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too easy?

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  too easy? nero <oldogf@yahoo.it> - 2023-08-09 17:17 -0700
    Re: too easy? whodat <whodaat@void.nowgre.com> - 2023-08-09 20:51 -0500
    Re: too easy? whodat <whodaat@void.nowgre.com> - 2023-08-09 21:48 -0500
      Re: too easy? nero <oldogf@yahoo.it> - 2023-08-10 16:45 -0700
      Re: too easy? nero <oldogf@yahoo.it> - 2023-08-10 16:48 -0700
    Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-10 11:37 +0200
      Re: too easy? nero <oldogf@yahoo.it> - 2023-08-10 16:52 -0700
        Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-11 12:53 +0200
      Re: too easy? nero <oldogf@yahoo.it> - 2023-08-10 16:54 -0700
      Re: too easy? RichD <r_delaney2001@yahoo.com> - 2023-08-12 12:01 -0700
        Re: too easy? whodat <whodaat@void.nowgre.com> - 2023-08-12 14:16 -0500
          Re: too easy? Volney <volney@invalid.invalid> - 2023-08-12 17:31 -0400
          Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-13 10:34 +0200
        Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-13 10:34 +0200
          Re: too easy? nero <oldogf@yahoo.it> - 2023-08-13 18:19 -0700
            Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-14 10:30 +0200
          Re: too easy? RichD <r_delaney2001@yahoo.com> - 2023-08-15 10:17 -0700
            Re: too easy? Athel Cornish-Bowden <athel.cb@gmail.com> - 2023-08-15 21:02 +0200
            Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-15 23:38 +0200
              Re: too easy? RichD <r_delaney2001@yahoo.com> - 2023-08-16 09:25 -0700
                Re: too easy? Prokaryotic Capase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2023-08-16 09:47 -0700
                Re: too easy? Paul Alsing <pnalsing@gmail.com> - 2023-08-16 17:51 -0700
                  Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-17 09:45 +0200
                    Re: too easy? patdolan <patdolan@comcast.net> - 2023-08-17 11:31 -0700
                Re: too easy? Tom Roberts <tjoberts137@sbcglobal.net> - 2023-08-17 13:03 -0500
    Re: too easy? Sylvia Else <sylvia@email.invalid> - 2023-08-11 11:40 +1000
      Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-11 12:53 +0200
        Re: too easy? Prokaryotic Capase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2023-08-11 11:02 -0700
          Re: too easy? patdolan <patdolan@comcast.net> - 2023-08-11 11:33 -0700
            Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-11 21:01 +0200
          Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-11 20:54 +0200
            Re: too easy? Prokaryotic Capase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2023-08-11 14:38 -0700
              Re: too easy? nospam@de-ster.demon.nl (J. J. Lodder) - 2023-08-12 12:07 +0200
      Re: too easy? nero <oldogf@yahoo.it> - 2023-08-18 18:38 -0700

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#617919

On Wednesday, August 16, 2023 at 11:25:53 AM UTC-5, RichD wrote:

> Toss a child's toy rubber balloon into a tub. It sinks. 
> Inflate it, it floats. Pump air into a thing, the thing grows lighter. 

No, you increase its displacement volume.

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#617957

On Wednesday, August 16, 2023 at 9:25:53 AM UTC-7, RichD wrote:

> Toss a child's toy rubber balloon into a tub. It sinks. 
> Inflate it, it floats. Pump air into a thing, the thing grows lighter. 

If I toss a cement boat into the water does it sink?

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#617985

Paul Alsing <pnalsing@gmail.com> wrote:

> On Wednesday, August 16, 2023 at 9:25:53?AM UTC-7, RichD wrote:
> 
> > Toss a child's toy rubber balloon into a tub. It sinks. 
> > Inflate it, it floats. Pump air into a thing, the thing grows lighter.
> 
> If I toss a cement boat into the water does it sink?

Like Larinda, for example?
<https://en.wikipedia.org/wiki/Larinda>

Many concrete ships exist, from dighy sized to oil tankers.
The generic term for ships of this kind is 'ferrocrete'
for iron reinforced concrete. 
(that 'iron' is of course mild steel) 

They have advantages, like cheap to build, easy to repair, strong,
and disadvantages, such as lower cargo capacity
for a given deadweight,

Jan

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#618019

On Thursday, August 17, 2023 at 12:45:30 AM UTC-7, J. J. Lodder wrote:
> Paul Alsing <pnal...@gmail.com> wrote:
> > On Wednesday, August 16, 2023 at 9:25:53?AM UTC-7, RichD wrote: 
> > 
> > > Toss a child's toy rubber balloon into a tub. It sinks. 
> > > Inflate it, it floats. Pump air into a thing, the thing grows lighter. 
> > 
> > If I toss a cement boat into the water does it sink?
> Like Larinda, for example? 
> <https://en.wikipedia.org/wiki/Larinda> 
> 
> Many concrete ships exist, from dighy sized to oil tankers. 
> The generic term for ships of this kind is 'ferrocrete' 
> for iron reinforced concrete. 
> (that 'iron' is of course mild steel) 
> 
> They have advantages, like cheap to build, easy to repair, strong, 
> and disadvantages, such as lower cargo capacity 
> for a given deadweight, 
> 
> Jan
My dad was out and back to the Aleutian Islands a few times during WWII.  After just one voyage aboard a concrete troop transport and witnessing a neighboring concrete hull crack in two on the Bearing Sea, he always chose air transport subsequent to that voyage.  Good thing for physics, too. You all know why.

