Focke Wulf documentation (appears either Feb or Mar45) has projected performance (calculated, not test results) for the D-12 in the following flight condition: 213F running on C3 (1870PS start u/notleistung, 2050PS sondernotleistung with MW50 injected at the third stage intake) VS10 propeller, take off weight 4400kg, Mk108 motorkanone/2xMG151 and ETC rack fitted, 730km/h at 9150 metres.
The Jumo 213 continued development as troubles with the D-9 were discovered (preproduction flight testing began mid43). The 213E-1, 213EB, 213F and 213F-1 became proposed in succession as the serial production version was sorted. Technically the whole 213 family was still under development, but had entered production.
With the 213E-1 motor fitted in a FW document I've got on pdf dated June44 the projection using B4 fuel, (1750PS) VS10 propeller, TOW 4550kg, Mk108/4xMG151 and ETC rack fitted, 695km/h at 10500 metres (Ta152H with same engine projected 690km/h at same height).
The Jumo 213F was fitted to serial production versions delivered, which actually means it's got considerably more power than a D-9 at all but sondernotleistung setting where it is equivalent, but the lower throttle heights for the first/second stage gears would still make it faster by up to 20km/h up to 6000 metres where you'll be doing around 680km/h at sondernotleistung (in a pole race you'd draw away then it'd stay where it was, then you'd draw away a little more, then it'd gain on you a little bit, all the way up to 5500m then you'd continue drawing away).
And then comes the trademark problem with the supercharger setup. You hit the third stage and pull nice from 7000-8000m topping around 705km/h at sondernotleistung and then it starts kicking the gears back and forth. You might pull to 9000m doing 720km/h if you don't overspeed under sondernotleistung, or you might have to wind it back and top out at something like 710km/h.
That was the truth about the Jumo, where it fell short from projections.
Now around about the same time this was being found out by the RLM, in November44 Tank put a Daimler in a Dora and it actually did 730km/h over the airfield, that was what sold them on the D-14/15 and the Ta152C and cancelling the Ta152B and E and plans to later switch the Ta152H to a Daimler.
Projected performance between the two engine families was actually about the same, it was just that the Jumo didn't achieve it.
My opinion on the graph you mentioned Sani? There's a typo and it's 670km/h because that matches the speed at that height in the June 1944 Focke Wulf performance estimates for the D-12, described above. Is it an original document reproduction or a third party table?
It might be worth mentioning though, the Jumo manages a reliable 1800PS at 8000 metres and the Daimler probably more than that and I don't think anything but a suped up P-47 superweapon can manage that, and they had their own problems in practise with pilot reports of turbo overspeeding from 8000 metres.
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Topic: Fw190D9 Early (Read 17059 times)
