French WW2 Engines

Laurelix · Apr 18, 2020

So I came across this on google images although don't know the source.

Notice how it states their Nominal Power at Sea Level and WEP power at sea level.

I was looking for this except that I was looking for it for HS 12Ycrs engine.

Does anyone have any documents for this engine?

I know that it has 835hp at SL with WEP but I don't know the nominal power of it at sea level.

tomo pauk · Apr 18, 2020

Whenever I see someone is quoting WER figures for non-American engines, it is time for face-palm.
Anyway:

Laurelix · Apr 18, 2020

tomo pauk said:
Whenever I see someone is quoting WER figures for non-American engines, it is time for face-palm.
Anyway:

Thanks, I love you man (no homo)

Laurelix · Apr 18, 2020

tomo pauk said:
Whenever I see someone is quoting WER figures for non-American engines, it is time for face-palm.
Anyway:

I have a book about Avia B-135 which used HS 12Ycrs and it states 860hp at 4000m and that the plane achieved 527km/h at 4000m during top speed tests.

Your source states 868hp at 2400 metres...
Am I missing something?

Bretoal2 · Apr 20, 2020

Laurelix said:
I have a book about Avia B-135 which used HS 12Ycrs and it states 860hp at 4000m and that the plane achieved 527km/h at 4000m during top speed tests.

Your source states 868hp at 2400 metres...
Am I missing something?

Yes, you missed that HS 12 Ycrs1 is not HS 12 Ycrs...

The 12 Ycrs1 was a 12 Ycrs with reduced diameter supercharger (in order to improve low-altitude performance). And 12 Ycrs was rated at 860 cv @ 4.000 m with 880 mm Hg boost (an 835 cv for TO).

Regards

Laurelix · Apr 21, 2020

Bretoal2 said:
Yes, you missed that HS 12 Ycrs1 is not HS 12 Ycrs...

The 12 Ycrs1 was a 12 Ycrs with reduced diameter supercharger (in order to improve low-altitude performance). And 12 Ycrs was rated at 860 cv @ 4.000 m with 880 mm Hg boost (an 835 cv for TO).

Regards

So how does it differ to HS 12Ybrs and HS 12Ydrs bevause both are 835hp at SL and 860hp at 4000m

Bretoal2 · Apr 21, 2020

HS 12 Ybrs = early version, "engine study HS73"
HS 12 Ydrs = improved version with provision for variable-pitch propeller
HS 12 Ycrs = same as 12Ydrs, but "HS77" family, incorporating a raised propeller shaft to give "moteur-canon" or "moteur-affût" arrangement.

All three engines gave same TO power, nominal power and critical altitude (same performances, if you like !)
And 12 Ycrs1 = same as 12 Ycrs, with derated supercharger, boosting low-altitude performance.

The "Tabulated data from Lage 2004" incorporated in the Wikipedia english notice of Hispano-Suiza 12 Y contains many errors and misreadings.

You must read the French version (I wrote it !)

Regards,

Laurelix · Apr 21, 2020

Bretoal2 said:
HS 12 Ybrs = early version, "engine study HS73"
HS 12 Ydrs = improved version with provision for variable-pitch propeller
HS 12 Ycrs = same as 12Ydrs, but "HS77" family, incorporating a raised propeller shaft to give "moteur-canon" or "moteur-affût" arrangement.

All three engines gave same TO power, nominal power and critical altitude (same performances, if you like !)
And 12 Ycrs1 = same as 12 Ycrs, with derated supercharger, boosting low-altitude performance.

The "Tabulated data from Lage 2004" incorporated in the Wikipedia english notice of Hispano-Suiza 12 Y contains many errors and misreadings.

You must read the French version (I wrote it !)

Regards,

Thx but what's the nominal power at SL?

if that HS 12Ycrs has 890 CV at SL at take off and 820 CV at SL at nominal, would it be incorrect to conclude that the normal version had
835 CV at take off and 770 CV at nominal?

