Soviet jet exhaust identification wanted

[Dmitriy1967]

The P11-300 engine. The engine and its modifications were installed on Su-15, MiG-21, Yak-25, and Yak-28 aircraft; a copy of the R-11-300 was produced in China (installed on the J-7 fighter).

 

[Rob de Bie]

14 hours ago, Duncan B said:

This has been a fascinating thread to follow. I have nothing to add to the discussion other than to say that the wreckage is remarkably clean, no corrosion, no moss or dirt on it, not even any cobwebs. Amazing, it looks like it could have been dumped there last week! (I'm not suggesting it was, just that it is remarkably clean for its age compared with wrecks that I am familiar with).

 

Duncan, I share your amazement at how clean the parts are. The corrosion part can (probably) be explained by the special metals and coatings required for the afterburner section. But moss grows everywhere I would think. Puzzling..

 

Rob

[Rob de Bie]

12 hours ago, KRK4m said:

 

Again, I'm not 100% sure, but I'll check in February when I'm back in the Krakow museum. In addition to the 200 engines on display, there is also an outdoor display of a dozen MiG-21s in all versions formerly used in Poland (F13, PF, PFM, PFMA, R, M, MF, U4, U6, US, UM and bis). I will compare the F13, PF, U4 and U6 nozzles (all later ones have blown flaps, so they must have an R-11F2S, R-13 or R-25 engine) with the individual airframe books and we will be clear. As for today - using deduction - I suspect that you answered yourself correctly with the bolded part of your statement above.

 

Michael, we will wait patiently for you to sort out the last remaining question. Thanks again for all your help in this thread.

Rob

[KRK4m]

Sorry, @Dmitriy1967, this is NOT the R-11F-300 - there are two layers of 18 segments around the nozzle (18 outer ones, called here petals) and 18 inner ones. Most probably this is the R-11F2S-300.

In original "bare" R-11F-300 there is only one layer of 24 segments around the nozzle. And we still have to find how does the R-11F2-300 nozzle look...

Cheers

Michael

[KRK4m]

My "February" turned out to be January 14 - quite unexpectedly, I had to go for an examination to the hospital located near the museum. Thus I dropped into the archives of the exhibition department and looked through the service books of all 15 MiG-21s they had. The R11F-300 engine is installed in only one airframe - it is Mig-21F13 serial 740809. The R11F2-300 engines are in Mig-21PF serial 761901 and 762006 as well as in Mig-21U serial 661217. The rest have R11F2S, R13 or R25. Then I went outdoors and looked at these 4 planes. The conclusion is this: the nozzle in Rob's photos is typical only of the R11F-300 engine of the Mig-21F and F13.

Not R11F2-300 and not R11F2S-300. Therefore, the crashed plane could not have been a Mig-21PF or a training Mig-21U, nor any Su-15. I cannot rule out the Yak-28 (perhaps some of its versions had R11F-300 engines), because the example in the Kiev museum has covers on its nozzles, and others photographed as Walkaround on the Internet have empty gondolas without engines.

Cheers

Michael

[Duncan B]

On 1/9/2025 at 8:09 PM, Rob de Bie said:

 

Duncan, I share your amazement at how clean the parts are. The corrosion part can (probably) be explained by the special metals and coatings required for the afterburner section. But moss grows everywhere I would think. Puzzling..

 

Rob

Especially when we look at the photo supplied by Dmitriy1967. That's got a general covering of grime and corrosion (and leaves) that I would expect to see on an old, unused engine.

 

Duncan B

[Rob de Bie]

On 1/14/2025 at 9:53 PM, KRK4m said:

My "February" turned out to be January 14 - quite unexpectedly, I had to go for an examination to the hospital located near the museum. Thus I dropped into the archives of the exhibition department and looked through the service books of all 15 MiG-21s they had. The R11F-300 engine is installed in only one airframe - it is Mig-21F13 serial 740809. The R11F2-300 engines are in Mig-21PF serial 761901 and 762006 as well as in Mig-21U serial 661217. The rest have R11F2S, R13 or R25. Then I went outdoors and looked at these 4 planes. The conclusion is this: the nozzle in Rob's photos is typical only of the R11F-300 engine of the Mig-21F and F13.

Not R11F2-300 and not R11F2S-300. Therefore, the crashed plane could not have been a Mig-21PF or a training Mig-21U, nor any Su-15. I cannot rule out the Yak-28 (perhaps some of its versions had R11F-300 engines), because the example in the Kiev museum has covers on its nozzles, and others photographed as Walkaround on the Internet have empty gondolas without engines.

 

Michael, thanks one more time for your research and kind help! According to Yefim Gordon's Aerofax book, the Yak-28B and 28U had the R11-AF300 engine - from memory the A signifies that the engine accessories were placed differently, because of the installation in an engine pod instead of a fuselage. Therefore I think (but have no solid proof) that the nozzles of the Yak-28B and U also looked like the wreck parts. Therefore the list of possible aircraft with this nozzle contain four types: MiG-21F, early MiG-21F-13. Yak-28B and Yak-28U.

 

Rob