Is RationalWiki a crackpot site?

[PartialDerivative]

Given your apparent inability of discussing something without making insinuations of irrelevant conspiracy theories I'll consider this answer utterly useless. It seems like you and that admin on RationalWiki would fit quite well together.

Thank you, my experience with it is limited to this one instance so I wasn't sure if this was a general thing with that site.

Interesting to see this. Someone agrees with you without showing any evidence you praise them. Someone else disagrees with you the same way and you flame them. Biased much?
Seems pretty clear that you already made up your mind, and only posted this topic to receive some confirmation.

 

[caveman1917]

Interesting to see this. Someone agrees with you without showing any evidence you praise them. Someone else disagrees with you the same way and you flame them. Biased much?

The latter person did not disagree "in the same way" but showed in their very next post an inability to even consider the point under consideration. In fact, as you can see in my statement you quoted, I've explicitly stated this as the basis for rejecting their claim as useless. If the former person had, after saying "of course it is", then proceeded to show an inability to even engage with the subject then it would have been rejected on the same basis.

 

[catsmate]

Sigh. If you have a conspiracy theory regarding MH-17 then feel free to take your own advice and go argue it there. But stop derailing this thread, thank you. And this goes just as well for any of the others among you who seem to find it impossible to discuss flight characteristics of the Su-25 without bringing up a bunch of junk about MH-17.

And yet your OP was based on a webpage about the nutty conspiracy theories about MH-17.

Given your apparent inability of discussing something without making insinuations of irrelevant conspiracy theories I'll consider this answer utterly useless. It seems like you and that admin on RationalWiki would fit quite well together.

Must try harder.

Betteridge's Law of Headlines

Exactly.

 

[caveman1917]

And yet your OP was based on a webpage about the nutty conspiracy theories about MH-17.

My OP was based on a webpage making claims about the flight characteristics of an Su-25, as well as observations which proceeded from me trying to correct the claims made therein. Are you capable of reading comprehension?

 

[caveman1917]

One can of course note that the crank claims are still being peddled in that article, with catsmate joining in what is apparently the methodology being used - ie making random insinuations about "conspiracy theories" which not only have nothing to do with the statements being refuted (ie flight ceiling) but seem nothing more than a diversion so as not having to engage with any contradictory evidence.

 

[Aepervius]

No it isn't, that's another misinterpretation of the data. The 5km is the maximum height for the safe use of the main cannon, not a reduced flight ceiling for carrying armaments. For instance in Afghanistan combat missions were regularly flown at 10km, or you could take a look at the youtube video I linked to where you can see that they're flying fully loaded.

That's your interpretation. All source I can find says 5000 meter fully armed. Not 5000 dogfight max altitude, and your own youtube does not shows pod loaded with missiles (or even tanks) (on a related note the blaring music is deafening). I doubt everybody would take dogfight altitude as the service ceiling altitude for armed flight when most of the service will be done NOT dogfighting.

In fact dogfighting does not change the profile of the airplane, loading the pod does. That is why the max ceiling change : change of aerodynamic profile.

 

[caveman1917]

That's your interpretation. All source I can find says 5000 meter fully armed. Not 5000 dogfight max altitude, and your own youtube does not shows pod loaded with missiles (or even tanks) (on a related note the blaring music is deafening). I doubt everybody would take dogfight altitude as the service ceiling altitude for armed flight when most of the service will be done NOT dogfighting.

In fact dogfighting does not change the profile of the airplane, loading the pod does. That is why the max ceiling change : change of aerodynamic profile.

The Su-25 is not a fighter jet but a ground attack jet, its main role is not dog-fighting but anti-tank use. Its main cannon, the GSh-30-2 is not recoil-less. The 5km figure is the height, above which, the remaining engine thrust after accounting for the recoil of the main cannon would be too low to prevent stalling.

your own youtube does not shows pod loaded with missiles (or even tanks)

Then why do the hardpoint indicators in the plane show them to be loaded? 5m40 into the video, the green lights under the outline of the aircraft. As much as the imagery might not be that clear, it does appear to show R-60s loaded on the other planes as well.

ETA: besides, if they're not loaded, then what are they firing (such as at 3m47)?

