As I veg here for a bit on a snowy Sunday (I swear I'll get outside and do some projects in a bit ) I figured a few of you car guys might also ponder the following videos...
Fast-forward to 1:00 to avoid the 1991-tastic intro graphics and music...
I'm certainly hopeful that jet technology has improved since the '80s, but the idea of unducted fan blades pushing more air from around the nacelle off of the same fuel consumption seems to make a lot of sense to me. The GE engine featured in this video has the exterior, unshrouded "props" being driven off of internal hot-side engine compression...in effect, it's like a turbocharger where the hot exhaust gases spin an additional wheel for more air movement.
Back when the video was made, they spoke of $0.50/gal fuel:wtf::no:!!! I'm pretty sure we've seen $8/gal for JetA at OSU Airport, and 100LL for general aviation Cessnas is still around $5-$6+/gal consistently. Can someone tell me why this technology never took off? (pun intended )
Another thought...as energy storage (battery) technology improves and becomes more reliable, I'd love to see a hybrid jet/electric fan system on planes where a jet-fueled engine could be used for take-off and acceleration, and electric ducted fans could then be used for cruising. In power-off situations, the fans can also be used as regenerative motors to recharge onboard batteries. I'd imagine the fuel savings would easily be 33-40%, though you would have to amortize the cost of the battery/electric fan technology over a long time for that to break even.
We live in a pretty marvelous time...considering airplane tech hasn't changed dramatically since the '50s - some Cessna designs still date back to post-WWII era, and you can look at Convair jetliners from 1958 and easily see similarities to modern passenger jets - but technology and propulsion is on the cusp of making some pretty major leaps. Looking forward to what the future has in store!