I think the light fighter (or medium-light, depending on what criteria is used) configured as roughly half the size of a heavy one and with one engine where the heavy has two is a very logical choice, technically sound and economically advantageous.
Yet has it ever been implemented?
The Mig-23 does not use an Al-31 engine, and the F-16 does use the engine or the F-15 but is it half the maintenance bill? ... is there any single engined fighter anywhere that actually uses a single engine that is also used on a heavier twin engined fighter that can be considered cheaper?
Perhaps the Me-110 uses two engines used in a Bf109 variant?
Not really a good example though is it?
I get that. Interestingly, my opinion is rather the opposite. A small country that has no heavy fighters is probably going to place more demands on their eventual light(er) ones. Light and heavy fighters make most sense together as part of the hi-lo mix of the countries that created them. A F-16 may not be the best choice if you need an attack plane with range and payload capacity, but maybe you cannot sustain a fleet with them and also F-15E. But ok that is just my opinion.
If you ignore the HATO bullshit 99% of countries really don't need fighter aircraft... do you think the sky would fall if Germany announced it was going to give up having an air force and that a civilian police authority would start using civilian aircraft modified with a few gun pods and air to air missiles for policing duties and customs roles... what do German fighter planes actually contribute anywhere and in any way?
Here in New Zealand we had an outstanding single engined jet fighter that you totally ignore... the Skyhawk.... it was so cheap even we could afford to operate it... it had wide variety of ordinance and could carry a huge payload for its size and could operate from aircraft carriers if needed... give it a modern radar and R-73s and it would be outstanding...
You could probably put a decent light radar set in a Buccaneer and a helmet mounted sight and give it R-73s and R-77Ms and have an amazing little fighter that could also operate from carriers... not amazingly manouverable but faster and longer ranged than an F-16 at low altitude with two nuclear bombs as a payload.
But you are fixated with the electric jet.... the first fighter that needed computers to fly and was always intended to be simple but was always going to be expensive because all of the computer hardware it needed to be so simple.
First I don't complain. As a matter of fact, older platforms lose relevance and need to be substituted. A modern one with state of the art aero, layout, and system integration technology is going to have advantages. Do you think the new 5G MiG fighter will use the same MiG-29 air vehicle?
They are just doing what they did with everything else... the T-90 is based on the T-72... to you they are idiots because not only have they upgraded the T-72 and the T-90 they have not replaced everything with Armata T-14s.
T-14s are not cheap. They will certainly be rather better than T-90s and upgraded T-72s, but so what... most of the jobs they will need them for an upgraded T-54 is probably able to get the job done... why send an expensive T-14 to do a job an upgraded T-72 can do just as well?
Older platforms might not have the same drag figures, they might be less expensive to operate and also do the job of getting the weapon to the right place in space to launch at the target and get the kill.
Now lets look at Israel... the cost of getting a standoff munition into the air over Lebenon and launch it towards Syria for it to be shot down outside Damascus... right now it might take an F-35 2 hours to perform the mission, at 80K per hour, while 5 years ago the mission would have been performed by an obsolete type like an F-16 at perhaps 15K per hour. They might have caught glimpses of the F-16, but then they might have caught glimpses of the F-35 too... all that really matters is that the F-35 is expensive for what it is and what it can achieve and the fact that it uses a single engine doesn't make it cheaper or better in any way at all.
The existence of the F-35 and Rafale suggests to me that it is the F-16 that is obsolete.
Second, since I don't share your opinion that light, single engine fighter = crap, I don't share your conclusion either. It can be better in many ways that are not strictly performance related, it can be cheaper to operate for instance and do its job as intended.
Well that is the thing, I think the evidence is clear that the idea that a single engined fighter is cheap = crap... F-35, F-16... assuming claims of the Gripen being cheap are true then if it is then its capability is poor compared with its twin engined competition, which means it is a poor alternative to having a better fighter.
A light single engine fighter is great... if it is unmanned. Then it can actually be made cheap.
S-70 suggests the Russians agree.
EDIT: I remembered there was in fact a design of an intake with variable ramps for the F-16. See there is no apparent change to the inlet's external dimensions:
That bleed slot would be terrible for RCS, as would the ramp moving up and down...
Plus... if it moves down and restricts the airflow... where does the excess air go?
Was it tested at all, or just a what if drawing?
Didn't you just tell MiG off for their promises that never make it to metal?
Yes, it was you who brought up the fuel issue and claimed the F-16 needed CFTs. I just demonstrated you it was still better in that regard than the MiG.
Did you? What conformal fuel tanks does MiG use?
One of the claims of MiG's team regarding their new MiG-29 family is that they have increased internal fuel by a 50% so that might be perceived now as shortcoming of the original design.
They also have TVC engine nozzles as an option which suggests manouverability is a problem yet no customers took up that option... confusing...
