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    PAK DP prospective long-range interceptor

    GarryB
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    Post  GarryB Wed May 16, 2018 4:18 am

    Actually if they only want to fly at mach 4.2 or so then a ramjet propulsion system would be fine...

    It is only at hypersonic speeds where scramjets start to become necessary.

    Rather powerful jet engines of today could be used with bypass airflow being used as a ramjet or scramjet at higher speeds...

    the MiG-25 had 11 ton thrust engines and the MiG-31 had 15 ton thrust engines... they have 25 ton thrust engines in their bombers... even the Saturn engine for PAK FA is 18 tons thrust.

    If it is a from scratch design they could easily make such an aircraft if there is money and will.

    New hypersonic cruise missiles suggests the problems of scramjet design are being mastered...
    Hole
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    Post  Hole Wed May 16, 2018 11:15 am

    There are rumours that a hybrid engine (turbojet/liquid-propellant rocket) has been developed by the RVSN academy in Serpukhov.
    LMFS
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    Post  LMFS Wed May 16, 2018 10:48 pm

    GarryB wrote:Actually if they only want to fly at mach 4.2 or so then a ramjet propulsion system would be fine...

    It is only at hypersonic speeds where scramjets start to become necessary.

    Rather powerful jet engines of today could be used with bypass airflow being used as a ramjet or scramjet at higher speeds...

    the MiG-25 had 11 ton thrust engines and the MiG-31 had 15 ton thrust engines... they have 25 ton thrust engines in their bombers... even the Saturn engine for PAK FA is 18 tons thrust.

    If it is a from scratch design they could easily make such an aircraft if there is money and will.

    New hypersonic cruise missiles suggests the problems of scramjet design are being mastered...
    Yes, apparently ramjets can operate above 5 M
    PAK DP prospective long-range interceptor - Page 9 Specif10
    This wouldn't be in the end much different to the J58 engine on the SR-71 right? A turbojet that bypasses increasing amounts of air from the compressor to the afterburner as the speed goes higher and ends up like a partial ramjet. That was a very expensive and specialized plane and was limited to 3.2 M, I wonder how the Russians plan to go beyond that and also why this is so important. In the end the future threats are going to be hypersonic missiles way faster than 4 M, reaction times for interception are going to be just very few minutes to begin with..

    It seems the PDE engine would be more capable for different speeds. This seems the most promising option, but I guess it is at least a decade away from any practical use, only tests in laboratory done until now.  dunno
    Hole wrote:There are rumours that a hybrid engine (turbojet/liquid-propellant rocket) has been developed by the RVSN academy in Serpukhov.
    Cool, do you have any source? This would be relevant if they indeed plan to make a near-space weapon. What amount of fuel and oxidizer would the aircraft need to carry in that case to accelerate beyond the limits of the turbojet and operate outside of the atmosphere? That would be a huge load...
    GunshipDemocracy
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    Post  GunshipDemocracy Wed May 16, 2018 11:49 pm

    LMFS wrote:
    This wouldn't be in the end much different to the J58 engine on the SR-71 right? A turbojet that bypasses increasing amounts of air from the compressor to the afterburner as the speed goes higher and ends up like a partial ramjet. That was a very expensive and specialized plane and was limited to 3.2 M, I wonder how the Russians plan to go beyond that and also why this is so important. In the end the future threats are going to be hypersonic missiles way faster than 4 M, reaction times for interception are going to be just very few minutes to begin with..


    I'd presume time to get so some important points over notth pole? or far east? Not sure if all will be hypersonic too. Apparently 5000km/h should be just fine. in 10 minutes it mover over 800km...

    As for PDE I've found only about rocket PDE in Russia

    The fuel explodes - the flight is normal
    Successful tests of the so-called detonation rocket engines have yielded very interesting results. Experimental design work in this direction will be continued.

    https://rg.ru/2018/01/18/levochkin-vozmozhnost-sozdaniia-detonacionnogo-dvigatelia-podtverdilas.html

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    Post  LMFS Thu May 17, 2018 1:56 am

    GunshipDemocracy wrote:
    I'd presume time to get so some important points over notth pole? or far east?  Not sure if all will be hypersonic too. Apparently 5000km/h should be just fine. in 10 minutes it mover over 800km...

    As for PDE I've found only about rocket PDE in Russia

    The fuel explodes - the flight is normal
    Successful tests of the so-called detonation rocket engines have yielded very interesting results. Experimental design work in this direction will be continued.

    https://rg.ru/2018/01/18/levochkin-vozmozhnost-sozdaniia-detonacionnogo-dvigatelia-podtverdilas.html

    Yeah, I simply don't know what scenario and threats they are considering, the plane is not going to be ready before say 20 years if everything works as usually. By then the speed of the threats that cannot be covered by a plane of the characteristics of a MiG-31 is going to be insane, just to react to the threat and take off takes more time than the missile to hit the target. A little lost here to be honest.

    BTW, that link you posted is fantastic! Best for everyone to take a look, this is essentially a revolution of propulsion.

    Anybody could translate what is written here?

    PAK DP prospective long-range interceptor - Page 9 Dvig1010
    GarryB
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    Post  GarryB Thu May 17, 2018 5:06 am

    There are rumours that a hybrid engine (turbojet/liquid-propellant rocket) has been developed by the RVSN academy in Serpukhov.

    If you look at the chart in LMFSs chart you will see that for low speed flight... ie subsonic, the most efficient propulsion is turbofan, simply because this moves a lot of air and is very fuel efficient. If you have a big airliner or cargo plane a turbo fan can generate a lot of thrust... most of which is driven by the huge fans at the front, but if you look at the rear you can see the small turbojet engine that actually drives the big fans... the little turbojet propels the aircraft by turning the fans rather than generating the thrust itself.

    If you want to go faster than the speed of sound however you can't use such a high bypass engine... it is called a high bypass turbofan because as I said most of the thrust is generated by the big fans at the front which don't actually go through the smaller turbojet engine inside it.

    If you make the big fan at the front smaller and longer and add an after burner at the rear you have a medium or low bypass turbofan engine... turbofans can get a big boost in thrust with an afterburner because the bypass air is cold and has not gone through the hot section of the engine so it is still oxygen rich.

