Engineered Success

 

By David Rusk

It had the look of being worn down and built up again and it told me of speed and anger tempered by grace and love. It was a racer, pure and beautiful and it was very different from most. It was Friday afternoon, the end of the last race day. The Senior TT was moved to the morning and the Isle of Man paddock now lingered in that weird post race energy, with muted voices and the clink of tools replacing revving engines. The final race was over and their world was now fueled by humanity instead of the machines. I had returned to the heartbeat of the event hoping to discover some kind of finality, an ending point to our chaotic three days on the Island and I walked right past it. Twenty feet on I stopped as my tired mind caught up to my eyes. An odd-looking race bike. A young man glances at me from under the shadowy tent. Wait, is that a stack of battery chargers (?) and a banner proclaiming Bath University Zero Emission.

I turned around.

Lawrence Beaumont, a mechanical engineering undergrad waited for me there and along with the help of twenty other undergraduates, the core group of six accomplished an amazing feat. They made a race bike that, in the hands of professional road racer Matthew Rees, placed fourth at the most prestigious motorcycle event in the world.

“I have been with the University of Bath since the start of their electric bike journey 3 years ago. This year was my 4th TT riding in the Zero class for the team and they have made amazing developments and progress over the past few years despite some unfortunate setbacks along the way.”

Matthew Rees – rider

This year’s rains burdened the riders with too much idle time. Add together dreary days spent in the paddock with no practice laps and the complex mind of a road racer and thoughts begin to, well race and uncertainty creeps in. Many, including Matt found it difficult to find the right head space. Then an oil leak at Quarry Bends during the lightweight qualifying prevented him from making the TT Zero practice, perhaps his most important seat time.

Matt continues.

“I would say the main difference when riding the electric bike compared with my petrol bikes is the handling due to the weight of the batteries. Corners need to be taken with more caution and due to limited practice sessions for the zero class, we struggled to get the bike set up perfectly. The CG (center of gravity) is very different from my other bikes and the weight of the bike also alters braking points, which takes a bit to get used to after years of learning almost 40 miles of braking markers for the petrol bikes.”

The core  members consist of mechanical, electrical and electronic engineering scholars. Students learning the integration of those disciplines meshed the team and created a near perfect combination and a near perfect TT Zero bike, the Phoenix.

The Japanese overlord of the electric world Mugen dominated, as they have since 2014 and riders Micheal Rutter and John Mcguinness continued tradition finishing first and second. Team Miria’s Ian Lougher completed the podium but in reality, there is two races within one and although officially fourth, Bath U was first among the mortals. In juxtaposition to eBay sourced Ducati forks with Maxton internals and a steel trellis frame, the Mugen’s have full factory support and boast prototype carbon fiber fork sliders, swingarm and a CF monocoque frame. After all, Mugen was co-founded in 1973 by Hirotoshi Honda, son of HRC founder Soichiro Honda and along with Masao Kimura means there is no shortage of yen involved with Mugen.

Electric motorcycles seem to be the future and no matter how much we will cling to the addictive violence of internal combustion with its infernal by-products, the TT Zero event is the proof of concept needed for revolution. Illustrating that prediction are the two numbers everyone is interested in, 300 peak bhp and 500 (!) Nm of torque available from 0 to 4500 rpm and an additional 1000 revs available through field weakening. 500 Nm at zero rpm. Think about that as you wring the neck of your super bike in search of its ‘measly’ <200 bhp and 100 Nm at a very busy 13000 rpm.

“Also, the power delivery is different. The bike has so much torque off a closed throttle, meaning that I have to ensure I’m smooth exiting corners.”

– Matt Rees

A break through in battery technology is needed before the full-on coup d`e’tat and it is inching closer. The Bath team’s battery package is designed to puke its full charge over a one lap sprint but questioned about normal usage on the race only design Sam Doyle, the team lead on accumulator tech gives the number of 250 miles (!) or 7 laps of the Sneafell mountain course. Well within usable range for inner-city or even commuters and sport riders.

Using the latest advancement in lithium battery technology, the team’s creation is more energy dense then the pouch type cells used by both Mugen and Nottingham University. The 18650 cells, so called for the size of 18mm diameter X 65 long, are notoriously difficult to manufacture because of the small form factor, about the size of a AA battery. The “engine” space between the trellis frame is occupied with 8 battery trays stacked together containing over 2000 individual cells and thanks to (mostly) Catherine Lin’s skill and patience, over 12,000 micro-spot welds were made connecting them to the copper bus-bars in the desired configuration.

