HS.12Z-89ter

[Laurelix]

Are there 2 different versions of the engine?

Because D.520Z with this engine achieved its top speed at 9150m with the engine doing 1300hp at 7500m

However D.524 and VG.39 are said to have this engine and yet their top speed is achieved only at 6000-7000m

another weird thing is how it has less horsepower at take off power at SL than its nominal power

 

[tomo pauk]

Are there 2 different versions of the engine?
Because D.520Z with this engine achieved its top speed at 9150m with the engine doing 1300hp at 7500m
However D.524 and VG.39 are said to have this engine and yet their top speed is achieved only at 6000-7000m
another weird thing is how it has less horsepower at take off power at SL than its nominal power

With 1-speed superchargers, it is often the case that nominal power at altitude is greater than take-off power.
BTW - perhaps it might be a good idea to post the original table(s), so nothing could get lost in translation.

 

[Laurelix]

With 1-speed superchargers, it is often the case that nominal power at altitude is greater than take-off power.
BTW - perhaps it might be a good idea to post the original table(s), so nothing could get lost in translation.

I mean nominal vs take off at Sea Level

 

[tomo pauk]

I mean nominal vs take off at Sea Level

I'd really love to see the original table.

 

[Laurelix]

I'd really love to see the original table.

I don't have the original table for that engine

 

[Laurelix]

D.520Z is said to use the 89ter engine (1300hp at 7500m)
It did

478km/h at SL
562km/h at 4000m
659km/h at 9150m

——

D.524 and VG.39 are said to have the 89ter engine as well but the power curve is much different to D.520Z. Their engine definitely doesn't have 1300hp at 7500m

Although they state 89ter for VG.39 and D.524 it's as if they actually had HS.12Y-51 because the power curve seems to match the D.551

 

[Bretoal2]

D 520 Z / SE 520 Z never flew, all datas are estimates.

As for M 520 T...

 

[Bretoal2]

The announced datas fot the Hispano-Suiza 12 Z were very changing between 1938 and 1946. In fact, this engine, with 1-speed or 2-speed supercharger, with carburetters or direct injection, never realised the anticipated performances.

The only "almost reliable" version was 12 Z-15 16 17 18. I gave their table recently.

The true story of this engine is still to be written !

 

[Laurelix]

The announced datas fot the Hispano-Suiza 12 Z were very changing between 1938 and 1946. In fact, this engine, with 1-speed or 2-speed supercharger, with carburetters or direct injection, never realised the anticipated performances.

The only "almost reliable" version was 12 Z-15 16 17 18. I gave their table recently.

The true story of this engine is still to be written !

VG.39 did fly and achieved 625km/h at 5800m

 

[Shortround6]

I am not sure what the puzzle is about the engine making less power at sea level.
The Merlin III made 880hp at sea level and 1030hp at 16,250ft (4953 meters) with no ram on 87 octane fuel.
This was perfectly normal with single speed superchargers.


Chart is suspect as soon as it says WEP unless that is a translation error.
There is no reason the French would be using an American term/rating from 1942 in 1939/40.
There is also an obvious misprint/typo in the so called WEP manifold pressure sea level/take-off line. 1500mm hg really????

 

[Bretoal2]

I am not sure what the puzzle is about the engine making less power at sea level.
The Merlin III made 880hp at sea level and 1030hp at 16,250ft (4953 meters) with no ram on 87 octane fuel.
This was perfectly normal with single speed superchargers.


Chart is suspect as soon as it says WEP unless that is a translation error.
There is no reason the French would be using an American term/rating from 1942 in 1939/40.
There is also an obvious misprint/typo in the so called WEP manifold pressure sea level/take-off line. 1500mm hg really????

Obviously 1050 mm Hg.

 

[Bretoal2]

VG.39 did fly and achieved 625km/h at 5800m

Yes but with an unreliable prototype engine. In that time, the 12Z 89 was said to give 1.200 cv.

 

[Laurelix]

So what's the power curve with 1200CV setting?

 

[Bretoal2]

Above, Arsenal VG-33; below Arsenal VG-39

The VG-39 engine is a problem for me.

The spacing of the exhaust pipes shows that it is indeed the 12 Z. But we also see that the air intake remained under the engine, so it is not a Planiol-Szydlowski supercharged 12Z, but one of the first models with an original Hispano-Suiza supercharger (the P / S had two lateral air intakes, the original HS only one lower – see VG 33 with its 12 Y-31).

There is therefore very little chance that the engine actually mounted on the VG-39 would have given the power and critical altitude indicated in the first message. And it is impossible to calculate any power curve interpolated from the 12 Z-17 I gave in another post, as the original HS supercharger lacked the « special » features of the P/S one, giving an almost « flat « curve from SL to critical altitude.

