Originally Posted by
Lord Lucan
perhaps there would be a possibility of recovering some of the energy used in the climb by using a windmilling fan to charge the battery during the descent
There would be loss of efficiency by doing this and in any case there would no need to keep the engines turning during descent. It might be more efficient to house the engines in the wing à la B2 and use conformal blocker doors to cover over the wing intake during descent and basically to glide from cruising altitude to somewhere between 5 an 10 thousand feet. I am sure there are a million and one different considerations to be taken into account regarding design not least fan diameter etc but personally I fail to see pure electric propulsion being used for anything other than an ATR sized aircraft on regional operations.