Μilitary Questions & Answers

Not in any way do I doubt Scramjets advantages. However, they still remain relatively untested, and aren't in service with anyone quite yet. Also, the minimum speed requirement of ~ Mach 5 isn't exactly a good thing. A Scramjet missile would need a very large and powerful solid-rocket first stage. 

GarryB, do you know why SAMs never implement "Aero-spikes" as found on the Trident series of ICBMs? They are said to improve aerodynamics by up-to/over 50%, which would result in a considerably greater range.

Mike E wrote:
Scramjets characteristics are still relatively unknown, so Ramjets would be the safer bet. Ramjets also allow for the missile to throttle down to around Mach 1, which could improve range dramatically.

Is that so?

From what I know, it's the other way around, efficiency increases with ram pressure, which is proportionate to speed. Correct me if I'm wrong  


"GarryB, do you know why SAMs never implement "Aero-spikes" as found on the Trident series of ICBMs? They are said to improve aerodynamics by up-to/over 50%, which would result in a considerably greater range."

Dunno exactly, but maybe high alfa angles have something to do with it?

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To Garryb:
"Creating a scramjet S-400 likely wouldn't make it smaller or lighter, so I doubt they will bother, but for very long range very high speed missiles scramjet propulsion will probably be the mode of choice."

I'd like to add that current scramjets able to emulate the performance of 48N6's/40N6's rocket engines are not yet available, even prototypes.
The best performing S-J, X-51 "waverider", goes only to about mach 6, while even middle tier s-400 missile has a burnout speed of about 8 mach, quite a significant difference. And I'm not even talking about 40N6 with ~12 mach

Yes and no, while Scramjets have been tested, they've never been put to use.

Scramjets do use a lot of use, with the benefit being speed. I would guess Ramjets are less efficient around Mach 5 (Scramjet speed), but more so at lower speeds (for obvious reasons) (I need a second opinion on this, correct me if I'm wrong).

Could be, I'm not sure. From what I've read, Spikes wouldn't be a problem at high angles of attack because of their small size and surface area.

Scramjets aren't "there yet", but when they are, you can expect big things.

Also, the minimum speed requirement of ~ Mach 5 isn't exactly a good thing. A Scramjet missile would need a very large and powerful solid-rocket first stage.

There are no hard limits of speed for scramjets... the SA-5 test just started testing at mach 5 because that is the normal flight speed of the SA-5 so that is when it started operating.

The engines in the SR-71 are a good example of what can be expected.

they work as standard turbojets for takeoff and landing, but as they accelerate to high speed bypass air that is sucked in the intake but goes around the outside rather than through the engine is increased. This air going around the engine is called bypass air, just like on a turbofan, engine, but in this case when the SR-71 is flying at mach 3.5 almost no air is flowing through its turbojet engines which produce almost no thrust. The bypass air has fuel added and operates like a ramjet and produces the thrust to propel the aircraft.

Having a variable cycle engine is likely the future.

In fact an onboard store of fuel and oxygen and the ability to close the intakes could be used for a space plane.

Use normal jet propulsion to take off from a runway with air sucked in the intakes and fuel used with the air coming in the intakes. Climb and accelerate to supersonic speed and close off the turbojet engine with bypass air acting like a scramjet with air still coming in the intakes and accelerate to mach 26... turn to a flight path to take you out of the atmosphere and close off the intakes and start feeding the O2 and burn it with the fuel and you pretty much have a rocket plane. So turbojet, scramjet, rocket propulsion.

GarryB, do you know why SAMs never implement "Aero-spikes" as found on the Trident series of ICBMs? They are said to improve aerodynamics by up-to/over 50%, which would result in a considerably greater range.

Not the best solution... an aerospike is used on missiles with rounded noses of poor aerodynamic design for supersonic flight. Trident has a round nose because of the design constraints to pack as much missile in as small a tube as possible so rather than an efficient long pointy nose is has a stumpy rounded nose which would be aweful for supersonic flight.

Another application is IR guided SAMs and AAMs because the IR optical sensor is most efficient with a rounded nose which greatly increases nose induced drag.

The example would be Igla with its aerospike to improve performance without compromising the shape of the nose optical port.

In comparison the Mistral has a pointed nose which effects its IR sensitivity and performance.

Very simply the Russians went for a good optical sensor performance and good flight performance,while the French compromised IR sensor performance for aerodynamic performance.

