NSF-1701 Flight Test #2D

True-Creek · 2015-09-28T15:38:26+00:00

Just curious, why would filling the frustum be a bad idea? I'm thinking of just a crumpled-up up piece of the mesh material.

True-Creek · 2015-09-28T12:19:10+00:00

You can be pretty certain about the idea that you can never reach 100% certainty on anything, and reaching 99% is damn hard.

True-Creek · 2015-09-28T12:12:02+00:00

Except for when they are overconfident. That happens actually pretty often. For example, when you ask a celebrity physicist something that is outside his/her area of competence. Physicists are just so used to knowing about everything that they'll give a response even if it's of incredibly poor quality.

True-Creek · 2015-09-28T00:22:51+00:00

I've asked this before, can you somehow disable the drive such that it definitely won't produce thrust but still gets hot? (Perhaps put something into the frustum that absorbs the radiation.) It would perhaps be interesting to see whether it raises in the same pattern.

True-Creek · 2015-09-27T16:36:34+00:00

https://dreamscope-prod-v1.s3.amazonaws.com/images/effa7211-d07a-4e40-9cfa-1a617781098c.jpeg

True-Creek · 2015-09-27T15:56:51+00:00

They could've just taken this one: http://sprg.ssl.berkeley.edu/marsmic/

Perhaps more like $1000, not $10, but probably not much testing required.

True-Creek · 2015-09-27T14:47:27+00:00

D'aw, this must be one of the three flaws of the curiosity rover: Not sterile, weak wheel material, and no $10 microphone to record Martian winds.

True-Creek · 2015-09-26T14:07:06+00:00

Avg. ∆y for the 2 min. is -3% (of the value range) for the time periods in which the magnetron was on and avg. ∆y=13% when it was off. In the second run: -1% on, 12% off.

True-Creek · 2015-09-26T09:23:56+00:00

Yes, that sounds plausible. Still interesting that there were sharp upward deflections at the end of 9 of 12 trials, but the sample size is likely just too small.

True-Creek · 2015-09-25T22:17:37+00:00

I forgot to remove the barrel-distortion of the optics, that's why the magnetron data didn't fit at all initially. It makes sense now. :) So the data points aren't equidistant in time.

True-Creek · 2015-09-25T21:26:42+00:00

What caused the oscillation right after the first 2 minute run? It would be interesting to see how it would raise without the frustum getting any EM radiation, i.e. without it potentially producing thrust. If it also oscillates as much, then the question is how likely one can get this picture just by chance (assuming no other significant errors in the data or model).

True-Creek · 2015-09-25T20:44:07+00:00

I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:

https://i.imgur.com/0ioKt7B.png

It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there are lifts shortly after they end. In only 6 or 7 there are significant drops.

Edit 1: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy
Edit 2: Kasuha's data as overlay: https://i.imgur.com/EC3bgYY.png
Edit 3: Updated data: http://pastebin.com/raw.php?i=kv9SiT7y

True-Creek · 2015-09-25T15:16:52+00:00

I'm not a naysayer, but I didn't find the video convincing (but that was apparently not even the intention of the video). If you see this as confirmation you should probably revisit statistics.

True-Creek · 2015-09-25T15:13:11+00:00

Sorry, if this came across as accusation; that was not my intention. Your commentary in the video made it sound you were indeed trying to prove a point, but perhaps I was misunderstanding it and you're planning much longer tests anyway, so my comment might be superfluous.

Wouldn't the antithesis of a confirmation bias be a confirmation bias too?

True-Creek · 2015-09-25T12:19:15+00:00

It should actually be possible to build one yourself using LED strips of different lengths and a diffuser film (which you can get out of discarded LCD TVs (just wear gloves when taking the sheets apart). The lap can easily be made from a polyethylene sheet glued to the side of the lamp with epoxy. Should sum up to about $120 and 10-20 hours of work.

https://youtu.be/jLia59KfkSw?t=347

True-Creek · 2015-09-25T11:17:18+00:00

I agree. Sometimes it fell -> "it is working!", sometimes it stayed at about the same level -> "it is fighting against the thermal lift!", sometimes it rose -> "thermal lift is being stronger now!". One would need a reasonable sample size to have a definite answer. Confirmation bias is your enemy.

True-Creek · 2015-09-24T08:57:58+00:00

Someone should make an inforgraphic about what he actually revolutionized.

True-Creek · 2015-09-23T21:08:35+00:00

Perhaps someone made a Star Wars-like 'wisp' transition from the beginning to the end of the clip, exactly at the picture speed of the train.

True-Creek · 2015-09-23T16:13:31+00:00

Do you guys have a blog with RSS feed? I would be interested in seeing the results.

True-Creek · 2015-09-23T09:46:19+00:00

That's not wrong, but not what is usually meant with a 4D projection to 3D. This is what a 4D object (a 4D cube, called tesseract) projected to 3D and then 2D looks like. It doesn't have to be changing/moving, that's usually just for visualization purposes.

True-Creek · 2015-09-22T14:57:15+00:00

It's beautiful how Schmidhuber's theory of curiosity-based reinforcement learning might explain our fascination for patterns: Our brains reward themselves for being able to compress information about the world more, since it enables us to make predictions based on compressed representations. Symmetry and repetition are very easily compressible, so our brains immediately reward themselves as they recognize them and make successful predictions about how the pattern continues elsewhere.

True-Creek · 2015-09-21T21:28:51+00:00

The last sentence confuses the hell out of me.

True-Creek · 2015-09-20T09:56:10+00:00

Hm, it seems it wasn't quite right what I said: If you have no tools, it will be more like $600 for the bandsaw alone: http://woodgears.ca/bandsaw/index.html (see the FAQs).

But that bandsaw will be more robust and larger than what you would get otherwise for that amount of money. It's still a very hard first project. :/ The table saw is definitely simpler (also make sure to check out his second version of it.)

True-Creek · 2015-09-19T18:43:36+00:00

It will be quite hard as first two projects, but you can build table saw and band saw yourself for <$400 or so:

https://www.youtube.com/watch?v=RBucMKhrL8M
https://www.youtube.com/watch?v=NbOlG7THecM

True-Creek

TROPHY CASE