gauge wirings and sockets) into which one could plug a three-phase aparatus. You will also notice workshops have thicker wirings (thicker gauge wire) which can sustain continuous use of higher currents. A quite common cause of electricity incendies happens when the aparatus inside the household/workshop consume more power than the wires can handle, so they catch fire after continuous heating (a too thin wiring cable will act as a heater until metling or eventually burning) and burn down the house/workshop. Hence, there are fuses and circuit breakers to prevent electric strikes and incendies. Even though your workshop has a 90A breaker, continuous use of 240V/89A could lead to electric problems noone wants to risk. Thus your electrician or whoever has built the wirings has limited the use inside the house so you could not use all three phases simultaneously. But if you'd check the entry cable into your facility (household/workshop), you might notice it is a very thick multiple (five or three) wire cable, out of which three wires are three-phase electricty. Feel free to check and let me know if this is incorrect, I am always open to learning about new grid technologies.

    In the USA, Continental bought the Centurion engine program and sells it across the country. So most probably we will be seeing more of them because the USA is a leader in small aircraft production. Hopefully someone will design a couple of improvements to the clutch and eletrconics so reliability would be improved compared to some previous models. So far so good, time will tell how this 155HP engine will evolve.

    Hangars and workshops are in a different league compared to households when electricty is concerned. Most often the distributor allows them more power (U x I = P, voltage times current equals power) than households so the wires would withstand continuous use of heaters, driers, welders, high power machines, etc. This electricty is more expensive, so naturally it is not that easy to 'plug in' a quick charge Tesla into a socket in a home. However, a slow charge is possible, to charge this same car slowly over a period of ten hours, like during the night when the grid is at a low (industrial machines not running). So yes, there are solutions, but the most imprtant thing is to see if there is a MARKET or demand.

    Transitioning to a C-152 can sometimes be complicated to a pilot who is used to different instruments/equipment positions of the C-172. The circuit breakers are in the different spot, the gauges, the indicators, the fuel selector valve is different, etc. And we as pilots get used to performing things according to check lists and automatically. For example, your hand reaches to check the fuses, but they are in a different position. These can sometimes shortly confuse even an experienced pilot, and take some time (a couple of hours) to adjust to. Electric aircraft don't need half of the instruments and gauges an ICE aircraft does, so it might be smart to take these into consideration when designing the electric aircraft to keep possible pilot confusion to a minimum.

    The same problem existed even ten years ago when electric aircraft were being designed and tested on a larger scale. The initial cost is high, electricity is cheap, batteries are hyperexpensive. And battery cells are expendable, they have to be changed from time to time depending on the quality. A good battery design is crucial, as well as cheap and reliable battery cells. So far it seems only Elon Musk has plans to do something about it on a larger scale. Without this, you are absolutely right that we are a long way from spread of electric flying.
     
  2. Jul 29, 2016 #42

    BJC

    BJC

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    In the USA, the standard residential electric supply is not three phase. It is single phase 240 volt with a grounded center tap that provides two 120 volt circuits.


    BJC
     
  3. Jul 29, 2016 #43

    BBerson

    BBerson

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    This is correct, I just installed the cable to my new house.
    One thing to consider, the service is 200 amp usually, but the main line can't handle everyone in the neighborhood using 200 amps at once to charge electric cars. Or even 50 amps, I suppose. Not sure what the grid can handle now but not enough to fast charge cars if everyone had one.
     
  4. Jul 29, 2016 #44

    DangerZone

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    It seems we are talking about different things. The residential electric supply in most residential households is monophase 220V to 240V as anywhere else in the world, the one you get in the sockets. In Europe, a monophase 240V is what is also in the sockets. However, the cable coming into the block/house from the local transformer is a larger cable with five wires, or in some other cases a three thick wire cable. It gets into the house panel and then from this panel it is distributed to the monophase wiring/cabling.

    So, I am trying to understand what kind of cable do you have from your local transformer to your house. Are you sure it is a single monophase cable for the whole house/block? Because this would not last long, and any copper wire thinner than 3mm diameter would not withstand a power surge of 240V and 200A as some have mentioned here.

    Would you happen to have a picture of this cable you installed to your new house? Just to get a better perspective and see that we are not talking about different cables/wires. What kind of cable do you have from your local High Voltage transformer to your house?

    Do you use this kind of cable:
    3570023110-30543-149x149xA.jpg

    Or this kind of cable:
    slika-1328724-56dd328280f6d-default.jpg

    when electricity is coming into your house/home? Or is it some other kind of wire/cable?
     
  5. Jul 29, 2016 #45

    gtae07

    gtae07

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    It would look something like this: 00377833.jpg

    Or are you asking how many conductors it would have?
     