 

[Aepervius]

The Su-25 is not a fighter jet but a ground attack jet, its main role is not dog-fighting but anti-tank use. Its main cannon, the GSh-30-2 is not recoil-less. The 5km figure is the height, above which, the remaining engine thrust after accounting for the recoil of the main cannon would be too low to prevent stalling.



Then why do the hardpoint indicators in the plane show them to be loaded? 5m40 into the video, the green lights under the outline of the aircraft. As much as the imagery might not be that clear, it does appear to show R-60s loaded on the other planes as well.

ETA: besides, if they're not loaded, then what are they firing (such as at 3m47)?

I have no idea but it is quite clear from the time stamp I marked there is no pod.

But you are definitively wrong. The armed altitude is not the dogfight altitude : It is the pod loaded altitude when aerodynamic of the plane is changed. As for your claim of the canon not being able to be used below a certain ceiling I find that nowhere to be found except by a few crank on MH17 threads. All NATO and armory web site I consulted, none
mention an max altitude for the canon.

 

[Aepervius]

Also I doubt the motor would be disturbed by the twin gun. It fire at most 3000 round per minutes, so 50 per seconds, at a muzzle velocity of 870 m.s-1 of 30*165 mm.

If it was enough order of magnitude to slow down an engine meant to propel a multi tons aircraft by a good order of magnitude, it would literally pulverize backward the BMP 2 it is also mounted on.

Now I may be wrong with my napkin calculation, so how about you show the source of your claim ?

 

[catsmate]

My OP was based on a webpage making claims about the flight characteristics of an Su-25, as well as observations which proceeded from me trying to correct the claims made therein. Are you capable of reading comprehension?

Yes I am. I'm also capable of understanding why people make such claims.

One can of course note that the crank claims are still being peddled in that article, with catsmate joining in what is apparently the methodology being used - ie making random insinuations about "conspiracy theories" which not only have nothing to do with the statements being refuted (ie flight ceiling) but seem nothing more than a diversion so as not having to engage with any contradictory evidence.

The entire nonsense about MH-17 being shot down by a Frogfoot is a conspiracy theory; one initiated by pro-Russian sources and peddled by Putin sympathasiers to try and cast doubt on the reality, that pro-Russian separatists shot down a civilian airliner with a Russian supplied missile system.

Also I doubt the motor would be disturbed by the twin gun. It fire at most 3000 round per minutes, so 50 per seconds, at a muzzle velocity of 870 m.s-1 of 30*165 mm.

If it was enough order of magnitude to slow down an engine meant to propel a multi tons aircraft by a good order of magnitude, it would literally pulverize backward the BMP 2 it is also mounted on.

Now I may be wrong with my napkin calculation, so how about you show the source of your claim ?

Indeed it would be nice for caveman, or anyone else who believes in the Frogfoot shoot-down nonsense, to show some reliable sources for the claim.

 

[caveman1917]

I have no idea but it is quite clear from the time stamp I marked there is no pod.

You did not mark a time stamp.

But you are definitively wrong.

I'm definitively wrong about them being loaded even though you can clearly see them actually firing missiles? And that's ignoring the status indicators in the plane itself.

The armed altitude is not the dogfight altitude : It is the pod loaded altitude when aerodynamic of the plane is changed.

Yes, which is the 10km figure.

As for your claim of the canon not being able to be used below a certain ceiling I find that nowhere to be found except by a few crank on MH17 threads. All NATO and armory web site I consulted, none mention an max altitude for the canon.

There is no max altitude for the cannon. Heck, it could probably even be used in space. There is, however, a max altitude for the plane using the cannon.

The plane has a twin R-195 turbojet, each providing about 45 kN of thrust at sea level. While the thrust-to-altitude profile depends on the specific engine, for the JT8D-17 the thrust at about 7km altitude is about halved. Assuming this is comparable, that leaves 45 kN of thrust for the R-195 at 7km.

The cannon is dual-barrel, projectile weight 390 g, muzzle velocity 870 m/s, rate of fire 50/s. Or a total of 390 x 2 x 50 = 39 kg expelled forwards, per second, at 870 m/s. This gives a backwards thrust of about 34 kN, leaving only 11 kN of forwards thrust = stall.

