NationStates

Manokan Republic wrote:"The hostile submarine using electro-magnetic sensors, however, can still detect ASW aircraft radar emissions at a much greater distance than the aircraft can detect the submarine by radar. Nevertheless, the threat of radar detection is sufficient to keep the submarine submerged. "

Just because it has the word "magnetic" in it doesn't mean the "electromagnetic spectrum" is actually a magnet.

You don't find a radar with a compass.

>Fixed MAD systems.
You do realize that MAD arrays have ranges in only the hundreds of meters right? Not exactly good for ocean surveillance.

The Corparation wrote:>Fixed MAD systems.
You do realize that MAD arrays have ranges in only the hundreds of meters right? Not exactly good for ocean surveillance.

No corp. He's pointing systems that have a hard time distinguishing 10,000 tons of submarine from a km away against background natural magnetism skywards in the hope that he'll see an F-22 before the F-22 drops a cluster of SDB's. He also thinks submarines use MAD to detect eachother and MPA (on a 10,000 ton metal tube no less) instead of y'know... sonar... or ESM...

Austria-Bohemia-Hungary wrote:

The Corparation wrote:>Fixed MAD systems.
You do realize that MAD arrays have ranges in only the hundreds of meters right? Not exactly good for ocean surveillance.

No corp. He's pointing systems that have a hard time distinguishing 10,000 tons of submarine from a km away against background natural magnetism skywards in the hope that he'll see an F-22 before the F-22 drops a cluster of SDB's. He also thinks submarines use MAD to detect eachother and MPA (on a 10,000 ton metal tube no less) instead of y'know... sonar... or ESM...

I'm pretty sure it is widely known that submarines primarily use Sonar for the obvious reason that it actually works.

Austria-Bohemia-Hungary wrote:

The Corparation wrote:>Fixed MAD systems.
You do realize that MAD arrays have ranges in only the hundreds of meters right? Not exactly good for ocean surveillance.

No corp. He's pointing systems that have a hard time distinguishing 10,000 tons of submarine from a km away against background natural magnetism skywards in the hope that he'll see an F-22 before the F-22 drops a cluster of SDB's. He also thinks submarines use MAD to detect eachother and MPA (on a 10,000 ton metal tube no less) instead of y'know... sonar... or ESM...

It isn't that they have trouble distinguishing the submarines. It's quite easy to distinguish them, since submarines are massive, fairly obvious things, and detectors don't need to be really sensitive to detect them. Most MADs in service with the USN are from WW2 or around abouts anyway, and use fluxgate detectors that are not very sensitive or Hi-Tech. There are new generations of MADs that were being made in the 1980s based on cryogenic SQUIDs and molten potassium detectors later on (the '90s) but these never made it to the field. Partly because the Cold War ended and submarine threats evaporated and partly because no one wants to fly in a rickety ass P-3 with some cryogenic tanks or molten metal flowing around them.

Ferromagnetically guided weapons were a threat in the 1980's (or possibly the 1940's, it's unclear) according to MGVoYN's patron saint, R.E. Simpkin, in his book Antitank, and I suspect had the Nazi powers had the capability to make 1980s semiconductors and cryonics fit inside a missile they would have been an actual threat to combat warships (at least until degaussing took place).

Anyway the thing he quotes is obviously talking about radars seeing radars, not MADs seeing MADs, nor about a submarine with a MAD detecting an airplane. I suppose, were the submarine's own magnetic field and the Earth field filtered out, you could detect an airplane by the magnetic energies of its internal mechanisms such as the engines, but since the plane is broadly made of aluminum or some non-ferromagnetic metal, it may not be as detectable as a submarine made mostly of steel. Then again, both titanium and aluminum are paramagnetic, but the plane is still an order of magnitude or two smaller in mass than the submarine, and more importantly the medium it flies through is not particularly conductive (haHAA) to magnetic detection. Water is.

