Honda Power Unit Hardware & Software

[Dr. Acula]

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

I don't think this really is the issue, because basically every turbocharger goes supersonic with its outer areas at full throttle.
We can calculate what would be the allowable diameter at 125000 rpm to stay subsonic, it's fairly easy. At least i think i got it right or its gonna be really embarassing...



So a maximum diameter of basically 5cm would be possible...I don't think any F1 manufacturer runs a turbo that small.

It's a common misconception that the blades of the compressor or fan needs to stay subsonic. If you look up the max rpm values for the fan of modern turbofan engines for instance, you will see they go far into the supersonic speed regime with their outer circumferential speed.
What is importent though is that the airflow stays subsonic, but the speed of the airflow does not perfectly corrolate with the speed of the blades.

[PlatinumZealot]

They ran less wing and Max had DRS both times he was behind Lewis.

Ho pin Tung says a smaller turbo is an advantage at altitude.

Sieper Ho Pin Tung isn't all knowing ... so don't believe every word he says and some parts he can't know because he ain't driving F1 which has completly different intakes as WEC or any other categorie he drives.

yes his knowledge is good for general analisys, but indept analisys is not his strong point

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

Mercedes compressor would be still dynamically proportional to the honda compressor even if the altitude changes.

[PlatinumZealot]

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

I don't think this really is the issue, because basically every turbocharger goes supersonic with its outer areas at full throttle.
We can calculate what would be the allowable diameter at 125000 rpm to stay subsonic, it's fairly easy. At least i think i got it right or its gonna be really embarassing...



So a maximum diameter of basically 5cm would be possible...I don't think any F1 manufacturer runs a turbo that small.

It's a common misconception that the blades of the compressor or fan needs to stay subsonic. If you look up the max rpm values for the fan of modern turbofan engines for instance, you will see they go far into the supersonic speed regime with their outer circumferential speed.
What is importent though is that the airflow stays subsonic, but the speed of the airflow does not perfectly corrolate with the speed of the blades.

Speed of sound increases with temperature and density!

[Capharol]

They ran less wing and Max had DRS both times he was behind Lewis.

Ho pin Tung says a smaller turbo is an advantage at altitude.

Sieper Ho Pin Tung isn't all knowing ... so don't believe every word he says and some parts he can't know because he ain't driving F1 which has completly different intakes as WEC or any other categorie he drives.

yes his knowledge is good for general analisys, but indept analisys is not his strong point

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

thanks subcritical but that is a bit out of my league

[Dr. Acula]

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

I don't think this really is the issue, because basically every turbocharger goes supersonic with its outer areas at full throttle.
We can calculate what would be the allowable diameter at 125000 rpm to stay subsonic, it's fairly easy. At least i think i got it right or its gonna be really embarassing...



So a maximum diameter of basically 5cm would be possible...I don't think any F1 manufacturer runs a turbo that small.

It's a common misconception that the blades of the compressor or fan needs to stay subsonic. If you look up the max rpm values for the fan of modern turbofan engines for instance, you will see they go far into the supersonic speed regime with their outer circumferential speed.
What is importent though is that the airflow stays subsonic, but the speed of the airflow does not perfectly corrolate with the speed of the blades.

Speed of sound increases with temperature and density!

Yes, but not with the rate you would need to compensate for the probable size of a F1 compressor. For instance if you compress the air to 3.5 bar absolute pressure at a temperature of 146°C which would be about the outlet temperature reached by the the compression alone if the inlet temperature was about 20°C you still have only a sonicspeed of about 460m/s.

[trinidefender]

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

I don't think this really is the issue, because basically every turbocharger goes supersonic with its outer areas at full throttle.
We can calculate what would be the allowable diameter at 125000 rpm to stay subsonic, it's fairly easy. At least i think i got it right or its gonna be really embarassing...



So a maximum diameter of basically 5cm would be possible...I don't think any F1 manufacturer runs a turbo that small.

It's a common misconception that the blades of the compressor or fan needs to stay subsonic. If you look up the max rpm values for the fan of modern turbofan engines for instance, you will see they go far into the supersonic speed regime with their outer circumferential speed.
What is importent though is that the airflow stays subsonic, but the speed of the airflow does not perfectly corrolate with the speed of the blades.