    A turbojet engine is a tube with a shaft down the middle with fans on it.... the fans at the front are big and suck air into the engine... the tube gets narrower in the middle to compress the air and heat it up... fuel is added in the hot section and burned further heating the air and the air then blows out the back generating thrust.

    To increase thrust fuel can be added in the rear exhaust area and burnt called an afterburner to increase thrust.

    A turbofan uses a small turbojet to turn a much bigger fan at the front. The engine is fully enclosed so the air driven by the fan at the front goes into the turbojet but also around the outside of the turbojet. In a high bypass turbofan like on an airliner the turbojet might stick out the back of the short fan section... the big fan section generates the most thrust because it moves a lot of cold heavy air... the turbojet is just there to turn the fan and only adds a tiny amount of thrust.

    A medium or low bypass turbofan has a smaller front fan and extends past the turbojet engine hot section... it generally has an afterburner and the cold bypass air has lots of oxygen so more fuel can be burned to create more thrust... generally a low and medium bypass turbofan can generate more thrust in afterburner than a turbojet because of this.

    The engine of the SR-71 uses the bypass air as a separate type of engine.

    The problem with a jet engine like the one in the MiG-25 or MiG-31 is that the rotational speed of the fan blades inside is limited by their strength... just like a rubber tire would shred itself if you put it on a supersonic car the engine blades in the MiG-25 and MiG-31 would shatter if you ever flew faster than about mach 3.2.

    The SR-71 gets around that issue by pretending to be a ramjet.

    A ramjet is a terribly simple concept... you keep the tube of the turbojet but you don't have a shaft or blades... it is just a hollow tube.

    For a missile like a Kh-31 or the new Kinzhal that means that empty space where the fuel is burned normally you can put a big solid rocket motor to get the missile moving... once it has burned out there is empty space for the air to flow through.

    So in a ramjet engine the air goes in the nose intake... the tube gets narrower and compresses, which heats up the air... in the hot section fuel is added and burned and so it leaves the rear at high speed generating thrust.

    In the SR-71 when the plane takes off it is operating as a turbojet, but as it gets faster and faster it starts pushing air around the turbojet engine, but there are no fan blades pushing that air... just the force of the air flowing through the engine... when the engine goes beyond a speed... say mach 1.8, all the thrust is now being generated by the air flowing around the turbojet engine with fuel being added in the rear afterburner like a ramjet.

    That makes the engines of the SR-71 a combined turbojet/ramjet.

    With their experience with scramjet engines the Russians can go one better if they want... there are two main problems with ramjets... first, they don't really work from a standing start so you need either a jet engine or a rocket to get them moving... for a missile the empty space means a rocket makes sense, but for a reusable aircraft another type of jet engine makes the most sense. the second problem is that they can't burn fuel at supersonic airflows, so even if you are flying at mach 5 you need an air intake that constricts and reduces the airflow down to subsonic speeds before fuel can be added and burned to generate thrust.

    As you can imagine, not having to slow down the air flow and being able to burn fuel in the air as it moves supersonically through the engine means a much more power engine that is much simpler in terms of intakes and very simple in design... few moving parts except fuel injectors really...

    That was a very expensive and specialized plane and was limited to 3.2 M,

    It was completely made of Titanium... it was expensive and difficult to work on. Its fuel had a very high flashpoint and everywhere it went on the ground it leaked that fuel everywhere... it didn't have fuel tanks as such it used the inside structure of the aircraft as the fuel tank, but its speed performance meant when it was cold there were enormous gaps between each plate meaning the fuel poured out when it was cold on the ground.

    The first thing it had to do when it took off was refuel...

    I wonder how the Russians plan to go beyond that and also why this is so important. In the end the future threats are going to be hypersonic missiles way faster than 4 M, reaction times for interception are going to be just very few minutes to begin with..

    Contrary to popular belief you don't need to move as fast as a bullet to intercept a bullet... Russia is not interested in protecting Europe or Africa or Asia for that matter... just Russia and it can position its defensive pieces so the threats have to come past them...

    That being said having a faster aircraft means interception further from the target and also faster reactions to attacks... not to mention an R-37M missile might have a normal interception range of 300km from a MiG-31, but launched much higher and much faster from a MiG-41 that reach might double without any modification at all.

    They don't seem to want longer range so I suspect northern bases will be used to reach out to the arctic... but I would also expect that a MiG-41 possibly with internal weapons carriage capabilities could carry Kinzhal internally to deliver a blow to any US ships operating in the arctic trying to swat down ICBMs... if that is the case then time is critical... assuming a US first launch the Russians wont have much time to start an attack on those ships before Russian ICBMs start passing over the north pole...

    Of course amusingly many of the new ones will be heading over the south pole... it will likely take about an hour longer to reach their targets in the US but the US will have no idea they are coming.

    Note most satellites take about 90 minutes to orbit the earth... if you watch the ISS go over it comes over again 90 minutes later... so 30 minutes from Russia to the US directly would mean another 60 minutes going the other way... roughly.

    It seems the PDE engine would be more capable for different speeds. This seems the most promising option, but I guess it is at least a decade away from any practical use, only tests in laboratory done until now.

    Well the question is whether PDE can be applied to all types of jet engine... in might not work with SCRAMJETs, but for mach 4.2 as I said you could do that with ramjet technology...

    Scramjet technology would still be preferable...

    This would be relevant if they indeed plan to make a near-space weapon. What amount of fuel and oxidizer would the aircraft need to carry in that case to accelerate beyond the limits of the turbojet and operate outside of the atmosphere? That would be a huge load...

    The ideal design would be a powerful medium bypass turbofan like an NK-32, but with the bypass component modified to operate as a ramjet or a scramjet.

    On paper there is no top speed limit for a scramjet, but as you exit the atmosphere of course the issue of no air to burn... so you block off the air intake and pump hydrogen and oxygen through the scramjet like a rocket engine.

    Or even better... keep the NK-32 but with the scramjet have a nuclear reactor to heat the air when the scramjet is operating on its own... that means takeoff with fuel but once operating at mach 1+ you could activate your nuclear scramjet and accelerate to orbital speed... now when you leave the atmosphere your scramjet will stop propelling you because there is no air flowing through... then you pump nitrogen through the hot parts of the nuclear reactor to generate high energy gas flow = thrust. Nitrogen is abundant and not a fire risk as it is totally inert... 70% of the earths atmosphere is nitrogen, and by cooling it to liquid state carry it in high density... in the worst situation where you need to get back into the atmosphere you could blast some nitrogen forward to slow down to below orbital speed to reenter the atmosphere safely.