 

Solid state batteries are the only radical departure from lithium ion but as China, the US, Thailand and others sink billions into new lithium sources and factories, the cost continues to plummet (85 % since 2010) and solid state is pushed further into the future. Tweaking of the current design keeps the world stuck in lithium limbo, as the flammable liquid electrolyte is on the verge of being replaced with polymer, increasing charge and storage while eliminating the danger of fire.

The motor is more power dense then a combustion engine but the battery has far less energy density then petrol, think of it as an efficient engine that needs a very large fuel tank. Unlike a Mugen, that encloses the rotor in a stationary case, the Bath team opted for an out-runner or external motor, where the outer casing is the rotor! The Japanese mega-team design benefits from the strength of mounting points on both sides of the outer case while the students must attach the motor to frame on only one side, at the narrow stationary inner core. The picture shows a spare mounting plate with the redesigned bolt pattern. The larger holes are pass-throughs for the 3-phase power leads.                                                                                  

 

The output shaft exits the engine core on the left side to grab hold of the chain but this effective design comes at a price. The offset chain amplifies a cantilever force acting on the one-sided attachment point and tries to tear the heavy motor off the frame. A serious and reoccurring problem the team has conquered by brute engineering.

Originally designed for the aeronautic industry, the Slovenian made Emrax 268 is a brushless <_600-volt engine, producing a peak 230 Kw or 306 bhp and is 268 mm in diameter X 90 width and weighs 43.9 lbs dry. The teams engineering prowess is evident in the battery design and its ability to feed the Emrax motor.

“Is that a Spondon swingarm?” I asked and Lawrence smiled at me as we stood and gazed at the machine, lost in the mechanical beauty. Adding to his elusive smile, “No, but your close. The tubing was bent, tacked and welded by an ex- Spondon fabricator at GIA Engineering. We determined the geometries and I made a few sketches from looking at his previous Spondon designs.” What a great answer I thought as I knelt to investigate the 1 ¾” diameter tube. The welds looked perfect.

Using their custom jig the students designed, laser cut and assembled over 80 sections of tubing for a frame that is far outside the norms to deal with the weight and changeable dimensions of the modular battery package.

After tack welding, the trellis exoskeleton was sent off to be finished by professional welders. Bike telemetry generated the data needed to fine tune and along with the build quality and confidence of the team, rider Matt Rees had the weapon and the peace of mind he needed to commit his all to the insanity that is the Isle of Man course.

 These young men and women have taken on this huge project in addition to their University courses, sacrificing time and intelligence apart from the education they signed up for. I have mentioned a few team members individually and would be remiss not to introduce the complete core members.

Sam Doyle – Technical Lead                                 Mark Portus – Mechanical Lead

Lawrence Beaumont – Race Engineer              Catherine Lin – Marketing

Robin Fells – Electrical Lead                                Matthew Rees – Rider

Rosie Coe = Project Manager

Chassis
Frame/steering head In-house geometry and designed. Assembled in student made jig and wielded by a professional chassis shop.
Front Suspension Stock Ducati 1098 forks rebuilt by Maxton
Front brakes HEL Performance billet 4 piston calipers and HEL lines
Rear suspension Custom Maxton shock mounted horizontally under sub-frame
Wheelbase 1450mm
Weight 250+ kg
Rake angle 24.5 degrees
Swingarm Geometries done in-house and constructed by an ex- Spondon fabricator at GIA Engineering
Engine/Battery
Type Water cooled, 3 phase brushless
Power 300 peak bhp
Torque 500 Nm available from 0 rpm
RPM Range 0 – 4500 with available overspeed to 5500 revs through field weakening effect
Battery Type Lithium Ion. 2000 + individual 18650 cells
Battery Output 600 + V
Electronics
Rider aids/Adjustments Engine/battery parameters incl’d traction control and pit lane limiter are available using the advanced MoTeC ECU but not implemented as of yet.
telemetry Full suite of on-bike sensors used for in-house simulations and real time adjustments

  The howl of the Senior bikes practice lap was gone, faded downhill towards the finish line in Douglas and the mountain seemed to relax. The cold wind replaced barking downshifts and the aerodynamic whoosh of the Zero bikes and from Creg-Ny-Baa, the racers road led back up to Kates Cottage where the setting sun tinted the peak gold. Just out of sight at The Bungalow, Joey watched the night come. Tomorrow the big bikes would race and I would meet a band of young students that are both fervent and humble, at once.

 

 

 

“The power and torque of the bike was unbelievable this year and it’s really exciting to think about future developments and the potential of the bike after more track time, which will allow us to get the weight distribution and set up spot on. The team have shown so much dedication and commitment and I’m so grateful for the opportunity to continue on this journey with them.”                                                                     – Matthew Rees

 

 

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