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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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#617232 — too easy?

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 

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#617236

On 8/9/2023 7:17 PM, 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

Generally speaking it is advised an individual achieve communication
skills before progressing to more advanced topics. As stated above
it is clear that you don't know enough to properly state the problem
you're attempting to solve. Stick with the accepted learning sequence
rather than jumping ahead into realms you're not yet capable of
understanding. Don't take this as a putdown, take it as a strong
suggestion that you slow down. The question(s) you're attempting
to ask will probably be resolved as a matter of routine as your
education progresses. Best to you.

[toc] | [prev] | [next] | [standalone]

#617239

On 8/9/2023 7:17 PM, 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

2nd attempt- the first got lost somewhere somehow.


Generally speaking it is advised an individual achieve communication
skills before progressing to more advanced topics. As stated above
it is clear that you don't know enough to properly state the problem
you're attempting to solve. Stick with the accepted learning sequence
rather than jumping ahead into realms you're not yet capable of
understanding. Don't take this as a putdown, take it as a strong
suggestion that you slow down. The question(s) you're attempting
to ask will probably be resolved as a matter of routine as your
education progresses. Best to you.

[toc] | [prev] | [next] | [standalone]

#617332

Il giorno giovedì 10 agosto 2023 alle 04:49:09 UTC+2 whodat ha scritto:
> On 8/9/2023 7:17 PM, 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
> 2nd attempt- the first got lost somewhere somehow.
> Generally speaking it is advised an individual achieve communication 
> skills before progressing to more advanced topics. As stated above 
> it is clear that you don't know enough to properly state the problem 
> you're attempting to solve. Stick with the accepted learning sequence 
> rather than jumping ahead into realms you're not yet capable of 
> understanding. Don't take this as a putdown, take it as a strong 
> suggestion that you slow down. The question(s) you're attempting 
> to ask will probably be resolved as a matter of routine as your 
> education progresses. Best to you.
.. thanks

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#617333

Il giorno giovedì 10 agosto 2023 alle 04:49:09 UTC+2 whodat ha scritto:
> On 8/9/2023 7:17 PM, 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
> 2nd attempt- the first got lost somewhere somehow.
> Generally speaking it is advised an individual achieve communication 
> skills before progressing to more advanced topics. As stated above 
> it is clear that you don't know enough to properly state the problem 
> you're attempting to solve. Stick with the accepted learning sequence 
> rather than jumping ahead into realms you're not yet capable of 
> understanding. Don't take this as a putdown, take it as a strong 
> suggestion that you slow down. The question(s) you're attempting 
> to ask will probably be resolved as a matter of routine as your 
> education progresses. Best to you.
.. thanks

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#617254

nero <oldogf@yahoo.it> 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 efficienty
> Iof the fligth

You really should do some work on your classical mechanics.
(suspends anti-homework rule for once)

In horizontal flight there are four forces,
Lift Drag, Thrust and Weight.
For steady horizontal flight Thrust must equal Drag,
and Lift must equal Weight.
So their is no theoretical minimum. L/D could be infinite.
For a real wing L/D will be about 10.
(order of magnitude, more for a sailplane, less for a jet fighter)
So to move through the air at speed v requires a power P of v times D.

So the fundamental equation for steady horizontal flight is

  v = L/D . P/W,   or P = vWD/L

You can take it from there, for practical planes and birds,
if you have an idea about v and W, and L/D.

Your turn,

Jan

PS For much more (then you may want to know)
I can recommend: 
The Simple Science of Flight_ From Insects to Jumbo Jets,
by Henk Tennekes.               
<https://mitpress.mit.edu/9780262700658/the-simple-science-of-flight/>

It is a delightful, and insightful little book.

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#617334

Il giorno giovedì 10 agosto 2023 alle 11:37:07 UTC+2 J. J. Lodder ha scritto:
> nero <old...@yahoo.it> 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 efficienty 
> > Iof the fligth 
> 
> You really should do some work on your classical mechanics. 
> (suspends anti-homework rule for once) 
> 
> In horizontal flight there are four forces, 
> Lift Drag, Thrust and Weight. 
> For steady horizontal flight Thrust must equal Drag, 
> and Lift must equal Weight. 
> So their is no theoretical minimum. L/D could be infinite. 
> For a real wing L/D will be about 10. 
> (order of magnitude, more for a sailplane, less for a jet fighter) 
> So to move through the air at speed v requires a power P of v times D. 
> 
> So the fundamental equation for steady horizontal flight is 
> 
> v = L/D . P/W, or P = vWD/L 
> 
> You can take it from there, for practical planes and birds, 
> if you have an idea about v and W, and L/D. 
> 
> Your turn, 
> 
> Jan 
> 
> PS For much more (then you may want to know) 
> I can recommend: 
> The Simple Science of Flight_ From Insects to Jumbo Jets, 
> by Henk Tennekes. 
> <https://mitpress.mit.edu/9780262700658/the-simple-science-of-flight/> 
> 
> It is a delightful, and insightful little book.
..thanks... your answer was much , but not enough

