Sepang MotoGP Test Photo Analysis: Honda's 'Ground-Effect' Fairing - Was It Hiding Something More Significant?

By David Emmett | Mon, 06/03/2023 - 00:31

There was a great deal of excitement when this unusual prototype bike (my shoddy phone camera photo) was spotted in the Repsol Honda garage at the Sepang test. Was Honda the latest factory to try out a ground-effect fairing? The obvious answer was yes, but this misses the point entirely. This bike spoke volumes about what HRC was up to at Sepang. And it had very little to do with aerodynamics. Or at least, it had very little to do with ground effect.

The changes at HRC – former Suzuki engineer Ken Kawauchi replacing Takeo Yokoyama as Technical Director – have see Honda go back to basics. At Sepang, Honda sent Marc Marquez out to ride the Honda RC213V with just a plain fairing, no aerodynamic wings fitted at all. "The new technical manager arrived in HRC, and he wants to understand many things about the concept," Marquez explained. "I was not asking about why this, why that. I was just riding."

Look beyond the ground-effect fairing on the strange prototype, and this bike too looks more like HRC going back to basics. To understand what Honda are up to, let's go through a few photos and parts, one by one.

First, the swingarm. Look at in close up (in this photo by Tom Morsellino) and it looks vaguely familiar.

This may be an aluminum swingarm, but this one was not fabricated by Kalex in Germany. This is an HRC item. In fact, it looks remarkably like one of the swingarms HRC used in 2017 and 2018, before they finally made the switch to carbon fiber. Here is Cal Crutchlow at Austin in 2017, captured by Scott Jones.

For comparison, here is one of my phone photos of the Kalex swingarm on one of the 'normal' 2023 prototypes:

The swingarm was just the tip of the iceberg, however. That bike was a real blast from the past, laden with parts from several years ago. But first let's start with what are 2023 parts:

  • The engine is a 2023 unit, as the clutch is the black item with relocated clutch bolts, not the alloy version used up until the end of the 2022 season.
  • The frame looks like the 2023 version trialed at Valencia, based on the one used by Takaaki Nakagami for most of last season. This appears to be the frame which was also being used on one of the more 'normal' 2023 prototypes both Marc Marquez and Joan Mir were using at Sepang, and which was ultimate rejected in favor of a version without a weld on the side beam.
  • The exhausts are the Akrapovic items used with the 2023 engine.
  • The tail looks like the standard 2022 Honda RC213V tail without the tail fins.
  • Now, back to what is different to the 'normal' 2023 prototypes, and which appear to have been pulled from several seasons ago.
2023
MotoGP
Sepang, Malaysia
Honda
Marc Marquez
CormacGP
David Emmett
Thomas Morsellino

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Comments

David,  very interesting report.  I am really interested on the influence and impact of former Suzuki engineer Ken Kawauchi replacing Takeo Yokoyama as Technical Director. think I made a comment back in Dec. that Honda could do worse than buying out Suzuki's rolling stock..   they took a more efficient tack by bringing Ken onboard.

but, this is going to be a great background story this year and I am very glad for your reports.

I dunno, maybe it’s just me, but it makes sense (to me) that you’d want to verify you had a fundamentally great bike before you start throwing aero at it? Trying to fix fundamental issues via aero (or electronics) brings to mind images of a silk purse and a sows ear.

In other news, sorry but I’m a late adopter of your long ‘n low vs short ‘n high proposition, I’m afraid. Yup, Pecco coulda/shoulda/woulda started much stronger on the long ‘n low in 2022…..but equally, given a less than 3 year old engine Fabio coulda/shoulda/woulda been gone-burger, out of reach, with just a handful more horsepower.

Sorry, but the jury is still out for me on that one.