    Yeah, I simply don't know what scenario and threats they are considering, the plane is not going to be ready before say 20 years if everything works as usually.

    Speed will always be useful for an interceptor... the problem has been the enormous cost simply because the turbojet and turbofan engine simply were not up to the challenge.

    Ramjets, or more specifically scramjets make it viable... once all the issues of heat are dealt with, but then they have said they have already developed heat resistant aluminium alloys...
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    Post  Hole Thu May 17, 2018 10:58 am

    Source: Russian Tactical Aviation since 2001 by Yefim Gordon
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    Post  LMFS Thu May 17, 2018 11:55 pm

    GarryB wrote:It was completely made of Titanium... it was expensive and difficult to work on. Its fuel had a very high flashpoint and everywhere it went on the ground it leaked that fuel everywhere... it didn't have fuel tanks as such it used the inside structure of the aircraft as the fuel tank, but its speed performance meant when it was cold there were enormous gaps between each plate meaning the fuel poured out when it was cold on the ground.

    The first thing it had to do when it took off was refuel...
    Wow didn't know that... what a disaster xD
    This is the cost of trying to go beyond what the technology allows at a certain time. MiG-41 should not repeat that IMHO
    GarryB wrote:Contrary to popular belief you don't need to move as fast as a bullet to intercept a bullet... Russia is not interested in protecting Europe or Africa or Asia for that matter... just Russia and it can position its defensive pieces so the threats have to come past them...

    That being said having a faster aircraft means interception further from the target and also faster reactions to attacks... not to mention an R-37M missile might have a normal interception range of 300km from a MiG-31, but launched much higher and much faster from a MiG-41 that reach might double without any modification at all.

    They don't seem to want longer range so I suspect northern bases will be used to reach out to the arctic... but I would also expect that a MiG-41 possibly with internal weapons carriage capabilities could carry Kinzhal internally to deliver a blow to any US ships operating in the arctic trying to swat down ICBMs... if that is the case then time is critical... assuming a US first launch the Russians wont have much time to start an attack on those ships before Russian ICBMs start passing over the north pole...

    Of course amusingly many of the new ones will be heading over the south pole... it will likely take about an hour longer to reach their targets in the US but the US will have no idea they are coming.

    Note most satellites take about 90 minutes to orbit the earth... if you watch the ISS go over it comes over again 90 minutes later... so 30 minutes from Russia to the US directly would mean another 60 minutes going the other way... roughly.
    I guess my doubt is essentially that I don't know what current or future threat has rendered the MiG-31 obsolete but can be countered by a 4 M plane. Or will it rather have an offensive role? Will it be used in near space, as the US are experimenting with the X-37?
    GarryB wrote:Well the question is whether PDE can be applied to all types of jet engine... in might not work with SCRAMJETs, but for mach 4.2 as I said you could do that with ramjet technology...

    Scramjet technology would still be preferable...
    As far as I understand, PDE implies simply a new and better way of understanding and controlling the burning of the fuel. I assume it could be applied both to rockets and to air breathing engines, with the advantage that constant-volume combustion seems to be 25% more efficient than constant pressure in a conventional rocket engine. In the interview posted by GunshipDemocracy two cycles are mentioned, pulse detonation and Humprey cycle, the last one considering a compression of incoming air, so air breathing. Also it is mentioned in the article explicitly the use of this engine for hypersonic weapons with the advantage that the incoming air does not need to be slowed down to subsonic speed, that constitutes by itself he core of a scramjet and speeds of 8 M are mentioned as easily attainable. Only the size of the engine would be much smaller because the detonation liberates heat much faster than the combustion.
    GarryB wrote:The ideal design would be a powerful medium bypass turbofan like an NK-32, but with the bypass component modified to operate as a ramjet or a scramjet.

    On paper there is no top speed limit for a scramjet, but as you exit the atmosphere of course the issue of no air to burn... so you block off the air intake and pump hydrogen and oxygen through the scramjet like a rocket engine.

    Or even better... keep the NK-32 but with the scramjet have a nuclear reactor to heat the air when the scramjet is operating on its own... that means takeoff with fuel but once operating at mach 1+ you could activate your nuclear scramjet and accelerate to orbital speed... now when you leave the atmosphere your scramjet will stop propelling you because there is no air flowing through... then you pump nitrogen through the hot parts of the nuclear reactor to generate high energy gas flow = thrust. Nitrogen is abundant and not a fire risk as it is totally inert... 70% of the earths atmosphere is nitrogen, and by cooling it to liquid state carry it in high density... in the worst situation where you need to get back into the atmosphere you could blast some nitrogen forward to slow down to below orbital speed to reenter the atmosphere safely.
    For the intended speed it would be a ramjet. A scramjet apparently has problems being started by a turbofan due to the later's speed limitations.

    The nuclear thing escapes my understanding. Apparently this was abandoned time ago due to risk, cost and complexity, but who knows?
    GarryB wrote:Ramjets, or more specifically scramjets make it viable... once all the issues of heat are dealt with, but then they have said they have already developed heat resistant aluminium alloys...
    Do you have any link?
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    Post  GarryB Fri May 18, 2018 3:32 am

    Wow didn't know that... what a disaster xD
    This is the cost of trying to go beyond what the technology allows at a certain time. MiG-41 should not repeat that IMHO

    Flying at high speed heats up the whole plane... after flying at mach 3 plus it must fly around a bit before landing to cool the aircraft... the aircraft itself gets about 30cm longer at top speed because of heat expansion... when it comes to take off it is still cold so there are 30cm worth of gaps between the external plates... they are sealed up as the plane heats up with friction...

    I guess my doubt is essentially that I don't know what current or future threat has rendered the MiG-31 obsolete but can be countered by a 4 M plane. Or will it rather have an offensive role? Will it be used in near space, as the US are experimenting with the X-37?

    Higher speed means it can cover a greater area... and with ramjet propulsion it wont actually be that much more expensive in terms of fuel to operate... if you think of it in car terms if you had special pedal car that could drive a car at a maximum of 50km/h... to move faster you normally need something else that is less efficient like a rocket motor. However if you develop an internal combustion engine that can drive the car at say 300km/h, then using a rocket on a pedal car to go 50km/h normally but can accelerate to 150km/h for a minute or two. The internal combustion engine is just a more efficient and effective way of propelling the car at better speeds.

