Originally posted by Zaphod58
Even if that ISN'T the 229 and is the Ho 9, I STILL don't see the recessed intakes, or extended exhaust that you talk about. Those are NOT recessed intakes. Recessed intakes would keep radar from bouncing off the turbines in the engines. There's nothing about those intakes would almost funnel the radar waves directly to the turbines which would cause a big RCS.

As far as the RAM goes, there's no way that the material they used would cause such a huge lowering of the RCS. The British Mosquito was made of wood and was routinely tracked on radar. Radar is capable of picking up birds, so just using would, and sawdust wouldn't make the huge difference in RCS that is claimed.

From what I know about jet engines back then they had enough trouble keeping them running sometimes, WITHOUT extended exhausts. The engines on the ME262 were notorious for stalling, and having other problems unless the throttles were slowly and smoothly advanced. If you extend the exhaust, you lose power. As most early jet engines were ALREADY underpowered you couldn't extend the exhaust without creating even more problems with the engines.

And I'm STILL not seeing any conclusive proof that Germany EVER developed antigravity technology, or how they can be developing antigravity, but already use it on the B-2.

[edit on 28-6-2005 by Zaphod58]

Zaphod58, if those (Ho9) are not recessed air intakes, what would you call them? And what would you call the air intakes on the Gotha229?

I have referred you to my post on your question and the simple answer is that I don't think there is any relationship between the "anti-gravity" (as you call it) on the B-2 and any project of the Germans----but, I will cover all bases with the following:

In the 1950s, two German scientists working for Franco, Kock and Mueller, developed something they called the "KM2 electomagnetic rocket". The source for this is one newspaper article claming an eyewitness to the tests and a Czech source. This may have actually been an electrostatic device using a T.T. Brown-type flame-jet generator. Also, there is a some new information (mentioned in one of my lasts posts) regarding an anti-aircraft device which was powered using an electrostatic charge. But, I am not putting my name to either one right now as having anything to do with "anti-gravitiy" or the B-2.

Originally posted by Zaphod58
Great answer to it Forschung, but it didn't answer the question. There are links provided in this topic that Boeing and other companies are DEVELOPING antigravity technology, and there are posts providing "proof" that the B-2 USES antigravity technology. You can't have it both ways, either it's been developed, or it's BEING developed.

"If it is strong enough, T. T. Brown found that movement would take place toward the positive edge. In other words, in the case of the B-2, if this were charged to the degree necessary and if the insulator held, the aircraft would move, as if flying downhill, toward the positive side. The flame jet generator can produce millions of volts of charge"

See the words in there that tell the whole story are "IF". If this condition is met, and If this condition is met then it CAN be used in this way. They wouldn't use a system like this in the B-2 for propulsion for that simple reason. IF the insulator failed, you just lost an airplane(probably).

Zaphod58, I have talked to a old retired engineer of the 1950s era who was told by his superior and the government to stop working on "anti-gravity" (how I hate that word) and get back to aerodynamics. This engineer claimed to have done something working.

There is no doubt in my mind that the Germans, during WW2, were working of field propulsion and had some success. The problem is that their methods were completely different from those said to be used by the B-2. You can think what you like but that is all I know for certain in my own mind.

I would call those normal intakes. Recessed intakes are like on the B-2, where they are flat and deep, and there is a "tunnel" that leads down to the fan blades, so that the radar waves can't bounce off them. Those intakes on the Ho 9 would do nothing to keep radar from hitting the fan blades on that engine. The shape of the B-2 fuselage partially blocks the radar from hitting the engines, and the flat, deep intakes keep the radar from hitting them and returning to the antenna. Recessed intakes are NOT round and sticking out on the side like they are on Ho 9. That's like saying the F-15 has recessed intakes, because they are forward from the engines.

