Is F-1 a quasi BM(ie doesnt leave earth’s highest atmosphere layers)?
My interpretation is F-1 is still exo atmospheric by default and the engine in the warhead is what limits the number of skip. I remember Patrames saying engine has enough fuel for 1-2 small deviations to confuse Arrow-3 mid course trajectory interception. The engine kicks in after the dive to cause the skip (pull up).
You are assuming that the weapon is always supposed to reach its full range. What if IRGC needs to use Fattah on targets in Kurdistan, fired from Azerbaijan Gharbi, for that they do not need high apogee for range so Fattah can just go for a quasi-ballistic trajectory without much KE gain, but if needed the weapon can still then establish a Lofted apogee then Quasi Ballistic Skip glide trajectory for speed. Its a choice.
For MRBM ranges, it needs high post-boost apogee otherwise missile will not reach full range. High apogee means it can have more stronger skips for more K.E.
Fattah-1's flight characteristics are very similar to Khinzal which is hybrid of exo-atmospheric+quasi-Ballistic trajectory. Chinese or other Russian Hypersonic missiles are not hybrid. This is why I am saying that it can be easily a nightmarish AL-HGV/BM from F-4. An F-4E/D "Dowran" can easily loft Fattah at high apogee over Iraq or Persian gulf for MRBM strike, MaRV can then perform skips for hypersonic speed.
The thinking was that the difference between F-1 and F-2 is the F-2 can do this naturally using its body shape (fined wedge design) where as F-1 still uses traditional warhead design hence need for small engine in RV stage to achieve any deviations. Hence why F-2 is considered a true HGV where as F-1 is merely a BM that has hypersonic capability with some limited maneuverability.
Fattah-1 is a hypersonic missile, a hypersonic MaRV with exceptionally high burnout V which is how its multifold faster than a traditional BM. Its closest cousin is Khinzal.
Fattah-2 is a traditional, unguided Hypersonic Glide Vehicle like DF-ZF/17.
I think that’s what also is the biggest limiter for F-1 speed vs F-2 speed, ie RV shape. I don’t dispute you could get F-1 speed higher, but it has to answer the laws of physics and forces acting upon it to not break apart due to its metallurgy construction and heat shield construction as friction increases the more you enter earth’s densest atmospheric layers.
My take is that Fattah-1 is designed for the following jobs.
- Without skips and max apogee it can have the range of Sejjil-II (~2500 KM) like a traditional solid fueled BM.
- With lofted apogee + skips its a hypersonic missile but range is reduced.
- Because of MaRV it is highly accurate for precision strike so it can be used as a AShBM.
- because of less weight and lofted PBV, it can morph into a AL-HGV but IRIAF is a joke of a force.
Fattah-2's job is just speed and nothing else.
I’m also not convinced F-1 and Keibar Sheykan-2 are not the same Missile with a slight variation (ie version A vs version B). With Iran you never know with these naming conventions.
I do not know what Kheybar-Shikan 2 is. My assumption initially and I have always maintained this is that Kheybar-Shikan + post boost lofted Apogee + stronger (or multiple) Skip-glides = Fattah-1. Kheybar-Shekan IMO was the first attempt by Iran to have a hypersonic missile at MRBM ranges. It took them 3-4 years to finally have the correct trajectory for enough KE that resulted in such a high burnout V that makes Fattah-1 a hypersonic missile while KS is just a single skip, pseudo-Hypersonic missile.
