SU-37: On the cusp of super maneuverability

[deathfromafar]

Urggg, I meant to post this:

http://www.militarytimes.com/multim...w=&state=vid&em=false&fn=/flv/20080714_rc_f22

Not sure if you've seen this version of the demo but it's pretty cool!

 

[warchild]

you realize of course i'm going to have to reread this several times just to soak it all in dont you?? :;chuckles:: Having been out of the military for fourty some years now ( argh) I only get to see civilian approved propaganda films from our nation as well as others. Its when i sit down with my calculator that i start scratching my head wondering how we could ever make some of the obviously overblown claims we make ( we, the russians, the chinese.. seems the only ones not boasting are the indians and israeli, and frankly, they both scare me ).. the numbers dont support it..
I'm surprised that the Pak Fa isnt stealthy. With those wings, it could carry a massive loadout. Make one hell of a strike platform.
i'm not surprised at what you say about the F-35 and SU-35. small, inexpesive ( comparitively ) and highly capable. more so than other nations leading fighters. And both of them developed for the same reason. The F-35 replaces/supplements the F-16, F-22, and F/A-18 and the Su-35 replaces/supplements the Su-27, and 37, with production and maintenance costs being the primary reasons for replacing/supplementing the f-22s and su-37s. If i'm not mistaken, the Su-30s are pimrily developed for export sales such as to India and south Africa.
One aircraft neither you nor i have mentioned is the T-90 (?) Pak Da.. To be honest, i dont even know if its a real plane or some teenagers bad joke. Would you know anything on that one??

I( just watched the video of the F-22. Pretty cool indeed. I made the initial flight model for the Iris F-22 using the same base fde as i'm using in the su-37. David made some small modifications to his liking and the rest is history, but to be honest, i didnt know half as much then as i do now.. Whats really amazing is if you watch the video in the link you just posted, then watch the video i posted above of the SU-37s flight model. They're almost identical. kinda scary in a good kinda way .. The f-22 is quite an impressive bird, buit without active canards, its limited. The SU-35/37 with their canards, can flip on its back without exiting their flight paths. the entire radius of their loop is contained within the su-35/37s control surface zone. the F-22 can exit a high AOA maneuver from many angles, the Su-35/37 can exit a high AOA maneuver from any angle, including a few i didnt believe were invented yet. I think the biggest telling though is that at Farnbourough ( SP? ) in 1999 after the show was over ( a show which Sukhoi was almost sabotaged by the folks who make the eurofighter ). and the su-37 and F-22 had flown, Director Simonov of Sukhoi issued a standing challenge to any nation to dogfight the Su-37. To this very day, Lockheed backpedals and makes excuses, and with the Crash of Su-37 #711 the showdown will never happen. Its a pity really. That would be one HELL of a dogfight. but as you say, the combat environment any more is getting frighteningly terrifying. Even for an old combat vet like myself.
I'm loving this conversation
Pam

PS.. Amen to being prepared. never overestimate yourself, and never underestimate anyone else. If we accept the facts that exist, then we can build against the negatives, the downsides, and strengthen/supplement the positives, the upsides. Its justnthat damnit, i'm an american. i do not like accepting that we arent what we once were any more.. but we arent. Humble pie can taste pretty fowl.. as in crow..

 

[napamule]

The Other F-22

I am talking about the Virtavia F-22 in FSX. Made a short video. I'm just showing off? Perhaps. But it remains that FSX has possibilities. It's the model that makes it all possible, not the pilot skills, or even the flight dynamics. My opinion of course. Link: http://youtu.be/2ar4dr1-WdA .
Chuck B
Napamule

 

[thunder100]

Part of the problem we/v had with TVC is that we in the US, havent been able to design seals between the engine and the nozzel that would remain sealed. also, our designs change the shape of the exhaust, crimping it and squishing it, and therefore, making it worthless.. Lyulka/Saturn overcame both of those problems. theirs works, ours??

