Primarily for general aviation discussion, but other aviation topics are also welcome.
#1883863
155 Wh/kg to be precise, I think because the Energy Storage SYSTEM includes ( as well as the cells) such things as enclosure,interconnects, BMS,cooling system, thermal event management etc. etc. This project has been managed in the most competent and professional manner. For anyone who missed it or wants to review, the excellent presentation of the project by the flight test engineer is here.
https://attendee.gotowebinar.com/reco.. ... 7172899344
#1883881
Hey Genghis

Not an apple for apples comparison as the E-NXT has a structural battery case and some other features that the other quoted systems do not. At an equivalent level ACCEL is also at 200Wh/kg which is no surprise given that it is the same cell as the Pipistrel.

If you PM me your email address I can send you the public presentations on the design. Any questions, happy to clarify.
#1883882
Genghis the Engineer wrote:That's about 150Wh/kg.

About equivalent to most vehicle battery systems, somewhat poorer than the Geiger and Pipistrel battery systems in energy density which are closer to 200 Wh/kg. I imagine it's relatively weight inefficient because it's designed to be very power efficient.

G


Hey Genghis

Not an apple for apples comparison as the E-NXT has a structural battery case (which is a real beast as it's doing a lot of work!) and some other features that the other quoted systems do not. At an equivalent level ACCEL is also at 200Wh/kg which is no surprise given that it is the same cell as the Pipistrel.

If you PM me your email address I can send you the public presentations on the design. Any questions, happy to clarify.
#1884327
Still doesn't add up; 100hp for an hour 475Kgs for a battery pack or 28Kgs for petrol.
B777 roughly 100,000 hp (90,000 ftlbs thrust) ,475,000kgs for 1 hour's worth of battery life.
Its Max Take off weight ........300,000kgs.

The only people who could possibly think batteries are the solution are Lithium miners.
#1884425
Flyingfemme wrote:Money, contacts, infrastructure, experience, personnel.

Mature supply chain, publicity.

That's what RR get out of this, but I really wouldn't underestimate the very considerable Rolls Royce expert and skilled input that made this possible. The did vastly more than just buy in a kitplane and put some batteries and motors in it.

G
kanga liked this
By johnm
FLYER Club Member  FLYER Club Member
#1884427
This is an interesting experiment in some ways and might allow a little prestige and publicity and historically that's what the UK has been good at.

Moving stuff into a practical commercial and large scale commodity production line less so, which is why participation in Airbus was so great.
kanga liked this
#1884429
Whilst this is very cool the limits of lithium based battery tech does seem to be the elephant in the room here.

Petrol = 46MJ/kg = 12.78kWh/kg

Efficiency of a aero piston engine is circa 33% , so the effective efficiency is 4.26 kWh/kg this is 21 times higher than the 200W/kg figures quoted here.

If you do the same calculation for Jet A1/High Bypass ratio Turbofans the ratio is even higher.

Putting a 5-700 Kg battery in a car in place of 40-50 liters of petrol works. The same cant be said of many aircraft.

I am not trying to say we should continue guzzling 100LL forever, but I think we really need to look at other alternatives, hydrogen for instance? It certainly has the energy density required......
#1884435
Genghis the Engineer wrote:That's what RR get out of this, but I really wouldn't underestimate the very considerable Rolls Royce expert and skilled input that made this possible. The did vastly more than just buy in a kitplane and put some batteries and motors in it.

G

Let's not airbrush Roger out of this. It's been his baby for as long as I can remember, although the original aim was not to break a speed record - he had other ambitions.
kanga liked this
#1884438
neilld wrote:Nice video here:


Very slick. But ....

I am sure the rights-free music is absolutely lovely and I am sure the editor and producer sat back and rubbed their hands saying "Beautiful"

But I wanted to hear the bloody aeroplane and I couldn't. If I want to listen to music I can go to Spotify. They totally missed the point. Bloody creatives. :evil:

Rob P