Musings.....

A glass of wine and a brief stint of mucking about on 2D design hopefully shows what the final shape of Projectile will be....

 

Best get started on the head cowling soon then!!!

 

 

Narrowing the Fraxle and Cutting the Shell

Having narrowed the back axle (baxle) last post, today we completed the narrowing of the front axle (fraxle?) to match and gave it a jolly good sand blasting while we were at it!!
Following reassembly came lots of measuring, sighting, squinting and sucking of teeth as the body shell was carefully marked for cutting the flip front which will give us access to the front axle and the batteries in a kind of bonnet...

Bonnet Shut







Bonnet Open!

 

Pretty good battery and axle access!!

 

Ooooh! that's pretty nice looking!!!

 

 Helmet is in the position it will end up when car is being driven

 

Finally we can get a really good idea of what the finished car will look like!!!

 

Narrowing the Back Axle and CNC lathe work

In my last post I brought you up to speed on the rebuild of Plume Projectile. Today was Greenpower afterschool club and the year 10's helped to reduce the width of the back axle (affectionately known now as the 'Baxle') by some 170mm. It now looks less ungainly and should also be a lot less prone to bending.....

View from the rear of the new, narrowed 'Baxle'

In addition to this sterling effort, our tame 6th former, Tom, has been hard at work all day sorting out our little Boxford CNC lathe. The feed rates and chuck speeds as supplied from Boxford were more than ambitious and were the cause of many a horrid graunchy noise during manufacture. Tom and I have now rectified this and Tom has managed to produce the first of a run of 8 aluminium spacer 'top hats' designed to spread the load and prevent us from crushing the delicate core of the aluminium honeycomb chassis material.




Tom, hard at work on the CNC lathe!

The End Result:

 

 

 

NICE!!!!

 

 

THE REBIRTH OF PLUME PROJECTILE

Way back in 2007, we built and raced a car by the name of "Plume Projectile"



Projectile racing in 2008

It was a pretty successful car and raced for three seasons, reaching a national ranking of 22nd at its best. Sadly, following the car's last race in 2009, the competition rules changed making it difficult to continue racing without a major rebuild, so Projectile was unceremoniously stripped of all her useful and re-usable parts (motor, wheels, brakes etc.) and consigned to the scrap heap.

Since then, the development of Darkside of the Plume has taken precedence and only recently has the decision been taken to re-launch Projectile with a new chassis. The plan was to have the car ready for the beginning of the 2013 season, but things never progress as fast as I'd like and we have made the decision to take our time and not rush the build at the cost of quality.

So here is the progress so far:

First, the back end of another roof box was cut off and a more aerodynamic "tail" was moulded from slices of MDF and Cellotex roofing insulation left behind by the builders....

After a bit of smoothing (not much!) we started to stretch 10mm thick strips of pink insulation foam over the mould, glue-gunning them along the bottom edge....

 



Once the mould was completely covered, the bottom edge was trimmed flush and a couple of layers of  thin fibreglass cloth were draped over and wetted out with resin....



Trimmed and fibreglass cloth and resin on the inside to add strength and durability and hey presto! the beginnings of a really lightweight yet strong, foam-core composite, pretty nifty body shell!!!

An so on to the chassis. We decided to push the boat out and fork out for a VERY EXPENSIVE 8'x4' sheet of aluminium honeycomb composite. It's very, very light but stronger than plywood of the same thickness! The body shell was placed on the sheet and drawn around and the honeycomb was cut out with a jigsaw. Here you can see the freshly fabricated front axle (pre paint) and the batteries in their rough locations...

 

The stiffening chassis sides were glue gunned into place (to be fibre glassed later) and a temporary back rest added....

 

 

 

Can't resist testing it for space! If a tubby chap like me can fit in, the students should have NO problems!!!

 

 

 

The side walls had to be cut down somewhat to fit inside the curved body shell, but still plenty strong enough I think! The brown goo holding it all together is epoxy mixed with micro resin balloons!! The back axle is in-situ and the whole thing is starting to look more like a car!!

