Harle Posted February 9, 2015 Posted February 9, 2015 How come Mig-21 doesn't have distance measuring capability for aiming assistance to gun down airborne targets like F-86 has? This question has been bugging me for quite a while, but no one seems to care around here. It's supposed to be a more advanced jet than Saber after all, is it not?
Flagrum Posted February 9, 2015 Posted February 9, 2015 These here don't care about it? http://forums.eagle.ru/showthread.php?t=131327 http://forums.eagle.ru/showthread.php?t=132696
Harle Posted February 9, 2015 Author Posted February 9, 2015 (edited) These here don't care about it? http://forums.eagle.ru/showthread.php?t=131327 http://forums.eagle.ru/showthread.php?t=132696 That not quite what I'm asking. I suppose it didn't have such (withing 500 m.) measuring capabilities IRL. Why was that allowed? Edited February 9, 2015 by Harle
Flagrum Posted February 9, 2015 Posted February 9, 2015 In the second thread there is a discussion of why and how the ASP does not use the radar for getting ranging information in air2air mode, but seems to use a fixed range of 300 m instead. It starts somewhere at the middle/end of the first page of the thread.
Harle Posted February 9, 2015 Author Posted February 9, 2015 (edited) In the second thread there is a discussion of why and how the ASP does not use the radar for getting ranging information in air2air mode, but seems to use a fixed range of 300 m instead. It starts somewhere at the middle/end of the first page of the thread. Yeah, I remember that radar limitation. So I was wondering why no additional equipment similar to Saber's radio range measuring whatever-it-was was installed to allow for precise aiming within 500 m. Edited February 9, 2015 by Harle
Fishbreath Posted February 9, 2015 Posted February 9, 2015 Space constraints, maybe? There's not a lot of forward surface area in the MiG. Alternately, it might just have been poor Soviet electrics—did other radars from the late 60s/early 70s have distance measuring capability down to close-in gunnery range? Black Shark, Harrier, and Hornet pilot Many Words - Serial Fiction | Ka-50 Employment Guide | Ka-50 Avionics Cheat Sheet | Multiplayer Shooting Range Mission
xxJohnxx Posted February 10, 2015 Posted February 10, 2015 Hi, Reading in this thread I decided to do some more research. While doing so with Google and other search engines becomes more difficult every day (because a lot of the hits are threads within this forum :D) I found some interesting documents. This one talks quit detailed about the history off the MiG-21 and also mentions some technical details. There a couple of interesting parts in there regarding this discussion: In a paragraph about the Ye-2, the early technology and aerodynamics test-bed: The new fighter was also required to be capable of operating from unpaved runways and performing a constant-speed vertical dive with airbrakes deployed. Its armament suite was set to include three NR-30 30mm cannon aimed via an optical sight coupled to a radar rangefinder, installed inside the nose coneWell, this was the requirement, let's see what was included in the actual production aircraft: In a paragraph about the MiG-21F-13: The MiG-21F-13 was designed from the outset to intercept transonic/ supersonic bombers and fighter-bombers at altitudes up to 20,000m (65,600ft). Interceptions were limited to rear-hemisphere attacks only, using the rudimentary SRD-5M Kvant radar rangefinder with a range of 0.5–7km. The Kvant provided missile launch and gun-firing distances; the associated ASP-5ND gunsight was used to assist accurate aiming during gun- and rocketfiring runs on both air and ground targets.The MiG-21F-13 was quit an early series produced model, how about later ones? Let's have a look at the MiG-21S: In a paragraph about the MiG-21S: The new radar was introduced together with the new R-3R (AA-2B) semiactive radar homing (SARH) missile which had a range of 0.8–7km; it was used for all-weather intercepts and was suitable against non-manoeuvrable targets. After launch, the fighter was free to manoeuvre within a limited space, keeping the target within the radar’s gumball limits (30° up/down and left/right) as the R-3R homed onto the reflected signal from the target, continuously tracked by the RP-22S. The radar’s rangefinding function provided the pilot with information about the maximum and minimum missile launch ranges at different altitudes and closing speeds (displayed on a mechanical needle display on the ASP-PF-21 gunsight). It also supplied range information for the employment of the GSh-23L 23mm cannon against air targets and for firing both the gun and rockets against ground targets. [..] The gunsight was the new ASP-PF-21 lead-computing gyro unit, enabling more precise firing against air targets with the GSh-23L cannon (carried in the GP-9 conformal gun-pod) as well as generating better aiming information for using the cannon, rockets and bombs against ground and sea targets. The gunsight, however, ‘toppled’ at 2.75G, thus limiting the ability to aim the GSh-23L cannon in a high-G turning dogfight. The MiG-21S also incorporated an improved Lasour-M datalink for receiving steering commands from a ground-based intercept control station. This was true for the MiG-21S with the RP-22 radar (the same as in the MiG-21Bis) and the ASP-PF-21 (the MiG-21Bis has the updated ASP-PFD-21 gunsight). I am not entirely sure how true the contend of the quoted document is, but it seems reasonable well put together at least. I unfortunately don't have the technical manuals available for the Bis where the said functions would probably be described (neither will they be written in a language I can comprehend), so it is quit hard to confirm those claims made in the document. However, similar information can be found at various locations in the net, so might be not entirely wrong. However, questions do arise how the range finding is done within the minimum range of 500m with the RP-22 radar. Too little data to 100% anything on that subject either, unfortunately. 1 Check out my YouTube: xxJohnxx Intel i7 6800k watercooled | ASUS Rampage V Edition 10 | 32 GB RAM | Asus GTX1080 watercooled
Harle Posted February 10, 2015 Author Posted February 10, 2015 Thanks for you extensive reply, John. Guess I'll try looking for some info on this subject in russian manuals.
Dirty Rotten Flieger Posted February 10, 2015 Posted February 10, 2015 I would like to know more about this. I had wondered about radar gun ranging and assumed it was possible. I didn't know about the 500m limit to the RP-22 radar though. It does seem strange that this function would not be available. IIRC the earlier Mig21 had no internal gun. Some what like the F4 phantom they assumed guns were obsolete and then realising no gun fighter was a bad idea strapped at gunpod under the mig. Maybe the RP-22 was designed for the gunless Mig21 and thats why it was not designed for ranging below the minimum range of expected mountable missiles...
Kobymaru Posted February 10, 2015 Posted February 10, 2015 IIRC the earlier Mig21 had no internal gun. Some what like the F4 phantom they assumed guns were obsolete and then realising no gun fighter was a bad idea strapped at gunpod under the mig. Maybe the RP-22 was designed for the gunless Mig21 and thats why it was not designed for ranging below the minimum range of expected mountable missiles... As mentioned by John, The most important new component, incorporated into the MiG-21S’ new mission suite, was the vastly improved RP-22S Sapfir-21 air-intercept radar, ... The radar’s rangefinding function provided the pilot with information about the maximum and minimum missile launch ranges at different altitudes and closing speeds (displayed on a mechanical needle display on the ASP-PF-21 gunsight).Also, the Gunless Mig-21 was one of the earliest versions, and the RP-22 came for the later versions. Let's all just assume that the ASP *should* have radar rangefinding information, and that LN will fix this soon™
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