Mclaren MP4-31 Honda Speculation Thread

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Wazari
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Re: Mclaren MP4-31 Honda Speculation Thread

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bigblue wrote:One question that is not particularly specific to the new engine, and so may be answerable in general terms is : how did the issue from last year's engine not get picked-up in pre-season dyno testing ?

To a non-expert in engine design it would seem that such a fundamental issue should have been very apparent by simulating laps of various cicuits. The only thing I can think of, off the top of my head, is reliability issues meant running at less than previously dyno'd settings (lower turbocharger speed or something like that). Even that seems a bit odd, did in-car installation show up issues never seen before leading to having to reduce recovered energy ? Would love to know !

Of course if the nephew can't say, he can't say ... don't get him in trouble !
If you think about it, Honda had no race data going into 2015 for their PU. As others have mentioned, with the limited testing allowed, you commit to a certain concept, design and layout and then you are stuck with that PU for the whole season. Nothing can equal real track data and experience for the true test of your PU. You discover your flaws and you cannot make major changes during the season. Issues arise from races that you did not foresee in the dyno room. So it's very difficult to translate dyno testing results to real race situations without a real race benchmark. Now that Honda has a full season of race data with this PU, major improvements come much easier as trouble areas are now clearly defined. It's hard to explain but things change when you bolt a PU into a chassis. It's a marriage that many times is like a human marriage. Issues that were never anticipated arise or a much larger issue than originally thought. Nothing beats real race experience....nothing.
“If Honda does not race, there is no Honda.”

“Success represents the 1% of your work which results from the 99% that is called failure.”

-- Honda Soichiro

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mclaren111
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Re: Mclaren MP4-31 Honda Speculation Thread

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Thank you Wazari-san for all your efforts =D> :D =D>

hemichromis
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Re: Mclaren MP4-31 Honda Speculation Thread

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Hi Wazari,
Could you say if the compressor is still expected to be a small fast rotating one or is it nearly as big as the Mercedes one as Arai alluded to?

I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)

R_Redding
R_Redding
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Re: Mclaren MP4-31 Honda Speculation Thread

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hemichromis wrote: I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
Which would be illegal .

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FW17
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Re: Mclaren MP4-31 Honda Speculation Thread

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R_Redding wrote:
hemichromis wrote: I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
Which would be illegal .
Not really; MGUH speed is capped at 120,000 rpm but there can be fixed ratio gear between the MGUH and turbo shaft allowing the turbo to run at an unlimited speed.

hurril
hurril
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Re: Mclaren MP4-31 Honda Speculation Thread

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Are there benefits to running the turbine and compressor at a very high speed?

R_Redding
R_Redding
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WilliamsF1 wrote:
R_Redding wrote:
hemichromis wrote: I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
Which would be illegal .
Not really; MGUH speed is capped at 120,000 rpm but there can be fixed ratio gear between the MGUH and turbo shaft allowing the turbo to run at an unlimited speed.
Oops .. Quite right .. I hadn't had quite enough coffee when I typed that ..

btw.. is there any evidence that anyone does use a geared connection between the MGUH and turbine/compressor ?..

Rob

hemichromis
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Re: Mclaren MP4-31 Honda Speculation Thread

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WilliamsF1 wrote:
R_Redding wrote:
hemichromis wrote: I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
Which would be illegal .
Not really; MGUH speed is capped at 120,000 rpm but there can be fixed ratio gear between the MGUH and turbo shaft allowing the turbo to run at an unlimited speed.
The connection between the compressor and the MGUH can also be clutched but both these methods would take more space.
Very interested in what they do here if they are keeping their high rpm philosophy.

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Wazari
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Re: Mclaren MP4-31 Honda Speculation Thread

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hemichromis wrote:Hi Wazari,
Could you say if the compressor is still expected to be a small fast rotating one or is it nearly as big as the Mercedes one as Arai alluded to?

I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
My understanding is that both the compressor and turbine are completely new designs. I don't know if that means larger. IMO, it was the turbine area that was more of an issue than the compressor side. I don't think the turbine was providing enough "umph" to the compressor and ultimately the MGU-H unit.
“If Honda does not race, there is no Honda.”

“Success represents the 1% of your work which results from the 99% that is called failure.”

-- Honda Soichiro

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mikeerfol
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Re: Mclaren MP4-31 Honda Speculation Thread

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Wazari, do you know if the car will have 2 or 3 exhaust tailpipes?

hemichromis
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Re: Mclaren MP4-31 Honda Speculation Thread

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Wazari wrote:
hemichromis wrote:Hi Wazari,
Could you say if the compressor is still expected to be a small fast rotating one or is it nearly as big as the Mercedes one as Arai alluded to?

I'm hoping big as Mercedes but revving to 150,000rpm!!!! ;)
My understanding is that both the compressor and turbine are completely new designs. I don't know if that means larger. IMO, it was the turbine area that was more of an issue than the compressor side. I don't think the turbine was providing enough "umph" to the compressor and ultimately the MGU-H unit.
Sounds good as their is more space in the turbine area if, of course, bigger is better!

Arai did say in a BBC article that the compressor would be "more or less" the same size as the mercedes one.

DarkAlman
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Re: Mclaren MP4-31 Honda Speculation Thread

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I'm partly embarrassed to ask this because I need to ask an engineer about basic physics for a moment...

My understanding of the fundamental issue with the turbine:

A smaller turbine with less mass means less over all torque right?
power = RPM * torque
So to transfer the same amount of energy as a larger turbine to the MGU-H you need to spin the smaller Turbine at much higher RPM.

The upside is reduced size, and a smaller turbine with less mass is easy to spool up. But the downside is reliability?
High RPM requires greater lubrication, generates more heat and requires greater precision and higher quality parts to prevent failure?

And in addition to the RPM limit in the rules, I assume that maintaining the RPM of the turbine during low-exhaust periods is more difficult since the lower mass turbine has less momentum?

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Duke
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Re: Mclaren MP4-31 Honda Speculation Thread

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I believe that is correct - they couldn't get it working at the desired RPM which meant they would never have the power required to be competitive and compounded the issue of ERS recharge and using more fuel.

hemichromis
hemichromis
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Re: Mclaren MP4-31 Honda Speculation Thread

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DarkAlman wrote:I'm partly embarrassed to ask this because I need to ask an engineer about basic physics for a moment...

My understanding of the fundamental issue with the turbine:

A smaller turbine with less mass means less over all torque right?
power = RPM * torque
So to transfer the same amount of energy as a larger turbine to the MGU-H you need to spin the smaller Turbine at much higher RPM.

The upside is reduced size, and a smaller turbine with less mass is easy to spool up. But the downside is reliability?
High RPM requires greater lubrication, generates more heat and requires greater precision and higher quality parts to prevent failure?

And in addition to the RPM limit in the rules, I assume that maintaining the RPM of the turbine during low-exhaust periods is more difficult since the lower mass turbine has less momentum?
I agree with everything but the last paragraph.
The rpm limit is for the MGUH not the turbo so there are ways to spin a turbo faster (gears or clutch).

I don't know why you would want the turbine to continue spinning during low exhaust moments when the MGUH will spool it up when it is needed.

DarkAlman
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Re: Mclaren MP4-31 Honda Speculation Thread

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Spooling up the turbine with the MGU-H requires energy from the battery.
So the less time you spend spooling up the turbine the more efficient the system will be overall.

I assume that a smaller turbine would require less energy to get spinning initially but would it require more energy at Max RPM?