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#617348

nero <oldogf@yahoo.it> wrote:

> Il giorno giovedì 10 agosto 2023 alle 11:37:07 UTC+2 J. J. Lodder ha scritto:
> > nero <old...@yahoo.it> 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 efficienty
> > > Iof the fligth 
> > 
> > You really should do some work on your classical mechanics. 
> > (suspends anti-homework rule for once) 
> > 
> > In horizontal flight there are four forces, 
> > Lift Drag, Thrust and Weight. 
> > For steady horizontal flight Thrust must equal Drag, 
> > and Lift must equal Weight. 
> > So their is no theoretical minimum. L/D could be infinite. 
> > For a real wing L/D will be about 10. 
> > (order of magnitude, more for a sailplane, less for a jet fighter) 
> > So to move through the air at speed v requires a power P of v times D.
> > 
> > So the fundamental equation for steady horizontal flight is 
> > 
> > v = L/D . P/W, or P = vWD/L 
> > 
> > You can take it from there, for practical planes and birds, 
> > if you have an idea about v and W, and L/D. 
> > 
> > Your turn, 
> > 
> > Jan 
> > 
> > PS For much more (then you may want to know) 
> > I can recommend: 
> > The Simple Science of Flight_ From Insects to Jumbo Jets, 
> > by Henk Tennekes. 
> > <https://mitpress.mit.edu/9780262700658/the-simple-science-of-flight/>
> > 
> > It is a delightful, and insightful little book.
> ..thanks... your answer was much , but not enough

Sorry, homework help hour is over.
Try reading Tennekes for yourself,
to get started.
But you really do need elementary Newtonian mechanics first,

Jan

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#617335

Il giorno giovedì 10 agosto 2023 alle 11:37:07 UTC+2 J. J. Lodder ha scritto:
> nero <old...@yahoo.it> 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 efficienty 
> > Iof the fligth 
> 
> You really should do some work on your classical mechanics. 
> (suspends anti-homework rule for once) 
> 
> In horizontal flight there are four forces, 
> Lift Drag, Thrust and Weight. 
> For steady horizontal flight Thrust must equal Drag, 
> and Lift must equal Weight. 
> So their is no theoretical minimum. L/D could be infinite. 
> For a real wing L/D will be about 10. 
> (order of magnitude, more for a sailplane, less for a jet fighter) 
> So to move through the air at speed v requires a power P of v times D. 
> 
> So the fundamental equation for steady horizontal flight is 
> 
> v = L/D . P/W, or P = vWD/L 
> 
> You can take it from there, for practical planes and birds, 
> if you have an idea about v and W, and L/D. 
> 
> Your turn, 
> 
> Jan 
> 
> PS For much more (then you may want to know) 
> I can recommend: 
> The Simple Science of Flight_ From Insects to Jumbo Jets, 
> by Henk Tennekes. 
> <https://mitpress.mit.edu/9780262700658/the-simple-science-of-flight/> 
> 
> It is a delightful, and insightful little book.
.. thanks ... your answer was much , but not enough

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#617474

On August 10, J. J. Lodder wrote:
> In horizontal flight there are four forces, 
> Lift Drag, Thrust and Weight. 
> For steady horizontal flight Thrust must equal Drag, 
> and Lift must equal Weight. 
> L/D could be infinite. 
> For a real wing L/D will be about 10. 
> So to move through the air at speed v requires a power P of v times D. 
> So the fundamental equation for steady horizontal flight is 
> v = L/D . P/W, or P = vWD/L 

You forgot buoyancy B.  The atmosphere is liquid.

If you pump air into a plane at high pressure, and heat 
to high temperature, it will float, no fuel needed.  
Hydrogen, even better - 

--
Rich

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#617476

On 8/12/2023 2:01 PM, RichD wrote:
> On August 10, J. J. Lodder wrote:
>> In horizontal flight there are four forces,
>> Lift Drag, Thrust and Weight.
>> For steady horizontal flight Thrust must equal Drag,
>> and Lift must equal Weight.
>> L/D could be infinite.
>> For a real wing L/D will be about 10.
>> So to move through the air at speed v requires a power P of v times D.
>> So the fundamental equation for steady horizontal flight is
>> v = L/D . P/W, or P = vWD/L
> 
> You forgot buoyancy B.  The atmosphere is liquid.