Magnetic field strength decays according to the inverse-cube law (double the distance, the strength of the field falls to 1/8th). There is no way around this unless you have discovered a magnetic monopole, which is a thing most notable for not existing. As such direct magnetic detection of anything is an inherently short range affair.

Austrasien wrote:Magnetic field strength decays according to the inverse-cube law (double the distance, the strength of the field falls to 1/8th). There is no way around this unless you have discovered a magnetic monopole, which is a thing most notable for not existing. As such direct magnetic detection of anything is an inherently short range affair.

A monopole obviously can't exist because it would be infinitely absorbing or emitting.
But if it did, wouldn't it still be inverse-cube?

It would be inverse-square like electrostatic force between electrically charged particles. Magnetic fields are inverse-cube because they are actually interactions between the poles of dipoles.

Austrasien wrote:Magnetic field strength decays according to the inverse-cube law (double the distance, the strength of the field falls to 1/8th). There is no way around this unless you have discovered a magnetic monopole, which is a thing most notable for not existing. As such direct magnetic detection of anything is an inherently short range affair.

A MEA-type magnetometer can supposedly can detect a Gotland out to 4.4 km, based on the napkin math PDF. o:

This puts it well above any air defenses that the sub might possess i.e. surface launched MANPADS adapted for underwater launch.

And possibly above IRIS-T launches, or at least sufficient warning to blind it with a DIRCM anyway.

Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Danternoust wrote:Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Steel is also heavy and, unfortunately, weight is much more important than life time of the airframe. It doesn't matter how long it can theoretically last if it is too heavy to fly.

The Manticoran Empire wrote:

Danternoust wrote:Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Steel is also heavy and, unfortunately, weight is much more important than life time of the airframe. It doesn't matter how long it can theoretically last if it is too heavy to fly.

Aircraft have substantial margins, this just means that wing loading is higher, and thus stall speed is higher, and thrust to weight ratio is lower.
I think I'll just use steel to offset improved fuel efficiency from newer engines.

Danternoust wrote:Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Steel corrodes, aluminum doesn't.

Danternoust wrote:

The Manticoran Empire wrote:Steel is also heavy and, unfortunately, weight is much more important than life time of the airframe. It doesn't matter how long it can theoretically last if it is too heavy to fly.

Aircraft have substantial margins, this just means that wing loading is higher, and thus stall speed is higher, and thrust to weight ratio is lower.
I think I'll just use steel to offset improved fuel efficiency from newer engines.

Steel is three times more dense than aluminium despite being 20-50% stronger. Do the math, take that out of your substantial margins and you're probably one fat pilot away from MTOW.

Gallia- wrote:

Danternoust wrote:Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Steel corrodes, aluminum doesn't.

Aluminum corrodes, it doesn't rust, but it corrodes.

Iltica wrote:Aluminum corrodes, it doesn't rust, but it corrodes.

Surface corrosion of aluminum protects the underlying aluminum from further corrosion (the same is true of copper). Which is unlike rust, which will continue to eat away at the underlying iron until the entire structure disintegrates.

Thus, while they might be ostensibly similar processes, their functional effects are vastly different.

The Manticoran Empire wrote:

Danternoust wrote:Hmm. Steel airframes in theory, last forever, (or are viable for a million flight hours.

Should my training aircraft use steel airframes to reduce lifecycle costs?

Steel is also heavy and, unfortunately, weight is much more important than life time of the airframe. It doesn't matter how long it can theoretically last if it is too heavy to fly.

This explains why the Piper Cub needed 10 miles of runway before it finally lumbered off the ground.

The Akasha Colony wrote:

Iltica wrote:Aluminum corrodes, it doesn't rust, but it corrodes.

Surface corrosion of aluminum protects the underlying aluminum from further corrosion (the same is true of copper). Which is unlike rust, which will continue to eat away at the underlying iron until the entire structure disintegrates.

Thus, while they might be ostensibly similar processes, their functional effects are vastly different.