Speed of sound increases with temperature and density!

In a centrifugal compressor, very little of the pressure increase happens from the blades themselves. The blades serve to increase the velocity of the airflow and the pressure increase happens in the diffuser as the gas slows down increasing pressure. Therefore at the tips the pressure of the gas is probably fairly close to ambient.

[PlatinumZealot]

460m/s is a good deal greater than 330m/s.

Anyway. Note that the air is accelerated by the compressor wheel before it reaches its tip. Also the air inside the volute is already moving at some speed. So in relative terms the compressor wheel needs to spin much faster to move at the speed of sound relative to air in the volute. Correct me if i am wrong here.

[gruntguru]

There is much mention of turbocharger "size". Bear in mind that for the compressor alone there are two independent dimensions governing its performance.

The first is the outer diameter of the wheel or "tip diameter". This dimension will determine the pressure ratio (ie boost limit) the compressor is capable of (at a given shaft speed).

The other "dimension" is the flow cross-section area - most easily measured at the circular entry ie the diameter of the "inducer" part of the wheel. This dimension determines the flow limit (ie horsepower limit) of the compressor.

These two "dimensions" are varied independently when designing a compressor, depending on the boost and airflow required. A similar process applies to the turbine end of the turbocharger.

[godlameroso]

Something to consider when discussing compressor sizing, and this is reading between the lines on my side. Generally a larger diameter compressor would give you more flow. But there are some limits other than speed/size to consider. If the Merc have a larger diameter compressor than Honda they very well may not be able to reach the max allowable RPM due to speed of sound limitations at the compressor tips (exceeding mach 1 in a compressor means an entirely different design). If the Honda have a smaller compressor they may be able to reach a higher RPM (closer to max allowed RPM) at high altitude density tracks and compensate for the density difference where the Merc or anyone with a larger diameter compressor cannot.

I don't think this really is the issue, because basically every turbocharger goes supersonic with its outer areas at full throttle.
We can calculate what would be the allowable diameter at 125000 rpm to stay subsonic, it's fairly easy. At least i think i got it right or its gonna be really embarassing...



So a maximum diameter of basically 5cm would be possible...I don't think any F1 manufacturer runs a turbo that small.

It's a common misconception that the blades of the compressor or fan needs to stay subsonic. If you look up the max rpm values for the fan of modern turbofan engines for instance, you will see they go far into the supersonic speed regime with their outer circumferential speed.
What is importent though is that the airflow stays subsonic, but the speed of the airflow does not perfectly corrolate with the speed of the blades.

Turbo airflow is very much supersonic in regions of the blades. Turbos operate in a regime where air is a compressible fluid after all.

[McMika98]

Honda should have two versions of turbo for next year, compact for high altitude circuits and larger for normal circuits. Vettel could not get past Albon with the slipstream, the engine was quite something.

[Big Tea]

Honda should have two versions of turbo for next year, compact for high altitude circuits and larger for normal circuits. Vettel could not get past Albon with the slipstream, the engine was quite something.

It would count as one more 'unit' used though.

[etusch]

Honda should have two versions of turbo for next year, compact for high altitude circuits and larger for normal circuits. Vettel could not get past Albon with the slipstream, the engine was quite something.

You are the one who must replace Helmut Marko as adviser but not only for Redbull, for Honda as well

[PhillipM]

I think it's already pretty likely that teams have revisions like that already in the PU plan - I'd be amazed if everyone didn't.

[McMika98]

Honda should have two versions of turbo for next year, compact for high altitude circuits and larger for normal circuits. Vettel could not get past Albon with the slipstream, the engine was quite something.

It would count as one more 'unit' used though.

They are allowed 3 turbos per year, and Honda never had issues woth the turbo so far.

[Big Tea]

Honda should have two versions of turbo for next year, compact for high altitude circuits and larger for normal circuits. Vettel could not get past Albon with the slipstream, the engine was quite something.

It would count as one more 'unit' used though.

They are allowed 3 turbos per year, and Honda never had issues woth the turbo so far.

This would leave them with just the 2 though, and only one to develop before fitting.