Forum: F-35 Lightning II

That_Engine_Guy wrote:

Not to mention...

The Hindustan Times wrote:

Dec 16/11: The Hindustan Times reports that perennial problems with Russian spares & reliability have become an urgent issue for the SU-30MKI fleet now:

“Prime Minister Manmohan Singh is expected to red-flag [SU-30] serviceability, product support and pending upgrade… at the annual [Russian] summit meeting…. Top government sources said that Air Headquarters has urgently requested the Prime Minister to raise the issue of engine serviceability with his Russian counterpart after few incidents of engine failures…. the top brass has conveyed to government that “shaft bearing failures” have occurred in some [AL-31FP] engines. “In peacetime, the fighter can land on the other engine but this can be a life and death situation in adverse conditions, said a senior official.”

Doesn't seem like we need to piss on Russian jet engines, they just crap out on their own. Doh

TEG

Does anyone know, have there actually been any single-engine landings of the Su-30MKI? Or any other Su-27 derivative? I'm unaware of any myself. Or was that senior official merely speculating that the second engine actually gave some sort of redundant capability?

My understanding was that no Su-27 derivative had ever successfully landed on one engine, because the wide engine spacing with such powerful engines caused very high yawing torque from the remaining engine at any throttle setting able to the plane in the air. An Su-27 or MiG-29 with one engine out is uncontrollable without essentially idling the second engine. But I could just be wrong. Is that untrue?

The Raptor's narrow engine spacing and pitch-only thrust vectoring weren't chosen in a vacuum. The US had 3D thrust vectoring on the X-31 and several other test beds. It evidently wasn't worth the trade-off. And while the center tunnel configuration does offer a lot of extra lift, past US designs with wide engine spacing were also prone to flat spins. At least 31 F-14s were lost due to spin, and the US hasn't designed a plane with a wide center tunnel configuration since. Sukhoi has seemed willing to continue building their planes with a wide center tunnel between the engines, despite at least some notable single-engine-out crashes in the MiG-29 and Su-27 familes. Is that willingness to more readily accept some aircraft loss perhaps another consequence of the Russian planes' airframe and engine life being sacrificed for price, thrust, and lift? With less to lose with each plane, it makes increasing more sense to trade the loss of a plane for better kinematics when things work right. Decisions affect the economics of other decisions. I for one am very glad the recent PAK-FA engine loss occurred while the plane was still on the runway; I don't want to find out if that design is also unrecoverable on one engine that way.

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Don't be reddicules here. Of course any Flanker can land with one engine. It is an Developing requirement when the thing was designed in the first place. That the Engines has a wide placment has nothing to do with this issue.
The Flanker is a huge fighter with large Wing area and the design have a very high lift.
The onboard FCS(flight computer systems) will automatical adjust if one engine are lost, of course it is not often it happend. While people here still like to piss on Russian Engines, they infact stall/fail very rarly during flight. Low TBO does not mean you can have reliable and good engines, they just need to overhoul or service them more often.

TEG@
Thats low, especial by your own standards.. That USAF colonial was a joke and you know this.

IAF did not bring with them any spare engines to Red Flag. sinse it would greatly increase expendes and why take any chances and put one jet out of operationl. Imagine what that means for the missed trainining time for pilots etc.
To even question the Su-30MKI engines are more suseptible to FOD is completly nonsens, and anyone with half a brain can see this.
For crying out load, any Flanker are ceterified to operate out of a class B airbase! Try that with the Tarmac slickers F-15/F-16.. Rolling Eyes

haavarla wrote:

TEG@
Thats low, especial by your own standards.. That USAF colonial was a joke and you know this.

IAF did not bring with them any spare engines to Red Flag. sinse it would greatly increase expendes and why take any chances and put one jet out of operationl. Imagine what that means for the missed trainining time for pilots etc.
To even question the Su-30MKI engines are more suseptible to FOD is completly nonsens, and anyone with half a brain can see this.
For crying out load, any Flanker are ceterified to operate out of a class B airbase! Try that with the Tarmac slickers F-15/F-16.. Rolling Eyes

Frankly, I'd value the opinion of a engineer with over 30 years of development experience than an internet troll. He brings evidence, experience and facts, unlike your conjecture, non-facts and derision. You didn't even respond to his argument he made, rather just made a few weak statements without any evidence and then proceeded to insult him.

