General Questions Thread:

medo wrote:Two engines mean better survivability. In case one engine is off or damaged, the plane could be returned with the second engine to the base and than repaired. In single engine plane damaged or off engine mean lost plane. This is the reason RuAF made a decision, that all their planes will be twin engine and they retire all single engine planes, although some were quite new in that time (MiG-23 and MiG-27).

Which is a good idea, I can't understand the single engine fetishists, the cost of maintaining a 2nd engine will be minimal compared to an entire plane that has crashed and been destroyed. I really hope Mig's 5th gen Mig-29 replacement isn't a single engine plane. If they make a single engine version than it should only be for export, and not for domestic use.

medo wrote:Which is a good idea, I can't understand the single engine fetishists, the cost of maintaining a 2nd engine will be minimal compared to an entire plane that has crashed and been destroyed. I really hope Mig's 5th gen Mig-29 replacement isn't a single engine plane. If they make a single engine version than it should only be for export, and not for domestic use.

What little I can find on the LMFS stipulates a single engine. That being said, I would speculate that a 5th generation MiG aircraft would be designed with naval applications in mind - that means dual engines (which are universally prefered for carrier operations - F-35C not withstanding).

This is just my opinion, but If the 1.44 can serve as any guide, MiG will retain two engines for the Fulcrum replacement.

Honesroc wrote:

medo wrote:Which is a good idea, I can't understand the single engine fetishists, the cost of maintaining a 2nd engine will be minimal compared to an entire plane that has crashed and been destroyed. I really hope Mig's 5th gen Mig-29 replacement isn't a single engine plane. If they make a single engine version than it should only be for export, and not for domestic use.

What little I can find on the LMFS stipulates a single engine. That being said, I would speculate that a 5th generation MiG aircraft would be designed with naval applications in mind - that means dual engines (which are universally prefered for carrier operations - F-35C not withstanding).

This is just my opinion, but If the 1.44 can serve as any guide, MiG will retain two engines for the Fulcrum replacement.

It wont be a single engine, VVS has declared that they will only have 2 engine fighters in the future. Likely Fulcrum's replacement will be 2 engines, however don't rule out a single engine version for export. I should also add that single engine is ok for drones.

I doubt about lmfs existance. I think after MiG-35, thays it. Just UAV's and subsystems. Lmfs has been discussed for forever. And MiG-35 still has no orders,

LMFS existence is on a piece of paper and nothing else.

And the VVS has ordered the MiG-35, its just MiG is unable to produce the aircraft yet because of all the subsystem delays.

TR1 wrote:LMFS existence is on a piece of paper and nothing else.

And the VVS has ordered the MiG-35, its just MiG is unable to produce the aircraft yet because of all the subsystem delays.

Not on paper, on computer to be exact.

sepheronx wrote:I doubt about lmfs existance. I think after MiG-35, thays it. Just UAV's and subsystems. Lmfs has been discussed for forever. And MiG-35 still has no orders,

Oh yes drones, we heard that before. Because you know Mig is neck-deep in Skat drone orders.....

But in all seriousness, the most technologically advanced drones are in U.S. inventory. One of the most advanced drones in US inventory was the RQ-170, so secretive of a project people doubted it's existence, and claimed Iran was engaging in a grand hoax. People couldn't wrap their heads around the idea that one of the most advanced drones ever created was defeated by Iran's 'Living-Fossil' of aerospace defense network (of course Autobaza made the difference).

That fact alone is a reason you can't justify replacing a light-fighter with a drone, and just because there's no flying prototypes now doesn't mean there wont be in 5-8 years. Another fact people have to wrap their heads around is that the PAK-FA (and its derivatives) will be expensive aircraft, and only a select few countries could afford to buy and maintain them. A cheaper, lighter equivalent is necessary that will likely sell much better on the export market, and countries like Brazil, Indonesia, Egypt, Malaysia, Algeria, etc. could participate financially in the development to mitigate costs. As far as the Mig-35 goes, a large part of the slowing down of that program was the failure to win the highly politicized MRCA tender, but surprise surprise FGFA program is moving at a snails pace even though the majority of the plane has already been developed *cough, PAK-FA, cough* but is that just mere coincidence? Well it's not, just like how the lack of quality control leaves the Sukhoi fighters built in India to be more crash prone...lets stop beating around the bush and just point out that the over-reliance of the Indian export market, and it's hot-mess of a aerospace industry is a large part of the problem. Only a few countries (such as India) could actually afford PAK-FA derivative aircraft, and instead of being overly-reliant on India, they should develop a smaller cheaper alternative and a more diverse export market, so that the Russian aerospace industry doesn't lose the future 5th gen aircraft export market.

