HS.12Z-17 Engine

Laurelix

Airman 1st Class
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Jun 13, 2016
It was used on the Yugoslav S-49C fighters and I literally cannot find any information regarding the power curve of the engine.

What it’s nominal power was at Sea Level, what the power was at over post at Sea level and the critical alt power.

All I can find it that the engine is rated 1480 horsepower
 

swampyankee

Chief Master Sergeant
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Jun 25, 2013
Where have you looked?

One very likely explanation is that the information you're looking for has not been digitized. It may be in an old issue of Jane's, or perhaps in a filing cabinet in the archives of Safran (the life history was Hispano-Suiza -> SNECMA -> Safran) or in those of IVECO (the Spanish side of Hispano-Suiza's engine business were sold to Enasa, which then was absorbed by IVECO). Another place the information may sit is the Museum of Aviation in Belgrade. It's also possible the same engine was used on other aircraft (according to Wikipedia it was), and there may be information in these companies' (or their successors') archives. The problem with these sources is that you may need physical access to the archives, which will be tough in these days of social distancing, or their may be quite significant fees to pay to the archive for the documents to be found, copied, and sent out. They're also not likely to do this now, as the archivist and archive staff are probably limited to one or two people trying to keep the mice out.
 

Laurelix

Airman 1st Class
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Jun 13, 2016
So far I came across
1800hp Take Off
1500hp at 2500m
 

Shortround6

Major General
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Information from "AIrcraft Engines of the World" 1953 edition, by Wilkinson

Listed under France.

take-off........................1300hp/2650rpm/46.6in (930mm)+3.3lbs
Military.........................1500hp/2700rpm/21,000ft boost not given.
Normal..........................1500hp/2400rpm/20,700ft boost not given.
Cruising.........................820hp/1950rpm/20,000ft boost not given.

there are no other Hispano-Suiza 12Z engines listed in this edition. This entry is listed as the 12Z-17. it is supposed to use 100/130 fuel. Single speed supercharger (8.82 gears) and direct fuel injection.

The 1949 edition lists a 12Z-1 and no other models, The -1 is listed as having a two speed supercharger (single stage) but the same fuel injection as the -17.

At the moment I have no idea what happened to any intervening models/versions.
 

Shortround6

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That is the information I have, I don't know how accurate it is, some of the 1940s French power figures seem a bit optimistic at times?
But the -17 engine may have been dialed back a bit, the 12Z-1 engine was rated at 2800rpm for take-off and military power and 2600rpm for "normal".
 

Bretoal2

Airman
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May 18, 2013
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Between 1942 and 1944, due to the occupation of France, development of the 12Z continued in Spain (Barcelona).

The engine was then announced for 1,800 hp at takeoff, 1,500 hp at 2,500 m. and 1,300 hp at 6,500 m, with a single-stage, 2-speed supercharger.

In 1945, development resumed in France and, initially, the same performances were announced. But these will never be achieved and 2-speed supercharger was abandonned. After type-tests, the 12Z-15 and 16 as well as 12Z-17 and 18 were approved with the performances given by these tables (dated December 31, 1947).

The 12 Z 17 & 18 were identical but turned in opposite directions. The 12 Z 15/16 were 17/18 specially designed to be mounted in tandem on the Arsenal VB10 aircraft.

All had a single speed Turbomeca (Planiol-Szydlowski) supercharger, ratio 8.31 / 1.
 

Laurelix

Airman 1st Class
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Jun 13, 2016
View attachment 578947 View attachment 578948 Between 1942 and 1944, due to the occupation of France, development of the 12Z continued in Spain (Barcelona).

The engine was then announced for 1,800 hp at takeoff, 1,500 hp at 2,500 m. and 1,300 hp at 6,500 m, with a single-stage, 2-speed supercharger.

In 1945, development resumed in France and, initially, the same performances were announced. But these will never be achieved and 2-speed supercharger was abandonned. After type-tests, the 12Z-15 and 16 as well as 12Z-17 and 18 were approved with the performances given by these tables (dated December 31, 1947).

The 12 Z 17 & 18 were identical but turned in opposite directions. The 12 Z 15/16 were 17/18 specially designed to be mounted in tandem on the Arsenal VB10 aircraft.