 

[caveman1917]

Yes I am. I'm also capable of understanding why people make such claims.


The entire nonsense about MH-17 being shot down by a Frogfoot is a conspiracy theory; one initiated by pro-Russian sources and peddled by Putin sympathasiers to try and cast doubt on the reality, that pro-Russian separatists shot down a civilian airliner with a Russian supplied missile system.

I'm not making any claims about who shot down MH-17, I'm making claims regarding the flight characteristics of an Su-25. But of course you know that very well.

Indeed it would be nice for caveman, or anyone else who believes in the Frogfoot shoot-down nonsense, to show some reliable sources for the claim.

Wow, what a way to try to show that RationalWiki is not a crackpot site. I've given plenty of reliable sources for the claim in my OP - as I did when correcting the article, all of which clearly show a 10km flight ceiling. Too bad there aren't any reliable sources for the contradictory claims in the article, especially that "defy physics" claim - that's just plain Alex Jones level stuff.

Are you trolling or something?

Please don't bother even responding anymore unless you've got some evidence to show for your claim of a 7km flight ceiling, as well as actually refuting all the evidence to the contrary.

 

[caveman1917]

 

[caveman1917]

The plane has a twin R-195 turbojet, each providing about 45 kN of thrust at sea level. While the thrust-to-altitude profile depends on the specific engine, for the JT8D-17 the thrust at about 7km altitude is about halved. Assuming this is comparable, that leaves 45 kN of thrust for the R-195 at 7km.

The cannon is dual-barrel, projectile weight 390 g, muzzle velocity 870 m/s, rate of fire 50/s. Or a total of 390 x 2 x 50 = 39 kg expelled forwards, per second, at 870 m/s. This gives a backwards thrust of about 34 kN, leaving only 11 kN of forwards thrust = stall.

This would all probably go a lot easier if people cared to remember that the Su-25 is not a fighter plane. It was not designed for air combat but for ground attack, specifically anti-tank operations. Its main mission profile is low-flying strafing runs on armoured columns, that's what the main cannon is for, not for dog-fighting. There was never any need for the cannon to be used at high altitude, hence why it wasn't designed for that and can't be used above 5km.

 

[pipelineaudio]

Betteridge's Law of Headlines

Wow! I thought rationalwiki was a bit slanted before but damn....

 

[Trebuchet]

Caveman, here is where I think your problem lies:
You appear to be trying to correct technical specifications of the airplane, and not just to support Russian conspiracy theories about the shootdown of MH17. However, you edited RW as a BoN (Bunch of Numbers) rather than joining up, at a time when such conspiracy theories were being promoted, including on Wikipedia by people with Russian IP addresses changing airplane performance information. It seems natural to me that the RW editor figured you to be another such vandal. The fact that you seem so stubbornly set on the issue doesn't help.

RW is not a crackpot site. It is an anti-crackpot site. I find it a great resource for info on various forms of woo, without being handicapped by Wikipedia's NPOV restrictions.

 

[theprestige]

Help me understand: Could a Su-27 shoot down an airliner at altitude, or not?

 

[caveman1917]

However, you edited RW as a BoN (Bunch of Numbers) rather than joining up

This is ad hominem reasoning. The truth-value of a proposition is independent of who produced it. If that edit were even made by, say, a cat accidentally walking over a keyboard then it still wouldn't change one iota about whether the claim is true or not.

at a time when such conspiracy theories were being promoted

Conspiracy theories were being promoted by both sides, Western media were in that respect not one bit better than their Russian counterparts.

including on Wikipedia by people with Russian IP addresses changing airplane performance information.

As it quickly turned out they were trying to enter the correct airplane performance information - think about that for a minute.

As I said earlier, I watched that particular edit warring play out on wikipedia back then. Russian IP claiming to be an Su-25 pilot edited flight ceiling, gets reverted and blocked. This repeats a couple of times. I go check actual sources on this and find that the editor was correct. Everything seemed to check out, including explaining the use of a Russian government IP address - as would be expected with a pilot in the Russian airforce. Seems the "Western" side to this was doing nothing but droning on about a page on some old export version of the Su-25 that they found on the manufacturer's website, with a good deal of racist ad-hom attacks thrown in against the Russian IP editors.