    A ramjet is not a rocket and would burn fuel at a fairly similar rate to a turbojet engine... the difference is that it can keep providing thrust at speeds well above where a turbojet would choke or simply break.

    The only issue is making your aircraft in a way so it can stretch and shrink with the heat changes... subsonic at 10km altitude the air temperature is about minus 60 degrees C and it will likely operate much higher than that.

    The new heat resistant alloys should make designing this aircraft much easier...

    For the intended speed it would be a ramjet. A scramjet apparently has problems being started by a turbofan due to the later's speed limitations.

    A ramjet is just a scramjet where fuel cannot be burned supersonically... I am sure with careful design you could make a ramjet operate in a scramjet mode... and don't fool yourself... the Soviets were testing ramjet engines in WWII on Polikarpov I-15 biplanes... a ramjet is a very simple engine that can operate over an enormous range of speeds... even a propeller could be used to get it moving if need be.

    The nuclear thing escapes my understanding. Apparently this was abandoned time ago due to risk, cost and complexity, but who knows?

    In a jet engine the air is compressed by narrowing the tube the air flows through... fuel is added and ignited to generate heat and expansion, which generates thrust... in a nuclear ramjet fuel rods that are superhot could also heat the air flowing through the engine... and could do so for years... because there is no combustion involved it would not be a scramjet but like a scramjet would not be limited by airflow speeds.

    The new nuclear propelled cruise missile the Russians have developed shows it works fine.

    Do you have any link?

    Sorry... no... all I remember is that it was posted on this forum, and I think it was in one of those new Russian technology threads....
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    Post  GunshipDemocracy Fri May 18, 2018 5:02 pm

    LMFS wrote:
    Yeah, I simply don't know what scenario and threats they are considering, the plane is not going to be ready before say 20 years if everything works as usually. By then the speed of the threats that cannot be covered by a plane of the characteristics of a MiG-31 is going to be insane, just to react to the threat and take off takes more time than the missile to hit the target. A little lost here to be honest.



    not sure why do you think it takes 20 years to develop  MiG-41, but as fr threats AFAIK  B-52 is going to stay till 2050 lol1 lol1 lol1


    For some strange reason you assume only hypersonic threats and 7,9km/s speed and fired from Estonia Shocked Shocked Shocked
    BTW 5 Ma still is only ~ 1,7 km/s  from US to Russia is say 8,500kms so 5000 seconds.  1hr 25 mins for reaction ?




    BTW, that link you posted is fantastic! Best for everyone to take a look, this is essentially a revolution of propulsion.

    Anybody could translate what is written here?

    Yup tonight , when all is quiet and no work anymore Smile











    Talking about  MiG-31 interesting founds:  

    MiG-31BSM
    Speed
    https://en.wikipedia.org/wiki/Mikoyan_MiG-31
    It is latest modernization variant first time contracted for production in 2014. for 60 airplanes to be modernized into BSM standard very similar in some aspects to BM variant. For BSM modernization variant MiG-31BS is used as base plane without refueling probe. Cockpit was improved thus enabling MiG-31BSM to fly long runs on maximal speed of 3000km/h without any damage. New faster central computer Baget-55-06 is used with addition of multi-functional displays one for pilot and three for weapons operator-navigator. Also there is a new set of navigation equipment. MiG-31BSM has multi-role capability with using anti-radar, anti-ship and air to ground missiles. Main visible difference between BSM and BS variant was the rear-view periscope added above the front cockpit canopy.[92]



    and MiG-25
    Ceiling:
    https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25
    On 31 August 1977, Ye-266M again flown by Fedotov, set the recognized absolute altitude record for a jet aircraft under its own power.[20] He reached 37,650 metres (123,520 ft) at Podmoskovnoye, USSR in zoom climb (the absolute altitude record is different from the record for sustained altitude in horizontal flight). The aircraft was actually a MiG-25RB re-engined with the powerful R15BF2-300. It had earlier been part of the program to improve the aircraft's top speed that resulted in the MiG-25M prototype.[11]
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    Post  LMFS Fri May 18, 2018 7:26 pm

    GarryB wrote:Higher speed means it can cover a greater area... and with ramjet propulsion it wont actually be that much more expensive in terms of fuel to operate... if you think of it in car terms if you had special pedal car that could drive a car at a maximum of 50km/h... to move faster you normally need something else that is less efficient like a rocket motor. However if you develop an internal combustion engine that can drive the car at say 300km/h, then using a rocket on a pedal car to go 50km/h normally but can accelerate to 150km/h for a minute or two. The internal combustion engine is just a more efficient and effective way of propelling the car at better speeds.
    I meant the space thing since it has been rumoured for the MiG-41, rockets would be eventually needed. Not that I see this feasible and practical for an interceptor in short to mid term, but who knows. Of course a ramjet is better than a turbojet with a rocket, in fact the specific impulse of the rocket is very low.
    GarryB wrote:A ramjet is just a scramjet where fuel cannot be burned supersonically... I am sure with careful design you could make a ramjet operate in a scramjet mode... and don't fool yourself... the Soviets were testing ramjet engines in WWII on Polikarpov I-15 biplanes... a ramjet is a very simple engine that can operate over an enormous range of speeds... even a propeller could be used to get it moving if need be.
    Yes, this careful design is the big issue at hand, otherwise we would have scramjets everywhere. Ramjets are not the big problem clearly, maybe they are very complex if the have to operate as turbojets too but it has been done long ago. I don't think the new plane is going to rely on old technology though... rather get a new propulsion concept. Develop PDE so that you have a very advanced interceptor with near space capacity (if you get really fast on your scramjet you will only need some oxidizer for sub-orbital manoeuvring) that allows you to effectively fight satellites and hypersonic warheads) and hypersonic flight in say 25-30 years is better than have a 4 M, complex partial ramjet aircraft in 20... the -31s are going to need retrofit irrespective Very Happy
    GarryB wrote:
    The nuclear thing...
    In a jet engine the air is compressed by narrowing the tube the air flows through... fuel is added and ignited to generate heat and expansion, which generates thrust... in a nuclear ramjet fuel rods that are superhot...
    Issue is this is radioactive and needs to be handled with extreme care. Probably more than dangerous to pilots and ground crews. A big headache. Only in a strategic weapon would this make sense.
    GunshipDemocracy wrote:not sure why do you think it takes 20 years to develop MiG-41, but as fr threats AFAIK B-52 is going to stay till 2050 lol1 lol1 lol1
    You can call me an optimist Very Happy
    Who knows, maybe the MiG-41 is stored in some shed at MiG since years, but if they have to approve the project, develop, test etc. etc. etc., considering how fast the threats are evolving... it is going to be at least that. The only thing sure is B-52 and Bears will be operating then xD
    GunshipDemocracy wrote:For some strange reason you assume only hypersonic threats and 7,9km/s speed and fired from Estonia Shocked Shocked Shocked
    BTW 5 Ma still is only ~ 1,7 km/s from US to Russia is say 8,500kms so 5000 seconds. 1hr 25 mins for reaction ?
    In that amount of time a guy with a MiG-31 can shower, dinner, check WhatsApp (calmly) and intercept in the spare time. No need for new ultra fast ultra expensive shit. The only case when that could make sense is when some smartass fires from Estonia as you say (or a Mk.41 in Poland) or highly hypersonic warheads are used. Point-black attack from SSBNs gives what, 3 to 5 minutes reaction time?
    GunshipDemocracy wrote:Yup tonight , when all is quiet and no work anymore Very Happy
    You speak Russian??
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    Post  GunshipDemocracy Sat May 19, 2018 3:55 am

