Changing shapes from BY-08 to BY-09

Two weeks ago, we unveiled our latest vehicle ‘BY-09’ for the upcoming 2009 Australian International Pedal Prix (AIPP). It’s been our most popular blog post yet. Whilst we’ve worked on all areas of the vehicle, the most visible change is to the vehicle’s aerodynamics. This new shape has come about through some fresh thinking with the aim of reducing the overall width, height and length.

Here’s some insight into our canopy development process…

Looking back before moving forward

Early concepts began towards the end of 2008, when as a team we reflected on the performance of ‘BY-08’ during the 2008 AIPP. The main conclusions pointed towards three areas:

• the need for a reduction in width, so that the vehicle would be more maneuverable through traffic.
  
  
• Improved visibility was another key objective, so that riders could see hazards in all conditions.
  
  
• The third and perhaps the biggest weakness was the strength of the canopy. In the past BYR has suffered from having an incredibly fast aerodynamic vehicle at the start, but little more than a sack of Kevlar and race tape come Sunday morning! 

How do you reduce a vehicle’s width and know it won’t tip over?

The first aim was to design a vehicle that could be a considerable amount narrower and still offer satisfactory level of stability around the bends.

From here we constructed a number of prototype frames before we were satisfied with the performance in terms of stability and drive system efficiency. From the final prototype, that I will talk more about in the coming weeks, we were able to determine the exact clearances and sizes required both to meet the event regulations and the ergonomics of each rider. At this point we worked closely with Bendigo South East College (BSE – formerly known as Flora Hill Secondary College) to ensure that the canopy would work for both teams. The school’s prototype chassis was more advanced earlier in the year and so it used to determine the canopy specifications.

A New Shape (but with some elements of old)

The shape is quite different from our BY-08 shape, but features some traditional BYR characteristics:

• The tail is pointy much like all previous designs however the keen observer may have noticed the absence of the integrated rear wheel pod.
• The profile, when viewed from the front or behind, follows the trend of tucking in over the top of the wheels, however the tuck is much more gradual compared to previous designs.
• The front of the vehicle is much more abrupt, this is to keep the vehicle to a length of 2700mm and maintain a crank length of 175mm.
• You will also notice that the windscreen is a lot further forward and is constructed from a curved piece of plastic, this has also helped to alleviate the fogging problem that has plagued BYR like a sick dog for a number of years.
• The roof is also lot flatter, enabling the rider just enough room to pedal and corner. The need for an arc or a parabolic type profile from the front is not necessary as it creates a large amount of excess frontal area.
• The other key difference is an elongated access door. This door is almost twice the size of previous designs and improves the serviceability of the internal workings.

 From CAD to polystyrene foam…

The design was completed on CAD using a series of lofts, the design itself took many hours to complete and was certainly a challenging task for resident CAD man Crowey. Once completed the design was sent to a Melbourne firm to machine the profile out of a large block of polystyrene foam. Astoundingly in only three days, over the Easter weekend, the plug was machined and ready for pick up. This was a little more efficient than the three months that it had taken with the 03, 04 and 06 plugs and the cost was quite reasonable too!

… and from plug to mould
Once the plug returned home the task was to give it a light sand to remove any blemishes then seal the plug in a coat of Epoxy resin before a coat of build primer was added. This was promptly rubbed back waxed up and a PVA release agent applied. The plug was then shipped to BSE were the students constructed the mould, released it, rubbed back any blemishes and waxed it up. This process from the completion of the design took only two weeks.

First Canopy

The first canopy was produced by students at BSE. This enabled them to effectively prototype our canopy as well as enable the students to complete their vehicle a little earlier. From the school’s design, we opted to make a number of small changes to increase the strength of the vehicle but generally the two canopies are very similar. This project has been a great way to develop skills and connections between BSE and BYR.

The finished product:
a Canopy of Carbon, Kevlar and Foam Core

The final design of the BYR canopy features a layer of carbon fiber as well as Kevlar and a polyurethane foam core. The critical areas towards the front, around the wheel and the roll bars all feature a foam sandwich construction with both carbon and Kevlar on either side of the foam. In the les critical areas foam ribs have been used with a single layer of Kevlar. Throughout the canopy west system epoxy resin has been used and the whole project has been vacuum bagged, reducing the resin content and forcing all the little fibers together.

Daryl’s final thoughts

"Overall I think the profile is reasonable as always if it was to be done again things would be done differently. The size is interesting I would think that the height of the vehicle would not be a lot more that other teams perhaps it is slightly wider than other vehicles but not by a significant amount." - Daryl King, BYR Chief Engineer

BY-09 Canopy Specifications:

Length	2700mm
Width	770mm
Height (floor to roof)	740mm
Height (ground to external roll bar)	930mm
Ground clearance	40mm
Materials	Carbon, kevlar, epoxy, polyurethane foam
Weight	6.8kg

Feel free to compare the table above and post a comparison with your vehicle’s canopy.