Here is the information I have for the Yak-9UT that we have discussed. I have seen bits and pieces of it in many of my reference books. But the most complete by far in a single reference has been
Soviet Combat Aircraft of the Second World War, Volume One: Single-Engined Fighters, by Yefim Gordon and Dmitri Khazanov
And reportedly this book was written in Russia, by Russian authors, using original VVS documents. So I will reference this book as my primary source, over my other references which are admittedly secondary western sources.
The primary information begins for the Yak-9UT begins page 157.
Yak-9UT:The Yak-9U and other Yak varients were used to test a range of armament alternatives; 23mm, 37mm and 45mm guns. To install these it was necessary to remove the synchronized machine guns, B-20 sychronized guns being installed instead.
The possibility of installing different engine mounted guns without the need for airframe modification was the designs most valuable feature, allowing a rapid change of armament, according to VVS requirements, during series production. The aircraft was designated Yak-9UT. Clearly, each armament installation a different effect upon weight, centre of gravity and flying performance, but the speed was the same as the Yak-9U. Handling was almost the same except for elevator load, which was heavy, this being the aircrafts most serious shortcoming.
Main advantage of the Yak-9UT was its heavy salvo weight , 13.2 lb/sec (6kg/sec) using the NS-37 and two B-20s..... <edit sniped>
Additional information can be inferred by reading the section on the Yak-9T, Yak-9TK, and the Yak-9K, starting on page 143, since the Yak-9UT is literally the late model Yak-9TK.
{from page 146} Most effort was concentrated on improving the Yak-9's armament. The synchronized 12.7mm UBS machine gun with 200 rounds of ammunition was replaced by the ShVAK (SP-20) gun with 175 rounds.
Now from the discussion and the designation, plus the later statement in the -UT section, I assume they mean the B-20 gun (20mm) with 175 rounds of ammunition, which incidentally used the same ammunition as the ShVAK.
{again from page 146}This thinking led to the next variant, the Yak-9TK, to be used in the development of engine mounted heavy cannon. In response to VVS requirements the aircraft was designed for the first time to mount any of the following guns: the 20mm ShVAK, the 23mm VYa, and the 37mm and 45mm NS. To install any of these weapons it was necessary to only change the attachement point and gun ammunition supply unit , and this could be done even under field conditions
So far the only inconsistency is in the above paragraph it references the 23mm VYa, instead of the NS-23 referenced in the -UT section.
{continuing on page 146}Yak-9K Universal gun mountings found their application on the Yak-9 later, when the Yak-9U went into series production. The NS-45 attracted the designers attention because of its unusual firepower, and work on its installation was continued on the Yak-9K ... <snip> The NS-45 was fed by a belt feed, as on the NS-37. The ammunition comprised 29 shells, the pilot having a shell store counter in the cockpit.
Now I understand you didn't want to include the 37mm or 45mm guns, but I thought I would include this information on those guns and their ammunition loads purely for informational purposes only, since it is the only place I have ever seen it stated. The only ammunition load out that I cannot find an ammunition count for is the 23mm cannon.
Lastly in our conversation yesterday Pyro, you said that your greatest hesitation about including the x3 20mm loadout or the x2 20mm + x1 23mm loadout, was that you hadn't seen any pictures of aircraft armed in this manner. So what I did was start to look for Yak-9's armed in this manner.
Here is a standard Yak-9U to use as our basis. In particular notice how the hub mounted cannon and two nose mounted cannon look. This picture is from page 160
Now for comparison purposes, this is the Yak-9UT, armed with the 37mm, the look that you said you expected too see for any of the heavy cannon installations with the large barrel and muzzle break (FYI for everyone else, the 45mm installation looks almost identical} This picture is from page 159
Now I couldn't find any picture of a Yak-9UT with either the x3 20mm option or the 23mm option. But I did find a picture of the Yak-9P prototype in 1943 that has the exact same armament (x3 20mm option) as the -UT. Note how, the nose and armament visually look identical to the standard armament Yak-9U. (ie no protruding large barrel with muzzle break or additional cowling bumps) Page 148
Similarly I found a picture of another Yak-9 prototype armed with the 23mm cannon. Again, note how it looks visually identical to the standard Yak-9U (ie no protruding large barrel with muzzle break or additional cowling bumps). Also it is pertinant to remember that these prototypes are the aircraft that lead directly to the -9TK and the -9UT. Page 148 also.
So my theory is that the reason you have never seen a picture of a Yak-9UT armed with the x3 20mm's or the 23mm option, is that you may have and you never knew it.
Since from the photographs, it seems that the only way to detect the changes of the USB MG's to the B-20 Cannon, or the installation of the 23mm engine mounted cannon, is by having an original documented photograph, or actual internal examination of the original aircraft.
Leonid, Sorrow, or anyone else, do you guys have anything more to add ?
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"
[This message has been edited by Vermillion (edited 07-28-2000).]