Originally posted by Zaphod58
I would call those normal intakes. Recessed intakes are like on the B-2, where they are flat and deep, and there is a "tunnel" that leads down to the fan blades, so that the radar waves can't bounce off them. Those intakes on the Ho 9 would do nothing to keep radar from hitting the fan blades on that engine. The shape of the B-2 fuselage partially blocks the radar from hitting the engines, and the flat, deep intakes keep the radar from hitting them and returning to the antenna. Recessed intakes are NOT round and sticking out on the side like they are on Ho 9. That's like saying the F-15 has recessed intakes, because they are forward from the engines.

Zaphod58, please read what I posted about the purpose of the Horten9, and its discovery by the Germans of a low radar return. The Ho9 used a standard turbojet engine, not a turbofan which didn't exist then. If the air intakes are recessed in my mind, then they are recessed air intakes. The picture is worth 1000 words. A rose is a rose by any other name and these are absolutely without doubt recessed air intakes.

What? what nosecone that moves back and forth? The only one that did that was the SR-71.

I'm NOT saying the B-2 was recessed because it's better, I'm saying the B-2 is recessed because it IS. Read this carefully, because it's the last time I'm gonna say it. I surrender if you don't get it after this.

The POINT of a recessed intake is ONLY for stealth characteristics. It keeps the radar from hitting the fan section of the engine. If you have a normal engine, and yes I admit that the fan section IS set back from the intake, radar will go straight down it, hit the fan section, and bounce right back out to the radar antenna thus increasing the RCS. A recessed intake, is set back on the airframe, is shapped differently, and has a smaller opening precisely so that the radar CAN NOT go down it, hit the fan section, and return. The intakes of the Ho 9 look just like any normal non-stealthy planes intakes. The REASON they put a fan section back from the intake is to let air travel down it to the fan section. The fan section of an engine is a GREAT way to create massive amounts of drag, which in the case of the Ho 9, the Me-262 and other fighters, would be Very Bad and cause all kinds of problems. The intakes on the B-2 were designed specifically for stealth purposes, which is why they are the shape, and size they are, and were put back on the airframe. If you notice in pics of the B-2 on the ground they had to put doors on top of the intakes, because when it's moving around on the ground it doesn't get as much airflow down the intakes, so it has to add air somehow. Once it's in flight it's not a problem.

A normal engine DOES sit back from the intake, that does NOT make it a recessed intake. That makes it a recessed ENGINE. The difference between the two is MASSIVE. A RECESSED ENGINE is designed that way so that the fan section doesn't create drag. A RECESSED INTAKE is there for stealthiness. That is the ONLY point of a recessed intake.

Lesson over. If you still don't get it after this, I surrender, you win, the Germans were decades ahead of everyone else and could have won the war if they had another year.

Originally posted by Zaphod58
What? what nosecone that moves back and forth? The only one that did that was the SR-71.

I'm NOT saying the B-2 was recessed because it's better, I'm saying the B-2 is recessed because it IS. Read this carefully, because it's the last time I'm gonna say it. I surrender if you don't get it after this.

The POINT of a recessed intake is ONLY for stealth characteristics. It keeps the radar from hitting the fan section of the engine. If you have a normal engine, and yes I admit that the fan section IS set back from the intake, radar will go straight down it, hit the fan section, and bounce right back out to the radar antenna thus increasing the RCS. A recessed intake, is set back on the airframe, is shapped differently, and has a smaller opening precisely so that the radar CAN NOT go down it, hit the fan section, and return. The intakes of the Ho 9 look just like any normal non-stealthy planes intakes. The REASON they put a fan section back from the intake is to let air travel down it to the fan section. The fan section of an engine is a GREAT way to create massive amounts of drag, which in the case of the Ho 9, the Me-262 and other fighters, would be Very Bad and cause all kinds of problems. The intakes on the B-2 were designed specifically for stealth purposes, which is why they are the shape, and size they are, and were put back on the airframe. If you notice in pics of the B-2 on the ground they had to put doors on top of the intakes, because when it's moving around on the ground it doesn't get as much airflow down the intakes, so it has to add air somehow. Once it's in flight it's not a problem.

