Guys,
I need some help. I love the MiG-17. I build in 72nd scale. If any of you have built the DML MiG-17 or J-5 kit you know that the nose is not correct. The top of it has a lump on it that bears no resemblance to reality.
In doing research to correct the kit I came across something that I can’t explain and that none of my reference mentions. I am posting here in hopes that someone has an answer.
I have used the following books as reference for the following.
OKB MiG by Butowski and Miller
Aerofax MiG-17 by Gordon
The MiG-17 Fresco in Detail and Scale by Slatton
Squadron/Signal MiG-17 in Action
Squadron/Signal MiG-17 Walkaround
Kagero MiG-17/Lim-5
All of the reference drawings in all of these books depict the curve on the top of the nose from the intake to the windscreen as a single radius curve. This is true no matter what version they are depicting.

MiG-17 drawings
This is true whether or not the SRD-1M radar rangefinder is present.

However, from photographs and personal inspection of two separate MiG-17s, I have found two different distinct nose profiles. One is the constant curve depicted in the drawings and illustrated in the photo below.

This is a Chinese J-5

This is a Mig-17 Fresco-A
But there is another nose profile. It rises higher than the ones above and then flattens out prior to the end of the nose panel in front of the windscreen

This is a MiG-17 Fresco-C at Nellis AFB

This is a Czech MiG-17 Fresco-C
The bump is present on some aircraft whether or not the SRD-1M antenna is present. It can be seen on some MiG-17 Fresco-A & Cs, some Lim-5/6 and some Chinese J-5. It is not present on any MiG-17 Fresco-D that I have seen. The nose profile on the aircraft with the alternate nose is also different when viewed from head on, but I don’t think that makes any difference for the purposes of this discussion.
Now can anyone tell me, for sure, anything about this alternate nose profile? Is it peculiar to a particular variant? Why do none of the mainstream western publications on the MiG-17 even mention it, much less illustrate it? I’d appreciate any accurate information on this issue. Thanks.