Xanadrone
Well-Known Member
Yes, the latest LiFePo4 technology already allows a good "energetic density" at more abordable prices than the Li-Ion ones and without the risk of firecrackers - ex:
https://www.ev-power.eu/LiFePO4-special-cells/Lithium-Iron-LiFePO4-Battery-Cell-LFP-3-2V-72AH.html
That means 0,230 kWh for 1.75 kg weight and 90 USD (without taxes) - say 4 lbs per unit including connectors.
Practically speaking, for an [ultra]light E-experimental plane, a pack of 15 would assure 3,5 kWh at 48V (13S for RC-freaks) and a max. discharge rate of 360 amps (5C), weighting 27 kgs (60 lbs) and for "just" about 1.5K USD.
Two such packs (7 kWh, 54kgs/120lbs) methinks would be just fine for a small one place E-bimotor to fly one hour at 50-60% power - and even double for a glider-style aircraft with good L/D.
An unlimited number of other combinations would certainly be possible for those unhappy with just 14-15 kW onboard (18-20 HP), such as the use of only one pack for take-off E-power boost and/or emergency use, along with a small IC engine for the level flight. Or other hybrid/small generator solutions etc. etc.
Btw, the favourable evolution of battery tech seems to be accelerating, and this made me not only sketch, but also calculate a few versions of some viable, simple and most of all affordable E-microlight. One without cross-country attributes for sure (for the time being at least), but perfect for cheapo leisure flights because the +2,000 recharge cycles of the new LiFePo4's would compensate rapidly the batteries cost.
So, I'll be back soon with the final version (3-views + performance estimations) for your precious aid - meaning constructive criticism, with or without 437 posts about some wrong angle of the winglets - luckilly it doesn't have any. :gig:
Just a few words for now: I tried to imagine an even smaller Cri-Cri, in biplane form (Mitja would say... topspeedish-small at just 9 ft. 6 in. long), but also less complex, expensive and time-consuming to build.
...Woud it fly though, despite its span of 16 ft.? And how good? - This would be the major point of debate, being a real theoretical nightmare at a first glance (prone position of the pilot, sesquiplane, inverted V-tail... or sort of, electric and/or IC-propulsion etc. etc.)
P.S: The pilot in the scale-image is... sort of me also, being 30 years younger and - more important - 30 lbs lighter :gig: than the actual Me.
