Ta 152 vs P47N: level speed

[moot]

TY

[Stoney]

My comments about exhaust thrust were only for the P-47N and weren't meant to apply to the Ta-152.  Also, at speeds of 460 TAS, we can probably count on higher prop efficiency for both aircraft, but to know for sure, we'd have to do some math.  I've found a good article online regarding figure of merit and propellor efficiency.  Of course, Tango has a copy of the Red Book, so he probably has the best gouge at least for the P-47.  I need to get MS Excel Solver going so I can start doing some multi-variable analysis.  It'd be nice to find the curve for eta-P at least, at each speed.  I don't know much about the design of the Ta-152 prop, but wouldn't a four-bladed, high-activity factor prop like on the P-47 not be the most optimal for extreme high speed flight at altitude?  Perhaps the Ta-152 gains some prop efficiency that's difficult to see.

I have no idea how to estimate how much exhaust thrust the Ta-152 would be capable of.  Wmaker, how much does that 200 lbs of exhaust thrust affect the speeds?  How did you choose that number?

EDIT:  Did the Ta-152H have a 3-stage blower?

[Wmaker]

Wmaker, how much does that 200 lbs of exhaust thrust affect the speeds?  How did you choose that number?

Not lbs, hp. I just threw 200hp in there to account for the exhaust thrust. Like I said, I just did a quick & dirty calculation to show that even with the rather large hp difference the data on these two planes is within the realm of possibility. It really wasn't meant to be extensive highly accurate analysis on the top speeds of these planes. That would for example need, like you said prop eff curves for those altitudes/speeds. The 200hp gives ~16 mph increase.

Moot, here's the table: http://www.mediafire.com/file/izvwudmnmzz/Speed table.xls You can play with the variables, the formula does the unit conversions.

[moot]

Thanks Wmaker   Like you said, I'm curious only to see an accurate general view of each factor's order of magnitude. Not necessarily an extremely precise calculation.

Stoney - I'll check the blower cfg in a bit.

[RATTFINK]

30k in a Ta 152 Höhenjäger (Height hunter) here I come

[Wmaker]

My comments about exhaust thrust were only for the P-47N and weren't meant to apply to the Ta-152.

If this was in response to my first post on this thread, then yes I totally understood that you were talking only about P-47's exhaust thrust or the lack of it. My comment wasn't a reponse to it but rather meant as an reinforcement to it. As P-47's exhaust thrust is used to turn the turbo while Ta-152's exhaust thrust is all used as straight jet propulsion.

[Wmaker]

Moot, forgot to mention that here's a nice air density calculator for US 1976 Standard Atmosphere...I think it should be a close enough match with AH and the CINA standard atmosphere the Germans were using during WWII: http://www.digitaldutch.com/atmoscalc/

[moot]

Thanks again.  The math's in the .js file

Stoney, as far as I can tell the 213E in the 152 was set up with a two stage, three gear turbo.