correct as-is Abrupt engine ATA change at 3200 m climb and 3000 m descend

[Bucic]

Is this normal? No MW used. Instant action mission - The Channel - Thunderbolt Dogfight.

 

bug 190 eng rpm abrupt change alt 3200m 2024-05-29 short track vanilla.trk

[razo+r]

Yes, that's just the supercharger switching into the high/low speed at that altitude.

[Bucic]

48 minutes ago, razo+r said:

Yes, that's just the supercharger switching into the high/low speed at that altitude.

Any more details on that? The Jumo thread by Yo-Yo has missing attachments.

[razo+r]

3 minutes ago, Bucic said:

Any more details on that? The Jumo thread by Yo-Yo has missing attachments.

What kind of details are you looking for?

Like general info, it's got a single stage two speed supercharger that automatically switches the speeds according to the ambient pressure and power setting. This is also represented on performance charts of the D9/Jumo 213, where the speed stays roughly the same at 3km and slightly above until it switches speeds.

[Bucic]

1 hour ago, razo+r said:

What kind of details are you looking for?

Like general info, it's got a single stage two speed supercharger that automatically switches the speeds according to the ambient pressure and power setting. This is also represented on performance charts of the D9/Jumo 213, where the speed stays roughly the same at 3km and slightly above until it switches speeds.

Charts mostly, but that can be found in image search.

For reference

https://forum.dcs.world/topic/94872-jumo-213a-for-dora/

 

An additional question right of the bat is - how is the variable speed achieved? Looking at this image from the Jumo 213 Handbuch it looks like the compressor impeller is gear driven so I assume there's a gear-shift routine happening... Looking at this yellow-background image from a Japanese article [source 1] I can't even tell whether it's the charger impeller or the cooling fan

00f6c8a6718cd6aae8e673c66327fede6d7b0387.png@!web

[source 1] https://www.bilibili.com/read/cv17619643/

[source 2] FW 190 D-9 Flight Trials — http://www.spitfireperformance.com/fw190/fw190d9test.html

[source 3] Russian blog article that includes Jumo development versions Германский авиационный двигатель Jumo-213 — https://topwar.ru/35771-germanskiy-aviacionnyy-dvigatel-jumo-213.html

[source 4] Junkers Jumo 213 — http://enginehistory.org/Piston/Junkers/Jumo213/Jumo213.shtml

 

[-article-pic.avif

Edited May 29, 2024 by Bucic

[saburo_cz]

The Jumo 213A das not have variable speed supercharger. It has two speeds with low and high gear.

 

A swirl throttle is on picture, not cooling fan or impeller.

[Bucic]

13 hours ago, razo+r said:

What kind of details are you looking for?

Like general info, it's got a single stage two speed supercharger that automatically switches the speeds according to the ambient pressure and power setting. This is also represented on performance charts of the D9/Jumo 213, where the speed stays roughly the same at 3km and slightly above until it switches speeds.

Is there a detailed climb profile specified for Dora? What in-cockpit IAS do I maintain for best ROC.

Best ROTurn speeds for different altitudes would be helpful as well.

[grafspee]

@Bucic 

 

Charger impeller is this thing on the left on each side view.. Those next to arrows on the right hand side are variable inlet guide veins. Those are for throttling supercharger in more efficient way then simple butter fly valve. High supercharger throttling is required at low alt and above alt when second supercharger speed kicks in. Jomo supercharger is gear driven single stage 2 speed so supercharger speed remain constant as long as engine rpm remain constant.

Edited May 30, 2024 by grafspee