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Mars helicopter
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CatalinaWOW:

--- Quote from: rs20 on April 12, 2021, 06:35:11 am ---
--- Quote from: CatalinaWOW on April 12, 2021, 04:44:55 am ---I don't know about the rest of you, but I was recalibrated on this over the weekend when a couple of TV reporters were at JPL and got to touch and handle a full scale model (perhaps backup hardware).  I envisioned this thing a couple of dozen cm tall, very toy like.  Instead it is something like a meter and a half tall.  The rotors span well over a meter.  And at design speed are turning over 2000 rpm.  Very advanced materials in the blades to deal with centrifugal effects.

--- End quote ---

The copter has a rotor span of 1.2m, but it's "only" 0.5m (4 dozen cm :-) ) high, not 1.5m (1.5m is nearly the height of the average adult woman).

--- End quote ---

Camera angles and all that.  In the pictures it appeared to be chest high to the female reporter.   I suppose I should have spent a few seconds googling it.  Even though I know once I clicked on that rathole I would have spent far more than a few seconds reading up on the design.   Even at half a meter it is far bigger than I imagined. 
MikeK:
Looks like it's postponed again.  Or at least they're not sure when it will fly.  They have to update software.  At least they're getting on with the primary mission...Thousands of photos from Perseverance have been uploaded in the past week.  Good!
GlennSprigg:

--- Quote from: Domagoj T on March 31, 2021, 05:35:37 am ---When I first heard about them planning on using a helicopter on Mars, I thought it was a joke. Helicopter in Martian almost nonexistent atmosphere? But apparently they were serious and this is probably even more impressive than the rover itself.

--- End quote ---

It's not an almost nonexistant atmoshere... It's an atmosphere of (virtually all) Carbon-Dioxide. THAT gas is heavier than the 'mix' we have here
on Earth. (Let off CO2 extinguishers here, and it stays low to the ground). Therefore it is denser. Now, yes, Mars is smaller than Earth, and so the
Gravity on Mars is less, and it's the amount of Gravity (as well as the depth of atmosphere!) that determines the ground Pressure, and the resultant
effectiveness of such a 'rotating-wing'.  However, the lower Gravity also means that the downward thrust that is required for lift, is much less!
In fact a 'helicopter' on Mars, would require much less Power/Lift/Weight ratios, than anything here on Earth...   8)
MikeK:

--- Quote from: GlennSprigg on April 16, 2021, 12:45:19 pm ---
--- Quote from: Domagoj T on March 31, 2021, 05:35:37 am ---When I first heard about them planning on using a helicopter on Mars, I thought it was a joke. Helicopter in Martian almost nonexistent atmosphere? But apparently they were serious and this is probably even more impressive than the rover itself.

--- End quote ---

It's not an almost nonexistant atmoshere... It's an atmosphere of (virtually all) Carbon-Dioxide. THAT gas is heavier than the 'mix' we have here
on Earth. (Let off CO2 extinguishers here, and it stays low to the ground). Therefore it is denser. Now, yes, Mars is smaller than Earth, and so the
Gravity on Mars is less, and it's the amount of Gravity (as well as the depth of atmosphere!) that determines the ground Pressure, and the resultant
effectiveness of such a 'rotating-wing'.  However, the lower Gravity also means that the downward thrust that is required for lift, is much less!
In fact a 'helicopter' on Mars, would require much less Power/Lift/Weight ratios, than anything here on Earth...   8)

--- End quote ---

Mars' atmospheric pressure is about 1% that of Earth.  That is an almost nonexistant atmosphere.  What it does have is mostly CO2, but it has so little of it.
james_s:
Whatever the case, I'm quite confident that the engineers who designed the helicopter had a sufficient understanding of aerodynamics and the Martian atmosphere to have properly accounted for all that. It's not like the thing was lashed together by a group of maker kids.
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