This relates to the point I made above, for the USSR to have MiGs taking off from rough airfields in point defence role may be all they needed in the 80's, for export customers and even VKS today that seems not to be the case anymore.
They have air intake grid protectors to reduce the risk of FOD, and they still train from motorways... as shown recently with Il-76s and Su-34s.
Make up your mind, below you say TVC for roll authority is relevant, but here you say the MiGs don't have it installed because they couldn't bother since it odes not compensate?
You said it was important because you thought the roll rate of single engined aircraft was better than twins. When I pointed out with TVC it isn't, you said only at low speed... which as I pointed out is when it is most relevant... ie in stalls.
I also said roll rate in general is not that critical... it only matters for a split second... you do understand that rolling on its own is not really an evasive manouver and a missile about to hit you cannot be evaded by continuously rolling because you are basically pivoting around the same point and maintaining your direction of flight. A roll to allow a hard turn only lasts for a fraction of a second and whether it takes 0.1 of a second or 0.05 of a second is not really that important...
What problem? I just say it makes more sense to use one type of engine than two and to profit from the advantages of different layouts when composing the fleet. I don't think two engine layout is "problematic"
Russia is just leaving a situation where it does not have enough different engine types... considering the variety of aircraft sizes and weights they have, just having one fighter engine type makes no sense at all...
One fin of course remains in the shadow of the nose at high AoA and now it is also not acceptable due to LO design issues. Most single tail planes have AoA limitations.
Indeed, but not every plane suffers for that... if you have that issue then don't fly in situations where AoA is a problem... or accept a little agro when you fly in the tattered parts of the envelope...
For the same capture surface it is lighter and marginally less draggy to have one big intake than two smaller ones. If this is relevant or not is difficult to say, that is why I posted the image with real figures. It is not a world of difference, but all needs to add up in order to get the best possible design.
But drag is only one issue... what about sucking shit up off the runway with a chin mounted air intake?
The square intakes of the Tu-22M3 actually increased RCS by 25% over the intakes like the MiG-23 used on the Tu-22M2... they kept them because if the difference in engine performance it resulted in meaning flight range and top speed increased dramatically.
I don't know exactly. The marginal disadvantage can be compensated or justified considering the whole design.
Despite its problems it was clearly considered superior to the nose mounted air intake of the MiG-21 that preceded it.
That is my personal opinion, from the perspective of someone that is not in the VKS or Russian MIC. I will sleep very well if they develop a twin engine fighter and will try to understand why they did it. It is not some kind of religious belief you know?
Maybe they like the fact that any increase in engine power is doubled in a twin jet, but also did you notice a pattern.
There are single engined aircraft and there are twin, but the only three engined aircraft I know of are commercial airliners that use the extra often tail mounted engine for a boost at takeoff and then cruise the rest of the flight. Then there are four and six and even eight engined aircraft... but no five engined ones and very few three engined ones... the vast majority are one, two or four.
Do you think that is an accident?
I would say there are obvious reasons to be a single engined plane but the fact that they are not the most common suggests very good reasons for that.
The MiG-21 is probably the best Soviet single jet fighter, but things have moved on and such a small plane simply does not have much growth potential or space for everything needed today...
The worst planes I know of are the VSTOL fighters.. the Yak-38s and Yak-38Ms and the Yak-141s... which actually had three engines each... which sounds super safe except it was the opposite... if any one of those engines failed during landing the result will be a crash and an ejected pilot... so safety wasn't improved with three engines... it was three times less safe than a single engined fighter... (the ejection systems on those aircraft were automatic because of the narrow safety margin... lost a lot of planes but fewer pilots were lost).
Who says the new fighter will operate from rough airstrips? The dorsal intakes are not there anymore in the new MiGs...
The intake doors are grids that allow air to flow through them so they don't need the upper louvers...
I consider, given the operational life and overhaul intervals, that Russian engines have roughly caught up with the state of the art in that regard. This is BTW a must for them, because otherwise their sales in the export market would suffer.
Yeah, cause there is no way they could survive not charging their customers for their 30 million dollar engines separately like the US does...
A customer in Africa asked if they want D-30K engines at 14 tons thrust at 800K US dollars for their Il-76 or if they want PS-90A engines at $6 million each but 16 tons thrust and reduced fuel consumption I am pretty sure what most will choose...
Ok be my guest, you are invited to better that data. But to make assumptions without figures to back them is not exactly better than at least finding analogues as I am doing. The thread is not limited to Russian planes BTW.
If we are going to only use western data then anything we come up with is pretty useless anyway isn't it?
How can you look a customer in the face and say single engined fighters are cheaper?
When you need three Gripens instead of one Rafale or Typhoon to get the job done... is it actually cheaper?
And do I have to mention F-35?