Surface corrosion isn't a huge issue on aircraft. Aluminum is more vulnerable to galvanic and stress corrosion than steel, and the aluminum oxide layer actually makes it more susceptible to pitting. These are the biggest airframe killers on non-pressurized aircraft.

Triplebaconation wrote:

The Manticoran Empire wrote:Steel is also heavy and, unfortunately, weight is much more important than life time of the airframe. It doesn't matter how long it can theoretically last if it is too heavy to fly.

This explains why the Piper Cub needed 10 miles of runway before it finally lumbered off the ground.

The Akasha Colony wrote:
Surface corrosion of aluminum protects the underlying aluminum from further corrosion (the same is true of copper). Which is unlike rust, which will continue to eat away at the underlying iron until the entire structure disintegrates.

Thus, while they might be ostensibly similar processes, their functional effects are vastly different.

Surface corrosion isn't a huge issue on aircraft. Aluminum is more vulnerable to galvanic and stress corrosion than steel, and the aluminum oxide layer actually makes it more susceptible to pitting. These are the biggest airframe killers on non-pressurized aircraft.

The Cub is a welded steel frame covered by cloth. It weighs 765 pounds empty. At max takeoff weight, the Cub weighs less than my truck.

Are we supposed to guess how much your truck weighs now?

Triplebaconation wrote:Are we supposed to guess how much your truck weighs now?

My truck weighs 3,500 pounds. The Piper Cub doesn't even weigh 1,500 pounds at full load.

I'm sorry, what's your point? First steel-framed aircraft are too heavy to fly, now they're lighter than your pick 'em up truck?

Triplebaconation wrote:I'm sorry, what's your point? First steel-framed aircraft are too heavy to fly, now they're lighter than your pick 'em up truck?

Trucks need to carry loads, not fly.

Triplebaconation wrote:I'm sorry, what's your point? First steel-framed aircraft are too heavy to fly, now they're lighter than your pick 'em up truck?

My point is you picked an aircraft that is light by design to defend the use of steel framed aircraft in general. In general, aircraft shouldn't use steel for the frame to save weight. This becomes more obvious for larger aircraft and fighters.

Ah, I think for the wings, the airframe will use steel. For the rest of the aircraft, as well as armor, it will use either aluminum or ceramics sandwiched by aluminum. The skin will use either steel or aluminum painted with a ferrite blend, as either would be radar absorbent.

https://thesovietarmourblog.blogspot.co ... ogeny.html

According to the article, the vast majority of fragments expelled behind the armour plate are smaller particles that are capable of penetrating 3-6mm of aluminium sheet at a distance of 0.5 to 1 meters. Although they do not seem powerful, these particles are far from harmless. Particles with the ability to penetrate more than 3mm of aluminium include particles with a mass of 2 to 50 grams and a velocity of 300 to 1,700 m/s. To gain an appreciation of the threat posed by such particles, note that a typical .22LR bullet weighs 2.33 grams and travels at 390 m/s and a 5.56mm M193 Ball bullet weighs 3.56 grams and travels at 990 m/s. As such, each particle that was found to be able to penetrate 3-6mm of aluminium would also be capable of causing lethal wounds.

According to a Czech study concerning the effect of typical machine gun bullets on the aluminium skin of common aircraft and the modeling of these effects, the thin fuselage skin of helicopters like the Mi-8 and other Czech aircraft presents no challenge to 7.62x54mm and 12.7x108mm B-32 bullets.

According to the table below taken from the study, the velocity limit for 12.7mm B-32 API bullets for the skin of an Mi-8 is just 40-58 m/s. The corresponding distance for this speed is the maximum firing distance of 6 kilometers, so technically, the NSVT is capable of piercing the skin of a utility helicopter from 6 km away. The thickest parts are the flanges at the two ends of the fuselage, measuring 3.7-4.7mm thick including the skin and flange itself, but this only represents a fraction of a percent of the surface area of the helicopter. Due to the very low velocity limits and large entry holes, a B-32 bullet is guaranteed to penetrate at any distance up to the maximum of 6 km and the incendiary content in the tip of the bullet will be expended inside the aircraft fuselage where it will do the most damage. Even so, the small incendiary content makes the B-32 bullet a second-rate option against aircraft. To sum up, the NSVT is easily capable of penetrating the thin skin of utility helicopters and common fixed-wing aircraft at distances far beyond the abilities of the commander to reliably engage them.