A normal engine DOES sit back from the intake, that does NOT make it a recessed intake. That makes it a recessed ENGINE. The difference between the two is MASSIVE. A RECESSED ENGINE is designed that way so that the fan section doesn't create drag. A RECESSED INTAKE is there for stealthiness. That is the ONLY point of a recessed intake.

Lesson over. If you still don't get it after this, I surrender, you win, the Germans were decades ahead of everyone else and could have won the war if they had another year.

Zaphod58, A cone which is fixed defeats the purpose of the cone. The cone MOVES according to air speed and the aerodynamic characterics of the aircraft and the engine itself. They move Zaphod58 or they wouldn't be there at all.

There is very little in your statement that I would dispute except. You are not understanding that the Ho9 was not built for stealthiness--nobody ever heard of stealth in those days. AFTER it was built, for whatever reason the intakes are recessed, it was discovered that the radar return was the lowest ever observed to date. That is why the Americans were interested in it. The B-2 was built for stealth and the intakes are much different but recessed, which was the basic adaptation to acheive a low radar return.

I have asked you what you would call the Ho9's intakes if not recessed. No response. So, lets go the other way. What would you call the air intake for the Mig21?

"I would call those normal intakes" I answered that a long time ago. I KNOW that the Ho 9 was not meant to be stealthy. But the ONLY, I repeat ONLY point of recessed intakes is for STEALTH. Ergo, if the Ho 9 wasn't built for stealth purposes, it COULD NOT have recessed intakes. It had RECESSED ENGINES. There IS a difference.

As far as the inlet cone, read this carefully. very very carefully.

"The earliest types of supersonic aircraft featured a central shock cone, called an inlet cone, which was used to form the shock wave. This type of shock cone is clearly seen on the English Electric Lightning and MiG-21 aircraft, for example. The same approach can be used for air intakes mounted at the side of the fuselage, where a half cone serves the same purpose with a semicircular air intake, as seen on the F-104 Starfighter and BAC TSR-2. A more sophisticated approach is to angle the intake so that one of its edges forms a leading blade. A shockwave will form at this blade, and the air ingested by the engine will be behind the shockwave and hence subsonic. The Century series of US jets featured a number of variations on this approach, usually with the leading blade at the outer vertical edge of the intake which was then angled back inwards towards the fuselage. Typical examples include the Republic F-105 Thunderchief and F-4 Phantom. Later this evolved so that the leading edge was at the top horizontal edge rather than the outer vertical edge, with a pronounced angle downwards and rearwards. This approach simplified the construction of the intakes and permitted the use of variable ramps to control the airflow into the engine. Most designs since the early 1960s now feature this style of intake, for example the F-14 Tomcat, Panavia Tornado and Concorde.

In one unusual instance (the SR-71), a variable air intake design was used to convert the engine from a turbojet to a ramjet, in flight. To get good efficiency over a wide range of speeds the Pratt & Whitney J58 could move a conical spike fore and aft within the engine nacelle, to keep the supersonic shock wave just in front of the inlet. In this manner, the airflow behind the shock wave, and more importantly, through the engine, was kept subsonic at all times. Additionally, and unusually for this engine, at high mach, the compressor for the J58 was unable to carry the high air flow entering the inlet without stalling its blades, and so the engine directed the excess air through 6 bypass pipes straight to the afterburner. At high speeds the engine actually obtained 80% of its thrust, versus 20% through the turbines itself, in this way. Essentially this allowed the engine to operate as a ramjet, and actually improving specific impulse (fuel efficiency) by 10-15%."