Get a new schtick or some education, its pretty easy to see through you.

Ok, this is not that difficult to understand. First of all the idea to bring that Red FLag blattering into this is nonsens. That Officer did not do his homework before entering that podium. He was wrong on many accounts. This is well known and has been up countless times before.
So who is the troll here?

Here is a read-up on an former USAF ground crew talking about the legasy AL-31F engines. No where does he thrash the engine, infact he says it is desiged and constructed with easy maintance access from ground crew with lesser knowledge cause it is a more simplyfied design, but this does not mean its a bad engines. In fact it gives you an edge too, you don't need to shift engines back to a main overhaul facility to service it.

http://www.eaa.org/warbirdsbriefing/art ... lanker.asp

Further more, the AL-31F engine famely are quite light weighted T/W. It has a deecent Fuel consumption.

One of the reason it has a low weight is due to high performance, but at the expense of lower heat tolerance and lower TBO. It also operate under very hars enviroments, both in Russia(cold) and in India(hot). Poor air base infra structure.. no shelters etc.
The engine do not stall under critical manuveres(air flow exeeds 30 deg or more).

IAF will order better and newer AL-31FM1 soon, aka super MKI.
You want better engines, then you have to pay for it too.

http://www.salut.ru/Section.php?SectionId=18

haavarla wrote:

Saturn has several Engines version in the test bench right now, but none of these engines are yet frozen or accepted as the final product.
There are the idl 117, Idz 129, Idz 130 or type 30 engines. All have different compressor design. I.E. numbers of compressor fans stages etc etc.
Afaik there are no AL-41F engine.. it died with the Mig-1.44. However they did put some of the R&D on archive, and started from there when the Pak-Fa program started.

I'm more interesting to see if and when Salut can get their AL-31FM2 engines certified and operational. It should give various VVS jets further performance increase. Like Su-30SM, Su-30M2, Su-34 and Su-27SM.

Given that the Russian engines and fighters still are far cheaper vs Western counterparts give the shorter life and TBO less importance or should i say relevance. Remember that the Su-35S airframe has "only" 6000hour of life..
While there are the Engines Life and TBO to consider, there are also equall or more important factors on any jet fighters. Like Fuel consumption, T/W and T/D(thrust/Drag) ratio. And then the overall design and how much high lift the design create.
All of the latest Russian design has exellente aerodynamic performance, that would imply a very well ballanced design and that their design fit well with VVS requirements and tactical /strategic doctrines.
What types of jets fit best for USAF does not mean it will fit VVS equally good and vice verca.

So while many people often have a field day, pissing on Russian jet engines, they often miss the bigger picture here.

The bigger picture here is they built expendables to be used like ammo in a war. After the Cold War they had to scramble to try and build like the West. They still haven't caught up.

And yeah, the Russian stuff is cheap to BUY. What about operating it where the men using it actually get to train with it? Or you can always store the good stuff and let the pilots fly 100 hours a year on the squadron dog.

haavarla wrote:

Don't be reddicules here. Of course any Flanker can land with one engine. It is an Developing requirement when the thing was designed in the first place.

That doesn't answer my question. Development requirements change, or aren't met. It was a development requirement of the F-35 that all three variants have identical combat performance except for the B and C using podded guns. Yet the F-35B can't carry the largest bombs, the F-35C is slower and has worse transsonic acceleration, and both the B and C have lower G-limits than the A. The RAH-66 had a design requirement to have a crew of one pilot, but as built it ultimately had both a pilot and a gunner. All those changes from initial requirements were approved by their customers. The Space Shuttle was supposed to be a flying taxi, but they never did solve the maintenance problems with the Teflon bearings in the liquid hydrogen pumps, or the durability of the black heat shield tiles' attachment to the airframe. Maintenance time made the launch-recovery-repair-launch cycle many times longer than the initial requirements. They carried on with the Shuttle program despite failing to meet those development requirements. I'm well aware that part of the point of having two engines on the Su-27 was to allow it to land on one engine in case the other one failed. My question isn't whether that was the intent, but whether it actually worked.

