Flight MH17 Downed By 'High-Energy Objects

originally posted by: Xcathdra

originally posted by: spy66
a reply to: Xcathdra

True. But dot you see the problem With this?

Russia is doomed they have no chance in hell to defend them selves.
They are the accused. The accused have a legal right to see the evidence.

The purpose of the investigation, as is stated in the report itself, was to determine the cause of the crash only. Responsibility for who brought it down is a separate issue all together and is not the focus of the Dutch investigation.

No it is not. Because the US have accused Russia, by that stating that they have evidence that proove With out doubt that it was Russa who delivered the BUK to the speratists who brought Down Mh17.

The US have also stepped up their sanctions and deplomatics to punish Russia for their involvment.

originally posted by: Xcathdra

originally posted by: spy66
EDIT: well the US actually are lambasting the process by forcing the EU to agree to sanctions.

Care to support this information by linking us to your source?

Last I checked the sanctions Germany is wanting in place were put in place by the US sometime back. We have not forced Europe to do anything.

That is the thing. How would you know?

I am taking a brake because this is getting stupid.

a reply to: spy66

One more time -

The purpose of the investigation, as is stated in the report itself, was to determine the cause of the crash only. Responsibility for who brought it down is a separate issue all together and is not the focus of the Dutch investigation.

Also Russia has done its fair share of blaming Ukraine so I really dont think there is room for your argument about just the US. I just posted an article on the page before this where the russian defense minister told Malaysia Ukraine is responsible.

If person A walks up to person B, pulls out a gun and shoots him dead, its up to the coroner to determine cause of death. His function is not to determine who the suspect is but to determine what killed person B. Even in the Ferguson MO fiasco, regardless of all the witnesses, what law enforcement states, etc the cause of death was not officially determined until the coroner makes his ruling.

The Dutch investigations team sole purpose is to determine what WHAT and not WHO. The latter part comes next.

originally posted by: spy66
That is the thing. How would you know?

That would be why I asked you to cite your source since the info I have seen does not support the accusation you made.

a reply to: spy66

Let's listen to what a Russian General has to say.

"Second. The holes left by the strike elements on the Boeing's outer skin indicate that the warhead blew up from below and sideways. A Buk missile strikes the target from above," he said.
Source: Russia Beyond the Headlines - rbth.com...)

Of course we know that it was struck from above and not from below, the evidence clearly points to this fact.

a reply to: spy66

No it is not. Because the US have accused Russia, by that stating that they have evidence that proove With out doubt that it was Russa who delivered the BUK to the speratists who brought Down Mh17.

Please post a link to a reliable source quoting an American official making the statement you claim.

a reply to: spy66

Frankly, Russia and the Ukraine as well should not be involved in the investigation process.

Would potential suspects be allowed to participate in the investigation of a murder?

Conflict of interest.

To imply or state that Russia and the Ukraine, for that matter, should be involved is just ignorant.

a reply to: spy66

Take a break instead. Will do you better.

originally posted by: spy66
Here is the video of the SU-25. You can see it at: 5:53

I think it's the 5:38 mark you are talking about. It shows 8700m's, not 8900m's. It is higher than the service ceiling, which everyone has acknowledged it is possible to exceed. It also shows it in a nose-up attitude. Unfortunately, we don't get to see the VSI and see what the climb rate is. If it is under 500', we could conclude it is not demonstrating performance beyond the service ceiling listed spec. It is wings-level, which makes sense, b/c at those altitudes you don't want to turn any lift into a horizontal component. You are using it all to stay in the air. Indicated airspeed is under 500 km/h. That's probably because thrust is being used in a vertical direction as well as horizontal.
So it is quite a bit lower than 35,000' (by 3km). It is also quite a bit slower than the 905 km/h cruise speed of a 777. Not close enough for an attack with cannons, and the damage isn't consistent with cannon fire. The R-60 is probably the most lethal weapon carried by the Su-25 for air-to-air purposes. We've already seen a R-60 hit a business jet carrying Botswanan president. The aircraft was damaged, but landed safely. We saw a R-60 hit a 707 (KAL 902. 707 is also smaller than a 777). The plane continued on and landed safely. On a frozen lake, no less. Neither disintegrated midair.

