Merryfield 2015

Joy at finishing the race

Merryfield 2015

Windy with impending thunder storm on a temporary circuit on the naval base airfield. Not as glamorous as historic Goodwood but with a short lap it proved more exciting.

Armed with race data from the previous race we changed the gear ratio, installed a dashboard with electronic read out so we could use our electronic speed controller to manage the power for the race distance and a hurriedly re-arranged back end to optimise the aerodynamics and power unit cooling.

Our goal was to finish both races without a tow truck.

No tow truck required, finished both races 11th and 12th and got a mention on the commentary.

Great racing wind swept and full of hay fever, the helmet was soaked inside with tears ūüėā

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Goodwood 2015

image4.0 am leave home,7.30 am arrived at Goodwood Motor Circuit for chainreactiongp’s first race of the season, frantic race preparation epoxy resin for nose cone, first time it had been fitted to the car. Batteries, brakes, new back power unit cover all had to be fitted for the first time, talk about leave it to the last minute! 8.30 Mot time, log book ready, car ready, we joined the queue for scrutineering. Passed our Mot, drivers briefing and rushed out for free practice. New batteries and ready for race one, 90 minutes of the historic Goodwood circuit. A last minute hitch with the brakes meant we had to start from the pit lane. Putting in consistent lap times and good pit stops, but the power gave out and Lydia who was driving decided she should retire to the pits, but frantic signalling from the track side telling her to stay out and cross the line to get the extra mileage, she got the message and ended up on the recovery truck half a lap later.

Race two started from the grid seat belt issue cost us two laps and then power failure with 5 minutes to go and poor Lydia returned to the pits on the recovery truck after a 45 minute wait. 3 hour journey home. image

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A chainreaction at chainreaction

imageA carbon fibre bonnet for light weight and aerodynamic shape and following the the f1 norm.

When you are 13 years old the use of such exotic materials is exciting and proved a challenge.

With help from the people at “Matrix Composite Materials “who kindly donated all the materials we needed to make the mould. We set about making a “plug” an exact replica of what we wanted, so with MDF, foam and lashings of car body filler we managed to make what we wanted.

imageThe next stage was where we caused a “chain reaction” laying up layers of polyester fibreglass and lots of polyester resin that once mixed with the catalyst cross links through a chain reaction and thermosetting to a solid.


The exciting bit cutting and laying up the carbon fibre cloth proved quite a challenge the cloth is very delicate and frayes just by looking at it.

We tried to economise on the resin and used polyester the results were good if you were go¬†ing to paint it, but as we wanted the raw look it was a bit scruffy.imageWe had another go, this time with the help of “C12 Carbon Fibre Developments”. Who very kindly layed up and epoxied a more robust plain weave cloth vacuum bagged creating a lighter 900g much smarter bonnet.









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Are you sitting comfortably ?



Driver comfort is not top priority in a race car. Our seat is fabricated from a single sheet of aluminium and formed in a traditional race car “bucket” style with neoprene foam padding.

The key, is its position within the car and it’s angle of repose.

The reclining angle did mean, upgrading the seat belt, to a 5 point harness. Significantly it means we can reduce the height of the drivers head in the car and therefore we can reduce the height of the roll bar, this in turn  reduces the amount of material needed reducing weight and drag.

We do however now need to reduce the height of the front roll cage as our smallest driver can no longer see out. We think this may be a safety issue?




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2014 in pictures



2014 remembered, Lydia setting up brakes, school workshop car park, Lewis Hamilton Hungarian GP fire, formula E and it’s baby, Castle Combe race MOT sticker, car upgrades, drivers.

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Staying in front



New 2015 Greenpower regulations have upgraded the frontal protection.

For the up coming season the rules now say that the area forward of the front bulkhead must be a minimum of 200mm deformable closed cell foam.

Should be easy just glue some foam onto the front and it’s done, right?

By adding to the front of the current spec car alters the length and with the aero dynamic upgrade we have planned for CR15 car means the car will be longer than the rules allow let alone fitting in the transporter van.

The knock on effect means we are re -thinking the whole shape of the car especially the front and back, driving position, seat, steering wheel, front and rear roll bars.

As if we we didn’t have enough to do.


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Speed is of the essence

Speed controller circuit board

Speed controller circuit board

More haste less speed or is it less haste more speed? either way it’s the same outcome.

Speed =distance /time.

So it should follow, that in a race where track position doesn’t count and the car that covers the most distance in a fixed time will win. Then the car with the most speed should travel the furthest distance.

But there is a twist, as in the current hybrid F1 and the new Formula E. Greenpower  racing has to be a managed race.

It would be easy to gear the car to gain max speed, we thought about gears and even aquired a six speed fully automatic gear cassette , but when you add in the drag, rolling resistance , weight and other inefficiencies we have decided to add an electronic speed controller with a wig wag throttle .

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Loosing weight


Chainreaction cr15 car

Chainreaction cr15 car

Showing holes cut in the chasis to remove weight

Developing the car inevitably requires adding new stuff, this comes with additional weight. One of the team goals this year is to remove at least the weight equivalent to the weight of that what is added.

Removing weight is proving much more difficult than you would think, but it does make you consider making new stuff out of lighter material or whether a component part is even necessary.

Obviously you could make use of light weight material such as aluminium, fibre glass, carbon fibre etc. but each of these have big draw backs in the school workshop environment and cost. Aluminium is difficult to weld at school, and composites are hazardous with fumes etc. of course they can be made off site or shop bought but that means the students loosing the opportunity for hands on manufacturing.







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Keeping the wheels on


New axle for chainreaction CR15 greenpower car

New axle for chainreaction CR15 greenpower car

Josh, year 10 student and Chipping Sodbury School Greenpower member with the Chainreaction f24 team. This week Josh has used the lathe to turn a new axle for the CR15 car, the old axle was shop bought. It had no land to hold the wheel bearing tight and as such was the CR14 cars weakness. The weight and pressure at race speed moving the bearing and the bearing in turn locking onto the axle and undoing the axle from the drive shaft, resulting in the rear wheel coming loose even a split pin through the axle to lock it to the drive shaft broke under the race speed pressure.

We have moved the whole drive shaft, the power unit and relocated the batteries to reduce the weight pressure and hope the new machined axle, complete with bearing lands, will solve the problem.

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