Can you point me to any actual incidents where a Flanker actually has landed with only one engine? Several Su-27s failed to land despite being built with two engines. Vladivostok, Russia, 2011, an Su-27 crashed on a training flight, with engine failure suspected. Radom, Poland, 2009, an Su-27 apparently lost one engine after a bird strike. The plane failed to recover and crashed, tragically killing both pilots. Primorye, Russia, 2008, I don't know if the official cause was ever released. However, eyewitnesses on the ground described a departure from landing approach consistent with, but not proof of, an engine failure. Paris Air Show, 1999, although it's a bad example because the plane had other damage, an Su-30MKI lost one engine in an accidental contact with the ground, and subsequently crashed. So, clearly cases exist of Su-27s that failed to land on only one engine.

I don't know of a single case of the converse, where an Su-27 managed to land with only one engine. But maybe the near-misses where the plane survived on only one engine didn't get any press. Maybe you know of some examples I don't know of. So again, if any examples really do exist, please provide one or more links to times when something in the Su-27 family lost one engine and landed safely on the remaining engine.

The A/B/C were never supposed to be "exactly" like each other.

1. The B's 'original' requirement (along with the A) was for 2x1000lb bombs. Pre-SWAT they thought that they could still keep the F-35C requirement of 2x2000lb in the A&B, but they had to go back to the 'original' spec of the smaller 2x1000lb load for the B.

2. The fact that the C is larger and has more drag was well known and nobody expected it to be as fast as the A or B. It's top speed has nothing to do with the Spec, as long as it can hit Mach 1.6 at a specific alt. The same goes for acceleration.

3. The B&C were never supposed to operationally use the same G limits as the A, mainly as a way of saving airframe hours on the B & C (the Super Hornet is also a 7.5 g airframe for the same reasons).

I'm not sure about all those incidents. But wasn't most of em with a flight display in mind, and with some pilot error as well? Doing critical manuveres at low altitude has it risk. You don't have sufficiant speed or altitde to recover. This has nothing to do with it beeing able to fly with one engine or not.

Take a look at airliners then.. one engine under each wing, how's that for wide engine placments! And they are designed to take-off, fly and land with one engine.
So why even think a military fighter like Su-27 cannot do this?
Wait.. could it be because its Russian design /build?

Last edited by haavarla on Jan 30, 2012 - 07:41 AM; edited 1 time in total

Quote:

The bigger picture here is they built expendables to be used like ammo in a war. After the Cold War they had to scramble to try and build like the West. They still haven't caught up.

And yeah, the Russian stuff is cheap to BUY. What about operating it where the men using it actually get to train with it? Or you can always store the good stuff and let the pilots fly 100 hours a year on the squadron dog.

You might wanna put up some sources of VVS pilots doing only 100hours each year.. That was the case earlier, and it was far lower back in the 90s, but if you have notice, we are in 2012 now.
The Re-structure of RuAF started in 2008, resulting in abanoming some 20 airbases and sacking 150-200000 air staff.
Also abandoming the air regiment structure in favor of Squadron size. and there are cuts in operational units as well. All this in order to save funds and get a more efficiant and dynamic AF.

The Mig-31 still has lots of life hour left and are under a upgrade program(Mig-31BM). These units have the same amount of hour as any western counterparts.

As far as service cost for Su-27, sure it does not come cheap. its a heavy interceptor class fighter. It is compairible to F-15 and EF-2000.
But just keep in mind that in Russia, never mind India the wages of ground crew are far cheaper than any western AF. So i think it compairs quite well on operational cost, don't you think?

haavarla wrote:

Quote:

The bigger picture here is they built expendables to be used like ammo in a war. After the Cold War they had to scramble to try and build like the West. They still haven't caught up.

And yeah, the Russian stuff is cheap to BUY. What about operating it where the men using it actually get to train with it? Or you can always store the good stuff and let the pilots fly 100 hours a year on the squadron dog.

You might wanna put up some sources of VVS pilots doing only 100hours each year.. That was the case earlier, and it was far lower back in the 90s, but if you have notice, we are in 2012 now.

I can do that.

Pg 187, Military Air Forces/Russia Section, Military Balance 2011, International Institute For Strategic Studies.

And to be completely accurate, they list it at 80~100 Hours.

haavarla wrote:

I'm not sure about all those incidents. But wasn't most of em with a flight display in mind, and with some pilot error as well? Doing critical manuveres at low altitude has it risk. You don't have sufficiant speed or altitde to recover. This has nothing to do with it beeing able to fly with one engine or not.