The one engine vs two engine debate is a long debate with numerous aspects.

In a nutshell, one engine means cheaper engine maintainence, generally lower drag because having one engine the aircraft is designed around can be smaller than an aircraft with two or more engines slung underneath. It does however mean that engine needs to be rather more powerful than if two engines were being used and lower thrust settings could be used to keep the aircraft airborne with a twin engined aircraft.

A direct comparison of the F-16 and MiG-29 show the differences fairly clearly however the maths was muddled because early MiG-29s used Soviet maintainence practises. The replacing parts after x hours reduces inspection time but can lead to perfectly good parts being replaced which can get expensive.

The SMT upgrades of the MiG-29 included on board testing equipment and diagnostic kit that made inspections cheaper and easier and reduced maintainence costs by a reported 40%... which is huge.

You can do mathematical calculations in terms of weight and drag and thrust and fuel economy and pretty much unless you are wanting a VSTOL aircraft you either go with one engine or two as an optimum combination of thrust and drag and maintainence problems.

there are no three engine fighters for a reason, though with scramjet technology that might change where a plane might have two turbojet engines to get it to mach 2 or so and then switch to a scramjet to accelerate to higher speeds.


the F-16 needs a powerful 12+ ton thrust engine and can only reach mach 2, while the two 8 ton thrust engines on the MigG-29 allow it to get to about mach 2.3.

With a variable intake ramp the F-16 could probably go rather faster than it does.

TR1 wrote:LMFS existence is on a piece of paper and nothing else.

And the VVS has ordered the MiG-35, its just MiG is unable to produce the aircraft yet because of all the subsystem delays.

Do we know how many they plan to purchase?

medo wrote:Two engines mean better survivability. In case one engine is off or damaged, the plane could be returned with the second engine to the base and than repaired. In single engine plane damaged or off engine mean lost plane. This is the reason RuAF made a decision, that all their planes will be twin engine and they retire all single engine planes, although some were quite new in that time (MiG-23 and MiG-27).

but how does affect existence of multi engines the capabilities of aircrafts?

GarryB wrote:The one engine vs two engine debate is a long debate with numerous aspects.

In a nutshell, one engine means cheaper engine maintainence, generally lower drag because having one engine the aircraft is designed around can be smaller than an aircraft with two or more engines slung underneath. It does however mean that engine needs to be rather more powerful than if two engines were being used and lower thrust settings could be used to keep the aircraft airborne with a twin engined aircraft.

A direct comparison of the F-16 and MiG-29 show the differences fairly clearly however the maths was muddled because early MiG-29s used Soviet maintainence practises. The replacing parts after x hours reduces inspection time but can lead to perfectly good parts being replaced which can get expensive.

The SMT upgrades of the MiG-29 included on board testing equipment and diagnostic kit that made inspections cheaper and easier and reduced maintainence costs by a reported 40%... which is huge.

You can do mathematical calculations in terms of weight and drag and thrust and fuel economy and pretty much unless you are wanting a VSTOL aircraft you either go with one engine or two as an optimum combination of thrust and drag and maintainence problems.

there are no three engine fighters for a reason, though with scramjet technology that might change where a plane might have two turbojet engines to get it to mach 2 or so and then switch to a scramjet to accelerate to higher speeds.


the F-16 needs a powerful 12+ ton thrust engine and can only reach mach 2, while the two 8 ton thrust engines on the MigG-29 allow it to get to about mach 2.3.

With a variable intake ramp the F-16 could probably go rather faster than it does.

well thats because doesnt matter the weight of engines. The 8 tons engine could use different fuel for example.
And probally the two engine aircraft may be bigger but whit a powerfull thrust can be obtained same speeds inspite drag. Ofcourse that would mean probally more fuel consumption but that is not a problem if you have aircraft carriers or you are close to enemies. Also for a single engine to be more powerfull that two engine aircraft means big one engine which lead also to big aircraft. So the advantage of single engine is not so big.
I want to ask:can be use two engines one above the other? Like they are vertically mounted?

