Menu Sign In Contact FAQ
Banner
Welcome to our forums

Double battery capacity in 2017

GA could build their own power electronics. Or do the sensible thing and buy from the automobile industry.

I somehow expect due to reduced engine weight / cost (it being mostly on the batteries), we might see more multi engines (suddently making a 4 or more engined plane doesn’t seem such a hassle, and the more engines the less excess power each needs to have to be able to maintain flight with 1 inop

OK, maybe I exaggerate a tiny bit, but the main point is much higher reliability and much less maintenance (none in practical terms, unless people start modifying stuff which they for sure will with microlights and experimentals; more power, better efficiency etc).

The elephant is the circulation
ENVA ENOP ENMO, Norway

LeSving wrote:

Also the technical aspects are important. A 350 hp Lycoming has 3-400 moving parts, an electric drive has one single moving part. The MTBF will be in the millions of hours (TBO becomes irrelevant, non existing), the maintenance costs will be close to zero.

To amplify what Peter already said, I wouldn’t overstate this too much.

Power electronics (and this will be serious power electronics) do have the potential for spectacularly catastrophic failure. While it can be made more reliable than a piston engine without a doubt, MTBF of millions of hours is unlikely. Just in the RC world we’ve seen Castle Creations (maker of ESCs for brushless motor powered RC planes and helicopters) get called “Castle Cremations” by many because they had a problem with their ESCs catching fire. Castle Creations is basically cottage industry, their factory is a small industrial unit where their ESCs are basically hand assembled. This will be even more so for GA power electronics – the market is tiny. Even in the case of mass market where highly consistent parts are put out in high volume by a factory – I had a high quality 1kW PC power supply go with a tremendous bang just a few months ago: one second working fine – the next second let’s say there was a “loud report” and the main house breaker tripped (a power transistor in the power supply had detonated).

I think that an electronic propulsion system can be made very reliable, but MTBF in millions of hours in GA – probably not.

Andreas IOM

Peter wrote:

Aviation (GA) electronics has a very poor history, which is why there is so much resistance

I see what you did there :-)

Andreas IOM

Peter wrote:

Then, when you have that sorted, move into Marketing.

Interestingly if you look at the article in the main body it says " just as safe", but in the picture it says “safest”… clever marketing as the picture will be shared and most people won’t bother reading the text?

Western life is so dependent on batteries that we can expect more improvements such as these… more than welcome. More from a convenience point of view; as the environmental impact is not as large as some have you believe.

an electric drive has one single moving part. The MTBF will be in the millions of hours (TBO becomes irrelevant, non existing), the maintenance costs will be close to zero.

You should get into electronics

Then, when you have that sorted, move into Marketing.

Most electronic devices have zero moving parts, therefore they must have an “MTBF in the millions of hours”…………….. What a ridiculous assumption. Have you heard of thermal cycling, for example?

Aviation (GA) electronics has a very poor history, which is why there is so much resistance (outside the homebuilding community) to e.g. electronic ignition. In the car business they build vast numbers and they get it right. GA avionics is often designed and built in spare bedrooms (might as well be). See the thread on avionics internals.

Administrator
Shoreham EGKA, United Kingdom

Cobalt wrote:

So after deterioration of the battery to around 75% of the original capacity, you have 10% the effective energy density of gasoline.

But that’s not nearly the whole story. You have to have an engine and a propeller as well. The 260 kW (350 hp) Siemens aero engine weighs 50 kg. A comparable Lycoming weighs about 250. This is 200 kg of batteries right there, or about 100 kWh (100 kW for one hour endurance). The motor is free of vibrations, less structure, you can optimize the RPM with no gearbox. It’s smaller, less drag. Requires very little cooling, very little cooling drag.

Also the technical aspects are important. A 350 hp Lycoming has 3-400 moving parts, an electric drive has one single moving part. The MTBF will be in the millions of hours (TBO becomes irrelevant, non existing), the maintenance costs will be close to zero.

The elephant is the circulation
ENVA ENOP ENMO, Norway

@what_next

13%-14% of the effective energy density of gasoline …


But the engergy of gasoline is transformed to motive power with an efficiency of 30 percent and less, whereas electrical power achieves almost 100%. So we are now approching 1/2 of the energy density of gasoline already

Taken into account – hence effective energy density – I assumed 30% of the gasoline ends up in engine output, compared to 100% in an electrical aircraft. Both are a (slight) over-estimate.

Cobalt wrote:


Probably going down to 10% as they age over many recharge cycles.

Why should that be? Going down by 10% maybe. My iPad is now almost 5 years old, recharged 4 to 5 times per week. It still holds about 80% of it’s original capacity.

From 13% to 10% is a reduction of 24%, sorry for percentages-on-percentages. So after deterioration of the battery to around 75% of the original capacity, you have 10% the effective energy density of gasoline.

Biggin Hill

@alioth those powered gliders are certified reality for over a decade now: http://www.lange-aviation.com and other manufacturers have electric gliders in their portfolio, too.

mh
Aufwind GmbH
EKPB, Germany
19 Posts
Sign in to add your message

Back to Top