DO-335 VS TA-152

[HoHun]

Hi Davparlr,

>I just have no idea of the thrust profile of the engine. Also, It would have been nice to have a SL top speed.

Unfortuntely, there are not many well-documented data points for the Dornier Do 335 around, and the speeds I have seen mentioned often do not specify the power settings.

I think that the 762 km/h top speed figure must have been reached on emergency power, so it's possible to reverse-engineer the Do 335 speed curve from the engine power curve as given in von Gersdorff et al. - result attached.

(Additionally, there is quite a bit of variation in the Do 335 data as the early development planes were all configured a bit differently, and as their role was it to work the bugs out, not all were up to full performance either.)

Accordingly, my curve can be seen only as a rough analysis.

(I have included a speed curve for the Ta 152H-1 from a German WW2 chart as that's the comparison suggested by the thread title

Regards,

Henning (HoHun)

[HoHun]

Hi again,

Additionally, here is a comparison of the power plants of the two types.

The higher speed of the Do 335 on the less powerful engine suggests that the Dornier could have been considerably faster than the Ta 152H-1 if it had received the Jumo 213E, too.

The advantage of the Jumo 213E is actually even greater than the shaft power chart suggests as the Jumo 213 series engines reportedly had a higher exhaust thrust output than the DB603 series engines and, more importantly, exhaust thrust of the three-speed supercharged Jumo 213E dropped off only above 9700 m (static), while the DB603A dropped off at 5700 m already.

Regards,

Henning (HoHun)

[Denniss]

The Do 335 used the standard MG151 - the 20mm version. The original, 15mm, version might have been existed in 1945 but was pretty useless.

I have the following data for DB 603 engines:
DB603A
1750PS take-off power at sea level, rated alt of 5.7km
DB603AA
1670PS take-off power at sea level, rated alt of 7.3km
DB603E
1800PS take-off power at sea level, rated alt of 7.0km

It's highly questionable to assume the Do335 used the old 603A except in prototypes, production versions either used the AA or E. Even the He 219 switched to the higher-powered 603AA in Summer 1944 and was to get the 603E in late 1944 so why should a high-performance fighter used this old engine with the low rated alt ?

[HoHun]

Hi Denniss,

>The Do 335 used the standard MG151 - the 20mm version. The original, 15mm, version might have been existed in 1945 but was pretty useless.

From what I've read in a contemporary firepower analysis report reproduced in "Luftfahrt International", the MG 151/15 was considered as a supplementary weapon to the MK 103, probably because of a similar muzzle velocity and trajectory. This might have been the justification for the 15 mm version appearing in late-war documents ... quite without doubt, the 20 mm version was much more effective by itself.

>It's highly questionable to assume the Do335 used the old 603A except in prototypes, production versions either used the AA or E.

Roger that, I've been using the DB603A only because it was used for the well-known 762 km/h top speed of the pre-series aircraft.

With regard to the DB603E, both Regnat and Griehl in their books on the type note that W.-Nr. 23014 - a pattern aircraft for the Do 335B-2 destroyer series equipped with the MK103 wing guns - when tested by the French on 25.4.1947 achieved 700 km/h at 1.5 km altitude. That's about 30 km/h faster than the speeds I indicated above, in spite of the additional drag of the wing cannon.

Regards,

Henning (HoHun)

[Denniss]

But the 15mm MG 151 would have to be explicity stated as the 15 mm version (MG 151/15). All references to MG 151 in wartime docs of at least 1944 (maybe even 1943) pointed to the then-standard MG 151/20.

[HoHun]

Hi Denniss,

>But the 15mm MG 151 would have to be explicity stated as the 15 mm version (MG 151/15). All references to MG 151 in wartime docs of at least 1944 (maybe even 1943) pointed to the then-standard MG 151/20.

At least, that's the more likely interpretation if the calibre is not given I don't know where the idea of the Do 335 - in some versions - was supposed to be armed with MG 151/15 cannon originated. Maybe it's just a simple misunderstanding, but if there is something better, I'd figure that the trajectory match to the MK103 that was obviously considered within the Luftwaffe might be the reason.

The document I mentioned is summarized here:

http://www.ww2aircraft.net/forum/avi...tml#post298384 (Info on Me262 with the BIG gun in the nose)

(In case the link does not take you to the exact post in that thread, it's post #36.)

Regards,

Henning (HoHun)

[Soren]

I have to agree with HoHun, the trajectory of the Mk103 & MG151/15 are very similar. And even by 1945 the MG151/15 was a very devastating armament.

[SoD Stitch]

Originally Posted by Denniss

But the 15mm MG 151 would have to be explicity stated as the 15 mm version (MG 151/15). All references to MG 151 in wartime docs of at least 1944 (maybe even 1943) pointed to the then-standard MG 151/20.

My understanding is that the MG 151/15 was used on the "A" variant, which used the lower-velocity (short-barrelled, kurz) Mk 103; whereas the more destructive MG 151/20 was used on the Zerstorer "B" variant, which deleted the engine-mounted Mk 103 and, instead, used two long-barrelled Mk 103's mounted in the wings, thereby maintaining comparable muzzle velocities.