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#618013

On 8/16/23 11:25 AM, RichD wrote:
> Toss a child's toy rubber balloon into a tub.  It sinks.
> Inflate it, it floats. 

Yes, because when filled with air it displaces more water than when empty.

> Pump air into a thing, the thing grows lighter.

Not true. Not even close. Note you did NOT weigh the balloon, and so 
cannot conclude anything about its weight.

Tom Roberts

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#617340

On 10-Aug-23 10:17 am, nero wrote:
> I should like to know the theoric energy in kwh necessary for keeping in air a kg for an hour ...
> It is the problem of all the birds , drones, plains , helicopters.....
> It is the number for calculating the efficienty  of the fligth

The answer is that there is no theoretical minimum. It's an engineering 
problem that seeks to balance structural weight, friction, generation of 
turbulence resulting in drag, and so on.

Sylvia.

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#617349

Sylvia Else <sylvia@email.invalid> wrote:

> On 10-Aug-23 10:17 am, nero wrote:
> > I should like to know the theoric energy in kwh necessary for keeping in
> > Iair a kg for an hour ... t is the problem of all the birds , drones,
> > Iplains , helicopters..... t is the number for calculating the
> > Iefficienty  of the fligth
> 
> The answer is that there is no theoretical minimum. It's an engineering
> problem that seeks to balance structural weight, friction, generation of
> turbulence resulting in drag, and so on.

The theoretical minimum must be for infinite span wings,
flying at zero velocity....

Jan

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#617381

On Friday, August 11, 2023 at 5:53:57 AM UTC-5, J. J. Lodder wrote:
> Sylvia Else <syl...@email.invalid> wrote: 
> 
> > On 10-Aug-23 10:17 am, nero wrote: 
> > > I should like to know the theoric energy in kwh necessary for keeping in
> > > Iair a kg for an hour ... t is the problem of all the birds , drones, 
> > > Iplains , helicopters..... t is the number for calculating the 
> > > Iefficienty of the fligth
> > 
> > The answer is that there is no theoretical minimum. It's an engineering 
> > problem that seeks to balance structural weight, friction, generation of 
> > turbulence resulting in drag, and so on.
> The theoretical minimum must be for infinite span wings, 
> flying at zero velocity.... 

How about large lightweight wings with volume 
sufficiently large that their buoyancy keeps the plane 
afloat? Maybe fill them with helium?  :-)

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#617382

On Friday, August 11, 2023 at 11:02:25 AM UTC-7, Prokaryotic Capase Homolog wrote:
> On Friday, August 11, 2023 at 5:53:57 AM UTC-5, J. J. Lodder wrote: 
> > Sylvia Else <syl...@email.invalid> wrote: 
> > 
> > > On 10-Aug-23 10:17 am, nero wrote: 
> > > > I should like to know the theoric energy in kwh necessary for keeping in 
> > > > Iair a kg for an hour ... t is the problem of all the birds , drones, 
> > > > Iplains , helicopters..... t is the number for calculating the 
> > > > Iefficienty of the fligth 
> > > 
> > > The answer is that there is no theoretical minimum. It's an engineering 
> > > problem that seeks to balance structural weight, friction, generation of 
> > > turbulence resulting in drag, and so on. 
> > The theoretical minimum must be for infinite span wings, 
> > flying at zero velocity....
> How about large lightweight wings with volume 
> sufficiently large that their buoyancy keeps the plane 
> afloat? Maybe fill them with helium? :-)
And how about explaining the lift of the standard airfoil in inverted flight in terms of the Bernoulli theory of lift, sans Newton.

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#617392

patdolan <patdolan@comcast.net> wrote:

> On Friday, August 11, 2023 at 11:02:25?AM UTC-7, Prokaryotic Capase Homolog:
> > On Friday, August 11, 2023 at 5:53:57?AM UTC-5, J. J. Lodder wrote:
> > > Sylvia Else <syl...@email.invalid> wrote: 
> > > 
> > > > On 10-Aug-23 10:17 am, nero wrote: 
> > > > > I should like to know the theoric energy in kwh necessary for
> > > > > Ikeeping in air a kg for an hour ... t is the problem of all the
> > > > > Ibirds , drones, plains , helicopters..... t is the number for
> > > > > Icalculating the efficienty of the fligth
> > > > 
> > > > The answer is that there is no theoretical minimum. It's an
> > > > engineering problem that seeks to balance structural weight,
> > > > friction, generation of turbulence resulting in drag, and so on.
> > > The theoretical minimum must be for infinite span wings, 
> > > flying at zero velocity....
> > How about large lightweight wings with volume 
> > sufficiently large that their buoyancy keeps the plane 
> > afloat? Maybe fill them with helium? :-)
> And how about explaining the lift of the standard airfoil in inverted
> flight in terms of the Bernoulli theory of lift, sans Newton.