Liquids are not compressible. End of story.

> If you pump air into a plane at high pressure, and heat
> to high temperature, it will float, no fuel needed.

Bzzzzzzttttttt! Even if you remove the atmosphere completely
from any modern airplane it will remain heavier than air. Floating
requires weight less than the amount of air displaced by the plane.

I'm shocked by this posting, worse even than Laurence's ignorance
of the basics.

> Hydrogen, even better -

Nope.

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#617507

On 8/12/2023 3:16 PM, whodat wrote:
> On 8/12/2023 2:01 PM, RichD wrote:
>> On August 10, J. J. Lodder wrote:
>>> In horizontal flight there are four forces,
>>> Lift Drag, Thrust and Weight.
>>> For steady horizontal flight Thrust must equal Drag,
>>> and Lift must equal Weight.
>>> L/D could be infinite.
>>> For a real wing L/D will be about 10.
>>> So to move through the air at speed v requires a power P of v times D.
>>> So the fundamental equation for steady horizontal flight is
>>> v = L/D . P/W, or P = vWD/L
>>
>> You forgot buoyancy B.  The atmosphere is liquid.
> 
> Liquids are not compressible. End of story.

I'm guessing the word he's looking for is "fluid".

I think it's best to consider any buoyancy as a modification to the weight.
> 
>> If you pump air into a plane at high pressure, and heat
>> to high temperature, it will float, no fuel needed.
> 
> Bzzzzzzttttttt! Even if you remove the atmosphere completely
> from any modern airplane it will remain heavier than air. Floating
> requires weight less than the amount of air displaced by the plane.
> 
> I'm shocked by this posting, worse even than Laurence's ignorance
> of the basics.

It requires a large volume to get the total weight down to zero. 
Consider a zeppelin like the Hindenburg and the size of its passenger 
compartment.
> 
>> Hydrogen, even better -
> 
> Nope.
> 

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#617551

whodat <whodaat@void.nowgre.com> wrote:

> On 8/12/2023 2:01 PM, RichD wrote:
> > On August 10, J. J. Lodder wrote:
> >> In horizontal flight there are four forces,
> >> Lift Drag, Thrust and Weight.
> >> For steady horizontal flight Thrust must equal Drag,
> >> and Lift must equal Weight.
> >> L/D could be infinite.
> >> For a real wing L/D will be about 10.
> >> So to move through the air at speed v requires a power P of v times D.
> >> So the fundamental equation for steady horizontal flight is
> >> v = L/D . P/W, or P = vWD/L
> > 
> > You forgot buoyancy B.  The atmosphere is liquid.
> 
> Liquids are not compressible. End of story.
> 
> > If you pump air into a plane at high pressure, and heat
> > to high temperature, it will float, no fuel needed.
> 
> Bzzzzzzttttttt! Even if you remove the atmosphere completely
> from any modern airplane it will remain heavier than air.
> Floating requires weight less than the amount of air displaced by the
> plane.
> 
> I'm shocked by this posting, worse even than Laurence's ignorance
> of the basics.

Indeed. But...
Once upon a time, long ago, lived the greatest inventor of all time.
His name was Daedalus, and he published a weekly column
in New Scientist, and later in Nature.

One of his great inventions was the vacuum balloon.
It had a 'double umbrella' structure.
With the latest in strong materials,
and if deployed at high altitude to begin with,
it might be actually possible to build one.
And with a solar powered small vacuum pump to undo the leakage
it would really float forever. (unkike helium filled ones)
(they are still working on it, at DREADCO)

Jan

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#617552

RichD <r_delaney2001@yahoo.com> wrote:

> On August 10, J. J. Lodder wrote:
> > In horizontal flight there are four forces, 
> > Lift Drag, Thrust and Weight. 
> > For steady horizontal flight Thrust must equal Drag, 
> > and Lift must equal Weight. 
> > L/D could be infinite. 
> > For a real wing L/D will be about 10. 
> > So to move through the air at speed v requires a power P of v times D.
> > So the fundamental equation for steady horizontal flight is 
> > v = L/D . P/W, or P = vWD/L 
> 
> You forgot buoyancy B.  The atmosphere is liquid.

Bzzzzzzttttttt!
The weight in the above is the -effective weight in air-.
The equation above does also cover balloons and Zeppelins.
It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0)
and even further to v = 0 for unpowered balloons.

And you are confusing 'liquid' and 'fluid'.

