Air resistance
Nicho...@aol.com
launcher, and have discovered a mistake in my code!
The mistake isn't quite relevant to the question I want to ask, but
related.
I've been modelling aerodynamic drag in the lower part of the
atmosphere as constant * airdensity * velocity * velocity.
I realise that the constant will vary according to the design (area,
shape), but I was wondering whether anyone could point me to, or give
me some idea of, the size of the drag forces on something like Scout
or Titan II.
Many thanks,
Nicholas Hill
Alan Erskine
news:cd3ba847-d884-4dea...@26g2000hsk.googlegroups.com...
> I've been writing a computer simulation for a small satellite
> launcher, and have discovered a mistake in my code!
Well, clearly, you don't work for Microsoft. If you worked for Microsoft,
you wouldn't have discovered the glitch. ;-)
Nicho...@aol.com
> <Nichola...@aol.com> wrote in message
Better still, I don't work at all.
mh...@ohiohills.com
>
> > Well, clearly, you don't work for Microsoft. If you worked for Microsoft,
> > you wouldn't have discovered the glitch. ;-)
>
> Better still, I don't work at all.
What, exactly, are you thinking about doing with the simulator?
I wrote a simulator for submarine design while I'm unemployed, and
it's not paid off for me!
Mike
Orval Fairbairn
<cd3ba847-d884-4dea...@26g2000hsk.googlegroups.com>,
Nicho...@aol.com wrote:
Drag coefficient is a function of Mach number and angle-of-attack, so
you would have to have that information in order to obtain anywhere
meaningful results.
Use one of the standard atmosphere models to get the density and
temperature profiles, since speed of sound is a function of temperature.
--
Remove _'s from email address to talk to me.
Nicho...@aol.com
drag co-efficient?
>
> Drag coefficient is a function of Mach number and angle-of-attack, so
> you would have to have that information in order to obtain anywhere
> meaningful results.
>
> Use one of the standard atmosphere models to get the density and
> temperature profiles, since speed of sound is a function of temperature.
>
> --
>
> - Show quoted text -
BradGuth
You'd be better off at getting that classified information from North
Korea, or perhaps China.
You could use our Saturn 5 formula as a how not to fly-by-rocket, that
is unless using them NASA/Apollo (aka DARPA) conditional laws of
physics.
. - Brad Guth
Orval Fairbairn
<a47bdf24-6d97-433e...@j22g2000hsf.googlegroups.com>,
Nicho...@aol.com wrote:
> True enough - but do you know of any formulae that give values for
> drag co-efficient?
A CFD program should probably help you get first-second order drag
curves.
Peter Stickney
There isn't any simple one-size-fits-all formula for the Drag Coefficient.
It depends on the vehicle's diameter (frontal area) length, nose shape, tail
shape, whether the body has straight or curved sides, whether it's stepped
in between stages, whether the rocket motor(s) are burning or not, and the
effects of transonic and supersonic flow.
A good place to start would be Ashley and Landahl's "Aerodynamics of Wings
and Bodies",
--
Pete Stickney
Any plan where you lose you hat is a bad plan
Pat Flannery
Nicho...@aol.com wrote:
>> Well, clearly, you don't work for Microsoft. If you worked for Microsoft,
>> you wouldn't have discovered the glitch. ;-)
>>
>
> Better still, I don't work at all.
>
"Work is the curse of the drinking class" - Oscar Wilde :-)
Pat
Nicho...@aol.com
figure. Air drag is significant, but might be called a 'second order'
effect. To put it another way - I know this is going to vary from
vehicle to vehicle as you quite rightly say - but what effect does air
resistance have on the size of payload? 1%? 10%? My current program
ignores air resistance altogether, and I am just curious as to the
size of error this introduces.