All had a single speed Turbomeca (Planiol-Szydlowski) supercharger, ratio 8.31 / 1.
I kinda have tough time understanding the graph

So
1150hp at Sea Level (Military)
1480hp at Sea Level (WEP)

I know it’s not really WEP but you get what I mean. That’s all I can get from the graph.

whats decollage?
 

tomo pauk

Creator of Interesting Threads
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Decollage = take off
Surpuissance momentalle = short-term (emergency) power. It is NOT equivalent to WER, since it involved both over-revving and over-boosting; basically, equivalent to the German 'Notleistung' term.
Regime nominal - normal (power) setting.
Croissiere max. - maximum contiuous (power setting).

At Bretoal's graph, there is note 'vitesse d'avion nulle' = 'speed of aircraft = zero', ie. no ram.
 

Laurelix

Airman 1st Class
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95
Jun 13, 2016
Decollage = take off
Surpuissance momentalle = short-term (emergency) power. It is NOT equivalent to WER, since it involved both over-revving and over-boosting; basically, equivalent to the German 'Notleistung' term.
Regime nominal - normal (power) setting.
Croissiere max. - maximum contiuous (power setting).

At Bretoal's graph, there is note 'vitesse d'avion nulle' = 'speed of aircraft = zero', ie. no ram.
How come the take off power works up until 7000 metres
 

Shortround6

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WEP is an American term and it is not going to translate well.
War Emergency Power and most translator programs are going to have trouble with that.


The Nominal power is most likely max continuous. Pre-war and pre variable pitch propellers that was an important rating. Less so with variable pitch props but many countries may have kept old terms in hopes of avoiding confusion. In the 1930s many engines were called or listed by their max continuous power as ti was the power that could be used in flight with no time limit even it it sucked gas like crazy.

The term Military Power is also American. And I mean American and not English. In America military power was the rating that could be used for a few minutes, usually 5 minutes but sometimes 15, however, to get such a rating the engine had to go through a type test of 150 hours (other countries had different requirements, usually a 100 hour test) amd of those 150 hours ten of them (?) had to be at the military rating. It was up to the manufacturer as to whether to go for the 10 hours in one continuous run or to break it into 120 five minute intervals separated by five minute intervals at idle. Again, other countries had different requirements.
Commercial engines had to do 10 hours at take-off power the same way, commercial engines never got a "military" rating which generally was done with a simulate atmosphere. that is the engine was supplied air at a density and temperature equivalent to the altitude the military wanted to use the engine at.


Tomo has given us some good translations to which I would add that Military power was allowed to be used multiple times in one flight as long as each use was under the time limit. The use of military power required NO notification to ground crew or squadron technical officer. In contrast EACH and EVERY use of WEP required not only verbal notification to ground crew and/or squadron technical officer but notes in the aircrafts log book. It was up to the ground crew and technical officer as to what extra maintenance procedures were need for each use of WEP. These had to be in accordance with recommendations and requirements from above and modified by experience and/or equipment/parts on hand.
Depending on the engine this might mean a quick look at the oil for metal particles and more frequent spark plug changes to oil being pulled and sent for analysis and on some engines either both or one set of plugs had to be pulled and at least cleaned every time WEP was used.

I would note that the British used different ratings than the Americans and the French or Spanish ratings might be a bit closer to the English.

The British used a 30 minute rating for climb or max continuous and then dropped to max rich mixture cruise and then max lean mixture cruise.
The Americans never used a 30 minute rating.
The engine in question is fuel injected and doesn't seem to offer much in the way of reich or lean fuel consumption.
 

Bretoal2

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May 18, 2013
I would guess that the "take-off" power is somewhat equivalent to the US MIlitary power.

Some engines were limited to 1-5 minutes at take-off power, many early WW II American engines were operated at the take-off power settings for their military rating (same rpm and manifold pressure)

The "surpuissance momentanée" (meaning, as understood by Tomo Pauk, over-revving + over-boosting) is said to be allowed 2 minutes max.

And "décollage" (TO power) must last "a short time".

The Hispano 12 Z was a very strange engine, based on a curious idea ... (see here VK 107 thread : Klimov VK-107 - help needed ). In fact, it never ran in a satisfying manner.

Note the very particular curves, where power is almost unchanged between SL and critical altitude. I think this was due to the (very particular too !) Turbomeca supercharger, identical to 12 Y's, but modified and very improved.
 

tomo pauk

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Note the very particular curves, where power is almost unchanged between SL and critical altitude. I think this was due to the (very particular too !) Turbomeca supercharger, identical to 12 Y's, but modified and very improved.

I've posted a bit about that S/C here: link
 

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