Helios are way cool. Decades ago, I was lucky enough to get 100 hrs in an HT-295...a converted Army U-10D. That was a very rare bird, which was converted as a tricycle gear airplane. It lost some of its versatility (max demo cross-wind of just 8 knots!), but the STOL capability was definitely still there. At MGTOW, that critter would clear a 50 ft obstacle from a standing start in 630 ft. Power was a 295 hp Lycoming GO-480, with the prop turning about 2200 RPM and the crankshaft turning at 3400 RPM. 30 years later, I still miss that airplane. It was one of the two coolest types I have ever flown...the other was a Lake Amphibian.
/Kevin