Thank you all for being gentle, I get that main undercarriage braking will put weight on the nose-wheel and I do not know what V2 is on this, but I assume that if V1 is 190(somethings) then 230 exceeds V2. So, if the wings are flying then there is no downforce on the mainwheels, hence no braking on the mainwheels, hence no nose-down moment caused by breaking (of the mainwheels)?
Perhaps we should first clear up what V2 was for this weight, both properly configured and clean?
Its not quite as simple as >V2 = flying. You can quite hapilly tear down the runway significantly faster than Vr and V2 without the aircraft flying - if you don't rotate the aircraft you wont get any angle of attack on the wing and you wont get any lift. (its a little more complex than that as the wing is 'built in' with a slight angle of attack- but nowhere near enough to lift the aircraft at anything other than insane speeds).
Lift = essentially angle of attack * speed squared. you need both angle of attack AND sufficient speed to generate the lift.
So if the aircraft doesn't rotate to angle the wing into the airflow, it ain't gonna fly.
I've watched a fair few russian aircraft take off, and some of them do seem to accellerate slowly and use alot of runway. (ever wonder why most russian airports seem to have 4000m of tarmac!). I can't comment on whats normal for a yak42 but if those timestamps are correct than thats a very very slow accel. 50 secs from 75 to 190 kph (40 to 105 kts) ! My car is significantly quicker than that! and another 15 secs from 190 to 230 (125kts) - and we can surmise that they went off the end of the strip round about that point - thats 65 secs to get to 125kts - even an old russian klunker can't be that slow. Gotta be something wrong with that.
Probably reading too much into an unoffical transcript, but I don't know about you but If i'm heading off the end of the runway and either of us call for Full thrust and nothing happens I ain't gonna call for it agian. I assume either pilot or the FE can firewall the thrust levers in a yak42? why wait and ask for it again when you are going grass cutting?
EDIT to add that I'm reading the 74, 76 bit at the beginning as speeds - but you could read it that the 'speed increasing' comment was the start of the roll in which case accell looks pretty normal. Who knows. No doubt someone will come up with an answer soon. Unless the laws of physics have changed recently theres only a handful of things that make an aircraft go off the end of the runway like that.