From what I know, it's the other way around, efficiency increases with ram pressure, which is proportionate to speed. Correct me if I'm wrong

It is a bit like a car... in top gear you move most efficiently using the least fuel... the worst performance is low speed accelerating, the best performance is top speed cruising with a low throttle setting to maintain speed by countering drag.

I'd like to add that current scramjets able to emulate the performance of 48N6's/40N6's rocket engines are not yet available, even prototypes.
The best performing S-J, X-51 "waverider", goes only to about mach 6, while even middle tier s-400 missile has a burnout speed of about 8 mach, quite a significant difference. And I'm not even talking about 40N6 with ~12 mach

Very true, but the key is that scramjets are in their infancy and have enormous potential.... in a range of applications.

I would guess Ramjets are less efficient around Mach 5 (Scramjet speed), but more so at lower speeds (for obvious reasons) (I need a second opinion on this, correct me if I'm wrong).

Ramjets choke on supersonic air, just like turbojets do. The fastest flying turbojet engine is the engine in the MiG-31 where all the thrust is derived from the turbojet engine. The problem is that as you approach Mach 3 the incoming air needs to be slowed down so when it goes through the engine in the hot section where fuel is added it is subsonic so the fuel burns properly. To achieve this the intake narrows and reduces the airflow into the engine, which slows it down to subsonic speed. Of course the limitation of speed of the engine is how fast it can push this air and the burnt fuel out the back... the speed it pushes it out determines how much thrust is produced... if the air through the hot section becomes supersonic it will flameout and stall and the air blown out the rear will greatly lose heat and energy and thrust will go down.

It is the same for a ramjet... if the air going into the hot section becomes supersonic it will flame out and stall and thrust will be lost.

Most ramjets are efficient in the mach 3-4 range but not much more... they still need a certain volume of air flowing through them to generate thrust to maintain flight.

With a scramjet the airflow is still controlled but can be allowed to go through much faster including supersonic or faster through the hot section meaning a lot more thrust and much higher speed.

the limitations on scramjets is heat... the insides can melt and the external surfaces of the aircraft can melt due to the high temperatures generated in high speed flight.

GarryB wrote:The limitations on scramjets is heat... the insides can melt and the external surfaces of the aircraft can melt due to the high temperatures generated in high speed flight.

What's the likeliness that Space Shuttle-style heat tiles make their way on to scramjet vehicles?

Thank you for all that info! 

I simply mean that Scramjets have to be accelerated in order to function. This isn't that big of a problem for missiles, but is for larger/heaver planes etc. 

The SR-71 really was a revolution, that engine technology was way ahead of its time. (Thank you Kelly!!!)

I completely agree, we will be seeing much more in the variable cycle area. (Just to let you know, I know the basics of Turbojets and jet engines in general. I used to know a TON on Scramjets, but it all came out of me.)

Ok, thank you for answering that for me. I guess it is more of a stop-gap solution than anything else. If I remember right, India is said to have a better solution in which the rocket somehow ionizes (?) the air in front of it, supposedly increase aero properties by ~45% .

That sounds reasonable, especially when Scramjets are "popular".

Heck, I feel Ramjets are still undervalued! (Yes I know, Scramjets are basically the same thing.)

That's is one advantage of Scramjets, they probably don't create as much drag. (By not slowing down the incoming air, causes air around the engine to "reroute".

Heat will always be an issue, but there are many ways of (for the most part) overcoming it. Look at MIRVs, they travel at Mach 10! (Albeit with heat shields.)

(I found the Indian aero technology, here it is; http://www.domainb.com/aero/mil_avi/miss_muni/20080910_Indian_technology.html )

magnumcromagnon wrote:

GarryB wrote:The limitations on scramjets is heat... the insides can melt and the external surfaces of the aircraft can melt due to the high temperatures generated in high speed flight.

What's the likeliness that Space Shuttle-style heat tiles make their way on to scramjet vehicles?

Very plausible, if not, engineers will find a better solution.

GarryB wrote:Not the best solution... an aerospike is used on missiles with rounded noses of poor aerodynamic design for supersonic flight. Trident has a round nose because of the design constraints to pack as much missile in as small a tube as possible so rather than an efficient long pointy nose is has a stumpy rounded nose which would be aweful for supersonic flight.

Another application is IR guided SAMs and AAMs because the IR optical sensor is most efficient with a rounded nose which greatly increases nose induced drag.

The example would be Igla with its aerospike to improve performance without compromising the shape of the nose optical port.

