FW190A vs FW190D9 : high alt performances

[I./JG52_Woutwocampe]

Its well know that one of the 190A shortcomings especially later in the war was that it wasnt well suited to intercept high alt bombers ; its BMW801 engine was a low/med alt engine. Until the Ta152 could be mass produced the Dora kind of acted as a stopgap between the Ta152 and the Wurger. But the Dora did well enough at higher altitude that it was actually itself produced in large quantity.

 

So it kind of came as a surprise to me that the the Jumo 213A in the 190D9 only as a single stage 2 speeds supercharger without aftercooler. Later Jumos had more evolved superchargers but, the mass produced 213A didnt. 

 

So the question is, what actually made the 190D9 that better than the 190A above 6000m?

 

-increased wingspan?

-increased rpm of the 213A compared to the BMW801?

-increased boost at nominal/combat/emergency power for the 213A compared to the BMW801?

-all of the above?

 

 

 

 

[CUJO_1970]

Well, there was no increased wingspan on the Dora-9. That came later with the Ta-152.

 

Simply, the answer is the supercharger./engine combination. The 801 as installed on the FW190A was a very compact arrangement that did not lend itself to supercharger development. With an inline, like on the 109 they could simply bolt a bigger charger to the side of the engine. The air intake on the Dora-9 supplied more air to the engine and gave it a better FTH. The Jumo was also a damn good engine that was capable of producing a lot of power.

 

Some 801 fighters (a small number) were equipped with external air intakes to increase air to the engine and increase performance at high altitudes. These are not to be confused with the dust filters used on the Jabos as they looked very similar. The Luftwaffe also had the more powerful 801E project, that used different supercharger/drive ratios and engine modifications that increased performance but they did not put it in mass production I guess due to resources and the war situation. The FW190A-9 did have a better FTH than the A-8 due to many of these design changes being implemented.

 

The 801TJ used on the Ju-388 was probably the best radial/turbo-supercharger combo of the war. It was an extremely compact turbo, and showed what the 801 was capable of at high altitudes.

 

 

 

 

[ZachariasX]

There is little to choose between late A series and early D9 series in terms of  performance besides the point that the D series lost considerable weight (almost half a ton) and got a slightly more powerful engine that later got boosted to 20% or so more power in later iterations. The airframe is much more that of a racer compared to the Antons.

 

Critical altitude of the blowers is about the same (IIRC even slightly lower for the 213E Jumo) but the improved airframe gave higher speeds for the D series. 6 km critical altitude was a design spec for single stage blowers issued by the RLM and BMW (and Jumo and DB) adhered to that.

 

The A series were not that comfortable in handling high up, something the elongated fuselage helped to improve. It is only the D13 series with the Jumo 213F that had a significanlty improved (and complicate) multi stage blower. (As in the Ta-152.) But there were only a handful of these aircraft.

 

Bottom line is that the D9 is not at all a „high altitude aircraft“ by late war standards, and neither is the 190A. 

 

 

[Supercharger]

Hello I./JG52_Woutwocampe

the word what you are locking for is supercharger efficiency. As the other guys already mentioned the BMW & JUMO where designed for the same full throttle height. If you compare the performance charts of an BMW 801D & JUMO 213A you can already see, that the BMW supercharging system is less efficient, in terms of it requires more power to keep the boost level. As an example:

 

BMW801D take off power loss between zero and 5700 Meter = 16,8%

JUMO213A take off power loss between zero and 6000 Meter = 10,9% 

 

The JUMO213A mentioned here is the first production version with a take off power of 1750 PS @ 3250 RPM, our engine in game is an upgrade running 1900 PS @ 3250 RPM(without MW50), but the supercharging system is the same.

This figures show that the BMW's supercharger/system is worse than that of the JUMO 213. And this discrepancy increases if you fly above the full throttle height. 

 

Edited July 27, 2021 by Supercharger

[Pict]

15 hours ago, I./JG52_Woutwocampe said:

Its well know that one of the 190A shortcomings especially later in the war was that it wasnt well suited to intercept high alt bombers

 

So what about earlier in war when the Anton was the premier interceptor against the 8th air-force bombers? Jg-2 flew them out of my local aerodrome in 43-44 and Egon Mayer developed the head on attack against the box formation with them.

 

Did the Anton engines get downgraded later or did the bombers fly higher?

[Supercharger]

1 hour ago, Pict said:

Did the Anton engines get downgraded later or did the bombers fly higher?

No they were not downgraded, and the bombers didn't fly higher. The problems for the Anton's arose when the B17's & B24's were escorted by Mustang's. 

[ZachariasX]

1 hour ago, Pict said:

Did the Anton engines get downgraded later or did the bombers fly higher?

The Antons supercharger was essentially built on the very compact P&W design licensed by BMW in the thirties. It was as @Supercharger said not a very efficient design compared to what RR or DB came up with toward 1940. But it was a very big and powerful engine that still gave it the edge over the competition in 1942 in terms of net power output. The compact design further made it possible to mount such a huge engine to an airframe as small as the 190. This is no small feat. But in 1944 competition had changed drastically.