Note also the very thick traces of smoke along cowling and fuselage, showing how bad and rough the 12Z engine worked !

 

[Laurelix]

View attachment 580083

Above, Arsenal VG-33; below Arsenal VG-39

The VG-39 engine is a problem for me.

The spacing of the exhaust pipes shows that it is indeed the 12 Z. But we also see that the air intake remained under the engine, so it is not a Planiol-Szydlowski supercharged 12Z, but one of the first models with an original Hispano-Suiza supercharger (the P / S had two lateral air intakes, the original HS only one lower – see VG 33 with its 12 Y-31).

There is therefore very little chance that the engine actually mounted on the VG-39 would have given the power and critical altitude indicated in the first message. And it is impossible to calculate any power curve interpolated from the 12 Z-17 I gave in another post, as the original HS supercharger lacked the « special » features of the P/S one, giving an almost « flat « curve from SL to critical altitude.

Note also the very thick traces of smoke along cowling and fuselage, showing how bad and rough the 12Z engine worked !

there is one option tho. We could work backwards. it will give us rough estimate.

D.520 with 850hp at SL at nominal power gave the plane 425-430km/h at SL.

D.524 with this HS-12Z engine could do 467km/h at SL.
467 / 425 = 1.0988
Cube it = 1.3267

850 x 1.3267 = 1127hp at SL nominal

467 and 430 doing the same process gives us 1088hp at nominal power which matches the data for SL output that I posted above.
It looks like 1088hp at SL is the nominal and 1160hp is the Take Off.

Since French class the engine output based on the output of the engine at established altitude, we can conclude it has 1200 power at that altitude. Since D.524 has top speed at 7000m but VG.39 has it at 6000m could mean that it's due to them getting different ram effect and the optimal alt should be roughly 5400m. Or maybe the supercharger worked more effectively on D.524 which could also mean it had more power at 5800m than VG.39 when it flew at 5800m, which could further mean its SL speed of 482 could be actually higher

D.524 achieved 467 at SL and 610 at 6000m

VG.39 is state at 625 at 5800m would mean a SL speed would average at 482.

VG.33 With 760 power achieved 442km/h at SL. With 1088 we would expect 498, however VG.39 is most likely more draggy.

 

[Bretoal2]

Neither the D 524, the D/SE 520 Z, nor the M 520 T have ever flown.

It is a risky exercise to compare estimated data with actual data observed during flight tests !

And above all I do not see the purpose.

The additional intake pressure linked to RAM effect is very random, you can't give a general rule - the D 520 prototypes had problems with the design of air intakes, and on some production aircraft defectuous sealing of the intake circuit produced some critical altitude losses.

Finally, the greatest drag of the VG-39, assuming that it exists, can be explained by an increased mass (modified and larger wing with more armament) and a larger radiator.

 

[Laurelix]

Neither the D 524, the D/SE 520 Z, nor the M 520 T have ever flown.

It is a risky exercise to compare estimated data with actual data observed during flight tests !

And above all I do not see the purpose.

The additional intake pressure linked to RAM effect is very random, you can't give a general rule - the D 520 prototypes had problems with the design of air intakes, and on some production aircraft defectuous sealing of the intake circuit produced some critical altitude losses.

Finally, the greatest drag of the VG-39, assuming that it exists, can be explained by an increased mass (modified and larger wing with more armament) and a larger radiator.

Ah ok but is there a chance D.524 had different supercharger than VG.39?

 

[Bretoal2]

The definition of 12 Z was very vague and changing in the spring of 1940 - as shown by the names HS 12 Z bis or 12 Z ter which were totally unusual for this manufacturer (variants with carburettors, injection, HS or SP supercharger, 1 or 2 speeds...).

All engines produced at that time were prototypes. And they did not ran very well.... (see exhaust smokes as pointed).

There is therefore a maximum chance that they have had different performances !

 

[elbmc1969]

Are there 2 different versions of the engine?

Because D.520Z with this engine achieved its top speed at 9150m with the engine doing 1300hp at 7500m

However D.524 and VG.39 are said to have this engine and yet their top speed is achieved only at 6000-7000m

Where did you get this table?

We don't know if all of the data in the table is from H-S, so we don't know the test parameters. For example, the French and the U.S. measured pressure from supercharger compressors at different places. The bench test setup for the -89 may have been different; H-S's loss of facilities in Paris may have cost them test equipment.

All engines produced at that time were prototypes. ...

There is therefore a maximum chance that they have had different performances !

This.