[Erich]

the 2cm MG 151/20 would of been used not the 15 which was in 45 regulated to airfield defense and even front line combinations on the Ost front for the Heer

as stated earlier could esily have been a misprint in official documentation which was somewhat common in 44-45. Just checked a late war April of 45 document - German LW on primary source materials for in-house inventory for the LW, sorry but it was all wrong with inaccurate numbers and even giving some units Bf 109's when in fact all they had was Fw 190's.

[drgondog]

Originally Posted by SoD Stitch

You are correct, the Pfeil did not have a "service record", as no units ever reached operational status before the end of the War.

However, on at least one well-documented occasion, a Do-335 was able to "walk away" from a flight of P-51's, without the Mustangs even managing to get in a shot, due to the -335's superior speed. As I said, the smart LW pilot would've used the Pfeil's advantages to his benefit, not gotten tangled up in a furball with a bunch of more manueverable Mustangs.

SoD - one I recall was Lerche's account in LW Test Pilot - You can bet the 51's had probably full load of internal fuel and ammo and the 335 was light - but even so - in most combats the dead never saw the living guy, and airplanes don't run around in constant full boost.

If the 335 was 20+ mph faster in many regimes, so what? Mustangs weren't immune from 190A7/A8 or 109Gs and had a similar speed advantage.

And the main reason the LW was "dog meat" in '45 was superior Allied numbers, not necessarily superior tactics or superior hardware; anybody who is outnumbered 10-to-1 is probably going to lose, I don't care how good you are. In '40, the French were "dog meat" to the LW due to the LW's superior numbers; you do the math.

In 1945, pretty true even though LW occasionally got local superiority. The big difference was the average pilot skills. "Math" is all about LW controllers exploiting holes in the bomber stream, late R/V's, missed R/V's.. etc.

The LW even got some examples of loacal air superiority in Nov/Dec 1944 but not able to exploit their advantage because of too mang kids with only a couple of missions behind them - flying against a talented and confident and well trained bunch of RAF and US and Sov fighter pilots - who also could put up numbers no worse than 1:2 or 1:3 fighter vs fighter at the point of attack no matter where along a 400 mile track

[lesofprimus]

Glad to see u back around here Bill, was wonderin about u...

[KrazyKraut]

I wonder why people think the Do 335 was much better vs. bombers than the Ta 152. In the configurations that were any close to combat ready it had one MK 103 and two 2cm (probably) MG 151s. That's nice but it's not really a lot better than one MK 108 and the same two 2cms.

In theory the 103 could hit bombers from beyond the range of their defensive gunners, but since the 335s would've (most likely) attacked in a manner similar to the Me 262 the difference between the two guns would've been insignificant.

Either that or you try to pick bombers from beyond 600m (like the Zerstorer Me 410s) and lose all your speed advantage over escort fighters.

[Soren]

Well had the Do-335 entered service then the version tasked with fighting the bombers would've most likely been armed with 3x Mk103 cannons plus the 2x MG151/20's. The Do-335 could no doubt also take more damage than the Ta-152 could, and crucially it could also operate as a two seat nightfighter. The Ta-152H was designed purely to be a fighter, not a bomber interceptor, and was therefore limited to that role.

So the Do-335 was definitely a useful design....HOWEVER, as with every other piston engined fighter it was rendered unnecessary & obsolete by the Me-262 which outdid it in every aspect.

[KrazyKraut]

How bad would the extra 2 MK 103s have affected its performance though? The advantage I see is that it could've made it home in case defensive gunners disabled the forward engine (though that would make it easy prey for escorting fighters). Considering the two DB-603s could power two of the later Fw 109 Doras or Ta-152 Cs, those may have been the better application. The Do could've made a good nightfighter and fast bomber (then again the Ar 234 was still better at that). The question is how bad of a bottleneck the engines were compared to airframes and pilot availability.

[KrazyKraut]

Originally Posted by HoHun

Hi Davparlr,

>I just have no idea of the thrust profile of the engine. Also, It would have been nice to have a SL top speed.

Unfortuntely, there are not many well-documented data points for the Dornier Do 335 around, and the speeds I have seen mentioned often do not specify the power settings.

I think that the 762 km/h top speed figure must have been reached on emergency power, so it's possible to reverse-engineer the Do 335 speed curve from the engine power curve as given in von Gersdorff et al. - result attached.

(Additionally, there is quite a bit of variation in the Do 335 data as the early development planes were all configured a bit differently, and as their role was it to work the bugs out, not all were up to full performance either.)

Accordingly, my curve can be seen only as a rough analysis.

(I have included a speed curve for the Ta 152H-1 from a German WW2 chart as that's the comparison suggested by the thread title

Regards,

Henning (HoHun)

There actually was a direct comparison in a recent issue of a German aircraft magazine (Flugzeug Revue??), maybe someone's got the issue? I seem to recall the data for the Do 335 was all projected though.

EDIT: I found it: FLUGZEUG CLASSIC - Ausgabe 07/08 - Shop - flugzeugclassic.de - Oldtimer der Lüfte