Pam

Without beeing deep insider there is annother US problem-->on the other side of the engine.Historically the US jets tend to flame out in high AOA configurations-->something was overcome in Russia since Mig-29.

And this part need to be solved even on UAV's(also my personal enemy's)

I was time ago with 2 buddy's(Marines pilots) at an airshow including SU-27.At a high AOA flyby(hoovering) both said that their F-18's(Both on C's but had flown E's as well) would simply fall out of air as the engines will almost instantly stall

And history always repeats itself.After a future bloody nose as a manmounted pilot can overcome the computers of UAV#s by sheer human unpredictability,the wheels will start to turn back

Lets see

Roland

 

[warchild]

I am talking about the Virtavia F-22 in FSX. Made a short video. I'm just showing off? Perhaps. But it remains that FSX has possibilities. It's the model that makes it all possible, not the pilot skills, or even the flight dynamics. My opinion of course. Link: http://youtu.be/2ar4dr1-WdA .
Chuck B
Napamule

::: That looks like you were having a blast..

 

[warchild]

Pam

Without beeing deep insider there is annother US problem-->on the other side of the engine.Historically the US jets tend to flame out in high AOA configurations-->something was overcome in Russia since Mig-29.


Roland

if you look closely at russian air intakes, you'll see slots on the bottom and sides. in the mouth of the intake theres an air damn that lifts up into position above the slots to funnel the air back into the mouth of the engine. Thats the part that changed. It isnt that we couldnt figure it out. its grade school simple. I just think that perhaps we havent had the right incentive yet. but that leads to a conversation area that isnt healthy for the forum so i would prefer we not go there..
Pam

 

[LonelyplanetXO]

Hm, F18's cant do high AOA? I suspect disinformation there... check this out from an airshow I remember a few years ago


this one's same display, better quality but doesn't show the really high AOA maneuvres in the first one.

LPXO

 

[deathfromafar]

The old Hornet is actually a heck of a lot more maneuverable than many give it credit for but rarely does it get seen to this level or better. I can't remember the last time I saw a US F/A-18A/C being flown like that. Mostly I saw Canadian Hornet demo pilots really wringing them out. But also factor in that average Hornet pilot experience and a slew of maneuver/configuration restrictions probably account for much of the average(some would use the word "lame") demos we've seen in recent years. The Viper and Hornet can get away with some high AoA tricks even though they lack louvered aux intakes that allow the engine to breath normally at high alpha. It is true that most of the newer dash series engines in the 3rd Gen US Fighters are not as susceptible to compressor stalls, surges, and flameouts(I'm referring to the F-16 and F/A-18) due to refinements in the core hot section components and in conjunction with good intake geometry/position. Still, they were never intended to cope with High AoA or extreme lateral airflow divergence(from extreme yaw) but the F-16MATV and F/A-18HARV did pretty well.

One other factor I didn't mention regarding TVC is that any aircraft that carries an external load and utilizing TVC may run into serious stability issues with an asymmetric load at high AoA. What this means is that when they are heavier on one side after firing even one weapon, the asymmetry "could" be significant enough to cause departure even in TVC post stall envelopes due to the weight asymmetry exceeding the moment values of the TVC control inputs. This is obviously accentuated up at higher altitude/lower air density. I'd be willing to bet that the TVC Sukhois have significant restrictions on TVC use in such configurations/envelopes to prevent departures and overstress on the airframe. The latter brings up the other question as to what gross weight/weapon loadout config restrictions(on conventional fighters with wing stations) might exist on TVC use at all altitudes. One advantage of the F-22 is that it keeps it's weapons internally close to the CG and is pretty much in the same drag and balance profile at all times.

Here's an interesting video regarding weight asymmetries and maneuver limits:

http://www.youtube.com/watch?v=Rv9YC-gaNYo

 

[Sundog]

For an idea on just how maneuverable an F/A-18 is, consider that one of the most maneuverable aircraft ever built was the X-31, which was optimized for post stall maneuvering. They conducted mock dogfights between the F/A-18 and the X-31 and sometimes the F/A-18 won. The only serious problem the Hornet has ever had is lack of range and not enough thrust. In a fight it had better kill it's opponent when it pulls a maximum post stall maneuver, because it probably won't survive long enough to get a second chance due to how much energy it bleeds in such a maneuver and the lack of power to quickly recover.