"The main purpose of an inlet cone is to slow down the flow of air to subsonic speeds before it enters the engine. Most engines require subsonic airflow to operate properly, and require a diffuser to prevent supersonic airflow inside the engine. At supersonic speeds, a shock wave forms on the leading edges an aircraft, causing significant pressure and drag. The shock wave has the added effect of slowing down the air that passes through it. The inlet cone is shaped so that the shock wave that forms on its point is directed to the lip of the intake; this allows the engine to operate properly in supersonic flight. As speed increases, the shock wave becomes increasingly more narrow. As a result, SOME inlet cones have the ability to move front-to-back to allow operation in a wider range of speeds.

Inlet cones on turbojets

Shock waves may also cause the compressor blades of a conventional jet engine to melt or shatter. Inlet cones prevent shock waves from forming inside the engine. Inlet cones are not used with turbojets anymore; they have been replaced by rectangular inlets, which serve the same purpose as inlet cones, but with a simpler construction.

Inlet cones on ramjets

When used on ramjets, the inlet cone has the additional purpose of compressing air by forcing the air through an increasingly small space. This is called ram air compression. It has the same effect as the compressor blades of a turbojet."

The ONLY point of the inlet cone (the pointy thing on the front of the engine) is to slow down airflow going into the engine because an engine can't run on supersonic air. New fighter engines don't use this cone because they use a square intake which functions the same way as the cone.
"Inlet cones are not used with turbojets anymore; they have been replaced by rectangular inlets, which serve the same purpose as inlet cones, but with a simpler construction."

And that is my last post on this matter. I've had it. You just don't get it. I'm gonna go beat my head on a brick wall now.


Emphasis added.

It wouldn't let me edit to add this, so I'm putting it here.

Notice the part about the SR-71 inlet cone.

"In ONE case...." The SR-71 is the only engine that *I* am aware of that has a variable nose cone, and that was ONLY because of the speed it flew at. When you're going Mach 5 you have to REALLY slow the air down a lot, there fore the vane would move into the engine, which would open ducts to allo the air to slow down further before entering the engine. Otherwise the engine would simply stall out because the air was moving too fast. Supersonic air going into an engine would immediately cause it to stall, and cease functioning.

*I wasn't going to get back into this, really I wasn't; honest *

.......and I'm only doing this cos I'm hoping to help here.
(crosses fingers in hope!)


Right, firstly moving jet intake nose cones.

Zaphod is right. Moveable intakes became necessary to slow air-flow going to the jet engine because they can't handle air at too high a speed.

I suspect Forschung may be referring to the moveable 'bullet' that was a feature of both the Junkers Jumo jets and the BMW jet exhausts (IIRC they were to do with gas flow and temperature control).
There was a similar looking, but fixed, 'bullet' at the front of the German jets to house the 2stroke starter motor & pull-chord.

These are just features of the jet engine design and not at all to do with any ideas of 'stealth'.

"Recessed intakes/jet engines".

I am not claiming to be an expert on stealth, I can only relate what I have read on the subject but I hope this helps.

The whole idea of a 'stealthy' jet intake design is to try to minimise the reflection and return of radar waves.
One of the big 'reflectors' in a jet aircraft is the engine itself. Radar waves are easily reflected off of the 'front face' (the compressor blades) of a typical jet engine.

This is especially so in the designs common to most pre-stealth aircraft. From the frontal aspect a long tube (even if, as with many 1960's high-speed designs, variable intake geometry, the inlet ramps and airflow speed controls etc, are fitted within it) with a jet engine at the end of it will reflect radar very well.

To avoid this happening with a stealt design designers now usually incorporate a serpentine intake so that the 'face' of the jet engine cannot be seen when looking down the intake.

Think of it as the difference between looking at the engines hung under the wing of a Lockheed L1011 Tristar and trying to look at the jet mounted at the tail on the same aircraft.

Simply putting your jet at the end of a tube doesn't do anything good for the radar return. It is not stealthy at all.
(I wonder if anyone ever looked at the Lockheed Tristar about this )

As for the Horten plane we are left to speculate as to which features they (correctly) recognised as 'stealthy' and to what degree they were successful.
The construction materials themselves undoubtedly helped and the general shape of the plane too and we know they were attempting to devise and refine RAM coating.

