Vympel R-27 'ALAMO' - History, Design, Performance & Discussion

So here we go again, can you prove the seekers of the export R-27’s operate in different frequencies to the originals?


Yeah ±55kts. F15 is 48kts lowest option for both hprf and mprf

I’m not going to disclose this information to you.

102 km/h

Okay that’s fine.


Nope. That 10-20GHz figure is just a brochure figure. 9-10 GHz must be towarda it. Why? Because receivers work at certain frequencies. The have a certain resonant wavelength where the impedance is low, several dB lower(in the order of 10s and remember that -3dB is 50% loss)

This is a physical characteristic, not digital/electronic where you can just say " I’ll now put the frequency at x and later at y and I’ll still have the same return strength". It doesn’t work like that.

Look at a simple dipole antenna. The resonant frequency is at half wavelength. If you change the incoming signal frequency, the signal recovered will be much of much lower strength. Claiming 10-20GHz is just not right, the wavelength at 20GHz is 50% of 10GHz. Soviets went for radio correction as the missile didn’t see the target(poor manufacturing, electronics etc) at longer ranges unlike sparrows (20 - 40 nautical miles for small targets), I’m pretty sure they wouldn’t allow further acquiring range loses.

You’ll not change the receiver antenna size everytime. Plus that information not only comes from SIGINT, but information from spies aswell like the one the guy in the other r27 thread has been yapping around. For what is worth, that document is accurate. I tried to find , indepenedently from it the frequency of the mig 31s radar knowing the diameter and amount of elements, assuming a half wavelength separation between the radiating elements, you can have an idea of the frequecy it operates( I was 0.5GHz if I remember correctly).


EH ben voilà

followed by incorrect azimuth limit

Its a shame we couldn’t have found this out like… a year ago when any of these potential inaccuracies would’ve made a difference in the SARH meta Lol

Maybe we’ll have to try to get a head start on the R-77s when they’re added instead of when R-77-1 comes out :P


and the roll limit report.

Yeah, even if it gets reported on the while its on the dev it’ll go ignored like my previous reports. And then just wait several months till for literally a fix that requires a single value change. Even flight performance issues get dealt/ fixed faster and I’m pretty sure they require far far far more complex testing to identify the issue and fixing it without performance drops in other areas.


And the classic to make stuff artificially overperform but ofc the phoenix cannot reconnect even if you relock…

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I should bug report the Phoenix SARH mode not having datalink reconnect lol


This should be introduced to all aircraft.And not only the Su-27, so it was rejected

Yep, though not all.

There are several exceptions

F15s try to relock the target thus keep illuminating. If it fails, it keeps illuminating till the expected time to hit gets to 0+5s. Or it switches to flood mode. Same with f14s when launched in PD(CW probably though the flood antenna?)

F16s, no idea but I expect a similar thing to the F-15 as it goes to MEM to reacquire the lock. And CW keeps illuminated.

MIRAGEs with their 530s up to the 530F they lock on the main tracking signal like the F15. Dunno what happens with the 530D which uses a CW transmitter.

Mig 23s, no idea. I haven’t read a single manual of them.

Tornado F3 no idea as it works like the su27/mig 29 with CW interleaved with the tracking signal.

Su27/mig 29 don’t have MEM to to try to reacquire and just terminate DNP mode

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Don’t many US Radar sets have the FLOOD mode too, which does the same thing as the MEM but locked forward like a boresight
Iirc it goes back to the F-4E possibly earlier

Sort of like a flood mode yes. On the phantom you can just light the CW, give speeds to look at and launch it. Though there’s no mention at all of what happens when lock is dropped.

Antenna No. The F15 is the only one with a flood horn antenna behind the main antenna for this specific scenario. The apg 65 has a guard horn( for mprf and RGH and nulfilling(for a wider illumination) horn like the F15. Unless the flat thing is the antenna which I don’t think. The AWG-9 only has the nullfilling horn( for CW or wider PD illumination). You can look at the pictures, no other antenna is visible

F-4’s with the APQ-120 variants have a is a 5 second memory(rate) relock attempt window (unless jamming is detected, in which case the radar will delay turning off the illuminator until five seconds after jamming is removed, or the radar is returned manually to search though this can be prevented by switching to BST or the RIO utilizing their hand control to take charge of the antenna).

BST mode appears to energize the illuminator regardless of lock on state, and the Doppler info can be simulated via the Aspect knob.

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Actually, there is

@MaMoran20 what value would this be in game? Reference Doppler width?

no. Its this

"dopplerSpeedGateSearchRange": 150.0

in m/s. This is for the Sparrow E2/E/F. 75m/s up and below. Which should correspond to~±145 knots and ~ in line with the manuals.

This is from the R27ER/R

"dopplerSpeedGateSearchRange": 100.0

±50 m/s while the manual states ±150m/s