  6. Jul 29, 2016 #46

    DangerZone

    DangerZone

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    Thanks, Gtae007, this makes it clearer now.

    Ok, do you have a grounded transformer like we do in Europe, that distributes cables (previously pictured) through earth/ground/walls/buildings:
    LMTS.jpg

    ...to your home/house electric panel, with fuses and connectors:
    img_3352-75901.jpg

    Or do these wires you posted a link to come from an old pole and a can-like small transformer, something looking like this (pic found on wikipedia):
    ae18a02e749733677455344d72631069.jpg

    And then it comes to a fuse box or electric panel, and if you have a power failure then there are people who come to climb on the pole like this:
    15470.jpg

    Could someone post a picture what does your home electric fuse box or electric panel look like?

    I tried to google this up, but it seems there are quite a few different grids in the USA, with different systems. It seems it is similar to Europe differences where Britain has one system, Baltic countries another, Scandinavian a third system and continental Europe another universal system.
    565px-ElectricityUCTE.svg.png

    This would certainly complicate electric quick charging of aircraft or cars/vehicles.
     
  7. Jul 29, 2016 #47

    DangerZone

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    Yes, that's also what I was asking. And how thick they are in diameter?
     
  8. Jul 29, 2016 #48

    BBerson

    BBerson

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    It is aluminum 4/0. About 1/2" conductor.
    Two black hot wires and one neutral.
    In the circuit load center, using one black and the neutral gives 120 volt single phase.
    Using both blacks would be 240 volt single phase.

    Three phase is 440 volt, I think, and not used in homes here. Not in very many small business either, the cost for installation isn't worth it.
    image.jpg
     
  9. Jul 30, 2016 #49

    annerajb

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    BTW Cost of installation varies thought.
    I been looking at this and utility supplies three phase transformer/service cheaply but depending on how far away you are from the transformer you have to pay either the underground digging or utility pole if you didn't have pole into the site or building.

    If you have a utility pole with 3 13.5KV power lines phases nearby they can just install one more transformer to provide you with three phase service.

    But yeah in summary US residential/most hangars can get 80amps - 100 amps for 5 hour charging.
    Airports that are not on a really rural area should also get from the utility three phase service depending on the utility they pay for the transformer you just pay for underground digging and concrete pouring for pad of transformer.
     
  10. Jul 30, 2016 #50

    BJC

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    Cables are not typical for above-ground service drops. What is used for above ground, is a bare twisted wire wrapper with two insulated wires.


    BJC
     
  11. Jul 30, 2016 #51

    DangerZone

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    Thanks for the pic, it is much clearer now. Gtae07 was right and so were others, this is a monophase cable and not three-phase cable coming from the transformer. What power limitations do users have, what are the main fuses per line, and at what load does the voltage drop below practical for continuous use?

    A typical limitation in Europe would be a 50A main fuse which is at 240V a 12kW max continuous output. During winter when electric heating is on, washing and drier active plus a TIG welding machine is run, the voltage drops in neighboring homes from 240V down to 218V to 220V, and 220V is guaranteed by the grid. Houses which need more power use both three-phase and monophase but the price is slightly higher, specially if one has a 100kW limitation which is needed to quick charge a Tesla S. Tesla S battery pack is nominally 85kW (it is around 78kW in real life), so quick charging requires a higher power limitation. A typical 12kW limitation household could thus not charge Tesla S but would need to spread the charging period over night for eight to ten hours, depending on how much other appliances are connected to the household terminals (sockets). If more electricity is consumed for heating or other machines, then the Tesla S might not even be charged fully till morning.

    Now, those aluminum wires from the pic look serious if they are half an inch of conductor. They seem to be aluminum so resistance would be slightly higher if more than 100A would be passed through them, this would heat the wires to above 60°C and cause a voltage drop. In other words, it would be very hard to pull more than 12kW/h of power through. Charging a Tesla S with a quick charger would be problematic without some more powerful wiring, but slow charging (like overnight) would be entirely possible.

    To get back on topic, the battery pack of the thread's electric aircraft is charged at 50A in a stable 240V grid. With the voltage drop and slightly higher resistance this would mean max 10kW/h for ten hours, so a 100kW/h battery pack. Quick charging this battery pack would be impossible at home or in tyšical households without three-phase electricty, so charging overnight or at a charging facility (an electric hangar?) would be the only practical solutions. And this much of electricty with the C-172 drag would come to two hours of flying tops. At 90 kts an hour cruise speed, this does not mean a lot of fun without a range extender. Even the 4 hours we can fly with the C-172 is not satisfactory, at least not to those who love to spend the weekends flying cross country.

    Ok guys, off the internet cause I gotta go flying, have fun.
     
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