Something else that should be noted is that a lot of those cool maneuvers you see flown using TV down low can't be performed at alt, since thrust drops with an increase in altitude. The Indian's learned this the hard way when they fought the USAF with their Su-30's. They kept trying to use extreme maneuvers with their TV at alt against some F-16 pilots, but it really just caused them, the Su-30's, to bleed energy rather quickly and they were stalling out. The F-16 pilots then just used their superior T/W at alt to go vertical and dive back down on the Su-30's. Though the USAF pilots said the Indians would be more formidable once they learned to properly apply their TV aircraft.

 

[warchild]

the assymetrical weight issues were addresed in the flankers by making the TVC selectable: manual or automatic.
And please dont get me wrong. i'm enjoying this conversation immensely and am learning loads. But i must admit that i find it quite humorous that when the SU-37 gets mentioned in these forums on anything more than a passing basis, that everybody has to drag out their american favorites. Why does that happen with this plane?? it doesnt happen with any other. I could talk till im blue in the face aout the eurofighter or the gripen. I could throw out Saab, and Dasault, and BAE all day and no one would blink, but mention an SU-37 and all hell breaks loose. you dont want to know the opinions of the rest of the world on our F/A-18s.. Its embarrasing. Our F-15 on the other hand Is highly respected. The russians even went so far as to create three complete new planes just to counter it ( two sukhois, two migs. the sukhois were part of the same family ). Our F-16?? The Su-27 Pilots and the F-16 pilots look at each other from afar and glare.

The SU-37 was a technology demonstrator. WAS.. it crashed. its gone now. it was a peaceful warrior, and judging by the reactions ive seen in this thread, it scared the pants off a lot of people. No insult meant, but try to look at the thread from an analysts perspective and the message is clear. Come on guys. The Su-37 was a plane. a damned good plane. So is the SU-35 ( which, since Russia is now a democracy and no longer our enemy, is offering to South korea in lieu of a debt that is owed). I dont mean to hurt anybodies feelers, but, they are all, just planes.
Now, I hate the Swastika, but, I admire and respect the German Warbirds. Theyre planes. I didnt like growing up thinking that each minute may be the minute that the idiots in moscow and washington turned the entire face of the earth into carbon ( seventeen times over ), but those days are behind us now. Time to put the hate and fears aside. its ok to love the f-22 and its ok to love the Sukhois..
lets try and keep the thread on subject. Ok??
Pam

 

[warchild]

For an idea on just how maneuverable an F/A-18 is, consider that one of the most maneuverable aircraft ever built was the X-31, which was optimized for post stall maneuvering. They conducted mock dogfights between the F/A-18 and the X-31 and sometimes the F/A-18 won. The only serious problem the Hornet has ever had is lack of range and not enough thrust. In a fight it had better kill it's opponent when it pulls a maximum post stall maneuver, because it probably won't survive long enough to get a second chance due to how much energy it bleeds in such a maneuver and the lack of power to quickly recover.

Something else that should be noted is that a lot of those cool maneuvers you see flown using TV down low can't be performed at alt, since thrust drops with an increase in altitude. The Indian's learned this the hard way when they fought the USAF with their Su-30's. They kept trying to use extreme maneuvers with their TV at alt against some F-16 pilots, but it really just caused them, the Su-30's, to bleed energy rather quickly and they were stalling out. The F-16 pilots then just used their superior T/W at alt to go vertical and dive back down on the Su-30's. Though the USAF pilots said the Indians would be more formidable once they learned to properly apply their TV aircraft.

