Upengined Ta 152H-1

[silence]

Stick a Jumo 213J in H-1 and what's kind of jumps can be expected in max speed and climb?

 

[pattern14]

The H-1 was "supposed" to have been good for 472 MPH, making it the fastest piston engine fighter of WW2, but records are still not 100% clear if this particular model (as opposed to the H-O) actually fired a shot in anger. Estimating any increase in performance by sticking a Jumo 213J would be an intriguing exercise, but a little outside of my technical scope. Maybe someone else out there can chime in??? I have no doubt the airframe was up to it, and the Ta 152 was capable of further enhancement, so lets see what someone comes up with.

 

[Denniss]

The 472 mph was supposed in very high alt with Nox injection, with pure engine power it was about 455 mph.
Not much is known about the 213J, a US postwar data collection claimed it was to have 2600 PS at 3700rpm (with MW 50).
Without that huge rpm increase, going just from 3 to 4 valves (maybe with slight rpm increase), it may have gained 100-200 PS in both boosted and non-boosted modus operandi.

 

[wuzak]

I am a bit sceptical about the claim of 3700rpm.

Even the standard 213's speed of ~3200 was high for the time. Remembering that its stroke was a half inch longer than the Merlin and V-1710, and nearly as long as the Griffon's (maximum speed 2750rpm).

 

[Shortround6]

They may have been able to pull off 3700rpm, the real question is at what cost and for how long?

Allison picked up 200rpm by using a different crankshaft with 27lb worth of counter weights that actually put less stress on the bearings at 3200rpm than the original crank did at 3000rpm.
The Russians picked up 200-300 rpm on the original Hispano by beefing things up and accepting a lower overhaul life.

Due to improvements in materials and design Both the Allison and Merlin gained large increases in engine life from the beginning of the war to the end of the war while increasing the power substantially while keeping the same RPM. If they had decided to trade engine life for power and used higher RPM?

Rolls Royce was running the R racing engine (Griffon stroke) at 3200 rpm in 1931, granted they had trouble running it for an hour at that speed but if they wanted to run 3200rpm on a Griffon in 1944/45 with what they had learned in 13/14 years?

We don't know what the Junkers engineers were trading for the 3700rpm ( or even if they really achieved it as the engine didn't go into service).

 

[stona]

The 472 mph was supposed in very high alt with Nox injection.

And that is close to the figure I have (via Harmann) for the H-1 with the Jumo 213 E of 469 mph. That is "hochstgescwindigkeit mit GM1" which I'd translate as "high [altitude] speed with GM1".

Steve

 

[tomo pauk]

...of 269 mph...

Typo, Steve?

 

[stona]

Typo, Steve?

Yep...corrected.

Steve

 

[silence]

469 vs 472 sounds like well within standard deviation. With a 213J it looks like a 600-700 hp jump - assuming the 213J performs as expected.

 

[DonL]

I have serious doubts about such a high jump!

I agree totaly with Denniss something about 100-200 PS makes sense, but not 600-700PS, And 2200-2300PS (inclusive MW 50) would be a good output performance for a 35 Liter engine.

 

[tomo pauk]

In case the RPMs really jumped to 3700 vs. 3250, the engine power would also jump considerably. Anyway, here is what informations (found at AEHS site, sorry about the quality) were presented to the allies just after the war (1900 PS at 33000 ft? vs 1320 at 32000 ft for Jumo-213E), take it for what is worth:

 

[DonL]

Thanks for the post Tomo, this information was new to me.

 

[Denniss]

Contra-rotating prop? I must have missed this on my copy.

 

[tomo pauk]

Here is the link with tables some pics (all DB enignes on the pics, though):

Daimler-Benz

Wonder whether someone has better quality copies of the tables, though.

 

[drgondog]

What are the gear changes to keep prop tip speeds below supersonic at 3700 rpm?

 

[tomo pauk]

Don't know; the reduction gear was all-new already, since it was to 'power' counter-rotating props, at least that can be read in the table.

 

[silence]

So what kind of performance gains are we talking?

 

[silence]

Here is the link with tables some pics (all DB enignes on the pics, though):

Daimler-Benz

Wonder whether someone has better quality copies of the tables, though.

No kidding - I've been wanting info like this for years.

 

[tomo pauk]

So what kind of performance gains are we talking?

Let's see how I'm good at cube root law The cube root of 1900 (PS at 33000 ft) is 12.3856. Cube root from 1300 (PS at 33000 ft, Jumo 213E) is 10.91392883. Ratio between those two is 1,13483599. Multiplying the speed of the Ta-152H (~470 mph) with that number makes ~533 mph.
Corrections welcomed

 

[silence]

Without that huge rpm increase, going just from 3 to 4 valves (maybe with slight rpm increase), it may have gained 100-200 PS in both boosted and non-boosted modus operandi.

How does the increase in number of valves increase the PS?