a bit offtopic about this software emulating ...
Lets say you compare 2 models with same aero and ICE power 1000hp@10000rpm vs 900hp@10000rpm
Can you access power-delivering curves?
Because I can see at least 2 types of (simplified) curves.
- one where on all rpms the difference is proportional
- and one where upto (say) 9000rpm power delivery is equal but then one engine flats out
I believe Honda vs Mercedes is type 2 , not type 1. Just a thought how to improve the emulation
Re: Honda Power Unit
Posted: 01 Nov 2017, 12:52
by iichel
I believe you should also take the gearing into your comparison and as you rightfully state, the power delivery curve (so indirectly also the torque curve). It's not that simple.
And then there' s of course the ERS deployment strategy (self sustaining, quali, derates)...
Yes. I was prepared for that question. I suppose the 35 place and 20 place grid drops could be construed to be a compressor wheel change!
Well I suppose they used about 1 turbo per race anyway so why not
Increasing wheel trim increases mass as well as the CG overhang (distance to first bearing). Secondly, the allowable unbalance for a given balance quality grade is proportional to rotor mass, so unbalance will increase too.
All these give you a lower frequency forward whirl mode, higher unbalance and a fair amount of extra inertia to accelerate.
And I'm not too sure how compressor efficiency varies with wheel trim, maybe GG can elucidate .
Both turbine and compressor can be kept relatively compact with the right wheels. The number and shape of blades along with inducer and exducer combinations along with their taper.
Single stage turbines have been done to death, I wouldn't be surprised if the answer is in some old dusty book TC has stashed somewhere I reckon.
I wonder how many blades they have on their turbine wheel, I suppose that information is on a need to know. Less blades means more surface area for the blades to affect airflow, however there has to be a compromise to get the best surface area vs best pressure ratio vs best response vs best harmonics and a host of other technical niggles you're probably more familiar with. My guess is 6-7 blades, maybe a 74-88 trim something wild like that.
Going buy power output maybe the wheel is about 80 mm inducer and 70 mm exducer... Less blades mean less surface area and less obstruction for more flow (more top end) however efficiency drops. They would use trial and error i guess.
The compressor wheel might have a loop hole. Honda could have made an air box with an adjustable " bullet" shape protruding into the turbine to tune the air flow charecteristics between races. The intake pipe to the turbine is free to change right?
Well I suppose they used about 1 turbo per race anyway so why not
Increasing wheel trim increases mass as well as the CG overhang (distance to first bearing). Secondly, the allowable unbalance for a given balance quality grade is proportional to rotor mass, so unbalance will increase too.
All these give you a lower frequency forward whirl mode, higher unbalance and a fair amount of extra inertia to accelerate.
And I'm not too sure how compressor efficiency varies with wheel trim, maybe GG can elucidate .
Both turbine and compressor can be kept relatively compact with the right wheels. The number and shape of blades along with inducer and exducer combinations along with their taper.
Single stage turbines have been done to death, I wouldn't be surprised if the answer is in some old dusty book TC has stashed somewhere I reckon.
I wonder how many blades they have on their turbine wheel, I suppose that information is on a need to know. Less blades means more surface area for the blades to affect airflow, however there has to be a compromise to get the best surface area vs best pressure ratio vs best response vs best harmonics and a host of other technical niggles you're probably more familiar with. My guess is 6-7 blades, maybe a 74-88 trim something wild like that.
Going buy power output maybe the wheel is about 80 mm inducer and 70 mm exducer... Less blades mean less surface area and less obstruction for more flow (more top end) however efficiency drops. They would use trial and error i guess.
The compressor wheel might have a loop hole. Honda could have made an air box with an adjustable " bullet" shape protruding into the turbine to tune the air flow charecteristics between races. The intake pipe to the turbine is free to change right?
I was thinking 74 to 88mm, less blades doesn't always mean more flow as you can make larger blades, the area of the space between the blades can be the same with 3 4 5 6 7 8 or 9 blades. If we think of each blade as an aerofoil you can easily see the effect of larger blades, in the same way you see the effect of a larger wing. Do you want a bunch of small wings or a few larger ones, you have to find the right compromise.
Re: Honda Power Unit
Posted: 02 Nov 2017, 07:37
by Wazari
There has been some interest about "oil burning" in this current PU. Here is a simplistic but IMO a pretty well summary of what is happening and why the limit on oil consumption being permitted:
Water vapor would need to be reclaimed pre-turbine. Unless you had some intentionally leaky gaskets.
5.8.1 With the exception of incidental leakage through joints (either into or out of the system), all
(and only) the fluids entering the compressor inlet and the fuel injectors must exit from the
engine exhaust system.
"Oil burning" potentially allowed by mandated oil catch tank vapor injestion.
7.3 Catch tank :
In order to avoid the possibility of oil being deposited on the track, the engine sump breather
must vent into the main engine air intake system.
Re: Honda Power Unit
Posted: 03 Nov 2017, 04:26
by ringo
Those two rules contravene.
I could make a case for leaking coolant water into a little catchment in the crank case and have that oily water mist mix sent to the breather.
Anyhow oil is the better loophole. and it makes you look back at the mercedes puffing out clouds of oil when they do the parade lap at the start of the races. That oil definitely went through the breather and into the cylinders.