> If you pump air into a plane at high pressure, and heat 
> to high temperature, it will float, no fuel needed.  
> Hydrogen, even better - 

You really need to think about this again,

Jan

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#617620

Il giorno domenica 13 agosto 2023 alle 10:34:54 UTC+2 J. J. Lodder ha scritto:
> RichD <r_dela...@yahoo.com> wrote: 
> 
> > On August 10, J. J. Lodder wrote: 
> > > In horizontal flight there are four forces, 
> > > Lift Drag, Thrust and Weight. 
> > > For steady horizontal flight Thrust must equal Drag, 
> > > and Lift must equal Weight. 
> > > L/D could be infinite. 
> > > For a real wing L/D will be about 10. 
> > > So to move through the air at speed v requires a power P of v times D. 
> > > So the fundamental equation for steady horizontal flight is 
> > > v = L/D . P/W, or P = vWD/L 
> > 
> > You forgot buoyancy B. The atmosphere is liquid.
> Bzzzzzzttttttt! 
> The weight in the above is the -effective weight in air-. 
> The equation above does also cover balloons and Zeppelins. 
> It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0) 
> and even further to v = 0 for unpowered balloons. 
> 
> And you are confusing 'liquid' and 'fluid'.
> > If you pump air into a plane at high pressure, and heat 
> > to high temperature, it will float, no fuel needed. 
> > Hydrogen, even better -
> You really need to think about this again, 
> 
> Jan
dear friends... relatively to the theoric efficiency against yhe gravitational strength, it is a good example of the efficiency the Solar Impulse 2 of Piccard (50%?) , the helicopters (10-20%?) ; the drones less than 1%(?)..
the aim of the post  is to find the theoric number of kwh for kg , using a logic theoric formulation ...

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#617648

nero <oldogf@yahoo.it> wrote:

> Il giorno domenica 13 agosto 2023 alle 10:34:54 UTC+2 J. J. Lodder ha scritto:
> > RichD <r_dela...@yahoo.com> wrote: 
> > 
> > > On August 10, J. J. Lodder wrote: 
> > > > In horizontal flight there are four forces, 
> > > > Lift Drag, Thrust and Weight. 
> > > > For steady horizontal flight Thrust must equal Drag, 
> > > > and Lift must equal Weight. 
> > > > L/D could be infinite. 
> > > > For a real wing L/D will be about 10. 
> > > > So to move through the air at speed v requires a power P of v times D.
> > > > So the fundamental equation for steady horizontal flight is 
> > > > v = L/D . P/W, or P = vWD/L 
> > > 
> > > You forgot buoyancy B. The atmosphere is liquid.
> > Bzzzzzzttttttt! 
> > The weight in the above is the -effective weight in air-. 
> > The equation above does also cover balloons and Zeppelins. 
> > It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0)
> > and even further to v = 0 for unpowered balloons. 
> > 
> > And you are confusing 'liquid' and 'fluid'.
> > > If you pump air into a plane at high pressure, and heat 
> > > to high temperature, it will float, no fuel needed. 
> > > Hydrogen, even better -
> > You really need to think about this again, 
> > 
> > Jan
> dear friends... relatively to the theoric efficiency against yhe
> gravitational strength, it is a good example of the efficiency the Solar
> Impulse 2 of Piccard (50%?) , the helicopters (10-20%?) ; the drones less
> than 1%(?).. the aim of the post  is to find the theoric number of kwh for
> kg , using a logic theoric formulation ...

Sorry, homework help hour is over. No more spoon feeding.
You are on your own until you show at least some willingness
to learn something for yourself.
(hint: the answer has already been given)

Jan

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#617791

On August 13,  J. J. Lodder wrote:
> > > In horizontal flight there are four forces, 
> > > Lift Drag, Thrust and Weight. 
> > > For steady horizontal flight Thrust must equal Drag, 
> > > and Lift must equal Weight. 
> > > For a real wing L/D will be about 10. 
> > > So to move through the air at speed v requires a power P of v times D. 
> > > So the fundamental equation for steady horizontal flight is 
> > > v = L/D . P/W, or P = vWD/L 
>  
>> You forgot buoyancy B. The atmosphere is liquid.
>
> Bzzzzzzttttttt! 
> The weight in the above is the -effective weight in air-. 
> The equation above does also cover balloons and Zeppelins. 
> It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0) 
> And you are confusing 'liquid' and 'fluid'.

Aluminum is heavier than water, it sinks. But if you pump air into 
a tank, it becomes buoyant.   Ask a scuba diver, they're 
experts on fluid mechanics, their lives depend on it.

