gasax wrote:
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"Electricity has no future in aircraft until the storage issue is sorted. The shear energy density of combustible fuels is orders of magnitude greater than the best (read very very expensive) storage solution we current have.
Specialist airframes - such a self launching gliders - can use what we presently have - until the cells get old and then their replacement costs make overhauling a Lycon seem like small change.
It all looks a very long way off unless there is a major break through in storage technology.
As for converting a Cessna 172? Why on earth would you pick that airframe for a technology which is challenged on payload, endurance and power?"
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I have an electric-powered modification on order for my glider.
Battery life is estimated as 1000 recharges before they deteriorate to 80 percent capacity. Say 100 per year for 10 years. I don't know the future cost of replacement batteries, but say £10,000 in 2021. So I am calling each use of the batteries as costing £10 per flight on which they are used. Not unreasonable. Electricirty recharge cost is negligible by comparison – but say £1 for a 1-hour usage.
Other marginal costs of flying with the FES (Front Electrical sustainer) include higher insurance and maybe some maintenance costs, but I doubt it comes to another £9 per hour of use, so my total “powered” cost is probably going to be below £20 per hour.
Previously, it was an unpowered pure glider, so this is all extra. If I were taking out an IC engine and replacing it with electric, it would be closer to a breakeven – maybe even cheaper, but I will never know.
For heavier aircraft and/or needing more endurance, I would agree that it needs a leap in storage technology. I have no idea how practical that is – but history suggests that tech improvements in future are unforeseeable, though they eventually yield increases of hundreds, or even thousands, of percent in performance.
Chris N.