How good was Ta152H

[Chuck731]

Ta152H had a big supercharger, long high efficiency wings that gave it high speed, good maneuverability and controllability at up to 42,000 feet. But how good was it at below 30,000 feet?

 

[gomwolf]

IMHO, it was little more maneuverable Fw190D-9 below 9,000m.

Its ordinary wing loading(202kg/m² at fluggewcht 4,750kg) and high CLmax(1.70) make that aircraft quite maneuverable, but its ordinary T/W ratio(0.141 at prop efficient 0.7, gross weight 4,750kg, maximum speed at sea level 579kmh, Engine power with MW50 2,050PS) means ordinary acceleration, rate of climb and sustain turn. However, it have advantage at higher altitude to enemies. Wider wing span means lower roll rate than Fw190, but roll rate of Fw190 was one of the best, so It was not bad I think.

Hmmm... It is quite better than I thought.


Oh... my mistook. I fixed its wing loading.

 

[Chuck731]

Hmmm, the Ta-152H seems to not have sacrificed very much at lower altitude for its long high aspect ratio wings. That is surprising. It is actually faster than the Ta152C at sea level. Obviously there was some weight penalty, as it weighed slightly more than the Ta-152C despite having 2 fewer guns. But in terms of performance the two are nearly an even match at most altitudes until high altitude boost kicked for the Ta152H above 11.5k meters.

Why is the speed vs altitude profile of Ta152H so jagged where as that for Ta152C is smoother? Does Ta152C have a continuously variable supercharger or something?

 

[gomwolf]

AFAIK, DB603L use first stage supercharger until 9km.

And as you can see, translated document have many errors on it(ex: weight). Even I cannot found untranslated original one. So you have to be careful when you read it.

 

[tomo pauk]

It was one speedy fighter, finally something able to equal W.Allies best. Shortcomings were low G loading factor (~5 vs. 8 to 8.5 at Allied fighters) and unprotected wing tanks, plus the obvious late coming in the war.

Hmmm, the Ta-152H seems to not have sacrificed very much at lower altitude for its long high aspect ratio wings. That is surprising. It is actually faster than the Ta152C at sea level. Obviously there was some weight penalty, as it weighed slightly more than the Ta-152C despite having 2 fewer guns. But in terms of performance the two are nearly an even match at most altitudes until high altitude boost kicked for the Ta152H above 11.5k meters.

Why is the speed vs altitude profile of Ta152H so jagged where as that for Ta152C is smoother? Does Ta152C have a continuously variable supercharger or something?

WIngs of the Ta-152 were not that long for the installed power, and wing area was also not that big. DB 603 engines were featuring variabe speed S/C.

AFAIK, DB603L use first stage supercharger until 9km.
...

DB 603L used both stages in same time, since both impellers were on same shaft - as it was the case with 2-stage Merlin, 2-stage Griffon or Jumo 213E and F.

 

[gomwolf]

It was one speedy fighter, finally something able to equal W.Allies best. Shortcomings were low G loading factor (~5 vs. 8 to 8.5 at Allied fighters) and unprotected wing tanks, plus the obvious late coming in the war.



WIngs of the Ta-152 were not that long for the installed power, and wing area was also not that big. DB 603 engines were featuring variabe speed S/C.



DB 603L used both stages in same time, since both impellers were on same shaft - as it was the case with 2-stage Merlin, 2-stage Griffon or Jumo 213E and F.

I didn't know that. Could you plz open your source include the information about load factor of Ta152?

 

[Peter Gunn]

You might peruse this old thread for starters:

Ta152H questions

Ta-152 has been discussed here pretty thoroughly, not just in the above thread either, do a forum search and you'll probably find some of the answers you're looking for.

 

[tomo pauk]

I didn't know that. Could you plz open your source include the information about load factor of Ta152?

This table floats on the 'net for several years now, load ('G') coefficient was 5 to -2.5 at 4500 kg:

 

[gomwolf]

Thanks!

 

[Chuck731]

Can a piston engined fighter develop anywhere near the thrust needed to sustain 5gs? If not, the 5g limit would have much less significance than it appears because it doesn't impact the aircraft's real maneuverability, only facilitate an occasional grab shot, or escape from a enemy extremely close on the tail.

 

[tomo pauk]

Can a piston engined fighter develop anywhere near the thrust needed to sustain 5gs?
...

Maybe yes, maybe it could not sustain 5, or 7, or 9G - but probably (certainly?) there was a reason why Western (US, UK) fighters were certified for 8+G sustained limit, and 12G ultimate. Probably people didn't wanted aircraft being destroyed in tight turns or when recovering from a dive.

