Mercedes W13

[Spacepace]

I don't know you can say that centre of mass has nothing to do with aerodynamics when the issue being solved is porpoising

I think we don't understand the full nature of Mercedes porpoising.

If it is a pure heave porpoising, then the center of mass doesn't matter. If there is a pitching component in the porpoising, then center of mass will change the pitching dynamics, but the fundamental origin of the porpoising is the floor stalling, not the center of mass. It would porpoise even if the center of mass was on the skidblock.

I think it's purely floor driven. People like to make a big deal about the center of mass on F1 cars, but it really doesn't very that much from what I've seen, and definitely not enough to cause the type of issue we have seen through testing!

Could it be front wing. The three cars to me that look the most poised and responsive all have the inner portion of the wing as high up as possible. Mercedes made a mistake in 2019 with the new front wings and had to copy Ferrari's design.

Now I am just speculating but could Mercedes be trying to work the front part of the floor harder by running lower. Compensating for the way they designed the front wing that works to condition the air next to the nosecone presumably to work the floor instead of downforce.

Red Bull changed to this kind of front wing and has seemed to unlock better balance

[pursue_one's]

Windsor says, "Red Bull has adopted an unusual concept with its front suspension. Currently under consideration by the Mercedes. "

[Henri]

realy hope they fix the bouncing.. the car has so much potential

[Mchamilton]

Okay, I put in centre of mass and porpoising into google and came across this interesting post in a boat design forum

https://www.boatdesign.net/threads/porpoising.1155/

Not cars obviously but seemingly the same thing happening

"I have a problem with porpoising on my 12' home-built duckboat whenever I get above 3/4 throttle. I am particularly interested in the center of gravity/center of lift relationship.

Doesn't moving weight forward only lessen the frequency of the occillation in accordance with consevation of angular moment. From what I've gleaned so far, and correct me if I'm wrong, here are the dynamics of porpoising: The boat has a fixed center of mass (COM). The hull has a center of boyancy (COB) that moves aft as the wet surface of the hull decreases at higher speeds. As the COB passes aft of the COM, gravity pulls the bow down rotating on the COB point. When the bow goes down, the COB immediately and rapidly moves forward of the COM. Stability is reestablished until the COB once again moves aft of the COM.

Moving weight forward, if my thinking is correct, should only increase the likelyhood of porpoising. Though initially this might bring the bow down, and hence, move the COB forward until speed is ultimately increased enough to shift it aft of the COM again, the forward shift of the COM only appears to deminish porpoising because as the radius of arc of the ocillating COM about the COB increases, the frequency of occillation decreases to preserve the angular moment.

Trim in causes the craft to run in a more bow down attitude which serves to keep the COB forward. Porpoising is prevented until enough power is applied to move the COB aft again.

This leave me with the counterintuitive solution of moving weight aft so as to move the COM aft.

There is the possibility of my boat being overpowered (by definition of this particular instability) which moves the COB aft to the extreme, and more so than any aft movement of the COM that I would be able to achieve.

In line with my thinking, the reason that a rocker hull is thought to porpoise more is because the bow rides high, and therefore, has further to fall making porpoising more pronounced as opposed to making it more likely.

I guess the trick then is to balance weight distribution, trim attitude, and power for the most efficient use of thrust."

Obviously a boat not a car but generally the same issue and a very interesting insights

4 2. Mass distribution
With the car resting on a horizontal plane the mass measured at the front and rear axles must
not be less than the mass specified in Article 4.1 factored by 0.440 and 0.540 respectively at
all times during the qualifying practice session. Rounding will be to nearest 0.5kg.

I dont see how centre of mass could be a significant factor when theyre limited to a 2% variation in weight distribution.
All the cars have same major components onboard, many of which are in basically the same position.

[izzy]

Someone was saying that Merc may have a Centre of Mass issue due to their concept, they are the ones that have this very extreme non sidepod body and thus suffer from extreme porpoising. Maybe they cannot spread their mass out enough to be able ro relieve the issue.

The porpoising comes from choking the flow through the floor tunnels doesn't it, as the floor gets pulled too low to the ground, and then as the flow stalls it releases and the floor bounces back up. And this tends to happen at a rate that gives the process a frequency that can coincide with a natural frequency of the car on its suspension. So I don't see how the lateral distribution of mass can make a difference to this.