a reply to: _Del_

Don't you think that airspeed is indicated in knots? that would mean a speed 926 km per hour, at this altitude it would probably stall if the speed is 500 km per hour.
The higher an aircraft goes, the higher the stall speed is.

a reply to: spy66

Actually, I did. There is a variant that can fly higher, that was recently introduced, but they are in very limited numbers, and only Russia operates them.

originally posted by: Aloysius the Gaul

originally posted by: tanka418

originally posted by: _Del_

originally posted by: tanka418
Along with a further assertion that an SU-25 can in fact reach 35,000 feet. Despite the dramatic lack of power of its engines.

Again, can you show me the RoC formula you worked for that? Or is that just, that you feel it can reach 70,000'?

L = 1/2(pv^2) A Cl

L is lift force,
ρ is air density,
v is true airspeed,
A is planform area, and
Cl is the lift coefficient

Does that work for ya?!!??

Indeed - looks good to me.

now can you tell me the values you used to determine that an Su-25 can easily reach 35,000 feet?

Some things need to known about the SU-25. It is a ground support aircraft, not unlike the A-10. It is intended to fly "low and slow" and inflict max damage to ground objects. To do this it requires "high lift" wings, and indeed, one of the requirements, surface area is dealt with in fine manner; the wings are larger than those of a F-16, we'll see hw that plays in all this in a bit.

The general equation for lift is:
L = 1/2(pv^2) A Cl (according to Nasa)

L is lift force,
ρ is air density,
v is true airspeed,
A is planform area, and
Cl is the lift coefficient

The values:
p ... air density. There are several air density calculators on the internet, most give a different value, but all agree on this in general:
23,000 feet: 0.03 kg/m3
35,000 feet: 0.02 kg/m3

We get to choose some reasonable airspeed, say around 400 mph (this is a 606 mph craft according to available specs

The surface area of the wings is stated to be: aprox 323 sqft

That leaves Cl or coefficient of lift. This value is typically rather variable, and can depend on many factors. I found a chart that list some typical maximum values, and if you do a search for coefficients of lift charts, you can find many that seem to show that most, especially military, craft enjoy a healthy Cl...

But since this value can be affected by things like weapon load, and other factors I thought we'd give our wee aircraft a horrible coefficient of lift, say; 0.1
At 23,000 feet
400^2 = 160,000
1/2(0.03 * 160000) = 2400

2400 * 323 = 775200 * 0.1 = 77520 Pounds of lift

At 35000 feet
1/2(0.02 * 160000) = 1600

1600 * 323 = 516800 * 0.1 = 51680 pounds of lift

As per the published specs (link above) this craft is: "14,600 kg (32,187 lb) (normal take-off weight)"

The lift produced is more than ample to support flight at 35,000 feet. And, it appears I was wrong about it's engnes...it sees that they produce nearly 10,000 pounds of thrust each (the SU-25 has 2 engines); so nearly 20,000 pounds of thrust on a take off weight of 38,000 actually isn't a bad power to weight ratio.

So anyway; for all the skeptics, and non-believers, there is it is: proof.

I expect to be told I'm wrong, and probably without showing us the "proper" method...that's fine, just understand that you can not twist science very far, and science will always provide truth and reality...as t has done here.

a reply to: tanka418

Are you sure it can reach 400 kts with a full load??

Also you have mixed your measurement systems - you cannot use air density in metric and wing area in square feet, for example.

Correcting for square feet into square meters your values have to be divided by about 10 c(roughly 10:1).

Correcting for knots into meters per second 400 knots is about 205.8m/sec - which, squared, comes to 42,343, not 160,000, and so cuts your values by about 1/4 in addition.

So right away your values are approximately 40 times what they should be.