 

The Germans were very keen on having efficient superchargers, rather than complex ones. This is best represented in the DB60X supercharger. RR went the extra mile by allowing complicated designs and going for two speed, two stage designs that are not trivial to make in a way that doesn‘t interfere too much with installing it in an aircraft.

 

Jumo started out with a very poor supercharger design for the Jumo211 that precluded the use of that engine in fighter aircraft. Bombers could use the engine. The Jumo213 was a huge step up.

 

[Pict]

52 minutes ago, Supercharger said:

No they were not downgraded, and the bombers didn't fly higher.

 

Thanks for the confirmation, that's what I thought,

 

 

7 minutes ago, ZachariasX said:

But in 1944 competition had changed drastically.

 

 

This is it. The Anton when compared to the fighters of 1944 and 45 was dated. That howver didn't preclude it from intercepting bombers at altitude,

Edited July 27, 2021 by Pict

[ZachariasX]

20 minutes ago, Pict said:

That howver didn't preclude it from intercepting bombers at altitude,

It certainly didn‘t. But 50 Mustangs flying at a very suitable blower setting and that are intercepting you absolutely make you wish for more power.

[Pict]

7 minutes ago, ZachariasX said:

It certainly didn‘t. But 50 Mustangs flying at a very suitable blower setting and that are intercepting you absolutely make you wish for more power.

 

Indeed, in 1944 this was what cut Mayer's career and life ultimately, P-47's but same principle.

 

Edited July 27, 2021 by Pict

[I./JG52_Woutwocampe]

Yep, the amount of Mustangs as well as the fact that they started to perform sweeps several kilometers before the box and caught Antons in their climb made it necessary to have a faster plane which would not lose steam significantly above 6000m in the final portion of their climb. That became more and more obvious in late 44 and 45.

 

And the german feared the B-29 looming too, which could fly faster and higher than the B-17 and B-24. 

[Bremspropeller]

As Cujo has already hinted at, one of the main shortcomings of the Anton was the inefficient supercharger-intakes on the inside of the cowling.

They not only had pressure-losses by bending the airflow around a lot, but they'd also suck in heated air, which didn't help compression.

 

An outside-scoop could be fitted within 15-20 minutes* and helped FTH by about 500m, as it did away with unneccessary airflow-bending, heating and it also offered increased ram-compression.

 

Those scoops were tested (and indeed Mayer seemed to have one aircraft fitted with those scoops for a time), but they never caught on.

For unknown reasons.

 

___

* Basicly just a sheet-metal job, replacing the supercharger's intake-panel.

[Pict]

9 hours ago, Bremspropeller said:

* Basicly just a sheet-metal job, replacing the supercharger's intake-panel.

 

Gotta admire anything simple and effective...especially when you're under the pump with your back to wall.

 

I wonder why they didn't catch on, no profit for a few manufacturers???

Edited July 28, 2021 by Pict

[ZachariasX]

10 hours ago, Bremspropeller said:

Basicly just a sheet-metal job, replacing the supercharger's intake-panel.

I am not so sure that it was that easy. The engine ran at its utmost limit and what seems as a practical idea may be a problem for regular production engines down low.

 

One has to keep in mind that engines in the test bed are never regular production engines, same as that double wasp „that did seven hours at WEP“ (or so) certainly wasn‘t what Boyington had in his Corsair. Same with the DB60X that did so and so much time on unicorn ratings. Engine testing doesn‘t work that way.

 

All parties involved were well aware of the ram effect. Not using that was usually a deliberate design choice. Still an interesting topic and I hope to find more hard info on why this was done without maximizing ram effect.

[I./JG52_Woutwocampe]

Didnt Graf fly an A6 with external supercharger intakes?

[CUJO_1970]

There were different intake variants used, most likely service tested in small batches. Part of the 801E project here I believe, where the intakes were at the wing root instead of the cowling:

 

And some pictures of the external cowling intakes:

 

Also intakes combined with the wide-cord prop:

 

5 hours ago, ZachariasX said:

I am not so sure that it was that easy.

 

I think he's right, at least based on German tests. There were hundreds of kits made to be used on production fighters, but no idea the numbers actually put in service.

 

It seems only that there was a drag penalty at low altitudes which decreased speed on the deck (no free lunch) but they were quite a bit faster at altitude (over 420 mph if memory serves) and with a smallish gain in the critical alt. 

[ZachariasX]

4 hours ago, CUJO_1970 said:

It seems only that there was a drag penalty at low altitudes which decreased speed on the deck (no free lunch) but they were quite a bit faster at altitude (over 420 mph if memory serves) and with a smallish gain in the critical alt. 

Yes exactly, down low the ram effect can‘t be used due to overboosting, but you are left with the drag of the arrangement. Also, to fight at altitude, the AS powered 109 were on place. Modest numbers in practise, but they were there and they did rather well higher up.

