MOTORSPORT
“In its original configuration the Juno
is fairly fast,” says Ryall. “But in line
with the bodywork improvements we
were trying to make it even faster. It
was a fairly logical next step to do
some CFD in order to improve things
even more and the project just
developed and evolved from there.”
“What started as a fairly simple
exercise to give us a little bit more
speed, turned into a complete
remanufacture and rebuild,” says
Ryall. “When everything is finished,
with a bigger engine and the new
bodywork it should weigh about the
same as the old car. The projected
all up weight including driver is 600
to 620kg depending how things
go, which gives us about 1bhp per
kilogram (1000bhp/tonne). It's really
a go-kart with very sticky tyres.
“We have bigger wheels and tyres to
give it a little bit more traction with
the increase in horsepower, but this
necessitated wider front and rear
guards,” says Ryall. “The additional
volume was created on the inside
of the wheel houses and we've
developed a system whereby we
can accommodate wide and narrow
tyres by swapping out the outside of
the front guards. The wider tyres will
fit underneath the back quite nicely.”
The moulds for all the new body
panels are made from carbon fibre.
“Most people make their moulds
from fibreglass for low volume
production, but the rigidity of the
mould is important,” says Ryall.
“So Gregor went the extra mile and
made carbon moulds. With carbon
moulds the part comes out of the
mould with more precision, there is
no flex or dimensional changes and
it fits exactly. With fibreglass moulds
there is usually a considerable
amount of hand finishing and fitting
required to make the bodywork fit
together as seamlessly as possible.”
“Precision is important because
in a race situation the scrutineers
tend to be exact to within about
plus or minus 2 mm, so you can't
afford to have bodywork that isn't
exactly to the right dimensions,”
continues Ryall. “We’re also using
some high-tech fixtures to fix the
bodywork to the frame - these are
used in satellites and are starting to
be used in some motorsport applications.
They are so discreet you
can't see them on the surface of the
car unless you look very closely.”
Juno make what they call the CN
and the SSC chassis. The CN is
slightly bigger, but the SSC seems
to have been more successful. “As
we were making a carbon body for
this car we decided to do some
fairly extensive CFD investigation to
improve the aero as well. The floor
is quite different to most sportcars in
that it's flat for most of the way from
the front splitter to the start of the
diffuser at the rear,” says Ryall. “It's
only needed under the pointed part
of the bodywork at the front, so the
floor is almost triangular, a bit like a
Formula One floor.”
Most of the expense in a project
of this nature is in the design and
the preparation of the plugs and
the composite moulds. “Once the
moulds are complete and we’ve
seen some good quality parts
coming off the moulds, we will get a
better idea of the costs involved to
build a fully carbon MATOS body,”
says Ryall. “By the time it’s finished
we imagine this will be a unique car
with the only close competitor being
the Norma M20 FC from Norma-
Auto-Concept in France.”
The carbon manufacturing process
of the moulds is a vacuum infusion
process with a relatively low
temperature cure, rather than the
more expensive autoclave process.
The finished body uses pre-preg
carbon with Nomex honeycomb
core construction. The plugs for
the moulds were made from CNC
machined laminated MDF. The
machining was done by Jackson
Industries in Auckland, who did
much of the machining for the
Americas Cup boat for Emirates
Team New Zealand.
Once the front is done the next
step is the rear bodywork and the
engine cover. “The rear moulds
were made using polystyrene plugs.
The polystyrene plug was covered
in fiberglass and a combination of
Duratec Polyester Surfacing Primer
and PTFE film,” says Ryall. “The
mould material is resin infused
carbon and is made up of three or
four layers, which is about 2 to 3
millimetres thick. Polystyrene doesn’t
like polyester resin, but epoxy works
fine.”
The baseline CFD analysis for the
original Juno was done with data
taken from the original body. The
car was measured and modelled
to produce point cloud data, which
was cleaned up and converted into
surface data, and then transferred
to CAD.
“There are two engine intakes on
either side of the engine cover for
the new engine configuration,” says
Ryall. “In the early stages there was
no real point in producing too much
detail for the engine cover until the
engine and the final details were
available. We feel we have achieved
a great result working this part out
as we went along. The rear fin is all
part of the support for the rear wing.
“We’re trying to use the existing
Juno mounting points so that we
can swap the various body panels
on and off easily,” continues Ryall.
The final car will be renamed MATOS
for commercial reasons with John's
business. The name is trademarked
already. The final look of the car will
be very close to smaller versions of
the pre-closed cockpit LMP cars.
“The 3D printed mirrors are one of
our favourite pieces,” says Ryall.
“These were designed and made
from CRP Windform material by
Dominik Scheurer, of Scheurer
Swiss based in Zurich. Dominik
has a background in LMP and
Formula 1, and is now also working
in aerospace. We are also grateful
to him for his advice in many other
areas of the build.
20 August 2019