    LMFS wrote:
    Who knows, maybe the MiG-41 is stored in some shed at MiG since years, but if they have to approve the project, develop, test etc. etc. etc., considering how fast the threats are evolving... it is going to be at least that. The only thing sure is B-52 and Bears will be operating then xD

    project as PAK-DP is already approved unless you think of technical design. Then is not.  Threats ar enot evolving that fast we kno wthat both B-21 , prompt global strike, satelites, X-37 and Bomber 2037 will be there.
    Perhaps Tu-95 and B-52 too. And surely An-2   lol1   lol1  lol1




    GunshipDemocracy wrote:For some strange reason you assume only hypersonic threats and 7,9km/s speed and fired from Estonia Shocked Shocked Shocked
    BTW 5 Ma still is only ~ 1,7 km/s  from US to Russia is say 8,500kms so 5000 seconds.  1hr 25 mins for reaction ?
    In that amount of time a guy with a MiG-31 can shower, dinner, check WhatsApp (calmly) and intercept in the spare time. No need for new ultra fast ultra expensive shit. The only case when that could make sense is when some smartass fires from Estonia as you say (or a Mk.41 in Poland) or highly hypersonic warheads are used. Point-black attack from SSBNs gives what, 3 to 5 minutes reaction time?
    [/quote]

    I will tell you in secret but hash nobody shall to know ok? interceptors are to fly over vast northern and eastern terrains of Russia where is close to US where hundreds of cruse missiles can fly or massive bomber drones attacks.

    For poitn blank you got S-400/S-500 and Pantsirs/Buks.


    GunshipDemocracy wrote:Yup tonight , when all is quiet and no work anymore Very Happy
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    you mean like moi ? ну что ты!


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    Post  GunshipDemocracy Sat May 19, 2018 4:41 am

    LMFS wrote:

    Anybody could translate what is written here?

    PAK DP prospective long-range interceptor - Page 9 Dvig1010

    I'm not a rocket engineer so not shoot messenger oki? What a Face What a Face What a Face


    детонационный жидкостный ракетный двигатель - detonation Liquid-propellant engine engine

    подвод горючего на охлаждение внешней стенки камеры - fuel supply for cooling the outer chamber wall

    кольцевая камера сгорания - annular combustion chamber

    инициатор детонационной волны - detonation wave initiator

    подвод окислителя в форсуночную головку - oxidant supply to the injector nozzle

    перепуск горючего из тракта охлаждения
    в форсуночную головку - fuel valve from cooling circuit into injector nozzle

    оребренные тракта охлаждения - cooling tunnel fins


    сопло с центральным телом - plug nozzle
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    Post  GarryB Sat May 19, 2018 8:58 am

    Cockpit was improved thus enabling MiG-31BSM to fly long runs on maximal speed of 3000km/h without any damage.

    So some simple maths... 3,000km/h = 3,000,000 m/h = 50,000 metres per minute = 833.333 metres per second, so assuming the speed of sound is 320m/s then that makes its speed mach 2.6.

    The MiG-31 originally had the capacity to fly at Mach 2.8 for about 5 minutes... it could fly at Mach 2.6 for about 20 minutes... we already worked out at 3,000km/h that is 50km per minute, so 20 minutes would take you 1,000km... and the original specs for Mach 2.4 meant it could fly as much as it liked at this speed.

    Now it seems it can fly as much as it likes at Mach 2.6, which is a significant step forward...

    Note most aircraft like the F-15 can on paper fly at mach 2.5 but it takes a lot of fuel to get to that speed and they can't maintain it for very long... most will never fly that fast because most of the time it is not worth it... and as shown it causes damage.

    At top speed in a MiG-25 you have to wear a pressure suit because the inside of the cockpit gets to 70 degrees C at high speed.

    at Podmoskovnoye, USSR in zoom climb (the absolute altitude record is different from the record for sustained altitude in horizontal flight).

    Note a zoom climb is not a vertical climb.... basically the plane flies horizontally to gain max speed and then noses up in a parabola like the arc of a bullet fired into the air... so it maintains high speed all along the path and does not slow down to zero and then fall back like it would in a vertical climb.

    When at the peak of the parabola the plane is maintaining altitude through momentum and cannot help but fall down along the path of descent... if the pilot tried to level off or climb further he would rapidly lose speed and stall and fall like a rock.

    I meant the space thing since it has been rumoured for the MiG-41, rockets would be eventually needed.

    It would not really benefit the MiG-41 to actually leave the atmosphere and fly in space... all the flight controls except engine vectored thrust would not do anything and it would basically be a flying rock.

    If there are threats or targets above in the vacuum of space then it makes more sense to get high and fast and launch a missile after it... or perhaps a laser or particle beam or whatever.

    Ramjets are not the big problem clearly, maybe they are very complex if the have to operate as turbojets too but it has been done long ago. I don't think the new plane is going to rely on old technology though... rather get a new propulsion concept.