 

[Greyman]

Can a piston engined fighter develop anywhere near the thrust needed to sustain 5gs?

With altitude, absolutely.

 

[BiffF15]

To sustain 5 G's he would probably need to be below 15k and in a high speed spiral.

Cheers,
Biff

 

[Kryten]

Would dive recovery be a more likely scenario to exceed 5G?

It's ok to talk about 5,6,7g instantaneously (F1 drivers hit 5G under braking) but these guys had no G suits or modern G training, you also have to question their physical fitness with poor diets and fatigue over time so in a sustained manoeuvre what is a realistic average maximum ?

 

[Chuck731]

With altitude, absolutely.

The ability to sustain Gs under its own power usually decrease with altitude, not increase, because the maneuvering envelope defined by the gap between maximum speed and stall speed decreases. At the top of its service ceiling, a fighter couldn't do much beyond fly straight and level at it maximum speed because pulling any Gs will stall the wings.

 

[drgondog]

Can a piston engined fighter develop anywhere near the thrust needed to sustain 5gs? If not, the 5g limit would have much less significance than it appears because it doesn't impact the aircraft's real maneuverability, only facilitate an occasional grab shot, or escape from a enemy extremely close on the tail.

5 G has a Lot of significance in an asymmetrical dive pullout (as in trying to evade someone on his six)

 

[Chuck731]

5 G has a Lot of significance in an asymmetrical dive pullout (as in trying to evade someone on his six)

I am not saying it has no significance. Only maximum sustained G Is significant over a much wider range of combat maneuvers and situations than max instantaneous G.

 

[GregP]

Maximum sustained g has little significance in combat. You want to get off-plane or off-angle, and you do it with hard pulls for short periods of time, not with a max-g sustained circle. I admit a Lufbery circle is a defensive maneuver where several planes get in a tight circle and cover each other, but it otherwise is not of much use in combat. The trick is to get out from in front of his guns with a combination of roll and pull that he can't follow exactly, and you get slightly farther away from the center of the gunsight with each maneuver. Yes, they would occasionally do a hard turn for maybe one complete turn, but it wasn't a very good maneuver to try if he had friends around.

Let me say it this way. Anything over 4 g's could be considered a maneuver, but EVERYONE could pull 4 g's and you weren't going to pull away from center gunsight much at 4 g's. If you pulled 6 - 8 g's for a 45° - 70° turn, you were probably nowhere near his gun convergence point, at least for awhile. The thing was to do several maneuvers in a row, rapidly. If completed, you might be out of easy sight from the enemy you were trying to evade, especially if his plane was not so good in maneuverability.

I was reading one account of a very successful Soviet pilot in a P-39. He would roll as fast as possible for the count of 3, and pull 90° as hard as he could. He would do that 3 times in a row, and maintained he was always out of his opponent's line of flight by a long way. He was not the only person to talk about doing evasion like that as I have heard several US pilots say essentially the same thing in other words. It is far from the only way to evade, but WAS used by some.

 

[drgondog]

I am not saying it has no significance. Only maximum sustained G Is significant over a much wider range of combat maneuvers and situations than max instantaneous G.

No, Chuck - the stress analysis is performed to size parts and systems to withstand max applied design load - independent of time interval, in which it is applied. Further, there was no applied force as a function of time to examine structural behavior for either reversible loads (like analysis for fatigue considerations for a helicopter) or examine structural components like spars or torque boxes' behavior under steady applied loads pushing components past the yield point.

A high G instantaneous load (say 10+G load to an 8G Limit Load airframe), applied to the airframe, say in an indicial gust, is more likely to kill a lot faster than a sustained load somewhat greater than Limit, but less than Ultimate. What happens when a steady applied load above Limit load is that the airframe in a local area is more likely to deform elastically (bent wings, buckled shear panels, sheared rivets, etc.) as a time rate of change moving the stress curve from elastic to plastic range - whereas the 'sudden' shock is likely to fracture/break the critical structures.

It is easier to achieve an instantaneous G load honking an a/c around to get a deflection shot - and harder to account for with the methods and tools available in the 30's and 40's. The max G applied during analysis was due to symmetrical Lift loads encountered in dive pullout.

 

[Greyman]

The ability to sustain Gs under its own power usually decrease with altitude, not increase, because the maneuvering envelope defined by the gap between maximum speed and stall speed decreases. At the top of its service ceiling, a fighter couldn't do much beyond fly straight and level at it maximum speed because pulling any Gs will stall the wings.

I was just gettin' at what Biff said after; using a spiral dive to keep the speed up while you pull/trim upwards and sustain the G levels. Thousands of feet certainly required.