But we also know this was all absolutely in its infancy; the materials, as has been pointed out, were also used in the British Mosquito and it certainly was not considered especially difficult to pick up on radar, we also know that simply shape alone does not make a plane stealthy (nice 90' panel lines and the steel tube construction under the skin would not be considered in any way stealthy today) and we know that the German RAM was crude to say the least.

Early radar itself must have been a factor - particularly the common use in Germany of the much longer wave 'metric' radar wavelengths as opposed to the allies much smaller (micro) wave centimetric radar.
It may well be that the Germans noticed the Ho9 was difficult to pick up on their radar sets whilst allied set would have had less difficulty.

That is the problem with the situation we have been left with, there is almost no empirical data to debate this over.

I'm really not trying to deny any German 'achievement' here but whilst the intent may have been there and a begining to understanding the concept I am far from convinced that the Ho9 is in any way an effective expression of it.

.......and if we are going to recognise achievement and a recognition of the concept then what about the wartime US work on RAM and reducing RCS?

RAM is the only genuine thing the Ho9 and B2 have in common uniquely IMO but, as I said before, the concept and investigation of RAM was not unique to WW2 Germany or the Ho9.

That is why I am saying that with a long experience and tradition of building flying wing designs, very large multi-jets included (and every one having the lateral handling problem - even with the very last one, the YRB-49A, where they hung 2 jets under the wing in pyloned pods, a little like the proposed Horten Ho18) along with the USA's own RAM & RCS work that the B2 has only American 'parentage'.

IMO it is merely an interesting quirk (and proof that physics has no 'nationality') that Germany also had independant work going on in these areas.

Originally posted by Zaphod58
"I would call those normal intakes" I answered that a long time ago. I KNOW that the Ho 9 was not meant to be stealthy. But the ONLY, I repeat ONLY point of recessed intakes is for STEALTH. Ergo, if the Ho 9 wasn't built for stealth purposes, it COULD NOT have recessed intakes. It had RECESSED ENGINES. There IS a difference.

As far as the inlet cone, read this carefully. very very carefully.

"The earliest types of supersonic aircraft featured a central shock cone, called an inlet cone, which was used to form the shock wave. This type of shock cone is clearly seen on the English Electric Lightning and MiG-21 aircraft, for example. The same approach can be used for air intakes mounted at the side of the fuselage, where a half cone serves the same purpose with a semicircular air intake, as seen on the F-104 Starfighter and BAC TSR-2. A more sophisticated approach is to angle the intake so that one of its edges forms a leading blade. A shockwave will form at this blade, and the air ingested by the engine will be behind the shockwave and hence subsonic. The Century series of US jets featured a number of variations on this approach, usually with the leading blade at the outer vertical edge of the intake which was then angled back inwards towards the fuselage. Typical examples include the Republic F-105 Thunderchief and F-4 Phantom. Later this evolved so that the leading edge was at the top horizontal edge rather than the outer vertical edge, with a pronounced angle downwards and rearwards. This approach simplified the construction of the intakes and permitted the use of variable ramps to control the airflow into the engine. Most designs since the early 1960s now feature this style of intake, for example the F-14 Tomcat, Panavia Tornado and Concorde.

In one unusual instance (the SR-71), a variable air intake design was used to convert the engine from a turbojet to a ramjet, in flight. To get good efficiency over a wide range of speeds the Pratt & Whitney J58 could move a conical spike fore and aft within the engine nacelle, to keep the supersonic shock wave just in front of the inlet. In this manner, the airflow behind the shock wave, and more importantly, through the engine, was kept subsonic at all times. Additionally, and unusually for this engine, at high mach, the compressor for the J58 was unable to carry the high air flow entering the inlet without stalling its blades, and so the engine directed the excess air through 6 bypass pipes straight to the afterburner. At high speeds the engine actually obtained 80% of its thrust, versus 20% through the turbines itself, in this way. Essentially this allowed the engine to operate as a ramjet, and actually improving specific impulse (fuel efficiency) by 10-15%."