[MiloMorai]

On 7/27/2021 at 7:53 AM, ZachariasX said:

There is little to choose between late A series and early D9 series in terms of  performance besides the point that the D series lost considerable weight (almost half a ton)

The empty weight of the D-9 almost 300kg heavier than the A-8. Loaded weight was almost 150kg lighter than the A-8.

[ZachariasX]

59 minutes ago, MiloMorai said:

The empty weight of the D-9 almost 300kg heavier than the A-8. Loaded weight was almost 150kg lighter than the A-8.

You‘re right:

Weight differences are not that big for T/O weight. Still, the D9 was, if anything, a step back in weight compared to the usual weight creep. The Ta-152 got considerably heavier.

[Bremspropeller]

On 7/28/2021 at 10:14 PM, ZachariasX said:

I am not so sure that it was that easy. The engine ran at its utmost limit and what seems as a practical idea may be a problem for regular production engines down low.

 

One has to keep in mind that engines in the test bed are never regular production engines, same as that double wasp „that did seven hours at WEP“ (or so) certainly wasn‘t what Boyington had in his Corsair. Same with the DB60X that did so and so much time on unicorn ratings. Engine testing doesn‘t work that way.

 

All parties involved were well aware of the ram effect. Not using that was usually a deliberate design choice. Still an interesting topic and I hope to find more hard info on why this was done without maximizing ram effect.

 

It really is that simple. There is no mention of engine-trouble arising from the external supercharger-intakes.

I think the reason was they maximized lower level airspeed before it became exident that higher altitude-performance was going to be a thing.

 

The Luftwaffe used to be "flying artillery", before the Allies came in at higher altitudes. Most of the early development-time in the 190 was spent getting the engine to work at all, so maximizing high altitude performance (which was still well compared to contemporaries in '41 and early '42) wasn't the highest priority.

 

The blunder only became evident, when the Spitfires (Merlins) recieved the second stage blower and when they (FW) realized the supercharger in the 190 couldn't cope with that. RLM didn't help by keeping priorities low for better high altitude solutions.

 

The lightened A-3/U7 with reduced armor and armament, as well as a longer-span wing - and external supercharger intakes - was shot down by RLM.

[ZachariasX]

2 minutes ago, Bremspropeller said:

It really is that simple. There is no mention of engine-trouble arising from the external supercharger-intakes.

Because you‘d have to throttle back down low to compensate for ram effect. The BMW ran at the very edge of burning its valves.

[Bremspropeller]

Why "throttle down", if you have a waste-gate?

The engine can only take so much manifold-pressure - granted. But if it's starving for air up high and can easily cope with the mod by regulating (dumping) the excessive pressure overboard down low, I'd rather take that solution. Especially if the aircraft can be re-equipped with the old intakes within 15-20 minutes.

 

As I've mentioned before, there was nothing stopping the LW to have one squadron with external intakes and two with internal intakes per Gruppe (or whatever ratio would have worked best) to cope with operational neccessities.

 

Their solution, however, was worse.

[MiloMorai]

27 minutes ago, ZachariasX said:

Because you‘d have to throttle back down low to compensate for ram effect. The BMW ran at the very edge of burning its valves.

The Merlin didn't.

[I./JG52_Woutwocampe]

Question about the 190A. At what alt does the supercharger changes to the 2nd gear?

 

 

[ZachariasX]

1 hour ago, I./JG52_Woutwocampe said:

Question about the 190A. At what alt does the supercharger changes to the 2nd gear?

Depends a bit on the actual rpm the individual aircraft is rated for in the field. IIRC about 8000 to 9000 ft. and critical altitude of the lower blower somewhere between 4500 to 5000 ft.

 

 

[I./JG52_Woutwocampe]

1 hour ago, ZachariasX said:

Depends a bit on the actual rpm the individual aircraft is rated for in the field. IIRC about 8000 to 9000 ft. and critical altitude of the lower blower somewhere between 4500 to 5000 ft.

 

 

 

Ok that makes sense. Yesterday I noticed that at 2300 meters, the manifold pressure was 1.65 ata so clearly the second supercharger gear was engaged. The gap between the crit alt of the first gear and the alt at which the second gear is engaged also explains why the performance/acceleration curve of the 190A is less that stellar around 2000/2500 meters. 

[tomo-pauk]

On 7/29/2021 at 3:46 AM, CUJO_1970 said:

There were different intake variants used, most likely service tested in small batches. Part of the 801E project here I believe, where the intakes were at the wing root instead of the cowling:

Hello,

Would you be so kind to point me (us?) to the right direction wrt. the article where these photos (showing the wing intakes) are published? Thanks in advance

[CUJO_1970]

On 2/6/2024 at 11:33 AM, tomo-pauk said:

Hello,

Would you be so kind to point me (us?) to the right direction wrt. the article where these photos (showing the wing intakes) are published? Thanks in advance

 

Hello tomo-pauk! -

 

Flugzeug Classic 9/2007 - FW 190 A-8, W.Nr.350155, TG+MG

 

These pics IIRC come from CZ Model forum here also: https://www.modelforum.cz/viewtopic.php?f=52&t=91020&start=645