But how great of a benefit is oil burning.
Wazari you seem to support that this does happen, but how much of a direct and indirect benefit is to be had from this?
Both turbine and compressor can be kept relatively compact with the right wheels. The number and shape of blades along with inducer and exducer combinations along with their taper.
Single stage turbines have been done to death, I wouldn't be surprised if the answer is in some old dusty book TC has stashed somewhere I reckon.
I wonder how many blades they have on their turbine wheel, I suppose that information is on a need to know. Less blades means more surface area for the blades to affect airflow, however there has to be a compromise to get the best surface area vs best pressure ratio vs best response vs best harmonics and a host of other technical niggles you're probably more familiar with. My guess is 6-7 blades, maybe a 74-88 trim something wild like that.
Going buy power output maybe the wheel is about 80 mm inducer and 70 mm exducer... Less blades mean less surface area and less obstruction for more flow (more top end) however efficiency drops. They would use trial and error i guess.
The compressor wheel might have a loop hole. Honda could have made an air box with an adjustable " bullet" shape protruding into the turbine to tune the air flow charecteristics between races. The intake pipe to the turbine is free to change right?
I was thinking 74 to 88mm, less blades doesn't always mean more flow as you can make larger blades, the area of the space between the blades can be the same with 3 4 5 6 7 8 or 9 blades. If we think of each blade as an aerofoil you can easily see the effect of larger blades, in the same way you see the effect of a larger wing. Do you want a bunch of small wings or a few larger ones, you have to find the right compromise.
That is the thing though, turbine blades don't work like aeroplane wing profiles. That is a weird sort of thinking.
There has been some interest about "oil burning" in this current PU. Here is a simplistic but IMO a pretty well summary of what is happening and why the limit on oil consumption being permitted:
Going buy power output maybe the wheel is about 80 mm inducer and 70 mm exducer... Less blades mean less surface area and less obstruction for more flow (more top end) however efficiency drops. They would use trial and error i guess.
The compressor wheel might have a loop hole. Honda could have made an air box with an adjustable " bullet" shape protruding into the turbine to tune the air flow charecteristics between races. The intake pipe to the turbine is free to change right?
I was thinking 74 to 88mm, less blades doesn't always mean more flow as you can make larger blades, the area of the space between the blades can be the same with 3 4 5 6 7 8 or 9 blades. If we think of each blade as an aerofoil you can easily see the effect of larger blades, in the same way you see the effect of a larger wing. Do you want a bunch of small wings or a few larger ones, you have to find the right compromise.
That is the thing though, turbine blades don't work like aeroplane wing profiles. That is a weird sort of thinking.
But they do. Especially when you begin to optimize the airflow and you use high flow turbines.
It all depends on the used dimensions and design pressures. Most automotive turbos are diagonal turbines (although most of the time they are called radial turbines) and therefore the blades should be "wing shaped" although most of the time they are not due to manufacuring issues.
(The optimum dimensions for a certain speed and pressure is given by the Cordier diagram like this or this)
But in F1 I certainly would expect them to just produce the best turbine shape without regard to manufacturing issues.
Re: Honda Power Unit
Posted: 03 Nov 2017, 09:54
by bigblue
There are a few reports in Japanese media that Honda had a qualifying mode available, but it was outlawed by tighter FIA rules. I guess it was based around oil burning, as what else is available, and recently tightened-up in the regulations ?
I forget where I first saw this mentioned (might be here, might be on autosport's forums), but a post over at autosport brought it up again. The links provided are to a Japanese web-site, where only a paragraph of a subscription article is visible, and of course they are written in Japanese, so machine translation has been used by the poster.
If true, it's bad timing for Honda as just as they implement this, it's outlawed (seems the regulations changed just before the Italian GP). Then again, the very smoky Mercedes probably has it developed to the last degree, so maybe not so bad (edit : forgot about Mercedes changing engines just before the regulation update, e.g. see this article on crash.net). Hopefully Honda's developed some expertise in this area which is still applicable within the tightened regulations.
There are a few reports in Japanese media that Honda had a qualifying mode available, but it was outlawed by tighter FIA rules. I guess it was based around oil burning, as what else is available, and recently tightened-up in the regulations ?
I forget where I first saw this mentioned (might be here, might be on autosport's forums), but a post over at autosport brought it up again. The links provided are to a Japanese web-site, where only a paragraph of a subscription article is visible, and of course they are written in Japanese, so machine translation has been used by the poster.
If true, it's bad timing for Honda as just as they implement this, it's outlawed (seems the regulations changed just before the Italian GP). Then again, the very smoky Mercedes probably has it developed to the last degree, so maybe not so bad (edit : forgot about Mercedes changing engines just before the regulation update, e.g. see this article on crash.net). Hopefully Honda's developed some expertise in this area which is still applicable within the tightened regulations.
It's a bit conspiracy but Fia doesn't do what they do with good intention. If oil burning keeps competition alive don't ban it in season. If oil burning ban would bring competition then do it.
Engine performances becoming closer but this time new rule is 3 PU for whole season. This is good for who? There is no hasitation. It's good for Mercedes.
