New electric motor 50Kgs 260KW

[Downunder]

RC electric aircraft are seriously lighter (1/3rd to 1/2) than the combustion engine equivalent simply because of the smoother loading and no vibration.

 

Of course this would translate into fullsize aircraft in the same way.

 

 

[SDQDI]

RC electric aircraft are seriously lighter (1/3rd to 1/2) than the combustion engine equivalent simply because of the smoother loading and no vibration.Of course this would translate into fullsize aircraft in the same way.

And the fact that no one is actually in them so the odd structural failure isn't too bad:wink:. But seriously the rc scene seem at times to be a lot more technically advanced than their bigger cousins I guess maybe because it is cheaper to do it at that scale.

 

 

[kasper]

Hmmm was that an ultracapacitor (Canadian) or the sacrificial aluminium/air 'batteries' that are really single life fuel cells (aluminium + electrolyte (water) + oxygen = electricity + aluminium hydroxide)?The ultra capacitors have been hyped and sold as just around the corner for decades while the aluminium/air battery/fuel cell has a shorter history ... but from a 'green' perspective the power that went into the aluminium to produce the battery/fuel cell and the fact its not rechargable makes it quite un-green at the moment ... though the aluminium hydroxide is able to be reprocessed into aluminium again ... but with the same high energy input that was needed to create it in the first place.

Ok - it is not an ultracapacitor its a genuine graphite/aluminium battery:

http://www.nature.com/nature/journal/v520/n7547/full/nature14340.html

 

And if the claimed recharge rate is achievable (under 60 sec) then this is a nice looking line of battery research that may work well in vehicles - cars or planes.

 

Long way off being commercialized but really interesting to read.

 

 

[Guernsey]

No wood or fabric?, Aluminium Burns brighter than a Hindenburg (Luftschiff Zeppelin #129; Registration: D-LZ 129),The English found this out in the Falcons war.

Were these Falcons at war with each other whilst flying over the Falklands? .

 

 

[Marty_d]

No, Falcons have always been at war with Commodores. Mind you there may have been a Commodore at the Falklands, or perhaps just an Admiral.

 

 

[Thalass]

Well I can get an off the shelf direct drive electric motor in the 447 power range (30kw peak, 25 continuous) with controller for under 10kg ... its just the batteries that stump me ... price n weight ... oh and the personally required parachute just in case the LiPos go a little 'fire happy' in the air :-/If it were not for the fact that I already have the F23 and the cost of the batteries/motor are so high I would be happy to give the old sapphire another make-over and turn her electric instead of just moving from 28hp to the 50 of the F23 conversion.

 

As its a 95.10 low weight thick wing sapphire (just under 135kg with 28hp engine) it both has the lift to fly on really modest power and the depth within the wing to put the batteries but I just can't justify the spend so the electric sapphire is sitting in system drawings and specs with costings ... maybe one day.

They've got a lower power density, but LiFePO4 cells are much more stable, even in a crash, and last 5000+ cycles instead of 500ish for lipo (or whatever it is)

But for future-tech I'm really excited about these cells: https://news.stanford.edu/news/2015/march/aluminum-ion-battery-033115.html

 

 

[kasper]

They've got a lower power density, but LiFePO4 cells are much more stable, even in a crash, and last 5000+ cycles instead of 500ish for lipo (or whatever it is)But for future-tech I'm really excited about these cells: https://news.stanford.edu/news/2015/march/aluminum-ion-battery-033115.html

Agreed, but lets face it the quoted cycles are not real or base lined - they are often related to a certain % of total loss in capacity to hold charge ... and not even then is there a specific % generally used or tested to allwo consistency. On a very small scale this can be seen in mobile phone batteries - iphone batteries s are supposed to not last nearly as long as they do in fact last and the degraded charge capabilities is not noticable to most users ... my iphone is coming up for 5 years and there is not a noticeable battery issue

The real stumbling block to use of battery power is recharge time - the new pipistrel battery plane is running an hours flight time and addressed recharge time by having short time swapout of battery packs. The real improvement will come with a fast recharge battery - the aluminium graphite battery claims a 60 second recharge cycle without thermal or chemical issues ie it does not become damaged by fast recharge nor does it have heat issues on recharge and its energy density on the test cells written up in Nature is not fantastic the possibility of building a couple of hours flight time of batteries into the airframe and recharging faster than you can pour petrol into the tanks would be a game changer.

 

If I could get that sort of recharge time on a system that has a system life cost (electric + allocation of battery costs) that was even equal to the current two stroke petrol engines then I would jump at it and go. I just can't get that ... yet. The engines are there, its the batteries that are still coming along.