Do your own homework,

Jan
 

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#617390

Prokaryotic Capase Homolog <prokaryotic.caspase.homolog@gmail.com>
wrote:

> On Friday, August 11, 2023 at 5:53:57?AM UTC-5, J. J. Lodder wrote:
> > Sylvia Else <syl...@email.invalid> wrote: 
> > 
> > > On 10-Aug-23 10:17 am, nero wrote: 
> > > > I should like to know the theoric energy in kwh necessary for keeping in
> > > > Iair a kg for an hour ... t is the problem of all the birds , drones,
> > > > Iplains , helicopters..... t is the number for calculating the 
> > > > Iefficienty of the fligth
> > > 
> > > The answer is that there is no theoretical minimum. It's an engineering
> > > problem that seeks to balance structural weight, friction, generation of
> > > turbulence resulting in drag, and so on.
> > The theoretical minimum must be for infinite span wings, 
> > flying at zero velocity.... 
> 
> How about large lightweight wings with volume 
> sufficiently large that their buoyancy keeps the plane 
> afloat? Maybe fill them with helium?  :-)

He is asking about flight, not balloons.
The best attempts so far are those human powered planes,
like the 'Gossamer Albatros'.
Typical wingspan: order 30 m, typical weight 100 kg (loaded)
Powerplant: 1 human at a perhaps 300 W,
for about 20 km/h cruising speed.
Endurance: a few hours at best.

They are museum pieces, and it is unlikely that those values
will ever be improved upon,

Jan


Jan

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#617413

On Friday, August 11, 2023 at 1:54:54 PM UTC-5, J. J. Lodder wrote:
> Prokaryotic Capase Homolog <prokaryotic.c...@gmail.com> 

> > How about large lightweight wings with volume 
> > sufficiently large that their buoyancy keeps the plane 
> > afloat? Maybe fill them with helium? :-)
> He is asking about flight, not balloons. 

Of course that is what he *meant*.
But the OP terminated his set of examples with ellipses: 
"It is the problem of all the birds , drones, plains , helicopters....."

Given the presence of ellipses, I believe that I am free
to *intentionally misinterpret* his question any way that
I want to.  :-)

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#617441

Prokaryotic Capase Homolog <prokaryotic.caspase.homolog@gmail.com>
wrote:

> On Friday, August 11, 2023 at 1:54:54?PM UTC-5, J. J. Lodder wrote:
> > Prokaryotic Capase Homolog <prokaryotic.c...@gmail.com> 
> 
> > > How about large lightweight wings with volume 
> > > sufficiently large that their buoyancy keeps the plane 
> > > afloat? Maybe fill them with helium? :-)
> > He is asking about flight, not balloons. 
> 
> Of course that is what he *meant*.
> But the OP terminated his set of examples with ellipses: 
> "It is the problem of all the birds , drones, plains , helicopters....."
> 
> Given the presence of ellipses, I believe that I am free
> to *intentionally misinterpret* his question any way that
> I want to.  :-)

OK, so next proceed to find out how many kWh that helium costs,

Jan

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#618211

Il giorno venerdì 11 agosto 2023 alle 03:41:02 UTC+2 Sylvia Else ha scritto:
> On 10-Aug-23 10:17 am, nero wrote: 
> > I should like to know the theoric energy in kwh necessary for keeping in air a kg for an hour ... 
> > It is the problem of all the birds , drones, plains , helicopters..... 
> > It is the number for calculating the efficienty of the fligth
> The answer is that there is no theoretical minimum. It's an engineering 
> problem that seeks to balance structural weight, friction, generation of 
> turbulence resulting in drag, and so on. 
> 
> Sylvia.
..now my home work is finished and the washmachine is running,,, so Lodder is happy . .
.. if a weigth ( one kg ?)is sustained by a table or wire , it makes a registrable effect ( elastic and permanent, in a long term  ) over the table or wire proportional to the weigth , gravity , time ...;
.. if the weigth is sustained by the air ( by propeller or wing ) , we must at least equalize the gravitational strength ....
The Solar Impulse 2 of Piccard (I wrote to him but no anser ..) was very efficient and  used for flying mediumly 15-20 kwh with a total weigth of 2000 kg .. so one kwh for 100 kg ..  so we had to arrive to a necessary minimum theorical using the physical formulation of our fathers .. or not ?

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