What other new single engined fighter is an option? Chinese... well of course they are cheaper...
There have been all sorts of projects both by MiG and Sukhoi for single engine, light (and not so light) 4G/5G fighter projects. Do you think they were very different to what I propose? Do you want to see some of them?
I am familiar with most of them, and all of them failed, because Russia does not need or want a light single engined fighter... it wants a capable affordable fighter.
It does not matter if you take a little longer checking the engines because there are two... and because there are two you don't need to be as thorough because of one fails you still have the other to get you home. With a single you better be sure everything is good because there is no backup.
Ok prove you are not doing the same... where is the data? I have some indirect ones, but you do seem to know a lot about the issue, since you are correcting me.
How about the data for the F-16 and F-15? Instead of pointless comparisons with the totally unrelated MIG-29, how about a comparison of the P&W F-100 engine that powers both the F-16 and the F-15?
I would have thought that would be the obvious place to start to be honest...
You already said:
The tables below illustrate class A mishaps in single and twin engine fighters. As reliability of engines has improved, both configurations have come to similar mishap rates:
Except similar mishap rates is a bad thing for single engined fighters doesn't it?
I guess Russians value having two engines apart in order to minimize the influence from one on the other.
It has nothing to do with guessing and everything to do with body lift that is accentuated with engine trunks and two jet engines at the rear...
Try it yourself.
Get a plastic shopping bag and flatten it so there is no air inside. Put the plastic bag around your lips and blow as hard as you can... the tiny amount of air in your lungs is nothing like what is needed to fill the bag with air. Flatten it out again and this time hold the bag a few centimetres from your face and blow again letting the air around you flow in too and you will more likely fill the bag much more than the last time.
Having two engines facing backwards with a fuselage forming a sort of wing with the engines drawing air through and over the fuselage enhances the lifting performance of the aircraft body.
Banking is crucial to turn, and doing it fast is indeed a good thing.
Doing it fast and doing it super fast is not that much of a difference... but having twin tails and twin engines and being able to pull high AoA means the turn itself can be more useful than rolling fast.
Rolling in a stall with zero airspeed or fuselage inertia is non critical (why would it be?)
Because stall recovery will either be gravity or engine power and being able to roll to enhance either one could be important... certainly being able to point your nose where you want is critical in a superstall and being able to roll so that you can direct your yaw to where you want your nose to be and hold it is the difference between fighting and falling.
and until the TVC came as said Sukhois and MiGs and all other planes have been more than ok without it. Stall recovery is relevant though, and it is guaranteed with TVC even if no differential or even 3D deflection is available, normal 2D are ok for that.
Even without TVC having two engines you can throttle gives you some control a single engined aircraft or closely coupled twins don't have.
I just demonstrated it is the opposite of what you claim, considering a twin engine jet which is actually far larger, like the MiG-29, that should have substantially more range but has little more fuel and clearly less range.
F-16A: weight empty 7,317 kg / internal fuel 3,162 kg (ratio fuel to weight is 0.43)
MiG29: weight empty 11,001 kg /internal fuel 3,453 kg (0.31)
You are not getting it... the MiG-29 and the F-16 were not made by the same company for the same contract... comparing their empty weight and their fuel fraction means nothing at all... if they were working for the same contract and the range was specified then the fuel fraction of the MiG would be much higher to meet that range requirement, but the fact that they were intended for totally different roles means a comparison is meaningless.
If you were really serious you would be comparing the YF-17 numbers to the YF-16 because they did compete together for the same job... the YF-17 lost and eventually became the F-18... perhaps the discussion should be why a single engined fighter design won the AF competition but such a plane was not even considered for a naval job if it is so fantastic and cheap and simple...
50% more cross sectional area is not a "marginal" difference in drag by any measure.
Not enough to make it slower.
BTW the F-16 can carry a 7 ton payload... does that cross sectional area include that?
In terms of thrust, F-16's TWR is better than that of a MiG-29.
So what. The TWR of an F-16 is probably better than that of a MiG-31... which one is faster... which one is suitable for operating over the arctic with 500kg AAMs as its primary weapon?
Beyond that, having a lot of thrust to compensate for a lot of drag is always a bad idea, because it will make you spend your fuel faster.
Fuel is cheap enough.
You should use F-16A values instead, those are the ones against which MiG-29 was designed.
And of course this is a case of apples vs oranges since those wiki values are far too superficial in one hand and given in different conditions for each plane, to make an assessment. You need EM charts, fuel rate tables and so on. If not, at least a good info source to start with is this:
Why would Russia care about fuel rate tables? Are they running out of oil?
I am sure the Red Baron would tell you the best fighter has the lowest fuel burn rate...
I am sure the fuel burn rate of a single like a Gripen or an F-16 or even an F-35 would be much more impressive than the fuel burn rate of an Su-35.