Su-27LL-PS(UV)

http://www.youtube.com/watch?v=VH25jbiaiRQ
07:45 ->
 
I saw a photo of Su-27 twin seater with a square section engine housing on the left side and normal round section engine housing on the right side. The square section housing protrudes far behind even the tail stinger, making the plane look seriously tail heavy
What was this experiment about?
 
2D TVC nozzle (reportedly) for for T-60S
http://www.secretprojects.co.uk/forum/index.php/topic,13938.0.html
 
PhominSu-27_091_1_zpsfe926281.jpg
 

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Why is it so large? F119's ab and 2D tvc nozzle was similar in size to normal AB and nozzle.
 
chuck4 said:
Why is it so large? F119's ab and 2D tvc nozzle was similar in size to normal AB and nozzle.
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It was their first attempt. P&W's 1st back in the day wasn't all that much to write home about either. Hell, I read somewhere, the production nozzles for the F119 are 600lbs lighter than the ones used even on the YF119/YF-22.
 
Understood, but this is a test article mounted on a Su-27, presumably attached to a al-31 engine. So its dimensions should scale to the al-31 and thus be suitable for comparison to the normal al-31 next to it.
 
flateric said:
chuck4 said:
Why is it so large?
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once more - (reportedly) for for T-60S
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Any chance that it might also be a bit larger due to the air-scoops (mixing in cooler air with the exhaust)?? None of the pictures show the front well, but it seems to have both dorsal and ventral openings.

Btw. Is there a reason (other than IR reduction) to have such intakes?
 
If you can lower the gas temperature passing through the moving nozzle you may be able to use other (i.e. cheaper) materials.
 
I am thinking if this experiment is simply to test the effect of TV in flight, then may be the al-31 engine's original after burner and nozzle is still there, and is actually encased in this new nozzle. This is why this new nozzle is so bulky.


If this concept had actually gone into production, It would have become a much more compact custom job designed for the engine core, not an bulky add on to an existing engine.
 
i dont remember other than the pitch axis control on a t-10 prototype the engine lose around 10% to 15% of it's trust with the square nozzel so soon it was abndoned and the rounded nozzle was incorporated instead
 
chuck4 said:
I am thinking if this experiment is simply to test the effect of TV in flight, then may be the al-31 engine's original after burner and nozzle is still there, and is actually encased in this new nozzle. This is why this new nozzle is so bulky.
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No.

This makes so little sense, I can't begin to imagine where you got this from.

If this concept had actually gone into production, It would have become a much more compact custom job designed for the engine core, not an bulky add on to an existing engine.
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Possibly, it was a test item after all.
 
From the fact that the new TV nozzle on the Su-27 is so large and bulky, compared to the nozzle on the standard AL-31 next to it, that the standard nozzle would fit completely inside the new nozzle, with room to spare.
 
you should read something like "How stuff works" on nozzle physics before making such wrong assumptions
 
this picture clearly shows the engine slot on parlay site ( i think i got the photo from there too )and in my books says that it was modified engine not just add-on nozzle
im asking my self right now if it was with the features of the Su-25 engines too im talking about the mixing in cooler air with the exhaust
 

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Not sure what books do you mean, but it was old good AL-31F
 
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Ivan Borislavov & Alexandur Mladenov Jet Planes volume 5 (Russia, 1961-1999) Airgroup2000
don't remember the page thanks flateric is there any drawnings of the nozzel plus one more question were the intakes on the both and the upper side of the engine used for gas-dynamic thrust vector control ? or just for mixing in cooler air with the exhaust as on the Su-25
 
not to speculate too much, but could it be a test nozzle for an still secret test aircraft?
 
try to read recent posts once more
 
[quote author=piko1]were the intakes on the both and the upper side of the engine used for gas-dynamic thrust vector control ? or just for mixing in cooler air with the exhaust as on the Su-25
[/quote]
last one
I think that Sukhoi staff knows better what engine they had on this bird than Mladenov&Co. - and they say that both engines were -31F
 
i understand you the first time but i was asking about the nozzle module plus i know that Mladenov and co are wrong for many things :D
 
kcran567 said:
not to speculate too much, but could it be a test nozzle for an still secret test aircraft?
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PLEASE read previous posts.


It is suggested to have been related to the Sukhoi T-60S program.


As to shape and size - it may well represent the entire exhaust section of the T-60S bomber.
 
some unconfirmed sources say that Sukhoi tried to drop out a disinformation that nozzle tests were "related to Sukhoi-Gulfstream SSBJ project"
even compared to PW monsters used on F-15SMTD it just looks too OVERSIZED for T-10. remember that there were parallel tests with axysymmetric nozzle on other testbed - Su-27LL-UV(KS) and it was much smaller...
and it's known that at least at some project stage T-60S was designed to use TVC
 
Here's one of Paralay's speculative drawings using the nozzle shape of the LL-PS(UV). Looks much more sensible in this context.
 

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thanks Paul but can the mixing the cooler air with the exhaust be the reason for the drop of the trust ?
 
most % of thrust losses is caused by transition from circle to square sections of the nozzle
 
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Normal thrust vector is in x-dimension (no steering, just straight to the back). If it moves additionally into y-direction its 2 dimensions. Add z-direction and you have 3 dimensions.
 

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