For Questions That Don't Merit Their Own Thread

[Mad Rocket Scientist]

Spoilers for Kim Stanley Robinson’s Red/Green/Blue Mars

Spoiler

 

 

 

[tater]

Check this out:

https://3d.si.edu/apollo11cm

3D scan of Apollo 11 CM, move around inside. Really cool.

[ARS]

Is there a type of landing gear for aircraft to land on soft, sandy surface ? (like beach or sand dunes, think a scenario of an impromptu airfield in the middle of nowhere)

[p1t1o]

25 minutes ago, ARS said:

Is there a type of landing gear for aircraft to land on soft, sandy surface ? (like beach or sand dunes, think a scenario of an impromptu airfield in the middle of nowhere)

yup

 

For snow:

 

These, though, did not work out: 

(B-36 experimental undercarriage)

[kerbiloid]

https://rutube.ru/video/5705a9aa39f99417aedd3acaba46335d/

and

Spoiler

 

 

 

[magnemoe]

2 hours ago, kerbiloid said:

https://rutube.ru/video/5705a9aa39f99417aedd3acaba46335d/

and

  Hide contents

 

 

 

Never seen some using an hovercraft for landing legs, awesome in that its the perfect one but probably pretty much drag from it.

The (B-36 experimental undercarriage) was not primarily for rough terrain landings. Back in the 1940 they had problems with bogie wheels on planes as you would not know if one of the wheel set lock up.
 One solution  was to use an track 
Don't think they ever got an ABS system but the switched to an bogie anyway

[Mad Rocket Scientist]

https://en.wikipedia.org/wiki/Benford's_law

This is bizarre.

[Gargamel]

26 minutes ago, Mad Rocket Scientist said:

https://en.wikipedia.org/wiki/Benford's_law

This is bizarre.

I LOVE Benfords law.  It's a great way to see if a group of numbers follows a natural distribution.  If a set of numbers have been faked, then there will be a propensity to use numbers more often than they should be.   Tax auditors can use it to see if the books have been cooked. 

 

[ARS]

What's these aircraft?

[Gargamel]

First one looks like a version of a messerschmitt 109.

EDIT: Upon consultation with another judge, we have decided to include the Hurricane as another possibility.

 

Edited April 7, 2019 by Gargamel

[Mad Rocket Scientist]

27 minutes ago, ARS said:

What's these aircraft?

[...]

This looks like a North American F-86D Sabre to me. 

 

[Gargamel]

I have also decided there needs to be a website similar to those of Ornithology and Dendrology.  Where one could describe various features of a plane, and it would show a list of possible candidates.   Bubble or inline canopy?  Prop or Jet?  Airscoop underneath or radial?   etc etc.  

Cause that second one looks like the offspring of an F-16 and a Mig-17.

[Mad Rocket Scientist]

2 minutes ago, Gargamel said:

I have also decided there needs to be a website similar to those of Ornithology and Dendrology.  Where one could describe various features of a plane, and it would show a list of possible candidates.   Bubble or inline canopy?  Prop or Jet?  Airscoop underneath or radial?   etc etc.  

Cause that second one looks like the offspring of an F-16 and a Mig-17.

This is how I feel when trying to find this kind of thing:

https://imgs.xkcd.com/comics/extended_mind.png

[Gargamel]

Since when did we allow Phil to have his own air force @Mad Rocket Scientist???

[ARS]

32 minutes ago, Gargamel said:

include the Hurricane as another possibility.

It's tail is rather tall, so... I guess Hurricane

5 minutes ago, Gargamel said:

I have also decided there needs to be a website similar to those of Ornithology and Dendrology.  Where one could describe various features of a plane, and it would show a list of possible candidates. 

I like that idea, giving tags on aircraft based on features for easy identification

6 minutes ago, Gargamel said:

Bubble or inline canopy?  Prop or Jet?  Airscoop underneath or radial?

Inline, Jet, underneath the nosecone, also have MLRS-like rocket pod under the belly, @MadRocketScientist's guess seems to be on point

 

 

[Mad Rocket Scientist]

Just now, Gargamel said:

Since when did we allow Phil to have his own air force @Mad Rocket Scientist???

It's a big air force:

I just copied that photo from wikipedia without noticing, but it's from the Philippine Air Force.

[Mad Rocket Scientist]

@ARS

I think I found a better match for the first plane: The Kawasaki Ki-61.

The Hurricane's exhaust and canopy don't match as well as this one.

 

EDIT: To narrow this down even further, this appears to be the Ki-61-I Hei

As opposed to the Ki-61-II Kai:

Note the small windows at the bottom front of the canopy.

Edited April 7, 2019 by Mad Rocket Scientist

[kerbiloid]

Spoiler

2 hours ago, ARS said:

 

 

 

Smooth and sharp shape, straight front edge of the fin, maybe it's Yak-9

Edited April 7, 2019 by kerbiloid

[tater]

Heheh. Love the "race tracking" behavior (a la Skylab):

 

[StrandedonEarth]

That makes me think that human colonies in microgravity will evolve to be pedi-dexterous (able to use their feet for grasping). That would be rather useful. 

