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Archive for the ‘technology’ Category

Air combat and stealth

Posted by picard578 on March 11, 2017

Introduction

For a long time, visual detection was the only type of detection possible. But in World War II, two significant advances appeared: radar, as well as radar- and IR- -guided missiles. Until 1970s, these were defeated through jamming and decoys. Early German attempts at building LO aircraft – Ho-229 – never got anywhere, albeit their RAM paint utilization at snorkels and aircraft was noted. In United States, first attempt at reducing the radar signature of aircraft was on U-2, by utilizing RAM paint, but it was not very successful. First actual stealth aircraft appeared in early 1960s – SR-71 Blackbird, which utilized shaping such as canted surfaces to reduce radar signature. In 1970s a second generation of stealth aircraft appeared with B-1A, and also began a programme of development of VLO aircraft. Result of that was diamond-shaped F-117, to soon be followed by B-2. All these aircraft successfully performed against enemy air defenses, but in the case of B-1A and later aircraft, their performance against air defenses was similar or identical to performance of conventional aircraft they were deployed alongside. Fourth generation of stealth aircraft are F-22, F-35, PAK FA, J-20 and J-31. While still stealth aircraft, they sacrifice stealth characteristics for the sake of better flight characteristics, allowing them to match conventional fighters in terms of maneuverability. However, their stealth requirements make them larger and heavier than comparable conventional aircraft, thus sacrificing kinetic performance for the sake of stealth.^1 Read the rest of this entry »

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Infrared (IR) sensors in naval use

Posted by picard578 on November 1, 2016

While they are mostly associated with fighter aircraft, IRST sensors are also used by surface forces, including navies. In naval use, IR sensors are used primarily as early warning devices, which means that shipboard IRST is integrated with ship’s self defense / point defense system. IRST detects targets and sends data to weapons systems, which then engage targets based on pre-determined priorities. In naval use at least, IRST will not replace radars because high humidity at sea level significantly reduces its range. However, it is still an important sensor, especially during the times of radar silence (e.g. threat from anti-radiation missiles). Also of importance is IRST’s immunity to jamming and passive operation, which makes them extremely important in electronically degraded environment. IRST’s shorter operational wavelength means greater resolution, and thus far greater ability to detect small targets as well as to distinguish between the low-flying targets and the background clutter. For these reasons, IRST and IR targeting systems are already in widespread use in air forces for purposes of both air-to-air and air-to-ground combat. Read the rest of this entry »

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PAK FA vs F-22

Posted by picard578 on October 11, 2015

Introduction

This article will compare upcoming Russian PAK FA with US F-22, since both air single-purpose heavyweight air-to-air fighters. However, since PAK FA is still in a prototype stage, article will by its nature be incomplete. I should also note that while some use the term “Raptorski” for PAK FA, it is entirely inaccurate. In fact, while the F-22 clearly draws its basic design from its F-15 predecessor, utilizing some aerodynamic advances introduced by the F-16 (such as aerodynamically unstable design and LERX), PAK FA in the same measure draws its basic design from Su-27. F-22, like the F-15, has two closely set engines, air intakes on sides of the cockpit and classical wing-tail surfaces with shoulder-mounted wing. Both have standard armament of eight missiles and M61 20 mm rotary gun. Su-27 and PAK FA on the other hand both utilize large LERX, wing-body blending and spaced podded engines. They also have basic standard armament of six missiles and 30 mm revolver cannon. If comparison should be drawn, then F-22 can be described as a stealth!F-15, and PAK FA as a stealth!Su-27, as neither presents clear design departure from their predecessor that the F-16 did. They are also both hugely complex to produce due to their stealth designs, and as a result both US and Russia have decided to supplement them with large fleets of 4,0 (and, in Russia’s case, 4,5) generation fighters.

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Airborne IRST properties and performance

Posted by picard578 on June 16, 2015

Introduction

IRST is a sensory device which uses IR (infrared) radiation for detection and targeting purposes. IR radiation has wavelength of 0,75 to 1.000 microns (micrometers), longer than wavelengths of color red in the visible spectrum (visible spectrum ranges from 0,39 to 0,7 microns, with violet at 0,4 and red at 0,7 microns). It is given off by all objects above absolute zero, though objects that are below average temperature of their surroundings will absorb far more IR radiation than they will give out. Unlike FLIR which is a targeting device, IRST can be used for initial detection as well. Read the rest of this entry »

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Fighter aircraft engine comparision

Posted by picard578 on December 6, 2014

Introduction

This article will compare several engines used in modern fighter aircraft: EJ200 (Typhoon), M88 (Rafale B/C/M), RM-12 (Gripen A/B/C/D), F-135 (F-35A/B/C), F-119 (F-22A), F404-GE-402 (F-18C/D), F-414-400 (F-18E/F, Gripen E/F), AL-31F (Su-27, Su-30, J-11). Read the rest of this entry »

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