    A combined turbojet ramjet is not old, and the turbojet could get improved performance with a pulse detonation fuel system... connecting that with a ramjet or scramjet would greatly increase the speed ranges where it would provide efficient propulsion.

    A ramjet on its own is very simple... air goes in a tube... the tube gets narrow and the air gets compressed... fuel is added and burned and exits out the back end of the tube producing thrust. Getting it to do that with a supersonic airflow would be tricky but the benefits would be enormous and lead to an even greater range of flight speeds open to the vehicle the engine is attached to.

    Jet engines benefit from just having to carry the fuel, whereas a rockets fuel by weight is 1/4 fuel and 3/4ths material that generates oxygen for the fuel to burn... you can get very high impulse figures from rocket fuel, but much shorter burn times and much increased fuel weights because you have to carry 3kgs of oxygen for every 1kg of fuel you carry... a scramjet can generate as much thrust as a rocket or even more and it scoops up its air as the vehicle moves, so you can either reduce the fuel weight by 3/4ths or carry four times more fuel...

    The problem in the past is that a jet engine burns fuel subsonically so could not match the high energy of a rocket, but supersonic burning in a scramjet means it can match or exceed exhaust speed of a rocket... when flying at mach 10... add a bit of fuel and burn it and the exhaust out the back could be moving at mach 14 or mach 15... in a ramjet you only get up to mach 4-6 because you have to slow the incoming high speed air to burn the fuel in the engine and then speed it up again to get thrust to maintain speed... in the distance between the hot engine section and the rear... so of course most of the thrust actually comes from the afterburner...

    (if you get really fast on your scramjet you will only need some oxidizer for sub-orbital manoeuvring) that allows you to effectively fight satellites and hypersonic warheads)

    There is a bit of a gap between mach 4.2 and 7km/s for items in low earth orbit... higher orbit stuff is even faster... 4.2 times 320m/s is about 1.4km/s.

    Issue is this is radioactive and needs to be handled with extreme care. Probably more than dangerous to pilots and ground crews. A big headache. Only in a strategic weapon would this make sense.

    You could use a ceramic mesh that covers the fuel rods and when they get very very hot so does the mesh... which transfers heat to the air flowing through it the air would be heated by the ceramic material and never get irradiated by the fuel rods... Normally the fuel rod are allowed to get very high and heat water under enormous pressure to generate very high pressure steam to drive turbines to generate electricity, but there is no reason why the heat could not be dissipated via a large heat sink in the airflow of a jet engine... a normal jet engine compresses the air and fuel is added and burned to further heat the air and get it moving fast, but a nuclear reactor could heat the air without combustion so there is no issue about having to slow the air down... a supersonic ramjet could be made simpler because there is no combustion... just heat transfer from nuclear fuel rods to the air flowing through the engine.

    In that amount of time a guy with a MiG-31 can shower, dinner, check WhatsApp (calmly) and intercept in the spare time. No need for new ultra fast ultra expensive shit. The only case when that could make sense is when some smartass fires from Estonia as you say (or a Mk.41 in Poland) or highly hypersonic warheads are used. Point-black attack from SSBNs gives what, 3 to 5 minutes reaction time?

    You miss the point... if an attack is detected a faster plane like a MiG-41 can go out further to intercept threats and neutralise things... So the MiG-41 can get most of the same targets and threats a MiG-31 can deal with but can hit them further away from Russian soil... possibly before they have launched their missiles... so attacking ships and bombers instead of chasing cruise missiles...


    Last edited by GarryB on Sun May 20, 2018 4:52 am; edited 1 time in total
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    Post  Arrow Sat May 19, 2018 9:27 am

    New hypersonic cruise missiles suggests the problems of scramjet design are being mastered... wrote:

    Russia does not currently have scramjet missiles in its equipment. They only test Cirkon, and nothing is known about it.
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    Post  Hole Sat May 19, 2018 10:36 am

    Traveling like a rocket would be a good way of making miles in a very short period of time.

    The MiG-41 could accelerated in the atmosphere, aim at its destination and switch to rocket mode. Swoosh...! Smile
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    Post  GunshipDemocracy Sat May 19, 2018 12:13 pm

    GarryB wrote:
    Cockpit was improved thus enabling MiG-31BSM to fly long runs on maximal speed of 3000km/h without any damage.

    So some simple maths... 3,000km/h = 3,000,000 m/h = 50,000 metres per minute = 833.333 metres per second, so assuming the speed of sound is 320m/s then that makes its speed mach 2.6.


    yes but only on like 3000meters Smile form ~ 12,000m speed of sound gets to 295,4 isnt it?  so 3000 you can fly 2,82 Ma with constant speed. But TVZvezda

    says something interesting: with new MiG-BM modernization there is also new special glass for cockpit that allows MiG-31BM to fly with 3400 km/h ... time:  1:30
    However he doesn't say : it flies but it can fly. I presume for a reason this "leak"

    He also mentioned about fighting air, land or space targets BTW



    This means it can fly 3,2Ma... constant speed  (944 ms right? Ma=2,95,4)


    Now it seems it can fly as much as it likes at Mach 2.6, which is a significant step forward...

    oh yes  it is with mach 3,2   Razz  Razz  Razz


    at Podmoskovnoye, USSR in zoom climb (the absolute altitude record is different from the record for sustained altitude in horizontal flight).

    Note a zoom climb is not a vertical climb.... basically the plane flies horizontally to gain max speed and then noses up in a parabola like the arc of a bullet fired into the air... so it maintains high speed all along the path and does not slow down to zero and then fall back like it would in a vertical climb.

    When at the peak of the parabola the plane is maintaining altitude through momentum and cannot help but fall down along the path of descent... if the pilot tried to level off or climb further he would rapidly lose speed and stall and fall like a rock. [/quote]

    the point here was that already MiG-25 proved dynamic ceiling can be in so called near space.
    https://en.wikipedia.org/wiki/High-altitude_balloon

    Eustace jumped form baloon on 41kms so there is air there Cool Cool Cool

    PAK DP prospective long-range interceptor - Page 9 File:Comparison_International_Standard_Atmosphere_space_diving


    and

    https://en.wikipedia.org/wiki/SpaceShipOne

    Spaceship one with speed of 3,500 km/h can have ballistic ceiling about 100 km although is rocket propelled.