Ditto with the atmosphere - 

--
Rich

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#617812

On 2023-08-15 17:17:38 +0000, RichD said:

> On August 13,  J. J. Lodder wrote:
>>>> In horizontal flight there are four forces,
>>>> Lift Drag, Thrust and Weight.
>>>> For steady horizontal flight Thrust must equal Drag,
>>>> and Lift must equal Weight.
>>>> For a real wing L/D will be about 10.
>>>> So to move through the air at speed v requires a power P of v times D.
>>>> So the fundamental equation for steady horizontal flight is
>>>> v = L/D . P/W, or P = vWD/L
>> 
>>> You forgot buoyancy B. The atmosphere is liquid.
>> 
>> Bzzzzzzttttttt!
>> The weight in the above is the -effective weight in air-.
>> The equation above does also cover balloons and Zeppelins.
>> It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0)
>> And you are confusing 'liquid' and 'fluid'.
> 
> Aluminum is heavier than water, it sinks. But if you pump air into
> a tank, it becomes buoyant.   Ask a scuba diver, they're
> experts on fluid mechanics, their lives depend on it.

That bit's OK, but ...
> 
> Ditto with the atmosphere -

... this bit is crazy. You can pump as much air as you like into an 
aluminium tank and it won't float away.


-- 
athel -- biochemist, not a physicist, but detector of crackpots

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#617829

RichD <r_delaney2001@yahoo.com> wrote:

> On August 13,  J. J. Lodder wrote:
> > > > In horizontal flight there are four forces, 
> > > > Lift Drag, Thrust and Weight. 
> > > > For steady horizontal flight Thrust must equal Drag, 
> > > > and Lift must equal Weight. 
> > > > For a real wing L/D will be about 10. 
> > > > So to move through the air at speed v requires a power P of v times D.
> > > > So the fundamental equation for steady horizontal flight is 
> > > > v = L/D . P/W, or P = vWD/L 
> >  
> >> You forgot buoyancy B. The atmosphere is liquid.
> >
> > Bzzzzzzttttttt! 
> > The weight in the above is the -effective weight in air-. 
> > The equation above does also cover balloons and Zeppelins. 
> > It simplifies to T = D and v = P/D for Zeppelins, (at incidence = 0)
> > And you are confusing 'liquid' and 'fluid'.
> 
> Aluminum is heavier than water, it sinks. But if you pump air into 
> a tank, it becomes buoyant.

Completely clueless, as usual.
And completely lacking in real world experience too.
Anyone who has ever handled a gas bottle of any kind
knows that bottles that are filled with pressurised gas 
are -heavier- than the same bottles empty. (in some cases a lot heaver)

> Ask a scuba diver, they're 
> experts on fluid mechanics, their lives depend on it.

Sure, that's why they use scales to know for sure
that they start with a full bottle. (or how much there is left)
Tarra and filled weight are stamped on the bottle.
A typical 12 litre scuba bottle will take 3.5 kg of air
at 230 bar.
The extra weight in a full bottle is quite noticable,
It is you who should ask,

Jan

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#617918

On August 15, J. J. Lodder wrote:
>> > > > In horizontal flight there are four forces, 
>> > > > Lift Drag, Thrust and Weight. 
>> > > > For steady horizontal flight Thrust must equal Drag, 
>> > > > and Lift must equal Weight. 
>> > > > For a real wing L/D will be about 10. 
>> > > > So to move through the air at speed v requires a power P of v times D. 
>> > > > So the fundamental equation for steady horizontal flight is 
>> > > > v = L/D . P/W, or P = vWD/L 
> 
>>>> You forgot buoyancy B. The atmosphere is liquid. 
> 
>>> Bzzzzzzttttttt! 
>>> The weight in the above is the -effective weight in air-. 
>>> The equation above does also cover balloons and Zeppelins. 
>>> And you are confusing 'liquid' and 'fluid'. 
>  
>> Aluminum is heavier than water, it sinks. But if you pump air into 
>> a tank, it becomes buoyant.
>
> Completely clueless, as usual. 
> And completely lacking in real world experience too. 
> Anyone who has ever handled a gas bottle of any kind 
> knows that bottles that are filled with pressurised gas 
> are -heavier- than the same bottles empty. (in some cases a lot heaver)
>
>> Ask a scuba diver, they're 
>> experts on fluid mechanics, their lives depend on it.
>
> Sure, that's why they use scales to know for sure 
> that they start with a full bottle. (or how much there is left) 
> Tarra and filled weight are stamped on the bottle. 
> A typical 12 litre scuba bottle will take 3.5 kg of air at 230 bar. 
> The extra weight in a full bottle is quite noticable, 

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.

--
Rich

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