 

The thing about MotoGP now is that ride-height devices and aero are such a fundamental change to vehicle dynamics that you can't design them separately. If you build a great motorcycle that works without aerodynamics, you will get your behind handed to you by motorcycles which were designed around aerodynamics and ride-height devices. The aero loads the front of the bike, which causes the balance of the bike to shift forward, which loses you rear grip. The ride-height device lowers the rear on corner exit (and crucially, on corner entry as well) which changes the way acceleration works and how a bike brakes.

Re: short 'n' high and long 'n' low - it's more of a framework for thinking about motorcycle behavior than an absolute design paradigm. The most fascinating thing about motorcycles is that they are highly complex and dynamic, so it's all shades of gray.

You're right, front aero loads the front. But because it loads the front, the bike has to be set up to cope with that, and from what I understand from people who are a lot smarter than me, this means sacrificing some rear grip. But completely agree, the real difference in CoG is ride-height devices. Put them together and you get a very complicated state of affairs.

I think it is also possible that it is not downforce stealing rear load but increasingly 'draggy' bikes causing rear spin. If the front is compressing with speed due to aero then the wings are increasing their angle against the flow, front area is increasing making the problem even worse. The rear is driving the bike but doesn't get any extra grip from downforce (currently...well, fins/spoons aside). I could be that in certain on track scenarios, a certain setup will hit a brick wall where there is not sufficient grip to drive the bike forward...the rear spins/wants to spin where not expected.

I saw the extra scoops I think. I have no idea if what I suggested is anything near a reality. I think it was late, sleepy head. However, those big front wings, if allowed to pitch around, would produce varying amounts of downforce and drag with that pitch. Possible to imagine a cycle of more pitch leading to more downforce leading to more pitch until it 'stalls out' leading to less downforce, less pitch and repeat....if sufficient change in pitch was available. I just wondered if unexpected and transient 'spikes' in drag could produce unexpected rear spin but I guess it would stand out like a sore thumb on the data from the front forks or imu. I think it was Dovi or Salvadori who talked about how stiff the springs and shocks have become in recent years. Makes sense. 

What is questionable to me about the "go back to the basics" hypothesis is that the 2018 machine, while great for MM93, was not what you might objectively call a "good" bike. Pedrosa, his teammate, finished 11th in the championship regularly finishing 7th or worse and the satelite riders were reliably outside the top 10 close to the back (I know they were on the slightly older spec). If you are trying to give MM a bike he was successful on then ok but if you want to make a competitive bike that path seems the wrong one. 

I do hope Honda get it right and can help give us some good racing this year.

It didn't sound to me like they were going to revert most of the bike back to 5 yrs ago and leave it, but rather understand what components and compromises worked and then maybe bring them forward into the new bike with the aero, ride height device, etc. It seems thorough of Ken Kawauchi to attempt to understand their situation from deep down.

Anyway one bike going well is better than none. If it's the 93 bike, that may very well be enough. What I don't understand is, what makes MM so different? So he loves to ride the front; is he really the only one? I know he is exceptional, has cat-like reflexes, yada yada. But why is Honda the only one having so much trouble dealing with different riding styles? Maybe they aren't but they are the ones with the magnifying glass on them because he is "a" GOAT.

Seems as if HRC find themselves in a similar position to Ducati in the Stoner era with the exception that the bike's relative performance went down considerably while under MM's direction. 93 was happy with HRC giving him what he wanted and the machine's performance under other riders falling. Stoner asked Ducati for things but they never delivered and in the end even he couldn't ride it. Either way you had a factory machine ridable by 1 guy. As long as that guy is a winner things are fine, and it is certainly a strategy that can work.

I think Marquez wants a bike he can win on, not a great bike. This eliminates one key risk every rider faces - your teammate. I wonder if HRC feels the same way at this stage. MM is amazing, but one has to ask himself if his level is the same as 3 years ago and if the same race (with such massive changes from Aero, ride height, tires) even exists. I'm willing to wager HRC is giving 93 what he wants and if the results don't look to be coming by mid-year the strategy changes as they'll know Marc's exit is coming. Will be fun to keep an eye on.