    I dont think 100 km is any fetish here. More important is fighting satellites, PGS (flying 50-90 kms) and X-37 kind of intruders. Perhaps also bombing of enemy CVS. Kind of modified Kinzhal fired form 50km can possibly fly 4,000km or so.







    In that amount of time a guy with a MiG-31 can shower, dinner, check WhatsApp (calmly) and intercept in the spare time. No need for new ultra fast ultra expensive shit. The only case when that could make sense is when some smartass fires from Estonia as you say (or a Mk.41 in Poland) or highly hypersonic warheads are used. Point-black attack from SSBNs gives what, 3 to 5 minutes reaction time?[/qutoe]

    You miss the point... if an attack is detected a faster plane like a MiG-41 can go out further to intercept threats and neutralise things... So the MiG-41 can get most of the same targets and threats a MiG-31 can deal with but can hit them further away from Russian soil... possibly before they have launched their missiles... so attacking ships and bombers instead of chasing cruise missiles...

    pls note that most of new bombers will fly as drones for one way mission over Russia so saturation attacks certainty are an option.
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    Post  GunshipDemocracy Sat May 19, 2018 12:16 pm

    Hole wrote:Traveling like a rocket would be a good way of making miles in a very short period of time.

    The MiG-41 could accelerated in the atmosphere, aim at its destination and switch to rocket mode. Swoosh...! Smile

    Spaceship One with 3000 km/h got to 112 km ceiling Smile


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    Post  jhelb Sat May 19, 2018 12:31 pm

    GarryB wrote:A combined turbojet ramjet is not old, and the turbojet could get improved performance with a pulse detonation fuel system... connecting that with a ramjet or scramjet would greatly increase the speed ranges where it would provide efficient propulsion.

    So GarryB, all the legacy subsonic cruise missiles that Russia still has, that are powered by TURBOJET ENGINES, can they be refit with Ram Jet or Scram Jet when these missiles are upgraded or will new TURBOJET engines be used to replace the old ones ?
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    Post  LMFS Sat May 19, 2018 12:38 pm

    GunshipDemocracy wrote:project as PAK-DP is already approved unless you think of technical design. Then is not.  Threats ar enot evolving that fast we kno wthat both B-21 , prompt global strike, satelites, X-37 and Bomber 2037 will be there.
    Perhaps Tu-95 and B-52 too. And surely An-2   lol1   lol1  lol1
    Then what is the state of the project? I thought work had been done until now on initiative of MiG and they hadn't received until now the official requirements, maybe I have missed the latest developments. With development of threats I mean that many of the ones you mention have not even been developed so their technical characteristics are not even close to being fixed.
    GunshipDemocracy wrote:I will tell you in secret but hash nobody shall to know ok? interceptors are to fly over vast northern and eastern terrains of Russia where is close to US where hundreds of cruse missiles can fly or massive bomber drones attacks.

    For poitn blank you got S-400/S-500 and Pantsirs/Buks.
    Thanks for that revelation Gunship lol1
    I am not getting a full list of deployment bases for the -31s but it seems they are in all military districts. The interceptors make sense in every front since with their mobility they can plug the holes in the AD: reinforcing against a saturation attack in some point, locate and track threats flying low altitude in other etc. Of course if you have no other means in the region they are even more important (though here I would say that too few planes with too few missiles per aircraft are available). Again, MiG-31 is already almost a 3 M plane (even more as you point out). That is not critically slow IMHO even when it is clear that the faster the better.
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    Man, I get dazed only trying to read those letters Very Happy
    Many thanks for the translation!!
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    Post  GunshipDemocracy Sat May 19, 2018 1:24 pm

    jhelb wrote:

    So GarryB, all the legacy subsonic cruise missiles that Russia still has, that are powered by TURBOJET ENGINES, can they be refit with Ram Jet or Scram Jet when these missiles are upgraded or will new TURBOJET engines be used to replace the old ones ?

    Missiles have aerodynamic shapes desinged for speeds they fly with. I never heard about making "cruise missile" hot rods Smile Especially that hypersonic speeds temperature min problem.
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    Post  LMFS Sat May 19, 2018 1:29 pm

    GarryB wrote:
    I meant the space thing since it has been rumoured for the MiG-41, rockets would be eventually needed.
    It would not really benefit the MiG-41 to actually leave the atmosphere and fly in space... all the flight controls except engine vectored thrust would not do anything and it would basically be a flying rock.

    If there are threats or targets above in the vacuum of space then it makes more sense to get high and fast and launch a missile after it... or perhaps a laser or particle beam or whatever.
    Hole wrote:Traveling like a rocket would be a good way of making miles in a very short period of time.
    The MiG-41 could accelerated in the atmosphere, aim at its destination and switch to rocket mode. Swoosh...! Very Happy
    The higher you fly the lesser the drag... those speeds cannot be maintained for long unless the plane can go very high. So in order to cover the vast expanses of Russia (and beyond if it was the case) it would make sense that the plane can accelerate with a scramjet fast and high enough to maintain that speed economically.
    GarryB wrote:A combined turbojet ramjet is not old, and the turbojet could get improved performance with a pulse detonation fuel system... connecting that with a ramjet or scramjet would greatly increase the speed ranges where it would provide efficient propulsion.
    The J58 is a turbojet that turns ramjet just as you accelerate. So this is quite old... but still apparently complex, maybe you know new concrete developments that address that complexity.
    GarryB wrote:A ramjet on its own is very simple... air goes in a tube... the tube gets narrow and the air gets compressed... fuel is added and burned and exits out the back end of the tube producing thrust. Getting it to do that with a supersonic airflow would be tricky but the benefits would be enormous and lead to an even greater range of flight speeds open to the vehicle the engine is attached to.
    Certainly, but this part of making the combustion supersonic is where the technology is still apparently stuck at. That is why PDE is crucial.
    GarryB wrote:Jet engines benefit from just having to carry the fuel, whereas a rockets fuel by weight is 1/4 fuel and 3/4ths material that generates oxygen for the fuel to burn... you can get very high impulse figures from rocket fuel, but much shorter burn times and much increased fuel weights because you have to carry 3kgs of oxygen for every 1kg of fuel you carry... a scramjet can generate as much thrust as a rocket or even more and it scoops up its air as the vehicle moves, so you can either reduce the fuel weight by 3/4ths or carry four times more fuel...