What about having 4 small engines around the single engine? Each of them could turn on for better maneuvers. Or small engines in front. In this the aircraft could do better in dogfights and escape missiles. Even moving angle could be added to those small engines. The engines could be put in x around single engine.

Also small engines could be puf in front of aircraft. Mounted in angle so the flame not touch the plane.

but how does affect existence of multi engines the capabilities of aircrafts?

An aircraft with a long operational life used in harsh environments, and possibly not getting the best maintainence attention on the front line introduces the possibility of engine failure.

when you only have one engine then an engine failure is fatal to the aircraft and possibly also the crew... which will be expensive. Even if single aircraft only increase the loss of aircraft due to engine failure by a few percent leading to perhaps the loss of 2-3 planes over a ten year period the costs in buying new aircraft outweigh any savings in single engine designs.

the odds on both engines failing is a small fraction of the chances of one failing... and more importantly the chance of the engine not being able to be restarted should also be included...

I have read some studies that claim single engine aircraft are worth it because the number lost to engine failure where two engines might have made a difference is negligible.

Of course the aircraft with the worst flight record in the Soviet military was the Yak-38 VSTOL aircraft which in theory is a single engined fighter but with two lift jets.

the Russian military has clearly chosen twin engine conventional take off fighters instead of VSTOLs for a range of reasons... on a deck at sea even just flying your Yak-38 through some hot air from the aircrafts own jet exhaust can make engine thrust plummet and the auto eject system throw the crew out of the aircraft.

the Harrier has killed rather more of its pilots than the Yak ever did because of the auto ejection system on the Yak, but the Harrier is a much more practical aircraft that has been rather more widely produced and deployed in real combat situations.

Even as good as it is however the Harrier would be terribly vulnerable to MANPADS due to its side mounted engine nozzles offering an IR target from a much wider angle than most conventional aircraft.

well thats because doesnt matter the weight of engines.

Of course it does. A heavier engine makes the aircraft heavier and requires more power to move it around the place.

The advantage of two engines instead of one is that the two engines can reduce demands for high power engines in a lighter over all set up.

Going back to the F-16... you pretty much need a 12-13 ton thrust engine to get decent performance which makes it a Flanker class engine. In the MiG-29 it uses two engines that a MiG-21 might have used if it was developed a bit later in the 8 to thrust class each... but the point is that with two 8 ton thrust engines the MiG pilot has 16 tons of thrust when he needs it... a 16 ton thrust engine for the F-16 would be possible, but very expensive and likely heavy.

I want to ask:can be use two engines one above the other? Like they are vertically mounted?

yes, the British Lightning had that arrangement... it was a very good interceptor.

What about having 4 small engines around the single engine? Each of them could turn on for better maneuvers. Or small engines in front. In this the aircraft could do better in dogfights and escape missiles. Even moving angle could be added to those small engines. The engines could be put in x around single engine.

It would be cheaper and simpler to just use a more powerful main engine... for instance in the example of the F-16 then the engine from the F-35 would offer plenty of thrust, or the engine to be fitted to the PAK FA in the 18 ton thrust range would be useful for a single engine light fighter that is heavier than a late model F-16.

Also small engines could be puf in front of aircraft. Mounted in angle so the flame not touch the plane.

Such small engines would not add that much thrust, yet would add weight and complication with wiring and fuel lines all over the place.

If you want to temporarily add thrust then I would suggest a couple of small scramjet engines mounted on the wing pylons taking fuel from the aircraft fuel system... sort of the opposite of an external fuel tank.

On an Su-35 you could fit them on the wing tips... but at the end of the day I would think it would be better off with jammer pods on the wing tips instead.

BTW extra thrust wont help evading AAMs or SAMs... you are much better off with a decent ESM suite and DIRCMs system.

magnumcromagnon wrote:

Honesroc wrote:

medo wrote:Which is a good idea, I can't understand the single engine fetishists, the cost of maintaining a 2nd engine will be minimal compared to an entire plane that has crashed and been destroyed. I really hope Mig's 5th gen Mig-29 replacement isn't a single engine plane. If they make a single engine version than it should only be for export, and not for domestic use.

What little I can find on the LMFS stipulates a single engine. That being said, I would speculate that a 5th generation MiG aircraft would be designed with naval applications in mind - that means dual engines (which are universally prefered for carrier operations - F-35C not withstanding).

