Again, this depends on where you fly. I fly out of Truckee usually, and a typical retrieve is from Carson City as I mentioned. It is only 20 miles away, but with a 4000 ft high ridge in between. 100% of the pilots flying cross country out of Truckee will have this problem eventually. It isn't dangerous - a perfectly good airport at Carson - but electric sustainers in their current state of development will not support that retrieve, but an ICE will. There are countless other similar examples in the Great Basin area of a "deep valley with limited exit" - and a good landing site at the bottom. If you don't fly over these, you don't fly in this area. That is not to say the electric isn't useful (and I didn't say that), just that it has limitations in some terrain that the ICE may not (as in the Alps example mentioned above).

On Tuesday, September 15, 2020 at 12:53:30 AM UTC-7, krasw wrote:
In order to climb out of deep valley with limited exit is problem that 99% of pilots will never have, and those 1% should reconsider another sport. This is not a problem meant to be solved with tiny engines.