No wonder you are confused!!

originally posted by: Aloysius the Gaul
a reply to: tanka418

Are you sure it can reach 400 kts with a full load??

Also you have mixed your measurement systems - you cannot use air density in metric and wing area in square feet, for example.

Correcting for square feet into square meters your values have to be divided by about 10 c(roughly 10:1).

Correcting for knots into meters per second 400 knots is about 205.8m/sec - which, squared, comes to 42,343, not 160,000, and so cuts your values by about 1/4 in addition.

So right away your values are approximately 40 times what they should be.

No wonder you are confused!!

No where near as "confused" as you think...but then again; your craft can't fly...

However, even after properly correcting for the air density, the wings still provide well over 32,000 pounds of lift at 35,000 feet. If we use a realistic coefficient of lift (something over 1) then it becomes rather easy for 35,000.

Sorry for the oversight.

originally posted by: Aloysius the Gaul
Also you have mixed your measurement systems - you cannot use air density in metric and wing area in square feet, for example.

And he's going to have to correct for weight/lift units as well... But, hey, math is just "unsubstantiated BS", right?

originally posted by: tanka418

No where near as "confused" as you think...

However, even after properly correcting for the air density, the wings still provide well over 32,000 pounds of lift at 35,000 feet. If we use a realistic coefficient of lift (something over 1) then it becomes rather easy for 35,000.

Sorry for the oversight.

Can you work an equation showing a Coefficient of lift at, say a healthy 1.0 for me/you (we'll keep the math simple)? I'd like to see your number and why you think it is well over 32000 lbf (you should probably stick to metric for the conversation, so that you don't have to keep converting back and forth for us).

Because my napkin number looks a lot less than that.

a reply to: tanka418

I didn't do the whole math, so I have no "craft" that can't fly. However the math will certainly allow "my" aircraft to fly with a more generous Coefficient of Lift - as you yourself said you used quite a harsh one.

So let's see how the math pans out using your values all converted to metric:

1/ p = 0.03 or 0.02kg/m^3
2/ v = 205 m/s
3/ A = 33.7 m^2
4/ Cl = 0.1

So the basic value generated without Cl at 23,000 feet is 21,243 kg. At 35,000 feet it is 14,162kg.

Now we can multiply that by Cl - let's give it a "reasonable" coefficient rather than a horrible one. Coefficients of lift vary with a number of factors - one of which is angle of attack.

So let's see what sort of coefficient of lift would require the Su-25 to fly at normal empty takeoff weight at 25,000 feet:

Normal takeoff weight (empty) is listed as 14,600 kg - so at that weight the Cl would need to be 14,600/21,243, or 0.688.

wiki'slift coefficient page shows a range of "typical" Cl's on a graph - 0.688 looks like it would "typically" be achieved at slightly more than 0 degrees angle of attack - which is pretty much what you'd expect an aircraft to have if flying fast.

so the metric math gives a figure that is reasonably close to the published specs - the aircraft looks to be able to fly at 25,000 feet, at a high cruise speed, with a small positive angle of attack.

At 35,000 feet the Cl would have to be 14,600/14/162 = 1.03. Such a Cl is by no means impossible using flaps or a higher angle of attack - about 5 degrees on wiki's graph - but of course that increases drag (as does using flaps) and the question then becomes whether or not the engines can generate enough thrust to overcome that drag at that altitude - which is a whole different set of equations.

So my question for your math is - were you using the right units? I'm pretty sure, for example, that speed should be in feet per second or something similar, not "knots".

I was taught using Imperial units, but long ago stopped using them so do not claim any proficiency in them now - so can you show your workings ensuring that you are using consistent units to achieve your result?

Thanks.

a reply to: Aloysius the Gaul

It's actually worse, because lift force (if we're sticking to metric) is going to come out in kg-m/s^2 (or Newtons). And that is one force acting on the aircraft. The other is gravitation (f=ma), so we have to subtract that which we haven't done yet, to find the net upforce generated by the wing...

a reply to: _Del_

which just goes to show how careful one has to be with units!!