This is just my opinion, but If the 1.44 can serve as any guide, MiG will retain two engines for the Fulcrum replacement.

It wont be a single engine, VVS has declared that they will only have 2 engine fighters in the future. Likely Fulcrum's replacement will be 2 engines, however don't rule out a single engine version for export. I should also add that single engine is ok for drones.

This is little off topic , but still good option for export. I have in mind, that Russia could very easily modify Yak-130 trainer into very effective single engine light multi-role fighter with placing 1 RD-33MK engine from MiG-29K. This engine is also good for over the sea operations, as this engine is for carrier based fighter. They need to redesign back part to install 1 bigger engine with afterburner and to enlarge the nose to install radar like Zhuk-M or Zhuk-AE.As Russian air force don't need single engine planes, they could make this version of Yakovljev "officially internationally" together with Novorussia and build a production plant to build or just to put together near Lugansk airport and of course in Russia too. This plane could have same carracteristics like South Korean FA-50 or Indian Tejas or Pakistani JF-17. It could be the basis for new Novorussian air force and could be as well very interesting for other ex-Soviet republics and many other states in Asia, Afrika and Latin Amerika as cheap and reliable plane.

medo wrote:
This is little off topic , but still good option for export. I have in mind, that Russia could very easily modify Yak-130 trainer into very effective single engine light multi-role fighter with placing 1 RD-33MK engine from MiG-29K. This engine is also good for over the sea operations, as this engine is for carrier based fighter. They need to redesign back part to install 1 bigger engine with afterburner and to enlarge the nose to install radar like Zhuk-M or Zhuk-AE.As Russian air force don't need single engine planes, they could make this version of Yakovljev "officially internationally" together with Novorussia and build a production plant to build or just to put together near Lugansk airport and of course in Russia too. This plane could have same carracteristics like South Korean FA-50 or Indian Tejas or Pakistani JF-17. It could be the basis for new Novorussian air force and could be as well very interesting for other ex-Soviet republics and many other states in Asia, Afrika and Latin Amerika as cheap and reliable plane.

You're basically describing MiG-33.. an old concept from MiG

Stealthflanker wrote:

medo wrote:
This is little off topic , but still good option for export. I have in mind, that Russia could very easily modify Yak-130 trainer into very effective single engine light multi-role fighter with placing 1 RD-33MK engine from MiG-29K. This engine is also good for over the sea operations, as this engine is for carrier based fighter. They need to redesign back part to install 1 bigger engine with afterburner and to enlarge the nose to install radar like Zhuk-M or Zhuk-AE.As Russian air force don't need single engine planes, they could make this version of Yakovljev "officially internationally" together with Novorussia and build a production plant to build or just to put together near Lugansk airport and of course in Russia too. This plane could have same carracteristics like South Korean FA-50 or Indian Tejas or Pakistani JF-17. It could be the basis for new Novorussian air force and could be as well very interesting for other ex-Soviet republics and many other states in Asia, Afrika and Latin Amerika as cheap and reliable plane.

You're basically describing MiG-33.. an old concept from MiG

True and there was also Sukhoy S-55 project more than 20 years ago. But they were only on paper if those projects ever come that far in development. On the other hand Yak-130 is in full production with all needed tools and systems developed. For Yak-130 it is just another version of plane, which could be quite quickly in production. Other option is to install two engines AI-222 with afterburners and it still need to reshape its rear end for longer engines. In this case we have all components already developed. Just to put them together in plane and test it.

Guys,

If you had access to the technology portfolio that was invented for the PAK-FA what kind of air craft would you build with it starting with a "clean sheet" design review optimized for a specific and narrowly defined mission?

Fiber mat stealth. Avionics that will hopefully go from a low-workload hover to forward flight and back again. Distributed aperture Infrared Search and Track. Advanced communications. Advanced engines. Helmet cueing that allows the pilot to look down through their own bodies. Cooperative Engagement Capability via the Combat Cloud.

For a start what would a single-mission fifth generation aircraft look like for the following roles:

A 5th gen cargo plane?

A 5th gen mid air refueling tanker?

A true 5th generation stealth drone?

A 5th gen ground attack close air support replacement?

