mzso wrote: ↑22 Feb 2021, 10:30
.....And how is that better than having the motor on a gas turbine's shaft? Which produces energy continuously at an ideal speed, rather than cyclically with high vibration and dead points with zero speed? (Or even rotary engines)
well ......
(regardless of prime mover type) many advocate .......
wholly-electric drive ..... combined with much more braking regen ....
so a MUCH higher peak power than the present 160 hp MGUK - ie about 1000 peak hp
but they expect this 1000 peak hp system to have a fixed relationship with the wheels (ie no 8 speed gearbox)
the cars leaving the grid or slow corners pulling 'one gear' over a 0 - 222 mph range and starting regen at 222 mph !!
that is inherently far from ideal on the electrical side
(the present 8 speed gearbox is a big help in keeping the electrical side closer to the ideal)
btw otoh and fwiw
turbofans that are c.60% efficient in cruise are 'on-design' .....
cruising at high speed and high altitude ie thin cold air and plenty of ram compression ..... and ....
huge - and have active control of blade lengths to keep clearances near zero
but 60% sounds like supersonic cruise aka 'supercruise' (Concorde or F-22 style - somewhat supersonic without reheat)
and there's thermal/thermodynamic efficiency, this factored by inertial efficiency ie propulsive efficiency
turboprops factoring for propulsive efficiency is clearer
gas turbine propulsive efficiency factoring is done by a gearbox