In comparison the Mistral has a pointed nose which effects its IR sensitivity and performance.

Very simply the Russians went for a good optical sensor performance and good flight performance,while the French compromised IR sensor performance for aerodynamic performance.

Yeah, seems true enough


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magnumcromagnon wrote:

GarryB wrote:The limitations on scramjets is heat... the insides can melt and the external surfaces of the aircraft can melt due to the high temperatures generated in high speed flight.

What's the likeliness that Space Shuttle-style heat tiles make their way on to scramjet vehicles?

Eh, I think space shuttle's (and other space carriers', actually) tiles are built for quite a different purpose. That is, to be used not in flight, but in descent.
And that descent is rough- flying at near 90 degrees AoA while slowing down from mach 20 to mach 2-3. I don't think the near future scramjet vehicles need that kind of strength yet.

What's the likeliness that Space Shuttle-style heat tiles make their way on to scramjet vehicles?

Ablative tiles could be useful for one use systems like rockets, but for reusable craft like the shuttle they are a pain in the backside... after every flight they need to be very carefully examined for wear or cracks with old tiles replaced.

A better solution would be to pump slush hydrogen fuel through the aircraft skin... it is very cold and would take the heat out of any surface... very much the same as if you throw a plastic bottle on the fire it will quickly melt and catch fire itself. Now take a similar bottle and fill it with water and throw it on the fire... the heat from the fire is absorbed by the water so the plastic does not get hot enough to melt because the water draws the heat away from the plastic.

I simply mean that Scramjets have to be accelerated in order to function. This isn't that big of a problem for missiles, but is for larger/heaver planes etc.

Certainly with a scramjet... with a heat limit rather than a speed limit the faster you can accelerate it the better... a rocket engine will accelerate it faster than it can accelerate on its own.

Even a pulse detonation engine can operate from stationary, but becomes rather more efficient as the aircraft moves faster. It is just like gears and internal combustion engines... very low gears and cold engines reduce efficiency and performance.

Heck, I feel Ramjets are still undervalued! (Yes I know, Scramjets are basically the same thing.)

A scramjet is a type of ramjet... think of it in terms of turbojets... an old end of WWII turbojet engine is still a turbojet engine. Comparing it to a modern turbojet engine and you could almost say they are different engines but the basic functionality is different. Without a variable ramp air intake a turbojet from a late WWII plane would stall at supersonic speed.. the same with a ramjet and a scramjet.

Obviously ramjets are incredibly simple, scramjets are slightly more complex, but until the ramjet is operating at very high speed the combustion will be subsonic anyway so a scramjet and a ramjet will be identical. It is only when the ramjet loses thrust and the scramjet continues to burn fuel supersonically and generates rather more thrust than any ramjet can generate that the differences become obvious.

That's is one advantage of Scramjets, they probably don't create as much drag. (By not slowing down the incoming air, causes air around the engine to "reroute".

The Scramjet at any speed can have the air intake wide open which means higher airflow, higher exhaust speed and rather more thrust.

Heat will always be an issue, but there are many ways of (for the most part) overcoming it. Look at MIRVs, they travel at Mach 10! (Albeit with heat shields.)

The period of time they travel at mach 10 is fairly short as they fall through the atmosphere... if we assume the atmosphere is only significant in terms of drag up to about 50km then we are talking about less than 20 seconds of reentry.

And that descent is rough- flying at near 90 degrees AoA while slowing down from mach 20 to mach 2-3. I don't think the near future scramjet vehicles need that kind of strength yet.

Good point... the space shuttle uses its wings and lower surface area as a sort of aerobrake, so it does rapidly heat up. Importantly the angle of entry into the atmosphere is critical... too steep and it gets too hot and you burn up. Not steep enough and you skip like a stone on flat water back up into space.

For high speed flight there are areas of the airframe that will be subjected to continuous friction heat... a Mach 2.86 the canopy of the MiG-31 can get to 70 degree Celsius... other external parts like the wing root get much hotter and cannot be made of Aluminium or it will melt.

''The coating evaporates once the object has re-entered the atmosphere. This novel method is path-breaking because additional energy is not required to reduce drag; objects which travel into space need to carry a much lower fuel load,'' Jagadeesh said."

If the coating evapourates on reentry then how can it operate as a substitute for heat tiles?

I am skeptical and would want rather more information directly from the people developing the technology.

GarryB wrote:

What's the likeliness that Space Shuttle-style heat tiles make their way on to scramjet vehicles?

