McLaren MP4-31 Honda

[tok-tokkie]

Early on in the testing they were doing something on the exhaust. So they certainly were investigating something there before they changed to the big elliptical strut in there. It may have been temp sensor but it could also have been pressure, gas speed or even a strain gauge.


In this picture there are 3 little stalks with a ring at the end inside the exhaust.


Concerning the drawing by PhillipM. Usually a cylindrical pylon (like a chimney or cooling tower) sheds vortices directly behind it. They alternate clockwise, anti-clock.

EDIT: In the Honda Engine thread there is a new picture of the massive blockage in the Ferrari exhaust.

[Big Mangalhit]

Well, it's not uncommon to see the interior of the exhaust where the pylon is glowing dull red, so probably still north of 500*c

I doubt that value. In the leaked picture of Ferrari engine telemetry (Ferrari power unit thread) we could see the Texhaust left and Texhaust Right to be 282ºC and 300,5ºC. Because these are left and right I imagine that are on the exhaust manifolds right after the ICE so the turbine will extract work/heat of these values and some more energy will dissipate into the materials so I imagine the air coming out of the exhaust is probably a lot, really a lot colder that 500ºC

Wasn't it decided that the telemetry was taken in in the garage at idle though ?
How much difference in exhaust heat would be seen at full power ?

I've got no idea !

Just wondering

You're right idle at 3377RPM which is probably a lot colder than full beans, but also a lot less extraction of heat from turbine. So conclusion I have no idea at all of the temperature although I still feel a lot of it would be extracted by turbine and dissipated I have no way of knowing it. Damn the car being in idle and not full beans

[jonas_linder]

Hi,

Long time lurker on this forum, but now I thought it was time to through a spanner in the fan (pun intended )

Hypotheses: the exhaust gases coming out of the turbine rotate around the same axis as the impeller. Maybe this (the pillar in the exhaust) is to straighten the air flow similar to what they do with the diffuser section in wind tunnels (see picture below)?

[PhillipM]

I doubt that value. In the leaked picture of Ferrari engine telemetry (Ferrari power unit thread) we could see the Texhaust left and Texhaust Right to be 282ºC and 300,5ºC. Because these are left and right I imagine that are on the exhaust manifolds right after the ICE so the turbine will extract work/heat of these values and some more energy will dissipate into the materials so I imagine the air coming out of the exhaust is probably a lot, really a lot colder that 500ºC

It's idling, under almost no load, and it's still at 300*c. Does that not indicate the opposite to you, that it's going to be pretty hot, given that it's running 300* EGT's already?

If it was far colder than the 300*c after the turbine that would throw out all of the other theories as well- you wouldn't need that wide a pillar for structural support as the temperature is so low it wouldn't soften appreciably - you wouldn't get enough temperature difference to allow for flex to let the wing move, and you wouldn't need that size of pillar to shield the DRS lines from the heat either.

[Gridlock]

Won't exhaust gases measured at 2 manifolds increase in pressure and temperature as they enter the smaller volume of the single exhaust pipe?

Been a while since GCSEs though..

[Big Mangalhit]

Too many variables to know for sure.

On one hand the car is under 5% open throttle and idling at 3300rpm so it is colder than usual on the other the turbine will for sure extract every ºC it can of the gas in order to produce work, it will also act as a diffuser and reduce the pressure of the gas. So I think we can't know if the increase of T at full throttle will be greater than the turbine effect in decreasing the temperature. Unless somebody as some more information.
As for shielding I don't know what temperature DRS cables start to became sensible but I think that maybe 300ºC is already too hot for electronics, no? (honestly no idea)
I am inclined to think that team do want the minimum cross section of exhaust to be reduced for some reason, as said previously they all converged for the minimum dimensions.

[PhillipM]

Well, we can know for sure as we know roughly what temperature dull red heat is for the exhaust tube. So we know it's at least that hot.

As for the minimum size being converged on - that could quite easily be aero related as anything. If it doesn't make much difference to power (given a few teams were larger to start with) then you'd want it as small as possible for rear end aero, especially as I believe the some of the rear regs for the bodywork/monkey seat are a set distance from the exhaust diameter (30-40mm or so), as well as the angle/cone regs from the centre axis.

[bhall II]

I'm 93.674% sure the exhaust "pillar," or whatever it's been dubbed, is a just an insulated segment of the wing pylon, which is also the conduit for the DRS control lines.

Prior to 2014, such lines could be run through an endplate via the beam wing in order to be connected to the DRS mechanism on the main plane.



Since beam wings have been eliminated, those lines now have to run through a central support. That support can either straddle the exhaust...



...or pass through it. If it passes through the exhaust, it probably needs to be insulated so the lines within won't bake.



(Or so goes my unsophisticated theory.)

[Gridlock]

If you want the area above the diffuser as unobstructed as possible (with as few yaw issues as possible) then using the exhaust interior is basically a 'freebie', no?

[bhall II]

Exactly.

[michl420]

In case of mclaren i am pretty sure the drs lines join the pylon above the exhaust, as it was last year.

[bhall II]

MP4-30 was equipped with several different designs, but I think all of them were variations of a "forked" pylon like this...

[DiogoBrand]

Rake comparison from the 2016 car comparison thread:



Of course there may be some optical illusions from one picture to the other, but to me McLaren's rake angle looks even bigger than Red Bull's, who are considered as the 'rake kings'.
I wonder if McLaren really achieved that amount of rake with stable and useful downforce.
Also, if it compensates the big compromise they probably have to make in suspension settings.
Edit: Also it is mentioned at some place that the cars with the biggest rake angles are the slowest at the speed traps, does it have a correlation or is it coincidence? Increasing the rake was always considered as a way to make downforce with little effect on drag, but if you look at it, it can increase frontal area by a fair bit.

[f1rules]

damm the car is looking good, come on mclaren honda, you cannot have f----- up that much with this beauty, prove us wrong

[CjC]

Rake comparison from the 2016 car comparison thread:
http://img1.auto-motor-und-sport.de/McL ... 934910.jpg
http://img3.auto-motor-und-sport.de/Red ... 934905.jpg

Of course there may be some optical illusions from one picture to the other, but to me McLaren's rake angle looks even bigger than Red Bull's, who are considered as the 'rake kings'.
I wonder if McLaren really achieved that amount of rake with stable and useful downforce.
Also, if it compensates the big compromise they probably have to make in suspension settings.
Edit: Also it is mentioned at some place that the cars with the biggest rake angles are the slowest at the speed traps, does it have a correlation or is it coincidence? Increasing the rake was always considered as a way to make downforce with little effect on drag, but if you look at it, it can increase frontal area by a fair bit.

Maybe you have answered your own question?
Maybe the slowest cars (most underpowered- Honda and Renault) have to push harder for rake because it is extra down force without the drag?

More powerful engined cars can afford to run 'draggy downforce'?