Regarding the racist dimension to all this, why are you so specifically making sure to say that it's a Russian IP address? Is this supposed to evoke some sort of a priori negative connotation to the claims they make? Is it supposed to evoke our conspiracist thinking, whereupon we'll assume the edit made by that IP address is due to some "disinformation campaign by the Kremlin" or something like that? If the latter, as lowly as you might think of Russians, don't you think that if the Kremlin were doing that they would know how to use a proxy server?

It seems natural to me that the RW editor figured you to be another such vandal.

"Figuring" would imply some sort of thought process going on, I'm not seeing evidence of that in this case. There's nothing "natural" about it, if he can't even be bothered to engage with any references provided then he shouldn't be bothering with reverting it either. And that's ignoring everything else, like the ad-hom appeals.

The fact that you seem so stubbornly set on the issue doesn't help.

Yes, I've certainly created a bit of a fuzz about it. Doesn't it make you wonder how many more instances of this sort of nonsense have happened but where the editor just silently gave up, and hence never came to light? Also, is that another instance of this "you appear serious therefor your claim is wrong" reasoning?

RW is not a crackpot site. It is an anti-crackpot site.

As far as I'm concerned the jury is still out on that. I checked the logic portal - that always gives a good indication of such things, and did indeed find it to be quite decent. On the other hand, I've also followed up on that "far-left" thing they have going and found it to be more close to crackpottery than what one could consider rational.

 

[caveman1917]

Help me understand: Could a Su-27 shoot down an airliner at altitude, or not?

Of course it can, an Su-27 is a fighter plane designed for air-superiority - including the taking down of AWACS aircraft, which would be similar to taking down a civilian airliner.

We are, however, talking about an Su-25 and not an Su-27. If you're asking "could an Su-25 have shot down MH-17?", in a strictly physical-technical sense it probably could. However, that doesn't mean it did and everything points to it not having done so. Not the least of which being that the AA missiles carried by the Su-25 are heatseeking and would've impacted the engine, whereas the Buk is radar-guided and would've come in from above. The latter is consistent with the damage pattern observed. The Su-25 would also have needed to be extremely lucky, since it can not keep up with the airliner.

I do remember that people claimed to have set up this mission in a military flight sim and were able to successfully fly it. I have no idea about the value of those claims as I didn't own the software - though it looked decent - and I don't remember where I found those claims anyway. This was 2 years ago.

ETA: it sure as hell couldn't have done it with the cannon though

 

[Aepervius]

You did not mark a time stamp.



I'm definitively wrong about them being loaded even though you can clearly see them actually firing missiles? And that's ignoring the status indicators in the plane itself.



Yes, which is the 10km figure.



There is no max altitude for the cannon. Heck, it could probably even be used in space. There is, however, a max altitude for the plane using the cannon.

The plane has a twin R-195 turbojet, each providing about 45 kN of thrust at sea level. While the thrust-to-altitude profile depends on the specific engine, for the JT8D-17 the thrust at about 7km altitude is about halved. Assuming this is comparable, that leaves 45 kN of thrust for the R-195 at 7km.

The cannon is dual-barrel, projectile weight 390 g, muzzle velocity 870 m/s, rate of fire 50/s. Or a total of 390 x 2 x 50 = 39 kg expelled forwards, per second, at 870 m/s. This gives a backwards thrust of about 34 kN, leaving only 11 kN of forwards thrust = stall.

About time stamp : look at the video a bit later, you see there is nothing under the wings.

That would be true if it was firing *constantly*. No fighter does that, it only in short burst because ammunition is very limited. Forget topgun films . But it has barely any munition to fire about 10 to 20 seconds and NO fighter will fire that long (technical detail I read are about 800 bullets).

Your reasonning is good if it had infinite ammunition it does not.

Again I reiterate : show me the technical doc saying the altitude is restricted due to that. You will not find it.

The restriction on altitude is due to the aerodynamic change when the pod are loaded.