yeahhh, the Su-30s use the Saturn/Lyulka AL-31FP which is a modified AL-31F. Base thrust is 22000 pounds. your not going to get much out of a horizontal of vertical maneuver with that. The SU-37 uses the AL-37FU, which produces a wet thrust of 31988 pounds. giving the plane a total thrust of almost 64000 pounds. twice its weight. Vertical climb speed is 48000 feet per minute. max altitude?? 48000 feet. its dry thrust is somewhere between 25000 and 27000 pounds. meaning that at 48000 feet its still delivering a useable thrust to weight ratio of approximately 1.5 to one. Its cruising speed is 840 knots, without afterburner. We can suspend our disbelief all we want, but the numbers are there. The reality is there. Frankly, the Su-37 was made to counter the F-15. it was the Pak Fa that was made to counter the F-22, and chinas more advanced designs ( if they're real ). I cant speak about the Pak Fa, as i have absolutely no verifiable information on it ( i require three sources of information ). But the SU-37?? I can talk a little on it. It was a good plane, like its older brother, the SU-35 has become.
Pam

 

[JohnC]

yeahhh, the Su-30s use the Saturn/Lyulka AL-31FP which is a modified AL-31F. Base thrust is 22000 pounds. your not going to get much out of a horizontal of vertical maneuver with that. The SU-37 uses the AL-37FU, which produces a wet thrust of 31988 pounds. giving the plane a total thrust of almost 64000 pounds. twice its weight. Vertical climb speed is 48000 feet per minute. max altitude?? 48000 feet. its dry thrust is somewhere between 25000 and 27000 pounds. meaning that at 48000 feet its still delivering a useable thrust to weight ratio of approximately 1.5 to one. Its cruising speed is 840 knots, without afterburner. We can suspend our disbelief all we want, but the numbers are there. The reality is there. Frankly, the Su-37 was made to counter the F-15. it was the Pak Fa that was made to counter the F-22, and chinas more advanced designs ( if they're real ). I cant speak about the Pak Fa, as i have absolutely no verifiable information on it ( i require three sources of information ). But the SU-37?? I can talk a little on it. It was a good plane, like its older brother, the SU-35 has become.
Pam

I've got to disagree here, it's just not possible for gas turbine's to produce that much thrust at altitude. There is a very strong correlation between thrust produced and atmospheric air density. Attached is a chart which illustrates the maximum Dry and Wet thrusts, as well as Thrust Specific fuel consumptions for the AL-31F. You can see that for maximum dry thrust; at ground static the engine produces 73kN (~16,400lbF) and at Mach 1.0 at 11km (36,000ft) this drops to 26kN (~5,850lbF). Afterburning thrust sees similar losses with 119kN (~26,750lbF) at GS and 52kN (~11,700lbF) at M1.0 & 36,000ft.

Note that at 36,000ft air density is 29.7% relative to Sea level; Note that if the comparison is only at M1.0; Max SL wet thrust is 140kN compared to 52kN (or 37% of Sea Level Thrust).

The empty weight of the Su-37 is almost 41,000lbs; given that the Maximum wet thrust of the AL-37FU is 32,000lbs at Ground Static; it's safe to assume that at M1.0 at 36,000ft, there exists an Engine Thrust to Weight ratio of 0.68. ON top of this, you always, always have to subtract the drag force of the aiframe plowing through the atmosphere. The Net Thrust to weight ratio at M0.8|36,000ft is probably well below 0.5 for this aircraft (which is quite super).

 

[warchild]

I think i might be confused here John.. I was obviously confused about the empty weight, even my own flight model has it correct, which would give the plane a Sea level thrust weight ratio of 64000/41000 or what is that that? 1.5:1 approx ( sorry, havent had my coffee yet ). So if at altitude we were doing only M0.8 ( which would allow for maneuvers without killing the pilot at that altitude ) and each engine were putting out less than or equal too one half of its total thrust, wouldnt that mean the total thrust of both engines would be combined and we would actually have a thrust to weight somewhere between .68:1~1:1 which i'm basing partly off what you said above, and partly off the SU-37s max speed at altitude of 1357 knots or M2.3. Just grabbed my first cuppa coffee.. bear with me here.. See, M0.8 would be just a little shy of 50% thrust at altitude just as its a little shy of .5 thrust 30000 feet, and a bit over .5 thrust at 19000 feet. (At see level, i'm sure its closer to .75 thrust as see level max speed is 756 knots ). ::chuckles:: Wanna kill a Sukhoi? Get it down low.
Pam