"The main purpose of an inlet cone is to slow down the flow of air to subsonic speeds before it enters the engine. Most engines require subsonic airflow to operate properly, and require a diffuser to prevent supersonic airflow inside the engine. At supersonic speeds, a shock wave forms on the leading edges an aircraft, causing significant pressure and drag. The shock wave has the added effect of slowing down the air that passes through it. The inlet cone is shaped so that the shock wave that forms on its point is directed to the lip of the intake; this allows the engine to operate properly in supersonic flight. As speed increases, the shock wave becomes increasingly more narrow. As a result, SOME inlet cones have the ability to move front-to-back to allow operation in a wider range of speeds.

Inlet cones on turbojets

Shock waves may also cause the compressor blades of a conventional jet engine to melt or shatter. Inlet cones prevent shock waves from forming inside the engine. Inlet cones are not used with turbojets anymore; they have been replaced by rectangular inlets, which serve the same purpose as inlet cones, but with a simpler construction.

Inlet cones on ramjets

When used on ramjets, the inlet cone has the additional purpose of compressing air by forcing the air through an increasingly small space. This is called ram air compression. It has the same effect as the compressor blades of a turbojet."

The ONLY point of the inlet cone (the pointy thing on the front of the engine) is to slow down airflow going into the engine because an engine can't run on supersonic air. New fighter engines don't use this cone because they use a square intake which functions the same way as the cone.
"Inlet cones are not used with turbojets anymore; they have been replaced by rectangular inlets, which serve the same purpose as inlet cones, but with a simpler construction."

And that is my last post on this matter. I've had it. You just don't get it. I'm gonna go beat my head on a brick wall now.


Emphasis added.

Zaphod58, If the only purpose of the cone was to reduce compresson, they would #-can the turbojet althogether and go to a ram jet. The purpose of the cone, form everything I was ever taught, is to use the shock wave generated instead of fighting it, to use it specifically at the very front of the axel compressor to compress the air so that the axel will have denser air to work with. A turbofan doesn't use this cone as far as I know, because it is a somewhat different engine. It is more efficient and coupled with an afterburner, can achieve speed. Also, a turbofan, as in the B-2 reflects less radar than an standard turbojet engine. If the Ho9 is "normal" why is most every other design different in that the air intake extends infront of the plane of the wing? The reason for the air intakes of the Ho9 are most probably as Waynos or Smikeypinky pointed out, the length of the engine and the size of the wing.

Originally posted by sminkeypinkey
*I wasn't going to get back into this, really I wasn't; honest *

.......and I'm only doing this cos I'm hoping to help here.
(crosses fingers in hope!)


Right, firstly moving jet intake nose cones.

Zaphod is right. Moveable intakes became necessary to slow air-flow going to the jet engine because they can't handle air at too high a speed.

I suspect Forschung may be referring to the moveable 'bullet' that was a feature of both the Junkers Jumo jets and the BMW jet exhausts (IIRC they were to do with gas flow and temperature control).
There was a similar looking, but fixed, 'bullet' at the front of the German jets to house the 2stroke starter motor & pull-chord.

These are just features of the jet engine design and not at all to do with any ideas of 'stealth'.

"Recessed intakes/jet engines".

I am not claiming to be an expert on stealth, I can only relate what I have read on the subject but I hope this helps.

The whole idea of a 'stealthy' jet intake design is to try to minimise the reflection and return of radar waves.
One of the big 'reflectors' in a jet aircraft is the engine itself. Radar waves are easily reflected off of the 'front face' (the compressor blades) of a typical jet engine.

