DELTAWING ENGINE
Extreme engineering
In designing an engine to meet the DeltaWing’s strict performance criteria, RML has come up with some novel solutions
T
he identity of the engine supplier for the DeltaWing has long been kept under wraps but, as Nissan
announced its support for the programme, it became clear that British engineering company, RML (Ray Mallock Ltd), was behind the architecture of the powerplant. Under the direction of Arnaud Martin, RML set to work creating a brand new engine for the project. RML was commissioned to design a bespoke engine based on the 1.6-litre turbo engine fitted to the Juke, and produced a prototype with relatively high weight, before refining it in the second iteration. The DeltaWing tested in the
US, completing 700km with the interim engine before the new unit was fitted for an extensive test programme at Snetterton in April, ahead of its much anticipated race debut at Le Mans in June. ‘The targets were set by Ben
Bowlby, and they included a fully dressed engine, complete with heat shields, turbo, exhaust manifold and so on, for less than 95kg,’ said Martin. ‘We believe that we should hit 90kg, but it was a lot of work in terms of choice of material and design of the block to make it as light as possible, while still maintaining durability.’ Other parameters included a
power output of 300bhp for the 500kg car, and a flat torque curve to be able to bring the car up to LMP2 speed in a straight line. But it was the weight saving techniques employed to meet all these criteria that set this engine apart from other models that will line up alongside it on the grid at Le Mans. ‘The weight of the chassis is
www.racecar-engineering.com • Le Mans BY ANDREW COTTON
more important than anything else,’ says Martin. ‘The car is less than 500kg and that is what gives it the incredible performance for power, so every kilo you put on it, you go backwards. It is more important to save weight than to find performance.’
TREMENDOUS FAITH It is a different way of thinking and, with the relatively low power output, the RML team was able to take some risks. By creating a crankshaft weighing just 7.8kg – achieved with holes bored into the unit – they have put tremendous faith in their choice of metals, and their engineering calculations. The engine revs to 7250rpm, and can go to 7500rpm where necessary, but any more than that and there is a worry that there will be torsional problems with the crank. There is, of course, a back-up plan with a heavier crank, but ahead of the first test of the car with the new engine fitted, and before it has even seen a dyno, Martin is confident the figures add up. ‘The crankshaft was a massive
weight saving, whilst achieving the same balancing characteristic as the crank in previous engines,’ Martin continues. ‘We use a certain percentage of reciprocating mass in our calculations. We have achieved exactly the same in this engine as in our other engines, while at the same time reducing the weight. The crank has tungsten balance weight on it, holes everywhere and is an interesting piece. I doubt you have seen one like it before. ‘Some of the weight saving
“It is more important to save weight than to find performance”
Low height carbon plenum is one of the few parts from the interim engine
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