votingprawn

6 ms·

1.
by votingprawn 3y ago
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) From the timings given you can work out the distance from
2.
by votingprawn 5y ago
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...
3.
by votingprawn 8y ago
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 sfc of a Nike is 40 grams / (kN second) (Should have g
4.
by votingprawn 8y ago
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 a Nike.
5.
by votingprawn 8y ago
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 also important. Ideally you want to match your motors
6.
by votingprawn 8y ago
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 industry and would adopt variable pitch in an instant if it didn&#
7.
by votingprawn 8y ago
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 for that publisher to get me the journal I needed, but
8.
by votingprawn 8y ago
That comparison only really holds if you ignore the stators, which the rotors are reacting against.
9.
by votingprawn 8y ago
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....wasn't. So we were bodging stuff together so that the
10.
by votingprawn 8y ago
I believe those are the homemade "star dials" / motorised planispheres mentioned in the first comment.
11.
by votingprawn 9y ago
Fair enough, no point trying to dispute a family anecdote!
12.
by votingprawn 9y ago
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 exact book I read it in, but the author stat
13.
by votingprawn 9y ago
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 cookie trays). I had a quick search and found the KC
14.
by votingprawn 9y ago
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 leaking so much fuel on the ground such that it needed immediate
15.
by votingprawn 9y ago
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 (nearly), but I suppose I could also have ended up
16.
by votingprawn 9y ago
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.wordpress.com/2016/03/25/car-sp
17.
by votingprawn 9y ago
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 this, assuming you still just want to get someone&#x2
18.
by votingprawn 9y ago
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 even know what the ITS industry is!) but I have ex
19.
by votingprawn 9y ago
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 the savoury snack equivalent, or fo
20.
by votingprawn 9y ago
Less efficient, generally speaking you want as few blades as possible. One in the ideal case but that's prohibitively difficult!
21.
by votingprawn 9y ago
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 relies on counter rotating rotors to cancel o
22.
by votingprawn 9y ago
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 (cabin noise in particular - thank you double glazing!) in my 20
23.
by votingprawn 10y ago
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 do you need to know?&quo
24.
by votingprawn 10y ago
> 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 conversations over "how" lift is generated
25.
by votingprawn 10y ago
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 inlet and exhaust nozzles are an integral part of the ins
26.
by votingprawn 10y ago
> I've read that due to the constant leaking while on the tarmac they would have to immediately rendezvous with a tanker to refuel after takeoff. To reduce structural loads the aircraft took off with a very light fuel load and refue
27.
by votingprawn 10y ago
> The Lockheed SR-71 for instance, derives a fair percentage of thrust just from the shape of the airframe, so the pilots actually throttle back a little once they reach Mach 2+! That sounds...unlikely. Do you have a source for this? I
28.
by votingprawn 10y ago
> IMU means gyro In aerospace the phrase IMU typically refers to the combination of accelerometers and gyroscopes.
29.
by votingprawn 10y ago
> both were contracted by ESA. Yes I'm aware of how ESA works and who built what. But I would have hoped the common connection would have greater instilled the need for checking for these sorts of errors, if the Schiaparelli inciden
30.
by votingprawn 10y ago
Whilst incredibly disappointing for ESA, this is unfortunately not their first IMU-failure rodeo. An Ariane 5 launch back in 1996 [0] suffered a catstrophic failure after the inertial reference units gave bad data, and the flight control co

More ›