Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Jetson One – Personal Electric Aerial Vehicle

jetsonaero.com

Post reply on HN
Print view View original

241–246 of 246 posts

Re: Jetson One – Personal Electric Aerial Vehicle

#241

Post by nradov »

mkl wrote: post #160
tdeck wrote: post #137

Earlier quoted context omitted.

This comment makes me wonder if something like this could be supplemented with human power to extend its flight range.

Not enough to be useful, I think. The Jetson One has a maximum power output of 88kW, and a very fit human (e.g. elite sprint cyclist) can briefly reach up to 2.5kW ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282832/#:~:tex... .).

Elite cyclists can only hit 2.5kW for a few seconds. Sustained output for about 20 minutes will only be in the 0.4kW range, and regular people can't even do half of that.

Re: Jetson One – Personal Electric Aerial Vehicle

#243

Post by [deleted] »

t0mas88 wrote: post #136
syntaxing wrote: post #15

Earlier quoted context omitted.

Because smaller prop means you need to spin faster to hit the same airflow. And efficiency usually drops by x^2 as a function of rotation velocity. Also, at high speed you have vacuum issues near the tip of the blade. Therefore, having four small rotors can easily be up to a magnitude less efficient than a helicopter.

Efficiency drops by "propeller" speed and then falls off a cliff when the prop tips go super sonic. So you really can't just make them bigger and spin faster.

[deleted]

Re: Jetson One – Personal Electric Aerial Vehicle

#244

Post by [deleted] »

t0mas88 wrote: post #148
hef19898 wrote: post #138

Earlier quoted context omitted.

That depends under which class the aircraft will be certified, depsite it being electric I could image that it falls under the ultra-light class (I'd have to look up the exact Name under EASA so).

EASA doesn't have rules for ultra- and microlight aircraft, they're only in national regulations. So then it depends on what the country you're in decides. But even if you're allowed to fly with only minutes of fuel reserve. The big question is whether you should want to. When you're in a more basic aircraft, that didn't go through all the certification requirements that other aircraft go through, it would not be a g…

[deleted]

Re: Jetson One – Personal Electric Aerial Vehicle

#245

Post by Spionbil »

gambiting wrote: post #145
namibj wrote: post #9

Earlier quoted context omitted.

At least small planes in europe (CS-23) aren't allowed to have humans within an (iirc ~15 degree) cone of them. This approach here seems to be done with no regards to such regulatory (and well-meant) requirements.

Sweden is very much "in Europe" and according to the company it's legal to fly it there.

From Unwind's Teknikens Värld link it seems to be mostly a technicality.

>Peter Ternström betonar att det egentligen är lagligt i Sverige också, eller snarare att det inte är olagligt, eftersom farkosten inte ingår i en klassificering.

Peter Ternström points out that it's actually legal in Sweden as well, or rather that it's not illegal, because the craft isn't part of any class rating.

Where the preceeding talks why they chose to sell to the US market first.

Re: Jetson One – Personal Electric Aerial Vehicle

#246

Post by Justin_K »

hwillis wrote: post #168
Jnr wrote: post #157

Lacks the safety features of airplanes (gliding) or helicopters (autorotation), has terrible rotor placement and small air time. I would advertise it as "your personal death machine". :) No amount of money would make me use that thing. EDIT: Ok, sorry, it says it has a parachute, but I still would not use it.

Electric motors can autorotate just fine: https://youtu.be/QADYnVeHQOQ You can't descend quite as slow as a normal engine because the motor has somewhat more friction at low RPM, even though it's similar to free-spinning at higher RPM. That makes for a rougher final approach but just as much glide distance and control. Small rotors will make it more of a hassle but should still be quite safe. Even if you do end up to…

You should look up auto rotate and variable pitch propellers
Post reply on HN