 

 

[Thalass]

Agreed, but lets face it the quoted cycles are not real or base lined - they are often related to a certain % of total loss in capacity to hold charge ... and not even then is there a specific % generally used or tested to allwo consistency. On a very small scale this can be seen in mobile phone batteries - iphone batteries s are supposed to not last nearly as long as they do in fact last and the degraded charge capabilities is not noticable to most users ... my iphone is coming up for 5 years and there is not a noticeable battery issueThe real stumbling block to use of battery power is recharge time - the new pipistrel battery plane is running an hours flight time and addressed recharge time by having short time swapout of battery packs. The real improvement will come with a fast recharge battery - the aluminium graphite battery claims a 60 second recharge cycle without thermal or chemical issues ie it does not become damaged by fast recharge nor does it have heat issues on recharge and its energy density on the test cells written up in Nature is not fantastic the possibility of building a couple of hours flight time of batteries into the airframe and recharging faster than you can pour petrol into the tanks would be a game changer.

 

If I could get that sort of recharge time on a system that has a system life cost (electric + allocation of battery costs) that was even equal to the current two stroke petrol engines then I would jump at it and go. I just can't get that ... yet. The engines are there, its the batteries that are still coming along.

As an airline guy I would be happy with a Metroliner replacement with battery packs in the nacelles that can be swapped out in 20 minutes. But for a private operator going cross country that's hardly practical. You'd need a Tesla style Supercharger, and the willingness to accept the possible (?) reduced cycle life it might bring.

 

 

[Marty_d]

If that article is correct then it sounds like they're on a winner. The fast charge would be a game changer as you say Kasper. I like the fact that they're flexible too - curved batteries that bolt onto sockets on the leading edge sounds good...

 

 

[SDQDI]

It would be awesome especially if you could regenerate enough power in a 60 second dive to fully recharge every hour or two.

 

 

[Marty_d]

Now they just have to make them out of the right grade of aluminium, so they can be incorporated as stuctural members in the airframe...

 

 

[Thalass]

There is one disadvantage of electric aircraft: In a conventional aircraft the MTOW is normally higher than the max landing weight. The designers save weight by reducing the strength of the airframe - safe in the knowledge that 99% of the time the aircraft will land after burning many tons of fuel. An electric aircraft will weigh the same on landing as it did on takeoff.

 

With a stronger airframe this wouldn't be a problem, but that means a heavier airframe and so less payload.

 

 

[kasper]

There is one disadvantage of electric aircraft: In a conventional aircraft the MTOW is normally higher than the max landing weight. The designers save weight by reducing the strength of the airframe - safe in the knowledge that 99% of the time the aircraft will land after burning many tons of fuel. An electric aircraft will weigh the same on landing as it did on takeoff.With a stronger airframe this wouldn't be a problem, but that means a heavier airframe and so less payload.

Counter to that is that the airframe (unless converted from internal combusion engine) need not be as strong in the area of the engine mounts etc as the vibrational carry-ones of the internal combusion engine are missing as is the mass of the engine itself. All in agreed that the MTOW = landing mass with electric BUT ultralights are all able to meet this already as are most light aircraft I know of. The area of lower landing weight really only kicks in in large aircraft ... at the rec aviation end of the field its not a big issue and pure electric from design should allow distributed load of battery and lower engine mass - allowing lower aircraft mass overall

 

 

[Marty_d]

Besides which, for any given takeoff in a small aircraft you would assume that there's at least a chance you're going to be landing with almost the same amount of fuel you took off with.

 

Plus the plumbing is a lot simpler.

 

 

[facthunter]

Engine mounts are designed basically relating to engine weight relating to manoeuver loads. (pick your figure) This is a much higher figure than vibration allowances might require if they could be evaluated easily They certainly affect component life where fatigue is a consideration, particularly high frequency vibrations.

 

Carrying engines and fuel in the wings enables a lighter structure. Nev

 

 

[kasper]

Engine mounts are designed basically relating to engine weight relating to manoeuver loads. (pick your figure) This is a much higher figure than vibration allowances might require if they could be evaluated easily They certainly affect component life where fatigue is a consideration, particularly high frequency vibrations.Carrying engines and fuel in the wings enables a lighter structure. Nev

maybe so but take a look through BCARS and you will find load factors in teh design test requirements that are related to the number of power pulses per revolution of the engine ... factually you may be thinking along the is it going to shake itself to bits BUT when you do the load tests on the structure IF you are certifying it then you are up against power pulses ... similar applied the JAR reqs.

 

 

[facthunter]

This has more complexity than we can go into here. As I understand it there isn't a formula used on our type of designs. going from memory on Bill Whitneys material, that goes into the pulses. I don't believe they are of a high order without harmonics happening. Gyroscopic loads On C-180's doing quick turns on the ground were breaking crankshafts over time caused by the bending loads and fatigue imposed by the gyroscopic precession.

 

A single cylinder engine (there have been some) might impose some higher torsional "shakes" that require some consideration. IF you can allow the engine to move in it's mounts a fair bit you are only resisting something close to the torque figure for the engine, and the thrust.

