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I propose a new topic to regroup information about French AFVs.

 

Days after days, information is overwhelmed under the inflow of photos about anything and everything.

It can be interesting to try to have dedicated topics to ease the quality of exchanges. 

 

So, if you have already posted interesting photos, documentations and view about French AFVs, you can quote them here. 

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This catalog shows the gap between companies proposals and the real Army purchase policy. For instance, we have been suffering from decades a deep lack of armored maintenance and repair vehicles in spite of there availability. 

 

Don’t know if it was already shown, the Leclerc T40 NEXTER proposal. 

VFa5oEZ.jpg

It was made as a first entry capable ISTAR platform. 

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On 4/20/2018 at 2:31 PM, Alzoc said:

 

Might as well repost this from the AW forum.

(Thanks @Laviduce for taking the time to incorporate the label in English directly)

The translations I did back then were quite literal since I'm not really a mechanics guy, so it may sound awkward.

Scans comes mainly from 2 books I have.

 

  Reveal hidden contents

 

V8X Hyperbar and the ESM500 gearbox:

 

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Principle scheme of the engine:

 

1) Autoadaptation valve of the turbine
2) Discharge valve
3) Turbine
4) Compressor
5) Air intake regulation valve (secondary combustion chamber)
6) Secondary combustion chamber
7) Cooling unit of air intake

8 Ignition

 

  Reveal hidden contents

 

Kinematic chain:

Didn't tried to translate that one since I'm not too good are reading this kind of diagram.

Ask if you need me translate something in particular.

  Reveal hidden contents

 

 

On 4/20/2018 at 10:54 PM, Walter_Sobchak said:

 

My Dad got to see the French engine in action back in the 90's. He said it was pretty insane how quickly it got up to full power.  

 

 

So what exactly is the design rationale behind the hyperbar engine?  From the Swedish MBT tests it seemed that the Hyperbar wasn't very efficient.  If I recall correctly, the Leclerc had even worse mileage than the Abrams.  Is the advantage that it revs up quickly and gives the tank good start/stop performance?

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6 minutes ago, Collimatrix said:

 

 

 

So what exactly is the design rationale behind the hyperbar engine?  From the Swedish MBT tests it seemed that the Hyperbar wasn't very efficient.  If I recall correctly, the Leclerc had even worse mileage than the Abrams.  Is the advantage that it revs up quickly and gives the tank good start/stop performance?

 

Just last week I was talking to my dad about this engine.  His memory is crap these days but he still remembers work stuff pretty well.  Back in the 90's he was in France and got to see a demonstration of this engine.  He said it was awesome to see it go from 0 to 1500 HP in "2 seconds".  I don't know if that's the actual time it takes, but that's how he describes it.  For sake of reference, I asked him how long it takes an AVDS-1790 (M60 tank engine) to go from 0 to full power (750HP), he said 17 seconds.  Again, no idea if these figures are correct, but that's how he described it. 

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32 minutes ago, Collimatrix said:

So what exactly is the design rationale behind the hyperbar engine?  From the Swedish MBT tests it seemed that the Hyperbar wasn't very efficient.  If I recall correctly, the Leclerc had even worse mileage than the Abrams.  Is the advantage that it revs up quickly and gives the tank good start/stop performance?

 

It's more or less an hybrid between a turbine engine and a classic diesel.

As far as I understand, the exhaust gas are reheated with a secondary combustion, goes through a turbine which drive a compressor increasing the admission pressure in the diesel. Basically it's a turbo that double as the APU.

 

The goal was to have most of the power available as soon as possible (0-32 km/h in 5s), just like a turbine but with a slightly lower fuel consumption than a turbine (actually I think that the Leclerc's consumption falls in between the M1 and the Leo 2).

 

The acceleration can be seen nicely in this video.

 

I'll re-read tonight to get back some figures, but as you said the engines had a lot of teething problems which showed during the Swedish trial.

 

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18 minutes ago, Alzoc said:

 

I'll re-read tonight to get back some figures, but as you said the engines had a lot of teething problems which showed during the Swedish trial.

 

In the case of the Swedish trials there are quite some infomations to put together in order to understand what happenned there (or could happened).

First the tanks used there, are the two first productions tanks (batch 1). These tanks were made as the production lines were being qualified in order to mass produce. The "activation" of those tanks were made at Satory workshop in order to  have a decent QA.

Second, those tanks were in the UAE right before the Swedish trials, they performed endurance tests in desertic conditions without problems (~ 800km). Both Giat Industries and the "customer" fired the tanks day and night with satisfying results.


