I can't imagine how a US spy-plane could have strayed over the border into Iran........

Tourist

The Iranians think they know... see my last post

I was being sarcastic.

Does anyone here really believe that the US needs to use a stealth UAV over Afghanistan, or that the Irani's have the capability to take charge of one of those little kids toy helicopters let alone a spangly new stealth toy?

I'm guessing (betting:E) engine failure or loss of datalink.

Thanks, Teeej.

I read that too. My question really is, is it press, political prancing, something that really happened or posturing? I guess without access to the real int, in't hard to tell. Yeas, it looks like something has been shot down. No surprises from anyonone that thet MAY have been UAVs flying there - I would hope they would be. I'd like to hear more on this one. Not one to jump to conclusions too quickly. Or speculate too much in public just yet.

On the other hand, what the hell am I doing here. Fair cop. Shoot me!! :rolleyes:

The remainder of today, then 10 days until SAM's deadline (oops, poor choice of word). I'm a bit worried about his absence from the discussion - perhaps he really has been taken into custody for questioning about his inside knowledge of military and geo-political sensitive areas...

I think the latest development is yet another example of Iranian paranoia/schizophrenia and how they want to be seen by their neighbours - as on the ball, high-tech, no nonsense hard liners, some of whom wouldn't mind having a a dash of the capitalist, secular western values that (almost) were once the norm in their country (setting aside the brutally repressive dictatorship that enabled it to be so).

As for the damage, I don't think it was inflicted by air delivered bombing, far too neat a pattern. More likely an unfortunate accident, or deliberate self destruction to stir the intel plot.

Mister B

SAM

:rolleyes:

Why, and I ask with a due sense of dread, would it have hit at a minimum of 120mph due to the height at which it flew?

It wouldn't be the first time a 'plane has 'landed' without anyone at the controls - whether on-board or remote.

F-106 Delta Dart - 58-0787 Pilotless Landing

(I accept that the '170 probably has a somewhat more unstable design than a Delta Dart.)

Tourist,

Presumably because terminal velocity for a non-streamlined human body is 55 ms-1 (or 120 mph). So it must be the same for everything. Oh, no it’s not!

That was, with mounting horror, kind of what I was concerned SAM was about to suggest.


"gravitational V2":ooh:

Tourist,

Could be another chance for a bet :O
(Although 5 pages of sam explaining himself might kill off the thread).

Uh .... what?

I will estimate an episode of posting while tipping a few ale bottles. :cool:

'Yes, I believe Tehran downed this US drone, through jamming.'

Really? And yet in the same post you state that the drone is designed to return to base if jammed.

'The HDD carries simple functions & complex navigational data. It also has "failsafe" data that should enable the UAV - if "interfered with" to abort it's mission & fly back to it's launch point'

Not very consistent are you.

Mundane Stuff
 

Sam, I realise that most of the time you are discussing the space time continuum with Stephen Hawking, with the odd spare minutes casting pearls our way but...do you think you could PM me with the 6 winning numbers for Saturday's lottery old chap?CB

SAM

"Terminal velocity of any solid object such as a ball bearing or cannon ball (or a human body) dropped from more than approx 500ft is around 120 mph."




My worst fears are realised.



I honestly don't know where to begin.

Somebody.
Anybody?

Nobody say the "R" word...

Tourist, you may say it.

Right. From my schoolboys book of basic physics, Terminal velocity is derived from the square root of 2 x the object's mass x g (nearly 10 m/s/s) all divided by the density of the fluid (air) x the presented area of the object times the drag coefficent.

In the case of a human body, a canonball and a broken remote control aircraft, a lot of those funtions remain the same. So you tell me if a canonball with a big mass compared to its presented area will fall faster, slower or at the same speed as a human body. And then extend that argument to the RC aeroplane.

Do the maths. You'll find there is a big difference.

...and as long as the altitude from which this body started its freefall is sufficient for it to reach Vt (a few hundred feet, but can't be bothered to work it out now), anything extra is meaningless. In fact, once it's reached Vt, it will start to slow down again as it enters denser air - increased drag and greater buoyancy. Simples!

Does that help you out, Tourist? You did know where to start, but sometimes it's just too much trouble, isn't it.

Why didn't the sycamore seed that hit me on the bonce the other day leave me reeling in pain? Surely even such a small object would cause harm at such a tremendous velocity?

At 120 mph, WW, it probably would. But then it has one wing attached to it, so there are some aerodynamics involved too. Which I know was your point and thank you for feeding me the line.

The drone, if that's waht it was and if it was shot down may also have been in a sycamore seed configuration and, therefore able to land on an Iranian cranium without causing so much as a bump.

I don't know what exactly it is that you are smoking but may I carefully suggest to reduce the dose ?! :E

On a more serious note:

Re terminal velocity:
If we take a cannonball we have a Force resulting from gravity which is
m x g which gives a gravtitational Force of 4/3x Pi x r^3 x Rho (Steel) (~8.000 kg/m^3) x 9,81 m/s^2 and an opposing Force of drag being Rho (Air) (1,2kg/m^3) /2 x Cw x Pi x r^2 x v^2.
Cw for a ball between 0,2 and 0,4.

Lets assume 0,4 as a conservative number:

This yields: 660 x sqrt (r) = V term (in m/s)
Cannonball with 4 inch diameter:
=> Vterm ~ 150m/s = 335 mph.
2 inch : Vterm ~ 105m/s = 235mph.

So there is no universal terminal velocity even for a cannonball (even when neglecting Reynolds dependency of Cw which is not exactly true, for a ball Re will reduce to 1/3rd at high Reynolds numbers).

"I don't know what exactly it is that you are smoking but may I carefully suggest to reduce the dose ?! http://images.ibsrv.net/ibsrv/res/sr...ilies/evil.gif"

That was my exact thought when I read SAM's post.