 

IF you chuck part of a prop blade or get ice on it shedding unevenly it will shake enough to make the instruments unreadable. I'm sure those loads are way higher than anything caused by power pulses.Nev

 

 

[kasper]

OK but BCARS - or CAP 482 to give it its real name is very clear on what I noted:

 

"S 361

 

Engine torque

 

a) The engine mount and its supporting structure must be designed for the effects of:

 

1) The limit torque corresponding to take-off power and propeller speed, acting simultaneously with 75% of the limit loads from flight condition A of S 333 b)

 

[and including the effects of engine thrust where this is critical];

 

2) The limit torque corresponding to the maximum continuous power and propeller speed, acting simultaneously with the limit loads from flight condition A of

 

S333 b) [and including the effects of engine thrust where this is critical]

 

b) For conventional reciprocating engines with positive drive to the propeller, the limit torque to be accounted for in S 361 a) is obtained by multiplying the mean torque by the appropriate factor from the following tables:

 

 

NOTE: ‘Positive drive’ includes direct drive, gear drive or toothed belt; for other drives (e.g. centrifugal clutch) and unconventional engines the appropriate factor must be agreed with the CAA."

 

 

[facthunter]

They have a formula, and you just apply it if you want to pass their rules. They are like that. My point is torque and thrust are low order forces and no matter how you play with them won't be hard to cope with. I mentioned a single and their treatment of it is consistent with what you would expect. What actual forces are transmitted to the engine mount will depend a lot on the rubber mounting and it's ability to absorb shock. . Nev

 

 

[Thalass]

Damnit. Because of this thread I've been eyeballing the Fisher Flying Products range, and several of their planes can fly with a Hirth F-33 engine - Motenergy produce electric motors with similar weight and power outputs. Urge to build... rising...

 

 

[Marty_d]

I spent until midnight last night pulling rivets on the wing - bottom skins now riveted. Urge to build - fading, urge to finish - rising!

 

 

[Marty_d]

There was a good Catalyst program a couple of days ago - "Battery powered homes". Basically they were making the point that as battery technology gets better and cheaper (and it is) - millions of Australians will take up home batteries to use solar-sourced power at night.

 

Relating to possible future aircraft use, they interviewed professor Thomas Maschmeyer, who invented the gel-based Zinc Bromine battery. It's cheaper than Lithium, longer battery life, more efficient, charges in a fraction of the time and the gel layer is fire-retardant, so it's a lot safer.

 

Major construction companies such as Lend Lease are already considering future homes with pre-fabricated wall panels containing inbuilt Zinc Bromine batteries. My thoughts are that parts of an airframe, such as the steel cabin frame and main spar, could also have battery panels moulded into or onto them.

 

I was captivated by this show. Besides the implications for aircraft, we're already planning to upgrade the solar system and add batteries. Plus now there's technology which hooks into the constantly changing wholesale price of electricity and sells your excess power back to the grid when the prices are high, which maximises the financial return from your solar. (IF you have the right contract with your electricity company...)

 

There was another professor on who made the point that efficient battery backup is a game changer - wind and solar now CAN produce baseload power.

 

Coal and oil are dead, they just don't know it yet.

 

If you're interested the program can be found here: http://www.abc.net.au/catalyst/stories/4398364.htm

 

 

[facthunter]

The main reason the existing structure is fighting change is they will lose control over your power and the pricing of it. Centralised structured and privately owned corporations, mainly but not limited to, especially in a monopoly situation will charge what they can get away with. This can be water , power, garbage disposal sewerage food supply, milk, communications transport ANYTHING. Nev

 

 

[Old Koreelah]

Thanks for that Marty, I'll iView it.

 

Catalyst (and Towards/Beyond 2000 before it) used to be the highlights of our family week, but I rarely turn the teev on these days. I spent the last thirty years trying to convert people to the solar revolution (a lonely voice in the wilderness). At long last solar is going mainstream.

 

 

[Marty_d]

The main reason the existing structure is fighting change is they will lose control over your power and the pricing of it. Centralised structured and privately owned corporations, mainly but not limited to, especially in a monopoly situation will charge what they can get away with. This can be water , power, garbage disposal sewerage food supply, milk, communications transport ANYTHING. Nev

They also have to face the realities of changing markets and technology. The smart ones will get in front of the wave and change their business model to continue making money in a different way. The others - well, natural selection has the answer for them.

 

As an example they showed an entire suburb being built with community battery banks and solar on every house. The residents gain solar credits by the amount of electricity they send to the battery bank and then use those credits at night. If it's done well with sufficient storage then theoretically the entire community can remain off grid. As it can cost $20k or more to actually connect a new residence to the grid, for a community of 6000 homes plus shops/schools/services etc you can use that $120 MILLION saving to create a pretty good local grid. And the residents won't have any power bills.