890 / 820 = 1.085366
835 / 1.085366 = 770

Bretoal2 · Apr 22, 2020

Laurelix said:
Thx but what's the nominal power at SL?

if that HS 12Ycrs has 890 CV at SL at take off and 820 CV at SL at nominal, would it be incorrect to conclude that the normal version had
835 CV at take off and 770 CV at nominal?

890 / 820 = 1.085366
835 / 1.085366 = 770

Bingo ! (or near miss...) The rated normal power at SL for 12 Ycrs/drs was 760 cv.

Note that 4.000 m. figure for critical altitude is not totally true. In fact, the designed critical altitude was 3.300 m. This was also given by bench testings and type-test.

BUT... many French companies preferred to give also the "puissance en altitude" where critical altitude was boosted by ram effect in the carburetor intake ! And so the was the 12 Ycrs... We see that Avia B-135 maximum speed was at 4.000 m - would the bench critical altitude be truly 4.000 m, the "real life" maximum speed should have been mesasured at higher altitude !

Bretoal2 · Apr 22, 2020

Just to help you getting lost in the jungle of the Hispano range (ca 1938....) !

Laurelix · Apr 22, 2020

Thanks
Here's a Bulgarian speed test results for Avia B-135

462km/h at Sea Level
478km/h at 1000m
495km/h at 2000m
511km/h at 3000m
527km/h at 4000m
529km/h at 4150m
519km/h at 5000m
507km/h at 6000m

tomo pauk · Apr 22, 2020

Laurelix said:
Thanks
Here's a Bulgarian speed test results for Avia B-135
...

Do you have some background data about this? Any chance for a hi-res picture?

Laurelix · Apr 23, 2020

tomo pauk said:
Do you have some background data about this? Any chance for a hi-res picture?

The best I can do is zoom in on it

Bretoal2 · Apr 23, 2020

Laurelix said:
The best I can do is zoom in on it

View attachment 578528

Thanks !

I bet the third row is RPM, but the right one ? Boost ? (in Hg mm ?)

Laurelix · Apr 23, 2020

Bretoal2 said:
Thanks !

I bet the third row is RPM, but the right one ? Boost ? (in Hg mm ?)

Must be yes

Laurelix · Jul 19, 2024

I'm puzzled by this…
B.135 uses HS.12ycrs engine

But I have no idea wether the Bulgarians got 462km/h at sea level with 760CV or 835CV engine power output.

It think that says 920 mmHg which is 1.21 ata / 36Hg

But is that nominal power or take off power for HS.12ycrs?

Bretoal2 · Jul 20, 2024

Laurelix said:
View attachment 789791
I'm puzzled by this…
B.135 uses HS.12ycrs engine

But I have no idea wether the Bulgarians got 462km/h at sea level with 760CV or 835CV engine power output.

It think that says 920 mmHg which is 1.21 ata / 36Hg

But is that nominal power or take off power for HS.12ycrs?

Seems the engine is running at full boost below 3.000 m (915/920 mm Hg) but don't turns at normal RPM ... Fixed pitch propeller ?

Shortround6 · Jul 20, 2024

Bretoal2 said:
Seems the engine is running at full boost below 3.000 m (915/920 mm Hg) but don't turns at normal RPM ... Fixed pitch propeller ?

You may have hit the nail on the head.

Bretoal2 · Jul 20, 2024

Shortround6 said:
You may have hit the nail on the head.

View attachment 789813

Thanks. I think this is a good illustration !

For Laurélix : with a fixed pitch propeller, you can't have maximum efficiency both at 0 m. and at rated altitude. You must choose.... (and if you choose ground settings, you can expect overrunning at altitude !).

Laurelix · Jul 20, 2024

Note:
HS.12ydrs is the same as HS.12Ycrs
Only difference is that Ycrs has motor cannon

HS.12ydrs1 and HS.12Ycrs1 are different to what B.135 has

It says
Nominal is 880 mmHg
Take Off Power is 960mm Hg

But the Bulgarian speed tests specifies 920 mmHg

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