    The problem in the past is that a jet engine burns fuel subsonically so could not match the high energy of a rocket, but supersonic burning in a scramjet means it can match or exceed exhaust speed of a rocket... when flying at mach 10... add a bit of fuel and burn it and the exhaust out the back could be moving at mach 14 or mach 15... in a ramjet you only get up to mach 4-6 because you have to slow the incoming high speed air to burn the fuel in the engine and then speed it up again to get thrust to maintain speed... in the distance between the hot engine section and the rear... so of course most of the thrust actually comes from the afterburner...
    It seems you suggest the combustion in a rocket is not subsonic, am I right or did I misunderstood you? It is also subsonic as in a jet. This is the difference in the detonation engine.
    GarryB wrote:
    There is a bit of a gap between mach 4.2 and 7km/s for items in low earth orbit... higher orbit stuff is even faster... 4.2 times 320m/s is about 1.4km/s.
    Exactly the point of the detonation engine. You can theoretically move all the way from subsonic to highly hypersonic since as you said you do not need anymore to slow down the incoming air. From the interview posted by GunshipDemocracy:
    Whether it is possible to use the detonation engine in hypersonic rockets?

    Pyotr Levochkin: Both it is possible, and it is necessary. At least because burning of fuel in him supersonic. And in those engines on which try to create the operated hypersonic aircraft, burning subsonic now. And it creates an array of problems. If burning in the engine subsonic, and the engine flies, let us assume, with a speed of five moves (one move is equal to acoustic speed), it is necessary to slow down a counter flow of air to the sound mode. Respectively, all energy of this braking turns into heat which leads to additional overheating of a design.

    And in the detonation engine process of burning goes at a speed at least two and a half times higher sound. And, respectively, we can increase aircraft speed by this size. That is it is already not about five, and about eight moves. It is the speed of aircraft really achievable today with hypersonic engines in which the principle of detonation burning will be used.
    GarryB wrote:You could use a ceramic mesh that covers the fuel rods and when they get very very hot so does the mesh...... a supersonic ramjet could be made simpler because there is no combustion... just heat transfer from nuclear fuel rods to the air flowing through the engine.
    Yes that is quite interesting, since it is a heat source without combustion and its associated problems. As to the radiation, the ceramic mesh could block radioactive particles from being emitted (hopefully) but gamma radiation is not going to be stopped that easily... nuclear things tend to be difficult to handle you know! Very Happy
    GarryB wrote:You miss the point... if an attack is detected a faster plane like a MiG-41 can go out further to intercept threats and neutralise things... So the MiG-41 can get most of the same targets and threats a MiG-31 can deal with but can hit them further away from Russian soil... possibly before they have launched their missiles... so attacking ships and bombers instead of chasing cruise missiles...
    Yes I understand the advantages of speed, only say that a 30% increase in speed is not bringing the weapon into another category capable of countering i.e. hypersonic threats, even more if the range is not very big. Still unsure about the project, what requirements, basic technologies and actual time frame will end up being implemented dunno
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    Post  GunshipDemocracy Sat May 19, 2018 1:40 pm

    LMFS wrote:
    Then what is the state of the project? I thought work had been done until now on initiative of MiG and they hadn't received until now the official requirements, maybe I have missed the latest developments.

    That's what I said only plans for PAK DP. Yes MiG is working on tis own but there is no independent MiG anymore. there is part os Rostekh isnt it? BTW MiGs-31 wont last more beyond 2030 so time is short really to get new interceptors.


    As for threats- once they are fielded you're like 10-15 years too late... You know what Us requiremnts and cocnepts are, what is technology in 10-15 years and your own also. so it is realistically feasible to figure out what are requirements.



    Thanks for that revelation Gunship lol1

    YW Razz Razz Razz


    I am not getting a full list of deployment bases for the -31s but it seems they are in all military districts. The interceptors make sense in every front since with their mobility they can plug the holes in the AD: reinforcing against a saturation attack in some point, locate and track threats flying low altitude in other etc. Of course if you have no other means in the region they are even more important (though here I would say that too few planes with too few missiles per aircraft are available). Again, MiG-31 is already almost a 3 M plane (even more as you point out). That is not critically slow IMHO even when it is clear that the faster the better.

    Perhaps this "extra" 2thousands km/h can add dynamic ceiling from 30 till 80-100 kms? Not to mention new level to technology for hypersonic transport/planes?


    GunshipDemocracy wrote:you mean like moi ? ну что ты!
    Man, I get dazed only trying to read those letters Very Happy
    Many thanks for the translation!![/quote]

    Cyrillic , as those characters on calculator mangers and consultants always avoid lol1 lol1 lol1
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    Post  GunshipDemocracy Sat May 19, 2018 1:47 pm

    LMFS wrote:
    GarryB wrote:You could use a ceramic mesh that covers the fuel rods and when they get very very hot so does the mesh...... a supersonic ramjet could be made simpler because there is no combustion... just heat transfer from nuclear fuel rods to the air flowing through the engine.
    Yes that is quite interesting, since it is a heat source without combustion and its associated problems. As to the radiation, the ceramic mesh could block radioactive particles from being emitted (hopefully) but gamma radiation is not going to be stopped that easily... nuclear things tend to be difficult to handle you know! Very Happy

    Hmm mesh can heat of course air but this is not about temperature but heat transfer, right? with mesh it is hard to imagine adiabatic expnasion ti si more like grill on steroids.
    More dense mash? mesh and you have problems with air flow.

    Perhaps microwave pulses to heat up air in explosive ways (adiabatic heating inshort) ? you got but that's the rocket science beyond my knowledge :-)
    Hole
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    PAK DP prospective long-range interceptor - Page 9 Empty Re: PAK DP prospective long-range interceptor

    Post  Hole Sat May 19, 2018 5:17 pm

    The MiG-25 and later MiG-31 were limited to M2,8 because of higher maintenance costs and shorter service life of the engines and the airframe, which could be damaged by overheating. One MiG-25 reached a speed of 3.400km/h as a few were stationed in Egypt, back in the 70´s.

    The thinking behind the MiG-31 was to move the point of intercept up to 1.000km beyond the border, so that they could attack bombers in the high north before they could launch there cruise missiles.

    Someone claimed the MiG-41 could possibly leave the atmosphere and travel trough space. The ultimate short cut.

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