Ablative tiles could be useful for one use systems like rockets, but for reusable craft like the shuttle they are a pain in the backside... after every flight they need to be very carefully examined for wear or cracks with old tiles replaced.

A better solution would be to pump slush hydrogen fuel through the aircraft skin... it is very cold and would take the heat out of any surface... very much the same as if you throw a plastic bottle on the fire it will quickly melt and catch fire itself. Now take a similar bottle and fill it with water and throw it on the fire... the heat from the fire is absorbed by the water so the plastic does not get hot enough to melt because the water draws the heat away from the plastic.

I simply mean that Scramjets have to be accelerated in order to function. This isn't that big of a problem for missiles, but is for larger/heaver planes etc.

Certainly with a scramjet... with a heat limit rather than a speed limit the faster you can accelerate it the better... a rocket engine will accelerate it faster than it can accelerate on its own.

Even a pulse detonation engine can operate from stationary, but becomes rather more efficient as the aircraft moves faster. It is just like gears and internal combustion engines... very low gears and cold engines reduce efficiency and performance.

Heck, I feel Ramjets are still undervalued! (Yes I know, Scramjets are basically the same thing.)

A scramjet is a type of ramjet... think of it in terms of turbojets... an old end of WWII turbojet engine is still a turbojet engine. Comparing it to a modern turbojet engine and you could almost say they are different engines but the basic functionality is different. Without a variable ramp air intake a turbojet from a late WWII plane would stall at supersonic speed.. the same with a ramjet and a scramjet.

Obviously ramjets are incredibly simple, scramjets are slightly more complex, but until the ramjet is operating at very high speed the combustion will be subsonic anyway so a scramjet and a ramjet will be identical. It is only when the ramjet loses thrust and the scramjet continues to burn fuel supersonically and generates rather more thrust than any ramjet can generate that the differences become obvious.

That's is one advantage of Scramjets, they probably don't create as much drag. (By not slowing down the incoming air, causes air around the engine to "reroute".

The Scramjet at any speed can have the air intake wide open which means higher airflow, higher exhaust speed and rather more thrust.

Heat will always be an issue, but there are many ways of (for the most part) overcoming it. Look at MIRVs, they travel at Mach 10! (Albeit with heat shields.)

The period of time they travel at mach 10 is fairly short as they fall through the atmosphere... if we assume the atmosphere is only significant in terms of drag up to about 50km then we are talking about less than 20 seconds of reentry.

And that descent is rough- flying at near 90 degrees AoA while slowing down from mach 20 to mach 2-3. I don't think the near future scramjet vehicles need that kind of strength yet.

Good point... the space shuttle uses its wings and lower surface area as a sort of aerobrake, so it does rapidly heat up. Importantly the angle of entry into the atmosphere is critical... too steep and it gets too hot and you burn up. Not steep enough and you skip like a stone on flat water back up into space.

For high speed flight there are areas of the airframe that will be subjected to continuous friction heat... a Mach 2.86 the canopy of the MiG-31 can get to 70 degree Celsius... other external parts like the wing root get much hotter and cannot be made of Aluminium or it will melt.

''The coating evaporates once the object has re-entered the atmosphere. This novel method is path-breaking because additional energy is not required to reduce drag; objects which travel into space need to carry a much lower fuel load,'' Jagadeesh said."

If the coating evapourates on reentry then how can it operate as a substitute for heat tiles?

I am skeptical and would want rather more information directly from the people developing the technology.

I agree on your second point, about using rockets to get the Scramjet "up to speed". Hopefully variable cycle engines will solve this problem soon enough. 

Yeah, what I meant to say is that Ramjets have never been fully utilized like Turbofans (for example). (I knew the differences already, but maybe other people will learn.)

That is true, but MIRVs also have to travel though the thick atmosphere, unlike missiles which might have a booster to get it "up high".
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I don't see it replacing heat tiles, as they would have to reapply after every flight. However, I do see its potential when it comes to reducing drag, which is almost invaluable. (Agni III, which is India's longest-range missile with a capability of striking targets 3,500 km away, may now have an extended range of around 5,000 km thanks to a unique solution discovered by Indian scientists at the prestigious Indian Institute of Science (IISc) here.) Those 1500 km are a huge deal.