Take a look at airliners then.. one engine under each wing, how's that for wide engine placments! And they are designed to take-off, fly and land with one engine.
So why even think a military fighter like Su-27 cannot do this?
Wait.. could it be because its Russian design /build?

Some single-engine-out Su-27 crashes were in airshows, some were on training missions. And airliners are an entirely different regime of thrust:drag:mass:lift:directional stability. When you show me an airliner with the ability to pull a 9g sustained turn and then do a Pugachev's Cobra, you can compare the two. It has nothing to do with whether or not it's Russian. The very-much-not-Russian F-14 had spin problems because of spaced engines too.

So please stop avoiding the question: yes or no, do you know of even one single instance where an Su-27 or derivative managed to land on one engine? If you are aware of even one Su-27 that landed with one engine out, this should be very easy. If you say anything else besides "yes" or "no" followed (if possible) by a link to information on the incident(s), or at least enough information on where and when that I can find a link myself, then I will have to assume the answer is "no."

Last edited by haavarla on Jan 31, 2012 - 05:14 PM; edited 1 time in total

I think i read about an incident with an IAF MKI landing with one engine. One engine erupted in flames in mid-flight. But i do not have anything to go by.
I'll try to sniff around and see if anything turns up.
If one were to compair the F-14 and Flanker. It is widly known that the Flanker posess more relaxed stability in the horisontal plane, right?
Hense it can do those crazy manuveres without entering uncontroled spin.
In the RuAF we never hear about near accidents if all turns out well. We always get to hear of crash, so go figure..
But that beeing said, there could be sources out there i don't know about.

Edit:
It should come as no surprise that the F-14 was i little twichy in various Aerodynamic handeling. Just read about former F-14 pilots whom flown the SH. They can tell you that the SH is an angel to land on Carriers vs the F-14.
I personly think that the F-14 back in the days would have gained a lot if the Vertical Stabz would have been enlargen..

My two cent.

They were a size constraint of the hangar deck. Directional stability is the reason that the F-14D could not take off in afterburner. At launch speeds it was well below Vmc for full throttle OEI handling. And actually T-10 relaxed static directional stability is what allows the crazy maneuvers, but it takes a large degree of dynamic directional stability to not go uncontrolled. If you watch the videos of Su-35S and F-22 doing airshow displays you see that they both perform similar j-turns, but the Su seems to overshoot its nose low pull up point and have to swing the nose back around to center. So they both have relaxed static stability, but the Raptor has greater dynamic stability (in the directional axis).

Actually this got me thinking about the T-50. Wide engines, small verticals. At low speeds they are going to be of marginal effectiveness (even though they are all moving, the low Reynolds number may cause them to stall out before they can produce the required load). "But it has 3-D TVC" yes I know, but with one engine inoperative its a matter of "does the TVC angle allow the thrust line to reach, or pass, the CG" if not then it will still be yawing out and the plane will be pushed sideways to a great degree for the duration of the flight, possibly allowing nothing more than the opportunity for the pilot to pull the D-rings. Again this is a low speed event I am talking about. I trust that the engineers involved are aware of such problems and have things in place. I am just stating what appears to be a risky area for a design with wide engines and small fins. May be the TVC moving thrust line closer to center (reducing the yawing moment) will allow the fins to do the rest with the reduced "bite" load.

Last edited by haavarla on Jan 31, 2012 - 06:02 PM; edited 1 time in total

Quote:

I can do that.

Pg 187, Military Air Forces/Russia Section, Military Balance 2011, International Institute For Strategic Studies.

And to be completely accurate, they list it at 80~100 Hours.

Me too. If you read through this, is says the average flying hour for these Mig-29 Pilots were 80-100 hours a year.
But that article is now several years old, so it are most likely higher to day.

http://www.16va.be/19_gviap_eng_part3.html

NB! This an interesting read-up, and stuff like this is hard/rare to come by.
Krymsk airbase are one of the most prioritized Airbase in whole VVS.
So natural this mean other pilots could have lower flying hour elsewhere..

To day Krymsk airbase operate the new Su-27SM3 Sq as well.

Forum: F-35 Lightning II

T-50 and F-35