## Honda Power Unit Hardware & Software

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Dr. Acula
43
Joined: Sat Jul 28, 2018 12:23 pm

### Re: Honda Power Unit Hardware & Software

subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
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...

$\frac{330m/s*60}{125000rpm*\pi}=0.0504m$

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
361
Joined: Thu Jun 12, 2008 2:45 am

### Re: Honda Power Unit Hardware & Software

subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
Capharol wrote:
Mon Nov 18, 2019 12:44 pm
Sieper wrote:
Mon Nov 18, 2019 12:22 am

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.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

PlatinumZealot
361
Joined: Thu Jun 12, 2008 2:45 am

### Re: Honda Power Unit Hardware & Software

Dr. Acula wrote:
Mon Nov 18, 2019 4:38 pm
subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
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...

$\frac{330m/s*60}{125000rpm*\pi}=0.0504m$

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!
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

Capharol
48
Joined: Sun Nov 04, 2018 4:06 pm

### Re: Honda Power Unit Hardware & Software

subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
Capharol wrote:
Mon Nov 18, 2019 12:44 pm
Sieper wrote:
Mon Nov 18, 2019 12:22 am

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
Strive for continuous improvement, instead of perfection.
"Most people seem to turn off their brain when they turn on the computer and log in to social media."

Dr. Acula
43
Joined: Sat Jul 28, 2018 12:23 pm

### Re: Honda Power Unit Hardware & Software

PlatinumZealot wrote:
Mon Nov 18, 2019 5:11 pm
Dr. Acula wrote:
Mon Nov 18, 2019 4:38 pm
subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
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...

$\frac{330m/s*60}{125000rpm*\pi}=0.0504m$

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
316
Joined: Fri Apr 19, 2013 7:37 pm

### Re: Honda Power Unit Hardware & Software

PlatinumZealot wrote:
Mon Nov 18, 2019 5:11 pm
Dr. Acula wrote:
Mon Nov 18, 2019 4:38 pm
subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
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...

$\frac{330m/s*60}{125000rpm*\pi}=0.0504m$

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
361
Joined: Thu Jun 12, 2008 2:45 am

### Re: Honda Power Unit Hardware & Software

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.
"The true champions are also great men. They are capable of making difficult decisions, of admitting their mistakes and of pushing harder than before when they get up from a fall."

- Ferrari chairman Sergio Marchionne

gruntguru
438
Joined: Sat Feb 21, 2009 6:43 am

### Re: Honda Power Unit Hardware & Software

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.
je suis charlie

godlameroso
355
Joined: Sat Jan 16, 2010 8:27 pm
Location: Miami FL

### Re: Honda Power Unit Hardware & Software

Dr. Acula wrote:
Mon Nov 18, 2019 4:38 pm
subcritical71 wrote:
Mon Nov 18, 2019 3:26 pm
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...

$\frac{330m/s*60}{125000rpm*\pi}=0.0504m$

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.
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee

McMika98
-36
Joined: Sat Feb 18, 2017 9:40 pm

### Re: Honda Power Unit Hardware & Software

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
69
Joined: Sun Dec 24, 2017 7:57 pm

### Re: Honda Power Unit Hardware & Software

McMika98 wrote:
Tue Nov 19, 2019 8:47 pm
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.
One test is worth a thousand expert opinions

etusch
93
Joined: Sun Feb 22, 2009 10:09 pm
Location: Turkey

### Re: Honda Power Unit Hardware & Software

McMika98 wrote:
Tue Nov 19, 2019 8:47 pm
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
317
Joined: Mon May 16, 2011 2:18 pm
Location: Over the road from Boothy...

### Re: Honda Power Unit Hardware & Software

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
-36
Joined: Sat Feb 18, 2017 9:40 pm

### Re: Honda Power Unit Hardware & Software

Big Tea wrote:
Tue Nov 19, 2019 8:50 pm
McMika98 wrote:
Tue Nov 19, 2019 8:47 pm
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
69
Joined: Sun Dec 24, 2017 7:57 pm

### Re: Honda Power Unit Hardware & Software

McMika98 wrote:
Wed Nov 20, 2019 10:12 pm
Big Tea wrote:
Tue Nov 19, 2019 8:50 pm
McMika98 wrote:
Tue Nov 19, 2019 8:47 pm
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.
One test is worth a thousand expert opinions