 

[JohnC]

No worries, it's easy to get confused. Once you're in the after-burning region of thrust, thrust increase is almost linear as Mach Number increases. Using 36kft as the example altitude; while the AL-31F produces about 52kN at M1.0 it produces a walloping 120kN at Mach 2.0. Also note that since fuel consumption is proportional to thrust...you go through fuel in a hurry when going that fast. If you're starting a M2.0 run with a Mirage III at 36kft (we really like that altitude), you should have a minimum of 3/4 of a tank of fuel.

As far as thrust to weight ratio is concerned, there are a few things to consider. (At Sea Level) Remember that 41,000 is the empty weight; that's when it's running on fumes. It can carry up to 21,000lb of fuel; which means the Ground|Static full fuel T:W ratio is only about 1.03.

So running from the Above. If Thrust (afterburning) increase with Mach Number. If you are traveling at M0.8|36kft; then engine thrust is about 38.7% relative to G|S; which would give a thrust of 32klbF*0.387 multiplied by two engines, or ~25,000lbF of total thrust. That gives an Engine thrust to weight ratio of 0.61 (no fuel) or 0.49 (half fuel). If you subtract the drag force of the airframe...which I can't easily do from this computer; but I would estimate that it's between 4-6,000lb (An Airbus A321 produces about 8-10,000lbs of drag at the same Mach|Altitude). Then Net thrust at M0.80|36kft is at best 21klbF, which gives Net Thrust to Weight ratio of 0.51 (no fuel) or 0.41 (half fuel).

Hope that was helpful?

 

[warchild]

Very helpful. But it reminded me of another question.. your mention of the fuel usage triggered it and its something i've been curious about for a very long time.
you se, one of the planes that got me started in working with flight models, was Ito's Boeing 2707. I still love that plane, or at least what might have been had it not been killed by politics and McNamara's wet dream for a swing wing bomber ( the B-1 ).
but while i was researching that plane, i got into drag, and learned that in trans sonic states, drag got very weird. Accordingly, as you approach the speed of sound, drag increases to almost double its normal value, but at mach 1.2 drops to less than half its normal value. The problem then ( 1963 ) was having engines powerful enough to overcome the drag between mach 1 and mach 1.2. hence, after burners on the concorde. But what i dont understand is the relationship between fuel burn and trans-supersonic travel.
lets say our base-line drag value for some aircraft is 5. That means that at mach 1 that drag value has increased to 10 ( ergo the need for afterburners in most planes with the SU-37 and F-22 being just plain weird ), but at mach 1.2 that base-line drag drops to 2.5. Understandably, you still need enough thrust to maintain trans-supersonic speeds, but, shouldnt you be able to throttle back a ways and save fuel?? Thats always confused me.
pam

 

[JohnC]

I think a really important place to start is how high the aircraft. Most Supersonic aircraft (there are several notable exceptions) reach maximum speeds achievable speeds between 36-45kft. With aircraft such as the SST, Concorde, and SR-71; speed is the primary aerodynamic concern in design (and I believe all three are exceptions to the generalization I just stated). This is evident by their long, slender airframes. The design of most supersonic aircraft is combat, which means maneuverability and payload capability enter into the criteria in a big way, and that can have large impacts on supersonic drag.