Now the next step is to mount the A-10's armored tub to an autogyro.

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The Super Tucano only has one engine, but for CAS, I should use two, would a turboprop in push-pull configuration be good? I think the rear propeller should be capable of reverse thrust.

Danternoust wrote:Ah, I think for the wings, the airframe will use steel. For the rest of the aircraft, as well as armor, it will use either aluminum or ceramics sandwiched by aluminum. The skin will use either steel or aluminum painted with a ferrite blend, as either would be radar absorbent.

While that can be done (it was on some Russian MiGs), I don't really see how it will be much better than other methods. Further, there really isn't any such thing as armor for aircraft. About the only armor aircraft ever really have is around the pilot's seat and the fuel tanks. That does very little against modern missiles so I would recommend saving weight and volume for more weapons, sensors, or countermeasures.

https://thesovietarmourblog.blogspot.com/2015/05/t-72-soviet-progeny.html

According to the article, the vast majority of fragments expelled behind the armour plate are smaller particles that are capable of penetrating 3-6mm of aluminium sheet at a distance of 0.5 to 1 meters. Although they do not seem powerful, these particles are far from harmless. Particles with the ability to penetrate more than 3mm of aluminium include particles with a mass of 2 to 50 grams and a velocity of 300 to 1,700 m/s. To gain an appreciation of the threat posed by such particles, note that a typical .22LR bullet weighs 2.33 grams and travels at 390 m/s and a 5.56mm M193 Ball bullet weighs 3.56 grams and travels at 990 m/s. As such, each particle that was found to be able to penetrate 3-6mm of aluminium would also be capable of causing lethal wounds.

According to a Czech study concerning the effect of typical machine gun bullets on the aluminium skin of common aircraft and the modeling of these effects, the thin fuselage skin of helicopters like the Mi-8 and other Czech aircraft presents no challenge to 7.62x54mm and 12.7x108mm B-32 bullets.

According to the table below taken from the study, the velocity limit for 12.7mm B-32 API bullets for the skin of an Mi-8 is just 40-58 m/s. The corresponding distance for this speed is the maximum firing distance of 6 kilometers, so technically, the NSVT is capable of piercing the skin of a utility helicopter from 6 km away. The thickest parts are the flanges at the two ends of the fuselage, measuring 3.7-4.7mm thick including the skin and flange itself, but this only represents a fraction of a percent of the surface area of the helicopter. Due to the very low velocity limits and large entry holes, a B-32 bullet is guaranteed to penetrate at any distance up to the maximum of 6 km and the incendiary content in the tip of the bullet will be expended inside the aircraft fuselage where it will do the most damage. Even so, the small incendiary content makes the B-32 bullet a second-rate option against aircraft. To sum up, the NSVT is easily capable of penetrating the thin skin of utility helicopters and common fixed-wing aircraft at distances far beyond the abilities of the commander to reliably engage them.

I'm not sure what the purpose of the ammo statements is.

Now the next step is to mount the A-10's armored tub to an autogyro.

It will require a lot alterations to the design of the autogyro.

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The Super Tucano only has one engine, but for CAS, I should use two, would a turboprop in push-pull configuration be good? I think the rear propeller should be capable of reverse thrust.

I don't see why the Super Tucano needs two engines. It's meant as a low cost, reliable aircraft to support ground operations. I see no reason to put another engine on it and can think of several ways that would negatively impact the aircraft, not the least of which being the increased complexity and decreased weapons load.