It's all quite surprising, as Mercedes have been good at suspensions recently, and they even dropped their hydraulic heave spring a couple of years ago to be ready. And they must have a suspension rig at the factory to find its natural frequencies and fix them. And why can't they prevent the floor dropping too low? Can anyone explain?

Could be that they can't simulate that well at high speeds?
Tbh, I don't think we can come up with an idea why as I think the team themselves don't know either.

Part of the trouble must be that the rules only allow the wind tunnel to go up to 180 kmh. We're probably not as clever as them are we but I was thinking it's something they know, how to have in effect a bump stop, but aren't allowed or can't have for some reason.

[Starbuckle486]

Okay, I put in centre of mass and porpoising into google and came across this interesting post in a boat design forum

https://www.boatdesign.net/threads/porpoising.1155/

Not cars obviously but seemingly the same thing happening

"I have a problem with porpoising on my 12' home-built duckboat whenever I get above 3/4 throttle. I am particularly interested in the center of gravity/center of lift relationship.

Doesn't moving weight forward only lessen the frequency of the occillation in accordance with consevation of angular moment. From what I've gleaned so far, and correct me if I'm wrong, here are the dynamics of porpoising: The boat has a fixed center of mass (COM). The hull has a center of boyancy (COB) that moves aft as the wet surface of the hull decreases at higher speeds. As the COB passes aft of the COM, gravity pulls the bow down rotating on the COB point. When the bow goes down, the COB immediately and rapidly moves forward of the COM. Stability is reestablished until the COB once again moves aft of the COM.

Moving weight forward, if my thinking is correct, should only increase the likelyhood of porpoising. Though initially this might bring the bow down, and hence, move the COB forward until speed is ultimately increased enough to shift it aft of the COM again, the forward shift of the COM only appears to deminish porpoising because as the radius of arc of the ocillating COM about the COB increases, the frequency of occillation decreases to preserve the angular moment.

Trim in causes the craft to run in a more bow down attitude which serves to keep the COB forward. Porpoising is prevented until enough power is applied to move the COB aft again.

This leave me with the counterintuitive solution of moving weight aft so as to move the COM aft.

There is the possibility of my boat being overpowered (by definition of this particular instability) which moves the COB aft to the extreme, and more so than any aft movement of the COM that I would be able to achieve.

In line with my thinking, the reason that a rocker hull is thought to porpoise more is because the bow rides high, and therefore, has further to fall making porpoising more pronounced as opposed to making it more likely.

I guess the trick then is to balance weight distribution, trim attitude, and power for the most efficient use of thrust."

Obviously a boat not a car but generally the same issue and a very interesting insights

4 2. Mass distribution
With the car resting on a horizontal plane the mass measured at the front and rear axles must
not be less than the mass specified in Article 4.1 factored by 0.440 and 0.540 respectively at
all times during the qualifying practice session. Rounding will be to nearest 0.5kg.

I dont see how centre of mass could be a significant factor when theyre limited to a 2% variation in weight distribution.
All the cars have same major components onboard, many of which are in basically the same position.

While I agree the weight distribution probably doesn't have a large influence in the porpoising I do believe the mass of the driver isn't included in the 0.440 / 0.540 rule. Or is it? Hamilton sits so far forward it looks like he drives a bus. A fast looking melting space bus.

[Mchamilton]

Okay, I put in centre of mass and porpoising into google and came across this interesting post in a boat design forum

https://www.boatdesign.net/threads/porpoising.1155/

Not cars obviously but seemingly the same thing happening

"I have a problem with porpoising on my 12' home-built duckboat whenever I get above 3/4 throttle. I am particularly interested in the center of gravity/center of lift relationship.

Doesn't moving weight forward only lessen the frequency of the occillation in accordance with consevation of angular moment. From what I've gleaned so far, and correct me if I'm wrong, here are the dynamics of porpoising: The boat has a fixed center of mass (COM). The hull has a center of boyancy (COB) that moves aft as the wet surface of the hull decreases at higher speeds. As the COB passes aft of the COM, gravity pulls the bow down rotating on the COB point. When the bow goes down, the COB immediately and rapidly moves forward of the COM. Stability is reestablished until the COB once again moves aft of the COM.

