What is the endurance and how long does it take to recharge?
According to this, the endurance at “WOT” (or whatever it is called for an electric airplane) is 15.20 minutes. 15 minutes is 900s. 900/76 = 11.8 So theoretically it can do 10-15 tows up to 600m on one charge, assuming it did that tow at WOT. On one day, around 20 tows is normally max (unless every single glider is used for landing practice). Already this aircraft will be a capable tow aircraft for one day with just one one charge.
The Extra 330EL is just a test bed for the motor, and using that engine in a more efficient airframe for towing could probably increase the efficiency considerably.
For a glider tow application, I would think it’s better to make a system that changes batteries fast (every 10 tows for instance), like a cartridge thing or something, rather than having one huge battery.
Put engine in a Eurofox, which seems to be a successful modern tow plane? Problem might be power supply to gliding club for charging, if site is not urban. Normal 13 amp supply possibly slow?
The battery in the Extra is smaller than the battery in my eUp. It takes about 8 hours from flat to max on 8 amp. 15-20 minutes on a fast charger.
The empty weight of your e-Up is probably higher than the MTOW of the Extra…
But your point stays – charging times for batteries are largely a problem of the past in car applications if you can make the return trip in one charge, or if you have the ability to charge at your destination. Fast-charging to 80%-90% is very quick these days, only the final 10% take long. In actual life, manufacturers appear to declare a lower than chemical capacity of the battery, and hence can charge to “100%” very fast, and also “100%” stays the same for longer as the battery ages. They can’t beat physics and chemistry, but they can beat psychology – the 10% hardly matter.
They got a model flying…
You have to think about some of the implications surrounding the availability of batteries with the energy density of petrol….
Firstly, aviation would be a long way down the list of paradigm shifting applications for this new battery. For instance, appliances might come ‘powered for life’ with internal energy, rendering much of the electrical grid redundant (apart from where it’s used to recharge cars and aeroplanes). And robots might at last be doing the housework.
Jet engines would be curious antiques, with turbofans powered by directly heating the air like giant fan heaters.
But there’s something else. These energy densities in a device that does not need oxygen in order to combust are far beyond the yield of conventional weapons technology. I’m not talking about the accidental explosions of electric cars that could take out whole streets, but devices deliberately made to instantly liberate all their stored energy on command. Not just IED’s, but terrifying new types of weapon on every street corner.
There’s a case for hoping that the electric car (and sadly aeroplane) are forever hobbled by low energy density. Long live petrol, a fuel so safe that you could bathe in it.
The Lilium Jet has flown
I always laugh at the zero-emission claims because the electricity has to be generated somewhere and short of using nuclear (which is not politically correct in many places) it tends to mean you just dump the acid rain on the country which is downwind from yours.
Peter wrote:
the electricity has to be generated somewhere and short of using nuclear (which is not politically correct in many places) it tends to mean you just dump the acid rain on the country which is downwind from yours.
Peter I don’t know if you have seen the latest news out of the energy sector – probably you do not follow it closely; and fair enough the UK is somewhat lagging in the sector. However, things are a-changing:
As a matter of fact most European energy operators are phasing out coal:
Peter wrote:
I always laugh at the zero-emission claims because the electricity has to be generated somewhere and short of using nuclear (which is not politically correct in many places) it tends to mean you just dump the acid rain on the country which is downwind from yours.
Norway: 100% hydropower. Sweden: 40-50% hydro, 40-50% nuclear + wind, France: 80-90% nuclear, 10-20% hydro etc All zero emission. Then we have Germany, Poland, UK and a few others that think coal and gas is cool 
Zero emission means zero emission lots of places. That some countries use coal instead of nuclear/solar/wind/hydro is their choice. Why is it politically correct to use nuclear in France and not in Germany? What makes it politically correct for Germany+Poland to be the number one polluters in Europe? I have no idea.
Electrical propulsion for all vehicles will come no matter what, not because of politics, but economics. The whole energy industry is going through a change right now that will completely change it for all future. Electric vehicles is just one small part of it.