As you may know, the U.S. has many incidents of where people...mostly civilians, people who have never served in the armed forces, are wearing uniforms, with medals. Most of the time they are claiming they are Ex-Navy Seals, rangers, or marines just so they can get respect, of which is something they don't deserve. Now recently this is starting to pop up in Canada as well. Recently U.S. veterans are becoming more aggressive with these "Stolen Valor" chaps, by filming them and calling them out in public. Where later they will be identified, put on the News and/or on Facebook. I imagine there are some cases where they are beat the crap out of them too, but that doesn't happen likely since everyone loves to sue people over there.

My question is, do Russians, have incidents where people are walking around, claiming they are Ex-VDV or Spetsnaz, while wearing fake uniforms? If they do, what do they do about it?

Such phonies exist in every country but good thing is in very rare cases they actually walk around in fake uniforms, most of the part such phoneys just take pictures and brag with them with their fake facebook,vk or whatever profiles.

The 21st century is the age of phony people online, being superhereos, top models and geniuses like only Marvel comics can create but in real life all are as boring as they can only be.

I'm sure it happens, although I can't say I've heard anything about the exposition of 'stolen valour' fraudsters in these parts.

Although it doesn't qualify as stolen valor as such, I witnessed quite an amusing episode myself when me, an army buddy and one of our other buddy's cousins were part of a big camping group, and at around 10 o'clock in the evening or so we took an inflatable dinghy out for a spin on the lake; bottle of whisky in hand of course.
Our idea was basically to row ourselves up to the all the camping fires we spotted in the distance - and crash the party.
We had quite a time doing it, but eventually we crashed the party of a few ex-VDV guys celebrating something or other. They started being a-holes when we asked if we could dry ourselves by the fire for a bit, but whatever. More seriously though, they started aggroing our buddy's cousin, who was wearing a telnyashka (part of the Naval and VDV uniform) - when he admitted that he hadn't served anywhere upon confrontation (he was barely 19).
Well we quickly got in the way and the situation didn't escelate further; although one of them told us that if the kid was wearing a VDV telnyashka than he would have punched him out.

As it was though - he was wearing a naval one in fact. Note that both me and the other guy served in the Navy, and the telnyashkas were also part of our uniform - but neither of us gave a damn that the kid was wearing one too, live and let live, and all that.
But for certain people it seems - they don't take kindly to anyone wearing something that they're not supposed to be.

If they let people crawl all over it with a tape measure then it is not secret.

If there is a guy standing next to it with a rifle who steps between you and the vehicle every time you move towards it then don't measure and certainly dont post your results.

ISIS v Egypt navy

look like wire anti tank

No sure if thermo head

twitter say the kornet

Book. wrote:No sure if thermo head

twitter say the kornet

A Kornet doesn't produce such a big explosion...it seems more like a small AShM or something.

ISIS missile ATTACK on Egyptian navy deadly hit


Look like small anti ship

Mike u right !

That is not an ATGM, this is explosion is vast and at least 100kg Warhead of explosives.

THis was just a small coast guard vessel - a 100kg warhead would rip it to pieces - but we only see some fire and then a burning ship. ATGM could cause this.

Book. wrote:ISIS v Egypt navy

look like wire anti tank

Raytheon had developed a naval version of the Javelin ATGM. Probably it is one of those, that the US recently air dropped to ISIS.

Walther von Oldenburg wrote:THis was just a small coast guard vessel - a 100kg warhead would rip it to pieces - but we only see some fire and then a burning ship. ATGM could cause this.

The explosion of even heavy Helibrone ATGM's are roughly the same size as the tanks they hit. This ship is not only several times bigger than the biggest tank but also the explosion is 3-5 times bigger then the ship. The payload of the missile is in ten fold figure of usual ATGM's with their 8-12kg warheads.

In comperision ATGM with the highest warhead payload infantry could have is a Kornet which also is Laser Beam Rider meaning it has a very distingive trajectory whirling around within the Laser Beam.

Also the most exported Kornet's are all HEAT warheads with directed shaped charge, meaning the explosion should be smaller than HE-Frag or Thermobaric warheads.

jhelb wrote:

Book. wrote:ISIS v Egypt navy

look like wire anti tank

Raytheon had developed a naval version of the Javelin ATGM. Probably it is one of those, that the US recently air dropped to ISIS.

Raytheon and Lockheed Martin also propagate that their Javelin and Hellfire are AShM's which they are not with lousy 8-10kg warheads with barely 8km range which would not make much more difference then using the normal HE-Frag warheads of Hellfire. Those are not AShM's.