This is especially so in the designs common to most pre-stealth aircraft. From the frontal aspect a long tube (even if, as with many 1960's high-speed designs, variable intake geometry, the inlet ramps and airflow speed controls etc, are fitted within it) with a jet engine at the end of it will reflect radar very well.

To avoid this happening with a stealt design designers now usually incorporate a serpentine intake so that the 'face' of the jet engine cannot be seen when looking down the intake.

Think of it as the difference between looking at the engines hung under the wing of a Lockheed L1011 Tristar and trying to look at the jet mounted at the tail on the same aircraft.

Simply putting your jet at the end of a tube doesn't do anything good for the radar return. It is not stealthy at all.
(I wonder if anyone ever looked at the Lockheed Tristar about this )

As for the Horten plane we are left to speculate as to which features they (correctly) recognised as 'stealthy' and to what degree they were successful.
The construction materials themselves undoubtedly helped and the general shape of the plane too and we know they were attempting to devise and refine RAM coating.

But we also know this was all absolutely in its infancy; the materials, as has been pointed out, were also used in the British Mosquito and it certainly was not considered especially difficult to pick up on radar, we also know that simply shape alone does not make a plane stealthy (nice 90' panel lines and the steel tube construction under the skin would not be considered in any way stealthy today) and we know that the German RAM was crude to say the least.

Early radar itself must have been a factor - particularly the common use in Germany of the much longer wave 'metric' radar wavelengths as opposed to the allies much smaller (micro) wave centimetric radar.
It may well be that the Germans noticed the Ho9 was difficult to pick up on their radar sets whilst allied set would have had less difficulty.

That is the problem with the situation we have been left with, there is almost no empirical data to debate this over.

I'm really not trying to deny any German 'achievement' here but whilst the intent may have been there and a begining to understanding the concept I am far from convinced that the Ho9 is in any way an effective expression of it.

.......and if we are going to recognise achievement and a recognition of the concept then what about the wartime US work on RAM and reducing RCS?

RAM is the only genuine thing the Ho9 and B2 have in common uniquely IMO but, as I said before, the concept and investigation of RAM was not unique to WW2 Germany or the Ho9.

That is why I am saying that with a long experience and tradition of building flying wing designs, very large multi-jets included (and every one having the lateral handling problem - even with the very last one, the YRB-49A, where they hung 2 jets under the wing in pyloned pods, a little like the proposed Horten Ho18) along with the USA's own RAM & RCS work that the B2 has only American 'parentage'.

IMO it is merely an interesting quirk (and proof that physics has no 'nationality') that Germany also had independant work going on in these areas.

I think I saw a TV program on the Mig 25 where the nosecone was moving back an forth.

German RAM coating was invented for submarines and only later was the concept, not the actual chemical paint, involved with the Ho9.

As I have said before, I am not a stealth engineer, but I don't have to be. For whatever reason and a reason involving steath, the Northrop engineers piled on an airplane and visisted the Gotha229. Since I don't read minds, I cannot say for certain what they were looking at but the point is that they were looking. Nobody, certainly not me, has ever suggested that Northrop didn't already know how to build a flying wing. They did for certain and this is one reason they were given the contract for the B-2.

I know I said I wouldn't answer anymore, but that is from JANES. I THINK that JANES knows a LITTLE bit about what they are talking about Forschung. Air CAN NOT go into an engine at supersonic speeds. If it does, then fan blades EXPLODE. By putting the fan cone in the engine, it slows the air down. You are also right in the sense that it DOES help to compress the air before it hits the fan section, but the MAIN purpose of it is to SLOW the air. As far as your ramjet goes, it's not even CLOSE to feasable. Ramjets only work at high speeds. How are you going to accelerate to those speeds? That's why the SR-71 used a Scramjet. It was a normal jet engine until it got to speed, then it was closer to a ramjet type engine. But even that wasn't a true ramjet. Ramjets are a great idea, but how are you going to put one on, oh say a 747?

As far as your argument to get rid of the turbojet? Read this carefully now......