When you talk about drag changing with Mach, I would be shocked if the drag force decreased so significantly shortly after the transonic region of flight. More likely, it's the drag coefficient. Since drag force is proportional to svelocity squared, it means you might see some decrease in drag force relative to transonic, but unlikely that it's down to subsonic levels. The ubiquitous proof of that is how few aircraft are able to super cruise. Combine this with the fact that afterburning mode converts fuel to thrust with about half the efficiency of wet thrust and that wet thrust produces 2-3 times the thrust relative to dry when at supersonic speeds and high altitudes; and it means you burn fuel about 4-6 times quicker when in wet thrust relative to maximum dry. The difference of this is so significant, that going super sonic (and staying there) usually has a well defined purpose centered on the concept of getting somewhere quickly, that supersedes the notion of conserving fuel.

 

[Sundog]

Yes, you can throttle back and save fuel once through the transonic region. That's how some aircraft achieve supercruise, they use after burner to get through the transonic region and then throttle back out of it to supercruise. However, before the advent of supercruise, which also requires serious thermal considerations for the airframe due to heat soak, most fighters were mostly subsonic, except for when reacting to a problem or engaging in battle, in which case they usually just go full burner and keep accelerating to give their missiles maximum energy when they launch them and of course to maximize Ps for the coming fight; if they survive the merge.

Also, the reason for the large drag rise around Mach unity is the reason it's named transonic. You have a combination of subsonic and supersonic flow around the aircraft which creates some serious mixing where the different airflow regions meet creating a lot of drag. So the drag drops as that is reduced once you have fully developed supersonic flow.

 

[warchild]

well, what i, in my own hick way, have always theorized is that as you move forward through a fluid, the density of the fluid increases with with speed due to the vehicle forcing the fluid around its body at a rate that is faster than the fluid is capable of moving. this would create a compression cone at the front of the vehicle which would become denser as the vehicle accelerates, due to the fact that at higher speeds, not only is the vehicle compressing the fluid it is traveling through, but the compression cone caused by the vehicle is also compressing the fluid in front of it. Ergo, the "barrier" effect. As the vehicle transitions through the leading edge of the compression cone the cone travels back along the vehicles surface till at some point falls behind the vehicle. What happens then, I dont know. I believe that may be entering the area termed hypersonic velocity. Also, what happens between the time the cone leaves the front of the vehicle and leaves the back of the vehicle, i dont know. thats a science i believe is called wave drag theory, and its pretty complex.
However, getting back to what i started with in this reply. I can see where the drag and the drag coefficient increases exponentially as the vehicle accelerates up to M1. but between M1 and M1.2 the vehicle pushes through the cone, and the leading edge of the cone, instead of being focused on a point directly in front of the vehicle, is now distributed around the vehicles surface. but see, this is the most confusing part. Since the cone is no longer in front of the vehicle, , and the thrust of the vehicle is focused on that point the drag drops, because the plane of thrust no longer travels through the compression cone. But, isnt the compression cone itself compressing even more of the fluid in front of it, and wouldnt that create some kind of bubble that really the vehicle could never get through?? If so, how does that work?? if not, I still dont get it.. Weird science..

 

[Paul Domingue]

Hm, F18's cant do high AOA? I suspect disinformation there... check this out from an airshow I remember a few years ago


this one's same display, better quality but doesn't show the really high AOA maneuvres in the first one.

LPXO

Watching this video brought to mind an interesting bit of documentation I ran across recently. The air show was in 2009 and this document is an analytical report submitted to the minister of defense in <st1:City><st1lace>Canberra</st1lace></st1:City> (May, 1998) on replacing the RAAF F/A-18. It is quite interesting and some what pertinent to the conversation (I think) since this is way out of my realm. :salute:

http://lpad.horizon-host.com/images/RAAF_replacing_FA-18_Hornet.pdf

 

[Paul Domingue]

Just out of curiosity Pam, is there any published threads or screenies of Paul Dominiques SU-37/35 project? (other than yours, of course).

LPXO

I’m constantly blown away by some of the model work out there and have a bit of an inferiority complex when it comes to my models. Pam has been such a great ego booster and her dedication makes me want to create something worthy of her work. Here are a few previews of my attempt at recreating this awesome aircraft.

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