[magnemoe]

3 hours ago, StrandedonEarth said:

That makes me think that human colonies in microgravity will evolve to be pedi-dexterous (able to use their feet for grasping). That would be rather useful. 

Not evolve that takes thousands of year for something who is critical for survival like disease resistance.  
Engineered is a bit faster. 
Add an prehensile tail while you are doing it, more features is always good. 

[Gargamel]

So let's say we have a metal (steel) rod, horizontal to the ground, about 200mm long and a diameter of about 20mm.   At each end of the rod there is a 50mm Diameter flat plate (think barbell), of some thickness that doesn't matter.   Resting on this rod (but captured, the rod runs through the inside of the ring) is a ring of the same material as the rod, of let's say 2mm thickness, but this can be a variable if needed, and an Inside diameter of 50mm, and an OD of 55mm. 

As we spin up the rod to higher RPM's, the ring starts to oscillate back and forth along the rod, as it also starts to spin due to friction with the rod.  The ring reaches the plates on the ends, and bounces back at the same speed it entered, or there about.   The ring seems to move faster as the RPM's increase.  The rod is perfectly level, and in the hypothetical, there are no other forces acting on the rod/ring other than gravity.  Consider the system to be contained in a vacuum for the hypothetical. 

Are there "simple" (I use that term loosely) equations that would describe this motion of the ring? 

 

In the real world example of this I encountered the other day, RPM's of less than about 200 would lead to irregularities in the ring's motion, and did not have a rhythmic motion.  RPM of about 800 led to a oscillation of about 1 second per length.   Anything over about 1500 RPM led to what was basically a centrifugal fan at one end creating enough air flow to keep the ring stuck at one end.    Without the effect of air flow though, I posit it would have continued to increase in oscillation rate, but only to a point, where loss of friction would have slowed/limited the rotation of the ring.   

The motion of the ring seems to be caused by it not resting perfectly perpendicular to the axis of rotation.  At first, if it was slightly off perpendicular, it would start moving slowly (there is no lag time in the RPM changes, they are practically instant), and then continue to angle it self as it moved, gaining lateral speed.   Upon bouncing off the flat plate on the end, it would reflect at the same angle it entered with. 

I had a picture of this in the CNC machine I encountered it, but later realized a silver object on a silver background really doesn't show the details needed for a good example of the description. 

Edited April 12, 2019 by Gargamel

[p1t1o]

On 4/6/2019 at 7:38 PM, Mad Rocket Scientist said:

https://en.wikipedia.org/wiki/Benford's_law

This is bizarre.

[Racescort666]

10 hours ago, Gargamel said:

So let's say we have a metal (steel) rod, horizontal to the ground, about 200mm long and a diameter of about 20mm.   At each end of the rod there is a 50mm Diameter flat plate (think barbell), of some thickness that doesn't matter.   Resting on this rod (but captured, the rod runs through the inside of the ring) is a ring of the same material as the rod, of let's say 2mm thickness, but this can be a variable if needed, and an Inside diameter of 50mm, and an OD of 55mm. 

As we spin up the rod to higher RPM's, the ring starts to oscillate back and forth along the rod, as it also starts to spin due to friction with the rod.  The ring reaches the plates on the ends, and bounces back at the same speed it entered, or there about.   The ring seems to move faster as the RPM's increase.  The rod is perfectly level, and in the hypothetical, there are no other forces acting on the rod/ring other than gravity.  Consider the system to be contained in a vacuum for the hypothetical. 

Are there "simple" (I use that term loosely) equations that would describe this motion of the ring? 

 

In the real world example of this I encountered the other day, RPM's of less than about 200 would lead to irregularities in the ring's motion, and did not have a rhythmic motion.  RPM of about 800 led to a oscillation of about 1 second per length.   Anything over about 1500 RPM led to what was basically a centrifugal fan at one end creating enough air flow to keep the ring stuck at one end.    Without the effect of air flow though, I posit it would have continued to increase in oscillation rate, but only to a point, where loss of friction would have slowed/limited the rotation of the ring.   

The motion of the ring seems to be caused by it not resting perfectly perpendicular to the axis of rotation.  At first, if it was slightly off perpendicular, it would start moving slowly (there is no lag time in the RPM changes, they are practically instant), and then continue to angle it self as it moved, gaining lateral speed.   Upon bouncing off the flat plate on the end, it would reflect at the same angle it entered with. 

I had a picture of this in the CNC machine I encountered it, but later realized a silver object on a silver background really doesn't show the details needed for a good example of the description. 

Without a visual, I don't think that I can give you the best answer but there is probably some perturbation that starts the ring walking from one end to the other. Why it does that is likely due to conservation of angular momentum.

As for your real world example, it probably behaves differently at different RPM due to various vibrations in your machine tools and imperfections in the parts.

[ZooNamedGames]

Do black holes orbit? In that, do they move around a star (if it's small enough), or if larger, do they orbit the center of the galaxy? If so, are there any special properties to orbiting black holes as far as orbital mechanics go? Or are they treated as extremely dense planets as far as they're orbital paths are concerned? I know other objects can orbit a black hole (assuming it's outside of it's Swartzchild Radius), but I was wondering if the inverse is true and black holes orbit as well.