lolachampcar
Well-Known Member
until the economics for hydrocarbon transport get much much worse..............................
You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
until the economics for hydrocarbon transport get much much worse..............................
For eVTOLs it's on a similar scale as a semi truck, at the low end of the Megawatt Charging System specifications, so definitely not an issue.How large of a power plant would you need to charge multiple aircraft at once? Range loss in winter
Of course, as long as it is a clean sheet design rather than a retrofit or incorrectly sized aircraft.Would the aircraft be able to carry the same weight load as a AV gas or jet fuel A/C?
As stated, Lilium continues to expand the flight envelope for their aircraft. They posted a video yesterday with it flying at 130 kph (70 kts compared to 45 kts in the previous video). At 1:35 in this latest video, the ducted fans are simply providing horizontal thrust with the wing being the sole source of vertical lift. As it slows down, the fans/motors transition back from providing horizontal thrust to only providing vertical thrust.I wouldn't call them turbines, but rather ducted fans, but yes, that's the setup of the Lilium. Ducted Fan refers to the layout of the propeller, while turbine refers to how it converts stored energy into useful work.
Similar to something like a Harrier Jump Jet, the Lilium directs all airflow from the motors straight down to hover. As it increases airspeed, the wings start generating lift, so the airflow from the motors can be directed to the rear to provide more thrust and less direct lift. As it slows down past the normal stall speed for the wing's airfoil, the "exhaust" again needs to be directed down to keep the aircraft from falling. Edit: in the video, you can see the motors start out pointing almost vertical and then at 45 kts, they are angled at maybe about 45 degrees. As they expand the flight envelope in their flight testing into even higher airspeeds, you'll likely see the motors angle back to almost straight horizontal.
A turbine, particularly in the aviation industry, refers to a gas turbine engine that typically burns Jet A fuel. The turbine is the core of the engine that burns fuel and produces thrust and/or rotation. You can have a gas turbine engine built in several different styles: turboshaft (common on all but the smallest helicopters), turbojet, turbofan, turboprop.
It's actually a pretty good overview with nicely presented charts, I did not find anything in there that needs debunking.Has this been debunked already?
The main problem with batteries is, landing weight is the same as take-off weight.
Which means EV planes should weigh close to the weight of an ICE plane with empty tanks. I am not even sure today we are anywhere close to that in terms of gravimetric density for even the highest energy density LiOn battery with Co & Ni.
What are you talking about? All the airplanes I have flown are designed to land with a full tank.
Or look up any regional turboprop specifications, maximum landing weight is generally very close to maximum takeoff weight. As in 95% full tank.
That is correct, as an Aerospace Engineer that has certified multiple platforms and systems that are directly applicable to this, we always end up certifying max landing weight very close to max TO weight except with special conditions. It's not as efficient really because the lighter an aircraft gets through it's flight plan the lower AOA needed to maintain lift and therefor the CoD reduced make for more efficient flying, but it can be accounted for just fine.
No, the 737 series does not have a fuel dump. It has to burn off excess fuel by flying circles, ditto for the A320 series. The max TO weight exceeding max landing weight is indeed an issue for quite a few commonly used civil aircraft. Electric aircraft can't avoid this issue, which in turn means structure need to be designed at-birth for the max anticipated future stretched version.Isn’t that one of the reasons they do a fuel dump if an aircraft for unforeseen reason has to land right after take off? (besides the risk of fire if it crashes)
Above is corollary to fundamental issue: energy density of a battery is a tiny fraction to the energy a pound of Jet A has.I disagree with the statement that "The main problem with batteries is, landing weight is the same as take-off weight." I think the main problem is overall weight.
"I believe that the laws of physics are here for our guidance, and should be followed whenever possible." - Garrison KeillorAbove is corollary to fundamental issue: energy density of a battery is a tiny fraction to the energy a pound of Jet A has.
It is the Law of God (aka, Physics)