If I had any decision, it would be a light fighter aircraft. An advanced aircraft designed around some 4+ gen tech like RD-93 engine. Zhuk-A radar (newest iteration), and using similar avionics to Su-35 like the L band radar on wingtips and new ecm eccm ew equipment. Gotta be cheaper than what is readily available so that it can be fielded in much greater quantity.

sepheronx wrote:If I had any decision, it would be a light fighter aircraft. An advanced aircraft designed around some 4+ gen tech like RD-93 engine. Zhuk-A radar (newest iteration), and using similar avionics to Su-35 like the L band radar on wingtips and new ecm eccm ew equipment. Gotta be cheaper than what is readily available so that it can be fielded in much greater quantity.

Well said.

Upgrade, after upgrade, design after re-design, Russia is going nowhere. PAK FA T-50 is simply a waste of money and waste of energy, a waste of precious ressources.
Iam afraid with this new cumbersome aircraft with a dubious effectiveness will ruin Russia. We have the definitive proof with US that stealth and heavy fighter bomber's concept does not work. It would be better to develop, to upgrade the Mig-35, and SU-35. This is largely enough.

jhelb wrote:Guys,

If you had access to the technology portfolio that was invented for the PAK-FA what kind of air craft would you build with it starting with a "clean sheet" design review optimized for a specific and narrowly defined mission?

The replacement for the Mig-31 will borrow technologies developed for the PAKFA. The same can be said about Su-35S.

So basically we will have to see how mature these technologies are that can be used in a variety of platforms.

[quote="nemrod"]

sepheronx wrote: We have the definitive proof with US that stealth and heavy fighter bomber's concept does not work. It would be better to develop, to upgrade the Mig-35, and SU-35. This is largely enough.

Must be why Russia (and China, and others to some degree) are all going with VLO large 5th gen fighters.

Because they haven't quite caught on to your realization about what works and what does not.

nemrod wrote:

sepheronx wrote:If I had any decision, it would be a light fighter aircraft. An advanced aircraft designed around some 4+ gen tech like RD-93 engine. Zhuk-A radar (newest iteration), and using similar avionics to Su-35 like the L band radar on wingtips and new ecm eccm ew equipment. Gotta be cheaper than what is readily available so that it can be fielded in much greater quantity.

Well said.

Upgrade, after upgrade, design after re-design, Russia is going nowhere. PAK FA T-50 is simply a waste of money and waste of energy, a waste of precious ressources.
Iam afraid with this new cumbersome aircraft with a dubious effectiveness will ruin Russia. We have the definitive proof with US that stealth and heavy fighter bomber's concept does not work. It would be better to develop, to upgrade the Mig-35, and SU-35. This is largely enough.

PAK FA is doing Russia a major benefit though. Because there is a huge push for tech development in RAM, engines, weapons and avionics. I think using the RAM to greatly reduce the radar cross section, along with shaping, and using the tech learned like in Zhuk Radar AESA tech as well as optronics used for PAK FA, would benefit greatly. Maybe what has been learned from the engine development could be incorporated to reduce costs on the RD-93 as well as increase efficiency. The program is very beneficial but it is an expensive aircraft and in today's economic climate and the demand for more modern aircraft and in numbers needed to help match against NATO/US (or at least be enough) is needed and a cheaper aircraft is very much needed.

Personally I would not change much... the PAK FA is already going to be a very good aircraft for a range of specialised missions, while advanced model MiG-35 and Su-35 and Su-34 and a MiG-31 replacement, plus a fifth gen CAS aircraft, PAK DA, and a naval carrier based PAK FA are pretty much all bases covered.


No one needs thousands of heavy 5th gen stealth aircraft... a couple of hundred will be plenty when supported by an air defence network plus 4++ gen fighters and interceptors.

Some might say it is bombers that have been largely redundant in a world with ICBMs and SLBMs,but bombers/cruise missile carriers add a conventional attack dimension ICBMs and SLBMs lack... plus they are a visible system that can be deployed in times of tension, yet stood down when calming down the situation is needed. Other nukes don't have that flexibility.

With a new generation of AAMs and ASMs the PAK FA will be a very potent fighter bomber aircraft.

Yes, but I suspect radar blockers would be more likely.

With modern jet engines the blades are not separate items fitted to a hub, they are often part of a disk which makes them rather stronger and better able to resist the impacts of foreign objects.