 

 

 

 

Close up detail of the proposed drivetrain. The bearings are SKF ultra low friction (supposedly 33% less than a standard bearing) they were pretty expensive and are running in housings modified by me to take them.

The cassette is custom build by me, I hacked 2 Shimano 10 speed cassettes and combined sprockets from each to create a cassette with only one or two tooth steps between each gear. The thinking is that we should be able to use it to keep the current more constant by compensating for upwind/downwind and uphill/downhill sections within every lap!!! We'll see...

 

 

Close up detail of the drive transmission system. The little silver steel pins locate into the disc mount holes on the driven wheel. This way we should be able to remove a wheel quickly if  needs be, by just undoing one central wheel bolt....

So this is how far we have got as of Friday 21st June.....Next step is to cut the nose off to provide a flip front battery compartment and front axle access. Lots of careful measuring and breath holding for that!!!

 

 

I might narrow the back and front axle a bit as well, they are REALLY wide!!!

 

 

GOODWOOD - OUR FIRST RACE OF THE 2013 SEASON



Kirt pushes the car into the pits for a driver change...

Sunday 9th of June saw us travel to our first Greenpower heat at glorious Goodwood. After a particularly early start (5.30am may have come as a bit of a shock to the new year 9 team), our car passed its annual MOT scrutineering inspection and spent the hour's practice session with members of the team acclimatising themselves to the controls of the car.

Come race time, the car started from the back of the grid of 45 cars but quickly started overtaking other teams and gaining positions throughout Charlotte Finding's 40 minute drive.
The second driver up was Billy Nightingale, who after a slightly delayed start, (the pit crew forgot to turn the car on before pushing it out onto the track!!!) continued to steadily gain places throughout his drive.
After a swift battery change and a second driver change, Kirt Cowell made his debut, quickly putting in a fastest lap of the day so far!! Cool calm and collected, Kirt managed to gain yet more places in his stint at the wheel (joystick?!).
Carlos de Costa had a shaky start to his turn in the car, after he was pulled over after just one lap, having forgotten to put on his driving gloves! Nonetheless, once on his way again, he quickly fell into a smooth lap time, gaining a couple of places during his debut.

Billy Nightingale gives the thumbs up!

After 2 hours and 40 minutes of the 4 hour race, it was time for our second battery change, and by this point the pit crew were working like a well oiled team, getting the final driver Liam Lynch on his way very swiftly indeed. Liam it is fair to say is pretty short and hence also light and aerodynamic (being short had to pay off somewhere in life!). He quickly notched up our fastest lap of the day and enjoyed making sustained progress through the field of other teams reaching 12th place at one joyous moment!
The last quarter of the race was briefly halted due to another team's roll-over before successfully continuing, with Liam holding onto 14th position well.
The penultimate lap was somewhat eventful, as young Liam, whilst waving to his Mum and Dad, drifted off the track and onto the grass, before hitting a bump and getting Darkside completely airborne!!! The car thankfully landed back on the track, fishtailing all over the place, with Liam wrestling to regain control. The final lap saw us black flagged by the race marshals, for our Dukes of Hazzard driving and we unfortunately lost a couple of places finishing 16th and completing 81.6 miles.

Charlotte battling hard with team USA

Following a bit of post race disassembly, it transpired that during its venture skywards, the car had suffered a horribly bent rear axle, which was quickly changed for a beefier one, ready for our next race at Ford Dunton Technical Centre on the 6th July.

PROJECT PLUME RACING

Project Plume Racing is now in its 7th season of the Greenpower competition, a National competition for schools where students have to design, build and compete in an electric car in a series of 4 hour endurance races. Plume School currently races its roof box based car "Darkside of the Plume".



Darkside of the Plume on the banked turn at Ford's Dunton Technical Centre Race

In this blog I shall attempt to keep you updated on our racing progress and also the development of Darkside and the build or our new cars "Projectile" and "Lignum".