Viewing profile — votingprawn

If you want to avoid doing the maths I think you can draw the problem out (assuming the world is a flat piece of paper and the source is located on the same piece of paper with you…

Its a mugin if anyone is interested (take the manufacturer specs with a handfull of salt) https://www.muginuav.com/product/mugin-5-pro-5000mm-super-la...

Doing some bistromaths on the stated hover performance. With a 231lb empty weight, 180lb rider, and 5 gallons of kerosene (ultra light version) you get 104kg + 81kg + 15 kg = 200kg…

Based on the spec I'm guessing it is an AMT Nike Five engines in the render, assume 1 is redundant: 705lbs to metric: 3134N. Divide by 4 = 784N which is _exactly_ the max thrust of…

Even if you disregard motor efficiency (which I don't, as with a battery powered vehicle you treasure every Wh more than you treasure every gram of fuel!), propeller efficiency is …

There would still be benefits to variable pitch propellers with an electric motor (motor efficiency, correct propeller pitch for the airspeed to name two). I work in the UAV indust…

I was a researcher at a reasonably big UK University until about 6 months ago, and I used SciHub fairly regularly. Sometimes I used it because we didn't have the right subscription…

That comparison only really holds if you ignore the stators, which the rotors are reacting against.

In the back of the van, parked up on the side of the runway at an airfield. We were flight testing a UAV and the data logging system that should have been finished weeks before....…

I believe those are the homemade "star dials" / motorised planispheres mentioned in the first comment.

Fair enough, no point trying to dispute a family anecdote!

They could do it back then too. If you dig past the internet comments and read some of the "primary source" books, the picture of the leaks is very different. I can't remember the …

I believe if you look for primary sources like pilots and ground handlers/mechanics you'll mostly find reference to small leaks (I think they were referred to as drips caught in co…

The SR-71 took off with a small fuel load to reduce stress and improve engine-out performance, that is why it was refuelled immediately after take-off. The mental image of it leaki…

I cashed out 20 bitcoins many years ago...and brought myself a nice graphics card with the proceeds. (i.e. $300) If I'd waited a few years longer I'd have been able to buy a house …

I reckon an RPi type camera would be perfectly sufficient to estimate speeds, probably to a higher accuracy than you ask. Edit: a quick search led me to this https://gregtinkers.wo…

I disagree with you regarding resolution and frame rates, I don't see why you would need a high speed camera. Something like a raspberry pi camera would be perfectly sufficient for…

I wonder if you could even use road markings or kerb stones as your calibration to save the effort of measuring things out. I'm admittedly rather unqualified in this area (I don't …

To give you a single perspective from the type of person who does occasionally sign up to "novelty" food subscriptions... I'm just not that in to candy. I'd pay $10/25 a month for …

Less efficient, generally speaking you want as few blades as possible. One in the ideal case but that's prohibitively difficult!

Those "power-free" landings require a collective pitch rotor system. The volocopter appears to be direct drive fixed pitch so it wouldn't be able to autorotate. It also presumably …

Whilst I like and appreciate the technology in the Model S, I too would struggle to class them as luxury along side the S class. I genuinely find the fit, finish, and comfort (cabi…

Its a somewhat common joke in our office that if you ask 3 researchers "What is lift?" you'll get 5 answers (and probably a bit of an argument). I think "It's complicated" and "Why…

> I'd be interested to see in this thread, who here has actually studied aeronautical engineering I studied Aerospace Engineering (PhD in Aerodynamics), and I stay out of internet …

Ah, so I guess it comes down to whether you consider the inlet and exhaust nozzles to be a part of the engine, or just a part of the air-frame. Personally I'm of the mindset the in…