Moving weight forward, if my thinking is correct, should only increase the likelyhood of porpoising. Though initially this might bring the bow down, and hence, move the COB forward until speed is ultimately increased enough to shift it aft of the COM again, the forward shift of the COM only appears to deminish porpoising because as the radius of arc of the ocillating COM about the COB increases, the frequency of occillation decreases to preserve the angular moment.

Trim in causes the craft to run in a more bow down attitude which serves to keep the COB forward. Porpoising is prevented until enough power is applied to move the COB aft again.

This leave me with the counterintuitive solution of moving weight aft so as to move the COM aft.

There is the possibility of my boat being overpowered (by definition of this particular instability) which moves the COB aft to the extreme, and more so than any aft movement of the COM that I would be able to achieve.

In line with my thinking, the reason that a rocker hull is thought to porpoise more is because the bow rides high, and therefore, has further to fall making porpoising more pronounced as opposed to making it more likely.

I guess the trick then is to balance weight distribution, trim attitude, and power for the most efficient use of thrust."

Obviously a boat not a car but generally the same issue and a very interesting insights

4 2. Mass distribution
With the car resting on a horizontal plane the mass measured at the front and rear axles must
not be less than the mass specified in Article 4.1 factored by 0.440 and 0.540 respectively at
all times during the qualifying practice session. Rounding will be to nearest 0.5kg.

I dont see how centre of mass could be a significant factor when theyre limited to a 2% variation in weight distribution.
All the cars have same major components onboard, many of which are in basically the same position.

While I agree the weight distribution probably doesn't have a large influence in the porpoising I do believe the mass of the driver isn't included in the 0.440 / 0.540 rule. Or is it? Hamilton sits so far forward it looks like he drives a bus. A fast looking melting space bus.

Im probably completely wrong, but wouldnt the driver being further forward, decrease the effect of porpoising? As his mass is forward of the centre of the lever, ahead of the floors throat so it has less of an impact? Probably increase the frequency though

[gluon]

Am I right to assume that porpoising is proportional to car weight and therefore worse with full tanks when the ride height is a bit lower?

If so, would it make sense that Mercedes has been focusing more than ever on extremely heavy long runs, trying to fix the worst case scenario for their porpoising and thus never really showing their qualy form?

[pimpwerx]

I think we should note how often Shovlin used the word "experiment" yesterday. I think they know how to solve the bouncing issue, but need to maintain performance while doing so. Hence, "experimenting" to see if they can find the best solution.

Based on their public statements, I'm expecting damage limitation until the EU leg kicks off in Italy.

[214270]

Useful article here, a lot of people have been opining that it’s the SIPS/mid-wing or even the lack of visible horizontal stay being looked at; it’s actually the rear stay and cascade only.

https://www.autosport.com/f1/news/what- ... content=uk

[Mchamilton]

Useful article here, a lot of people have been opining that it’s the SIPS/mid-wing or even the lack of visible horizontal stay being looked at; it’s actually the rear stay and cascade only.

https://www.autosport.com/f1/news/what- ... content=uk

Ive been suprised how many people havent understood what the contention has been about

[Vanja #66]

I think we should note how often Shovlin used the word "experiment" yesterday. I think they know how to solve the bouncing issue, but need to maintain performance while doing so. Hence, "experimenting" to see if they can find the best solution.

Based on their public statements, I'm expecting damage limitation until the EU leg kicks off in Italy.

This is how I see their situation as well. Raising the ride height will solve it, quite easily. I will be very surprised if they risk damaging the powertrain components with constant bouncing in the race, simply because they "refuse" to raise the ride height. They would keep high-speed corner performance, but to risk double DNF and wasting two sets of PU components? I don't know, I really don't see it.

[barten]

Merc probably also wants to adjust their simulator to incorporate the porpoising effect given that this will be a prevailing issue over the next years. This investment into better correlation probably consumes resources otherwise spent for performance right now, but should pay off in the future. Keep in mind how merc bounced back last season with minimal effort in terms of car updates. The season is long, they will get there for sure.

[AeroDynamic]

confirmed to be an issue (bouncing) in the fast corners

[izzy]

confirmed to be an issue (bouncing) in the fast corners

god no wonder it's so slow! Sky live was just showing Lewis gaining .09 on Charles in T4, braking later, so it has downforce doesn't it. They have to get this stalling fixed then it could be good. Oh fast lap incoming...