"There are not many models of turbojet still produced, as they are considered obsolete in favor of turbofan engines. Turbojets were used extensively for many years in both military and civilian applications."

They ARE, I repeat ARE canning the turbojet.

As far as the length of the Ho 9 intakes, again, it goes back to the fan section of the engine doing Bad Things to your drag ratios. What they have on the Ho 9 prototype in the pictures Waynos posted is a BLENDED INTAKE. It blends into the fuselage of the aircraft becuase if you have a round intake like on the 229, unless they're right up against the fuselage the space between then engine and the fuselage creates more drag, leading to a loss of efficiency. So on the Ho 9 they extended one side of them, and blended them into the fuselage. The length of them is probably because of the size of the engine more than ANYTHING else.

Originally posted by Forschung

I think I saw a TV program on the Mig 25 where the nosecone was moving back an forth.

The MiG 25 MAY have moveable spikes, but 99.999999999999% of engines are just there to slow the airflow into the engine to keep the fan section from blowing apart.

[edit on 1-7-2005 by Zaphod58]

Originally posted by Zaphod58

Originally posted by Forschung

I think I saw a TV program on the Mig 25 where the nosecone was moving back an forth.

The MiG 25 MAY have moveable spikes, but 99.999999999999% of engines are just there to slow the airflow into the engine to keep the fan section from blowing apart.

[edit on 1-7-2005 by Zaphod58]

Zaphod58, I am not a air-intake specialist and I do respect your opinion. It was explained to me that the nose cone generated a shock wave in line with the cone. The object of the nose cone, according to this presentation, was to make it so the shock wave further compressed the air the moment before it was fed into the compressors. With a fixed cone, this shock wave would vary (move back and forth) according to the airspeed, the speed of the aircraft. So, the cone moved to accomodate the shock wave and keep it fixed at the point where the air would be most dense.

What you say about mach number breaking compressors makes sense, I will admitt that. Also, at high mach numbers, why would you need to compress the air at all? Perhaps the cone breaks the airflow in order to save the compressors yet allow allow for increased density and allow them to work well without direct exposure.

The purpose of the cone, and of the intake shape now, was so that at high speeds, the air would compress, which would cause it to slow to subsonic speeds, thus not blowing apart the compressor blades. It doesn't have to move for it to do that. The cones in all airline/transport engines are fixed, as are the cones in most fighters, that have them. Many fighter designes have moved away from them however, as they have found they can use the intake/inlet shape to do the same thing that the cone did. The square intake on the F-15 is an example of this. Only the top portion of it moves, but it's the shape that matters. The square opening, along with the snake like inlet forces the air to slow down as it travels down it to the fan section. That's why most modern fighters have a curved inlet leading to the fan section, and no cone on the compressor section.

As the air hits the cone, it "splits" for lack of a better word, hits the side of the intake, and is forced into a smaller area. The rason that you don't have to have a moveable cone with most engines, is that even with the shockwave moving back and forth, it's moving back and forth along the cone itself, and will be slowed before hitting the compressor blades. It doesn't matter to the compressor WHERE the air is slowed, as long as it's subsonic before impacting the blades.

The reason that the SR-71 has the moveable cone, is because at high speeds the engine became basically a ramjet. The movement of the cone backwards, forced the air into a smaller space, which opened ram air doors to allow more air into the intake, and the ramjet to operate. It wasn't a TRUE ramjet in that it still had moving parts, but it acted like a ramjet due to the speeds. Some designs DO incorporate a moving cone, but it's not NECESSARY to the function of the engine. A moveable cone will allow them to control the shockwave better, but again, the air will still be slowed with a fixed cone, it will just be closer to the compressor when it's slowed.

Zaphod58, many aircraft now use turbofans because they are more efficient and these lack the cone. Otherwise, since I already stated everything I know regarding cones, I will bow to your superior knowledge in this area and accept your explanation.