Automotive

Published on November 3rd, 2020 | by Subhash Nair

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SSC North America Explains Land Speed Record Situation

Earlier this month, it was reported that SSC North America had broken the land speed record for a production car when their Tuatara achieved an average top speed of 316.11 MPH, or 508.73 KMH between two runs.

However, once they released a video depicting the event, speculation from online viewers began to arise. This was especially concerning, given that SSC North America themselves were publicly doubting the validity of the previous record set by Bugatti.

SSC North America’s response to the accusations seem to be pretty level headed. Essentially, they’re saying that the record was indeed set, but the video depicting the record was problematic. The way it was edited seemed to show some inconsistencies as footage from different runs were used.

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Additionally, there might have been an issue with the GPS calibration that the company is currently working to resolve. In the meantime, a rerun of this record is most likely being planned in order to remove all doubts that the SSC Tuatara is indeed the fastest production car of all time (until the next one comes along).

Here’s the press release with more.

PRESS RELEASE

On October 10, 2020, SSC North America realized a dream that was a decade in the making, when our Tuatara hypercar achieved an average top speed of 316.11 MPH. 

In the days since, there has been a swirl of interest and speculation about how and whether the Tuatara had achieved that speed. 

The good news: we did it, and the numbers are indeed on our side. 

The bad news: only after the fact did we realize that the depiction of the speed run, in video form, had been substantially incorrect.

The following is a long explanation of what and how this happened, to the extent we now know. I hope it will serve to build trust in the SSC team, and in the exceptional feat the Tuatara has earned. 

The Video

Three years ago, SSC began working with Driven Studios, a video team to document what seemed like every waking moment of the Tuatara hypercar and those who’ve created it.

They’ve since interviewed virtually every team member and consultant, captured the car in build and throughout extensive testing, and have played a key role in not only capturing, but in producing the record run on October 10 in Pahrump, Nevada. They have become a trusted partner of the SSC family.

On the big day, October 10, there were video cameras everywhere — in the cockpit, on the ground, and even secured on a helicopter a low-flying T33 to capture the car at speed. 

The morning of the run, the record was achieved, we were over the moon. We kept the news under embargo until October 19, with hopes of releasing a video to accompany the press release.

On October 19, the day the news broke, we thought there were two videos that had been released — one from the cockpit, with data of the speed run overlaid, and another video of b-roll running footage. The cockpit video was shared with Top Gear, as well as on the SSC and Driven+ YouTube pages.

Somehow, there was a mixup on the editing side, and I regret to admit that the SSC team hadn’t double checked the accuracy of the video before it was released. We also hadn’t realized that not one, but two different cockpit videos existed, and were shared with the world. 

Hypercar fans have quickly cried foul, and we hadn’t immediately responded, because we had not realized the inconsistencies — that there were two videos, each with inaccurate information — that had been shared. This was not our intention. Like me, the head of the production team had not initially realized these issues, and has brought on technical partners to identify the cause of the inconsistency. 

At first glance, it appears that the videos released have differences in where the editors had overlaid the data logger (which displays speed), in relation to the car’s location on the run. That variance in ‘sync points’ accounts for differing records of the run.

While we had never intended for the video captured to play the role of legitimizing the run, we are regretful that the videos shared were not an accurate representation of what happened on October 10.

Driven Studios does have extensive footage of everything that transpired and is working with SSC to release the actual footage in its simplest form. We’ll share that as soon as it’s available.

‍The Car

On the day of the speed run, SSC used Dewetron equipment to track the Tuatara, and verify its speed, as measured by an average of 15 satellites across the two runs. We chose Dewetron for the sophistication of its equipment, and using that has given us confidence in the accuracy of the car’s measured speed.

People have sought additional details, which hadn’t provided in earlier press materials, and those technical specifications are listed below:

Tuatara (Top Speed Model) Tech Specs

Ratios/Speed, using the 2.92 final-drive ratio

     Gear Ratios/Top Speed (Gears 1-6 have 8,800 RPM REV LIMIT)

     1st Gear: 3.133 / 80.56 MPH

     2nd Gear: 2.100 / 120.18 MPH

     3rd Gear: 1.520 / 166.04 MPH

     4th Gear: 1.172 / 215.34 MPH

     5th Gear: .941 / 268.21 MPH

     6th Gear: .757 / 333.4 MPH  @8800 * 

     7th Gear: .625 / 353.33 MPH  (Estimated max @7,700RPM in 7th gear – Designed as mainly an overdrive highway cruising gear)

* FYI: Cross reference validations from data log-

Oliver is travelling at 236mph when he shifts from  5th to 6th at 7,700RPM (which tracks almost exactly to the gear-ratio data) and he pushed close to the top of 6th  achieving 331.1 MPH at 8,600 RPM which tracks with our theoretical of  333.4mph @ 8800 RPM. 

Aerodynamic Specs:

Drag goes from 0.279 up to 0.314 at 311mph (500kph) 

Car is producing approx. 770lbs of downforce at 311mph

It is calculated that car needs 1,473HP to achieve 311mph (500kph) 

In order to calculate the required power the following assumptions were made:

     – The rolling resistance coefficient of the tires has been obtained from the manufacturer (Michelin Pilot Sport Cup 2) declared energy class: E.

     – The overall drivetrain efficiency (from crankshaft to wheel) has been set to 94%.

     – The air density has been set to 1,205 kg/m3 (which is found at 20°C at sea level).

     – The vehicle mass has been set to 1474 kg = 1384 kg curb weight + 90 kg driver.

Tires:

     Michelin Pilot Sport Cup 2

     Rear Tire Diameter / Circumference: 345/30ZR20 

     Normal Running Pressure = 35psi

     88.5” Circumference

     28.185” Diameter

     WORLD RECORD RUNNING PRESSURE = 49psi

     89.125” Circumference

    28.38” Diameter

How the Speed Was Measured

The SSC team received a piece of Dewetron equipment for its use in the speed run. The SSC team was trained remotely (due to COVID) on the use of that equipment. 

The Dewetron equipment includes sensors placed in the vehicle, that tracked an average of 15 satellites over the course of the Tuatara top speed run. 

Two independent witnesses, not affiliated with SSC nor Dewetron, were on site to view the speeds measured by the Dewetron equipment. SSC intends to submit proof of what those witnesses had seen on the Dewetron equipment to Guinness for verification. 

On October 22, Dewetron sent a letter to SSC confirming the accuracy of the equipment and speed sensor they had provided to SSC, and that letter will also be submitted to Guinness as part of application for the world top speed record. 

As an additional step, SSC is in the process of submitting the Dewetron equipment and speed sensor for further analysis and verification of that equipment’s accuracy.

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About the Author

Written work on dsf.my. @subhashtag on instagram. Autophiles Malaysia on Youtube.



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