Third, S1 tanks (at least the first two batches) were known for their engine unreliabilities. Those were a combinaison of multiple sensors that either put the engine in damage control mod (an iron filling sensor in the engine block) or induced an inadequate air pressure in the engine leading to surging (an air temperature sensor). The iron filling sensor was purely removed on later batches due to its uselessness. The air temperature sensor reliability was enhanced.

Fourth, from what I heard, the swedish crew sent to train on the Leclerc arrived in winter 1992 where the others arrived during summer 1992. I believe this is linked to the fact that the trials in the UAE were in progress during the summer. But what about the level of proficiency of the crew?

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1 hour ago, Alzoc said:

 

It's more or less an hybrid between a turbine engine and a classic diesel.

As far as I understand, the exhaust gas are reheated with a secondary combustion, goes through a turbine which drive a compressor increasing the admission pressure in the diesel. Basically it's a turbo that double as the APU.

 

The goal was to have most of the power available as soon as possible (0-32 km/h in 5s), just like a turbine but with a slightly lower fuel consumption than a turbine (actually I think that the Leclerc's consumption falls in between the M1 and the Leo 2).

 

The acceleration can be seen nicely in this video.

 

I'll re-read tonight to get back some figures, but as you said the engines had a lot of teething problems which showed during the Swedish trial.

 

148L/10Km for M1A2.

138L/10Km for Leclerc.
72L/10Km for Leopard 2.

 

 

Source:
http://www.ointres.se/projekt_stridsvagn_ny.htm

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So various figures.

 

Autonomy:

 

150 km on road/dry dirt at 50 km/h : Fuel consumption of 200L (2 external fuel drums)

450 km on road/dry dirt at 50 km/h with the internal fuel (1300L)

Total refuelling time: 10 minutes

 

Engine power repartition:

 

Gross: 1500 hp

Forced air intake: 200 hp

APU (turret, FCS, NBC, air-conditioning): 27 hp

Lubrication pumps: 80 hp

Heat loss through mechanical friction: 50 hp

Which leave about 1100 hp available for the propulsion itself.

 

Engine:

 

Diesel: 4 times, 8 cylinders V shaped at 90°

Overfeed rate (turbo): 7,5

Volume: 16,47 L

Compression rate: 7,8/1

Gross power: 1500 hp at 2500 rpm

Maximal torque: 4500 Nm at 2000 rpm

weight: 2100 kg

Total volume: 1,87 m3

 

 

Turbine: TM 307B

Use: Turbo and driving a 9kW generator (there is another one of 20 kW normally driven by the diesel), and heating the engine when it's too cold.

 

Transmission:

 

ESM500 automatic

Direction: hydrostatic 1200 hp

Braking: hydrokinetic (?)

Gears: 5 fwd 2 rwd

 

General performances:

 

Max speed: 72 km/h

Max reverse speed: 38 km/h

0-32 km/h: 5,5 s (and not 5 as said previously apparently)

 

 

 

 

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  • 2 weeks later...
On 4/24/2018 at 5:29 PM, Walter_Sobchak said:

 

Just last week I was talking to my dad about this engine.  His memory is crap these days but he still remembers work stuff pretty well.  Back in the 90's he was in France and got to see a demonstration of this engine.  He said it was awesome to see it go from 0 to 1500 HP in "2 seconds".  I don't know if that's the actual time it takes, but that's how he describes it.  For sake of reference, I asked him how long it takes an AVDS-1790 (M60 tank engine) to go from 0 to full power (750HP), he said 17 seconds.  Again, no idea if these figures are correct, but that's how he described it. 

Just out of curiosity, doesn't hybrids with electrically assisted turbochargers make the hyberbar engine obsolete? 

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56 minutes ago, Xoon said:

Just out of curiosity, doesn't hybrids with electrically assisted turbochargers make the hyberbar engine obsolete? 

 

Depends on what you mean by hybrids with electrically assisted turbochargers.

If it is what is described on the fig 1 of that paper then it's simply an hyperbar engine with an added battery (the turbine already serve as an APU in the Leclerc so there is no reason that would forbid turning the generator into a motor if needed).

 

Spoiler

3qk8mC.jpg

 

If we are talking about adding electrical engine to drive the tracks at low speed while the diesel gets up to speed, then yes the turbine turbocharger becomes useless since an electrical engine will gives an even better acceleration.

 

Edit: Maybe you were thinking about removing the turbine completely and drive the compressor of the turbo with an electrical engine only. It is also a possibility.

 

Where there is a question however is in how compact the whole powerpack will be. One of the big advantage of the hyperbar engine is it's insane power density.

Given the size of current battery I think that's it's unlikely that an hybrid engine (Diesel-electric) plus it's battery would be more compact than an hyperbar engine (especially when considering than in the V8X the turbine is the APU and thus doesn't necessitate to add one).

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