Jumo 210 questions

[Denniss]

I'm looking for Jumo 210 specification, there are some available in the net but they do not agree well on the specifications except for the existing engine models.

What I have seen is there were several major types with some of them having a subtype.
Jumo 210 A, often reported to be rated at about 610PS
Jumo 210 B/C, often reported to be rated at about 640PS
Jumo 210 D/E, often reported to be rated at about 670PS
Jumo 210 Da/Ea, reported as D/E with two-speed supercharger and about 680PS
Jumo 210 G and Ga, fuel-injected version of Jumo 210D, the Ga is often reported as G with two-speed supercharger, about 730PS

Jumo 210 C, E and Ea are geared to slower propeller speeds, similar to what DB did with B/Ba-version of DB 601A/Ba

Questions:
Is it true the 210D had a single-speed supercharger and the 210 Da a two-speed ?
->The B-1 captured in spain was reported to have a two-speed supercharger but is most often listed only as Jumo 210D.
Are 210D and 210Da the same engine with only some minor differences, maybe the ability to mount an engine cannon ? Or does the little a means "ausländisch" (foreign) = export model?

If the power settings are true is it safe to assume they are take-off power at sea level ?
-> At least the Jumo 210D or Da have 680PS take-off power as I've seen a chart from a Bf 109B manual but without specifying the engine model.

 

[Denniss]

This is the chart said to be of a Bf 109B-1 with Jumo 210D (or Da?) I had on my HDD, sadly I've lost were I found it.

 

[Aurum]

On the authorized Junkers page regarding this engine is stated that volume of JuMo 210G was 21 liters instead of 19.7 as for former variants.
Is this a typo or in other case it should be the volume of one cyl. 1.75 L instead 1.64 L and if stroke was the same 136 mm then bore should be increased to 128 mm instead of 124 mm as usual for 210-ies.

Besides that compression ratio was decreased. What for it was made? It could be done by increasing stroke by the way! But in this case stroke should be 145 mm, compression ratio in this case is 6.85 (instead of 6.5 in the table). But this seems for me too big.

What is the answer enigma?

 

[Deleted member 68059]

Sadly I have very very little on the 210, but I have a few technical reports on it by the DVL.

This is one page from a report on the 210B, which has some specifications. I`ve manually added the "compression ratio" myself as its on the 2nd page
but has no other data, and saves me sending a whole image upload for just one number.

(In other words I think the 6:1 is rounded up....)

 

[johnbr]

Ju-210d