Interview with Honda Racing's Graham Miller
As Honda Racing F1 Team’s new full-scale wind tunnel nears completion, here follows the BARHondaF1.com interview with Graham Miller, Director of Wind Tunnel Operations and Support Services. Miller provides a progress report on the all-important wind tunnel project and gives an insight into the significance of aerodynamics in the design of a modern Grand Prix car.
How important is aerodynamics to a modern Grand Prix car?
"Aerodynamic development of cars has become paramount in Formula One; it has been big news in the sport ever since Lotus began experimenting with race car wings back in the late 1960s. In the late 1970s the concept of ‘ground effect’ – where the entire under-body of the car acts like an upside-down aircraft wing, literally sucking the car into the ground – was developed. At that point the Formula One world really sat up and took notice and began to take aerodynamics very seriously, with teams beginning to understand the importance of wind tunnel technology. Nowadays, aerodynamics absorbs at least 15% of a typical team’s car development budget and using wind tunnels is the only way to remain at the forefront; they are one of our most important design tools."
Where is the new wind tunnel being built?
"On site here in Brackley. We have demolished an existing unit to make way for the new three-storey building that will house the wind tunnel."
When did work start on the project, is it still on schedule and when will it be fully functional?
"Construction began on site exactly a year ago, in December 2004, by starting to dismantle the existing factory unit to make way for our new facility. The programme is absolutely on schedule and we plan to be productively testing in July 2006."
What does a wind tunnel cost and do you need a specialist company to build it?
"A full scale facility such as ours costs in the region of £30m. The wind tunnel itself is a specialist piece of kit, as is the 'rolling road' system on which the test vehicles sit, so it is a very technical and complex construction project in which the building constructor needs to work concurrently with the airline manufacturer and rolling road provider. Excellent teamwork and communication is essential in getting the project completed within the minimum timeframe."
How big are the fans and how powerful are they?
"The main fan has a blade diameter of over 5m and is powered by a 3,000 horsepower electric motor, generating a torque of 32,000 ft-lb at 500 rpm. In total there are 16 rotating blades and 27 stator blades – non-rotating blades that are a structural part of the fan construction. This fan will move around 1000 m3 of air per second so we'll be getting wind speeds of 80 metres per second in the test section!"
What else will be included in the building?
"Obviously there will be the wind tunnel itself plus all its associated plant, including drive cabinets for the fan and rolling road, electrical transformers, air compressors and vacuum pumps, as well as a fully-integrated manufacturing facility. In addition, there will be a fully-equipped server room which houses the servers for the wind tunnel plus provides an essential disaster recovery facility for the site as a whole in the event that something should happen to the main server room in the main HQ building, plus a museum and a presentation suite so that we have an impressive environment in which to entertain our guests as well."
Honda Racing F1 Team already has a half-scale wind tunnel at Brackley; what are the advantages of a full-scale facility?
"With good execution, the full scale tunnel will be vastly superior in terms of accuracy. It's what we call a 'closed-jet' tunnel which generally gives you a better quality of air flow. In the ongoing quest to improve the accuracy of the aerodynamic test data, the trend is towards large scale models which give better reproduction of vehicle surface features and higher accuracy. This naturally demands large-scale test sections which leads to higher capital costs and, ultimately, higher operating costs.
The existing Honda Racing F1 Team smaller scale wind tunnel is different: it has an 'open jet' configuration. As the name suggests, open jet tunnels have an open test section in which we can remove the two walls and ceiling. In principle, the jet allows the flow field around the model to relax to something close to that experienced in ‘free air’ on the track. Another advantage is that it offers increased visibility and access for the test engineer. The disadvantage with open jet tunnels is that outside forces can affect the airflow in an unpredictable way. Aerodynamic test data is not generally as accurate as that obtainable from full scale, closed jet tunnels.
The ultimate goal is the achievement of a near perfect match between the flow field generated in the wind tunnel with that in free air. To achieve this, our new tunnel features a test section with walls that can be shaped to vehicle contour and yaw angle."
Which parts will be tested in the tunnel?
"We plan to test both model and full size parts within the latest tunnel, and obviously continue with scale testing in our existing facility. As with most teams, we will continue to chip away with incremental changes to improve lap times. This can involve any aspect of the car surface and typically includes the front and rear wings, the sidepods and the area immediately preceding them and, of course, the engine cover and floor."
What conditions can you simulate in a wind tunnel?
"A good wind tunnel is an essential component of a successful Formula One team. They provide measurements for both downforce and drag, which have a major effect on the overall performance of the car. But I think it’s fair to say that teams are still some way from replicating a car’s behaviour on the track from inside a laboratory, which is effectively what a wind tunnel is. The major test equipment in the wind tunnel customised to work on a Formula One car is the rolling road section, which is needed to simulate the strong aerodynamic effect associated with the car moving close to the ground. The rolling road is itself within a turntable so that we can skew the car towards the wind. This has a major effect on downforce because when a car comes to a corner it will find itself at an angle. If your car suddenly drops off in downforce right when you need it, then you’re in a bit of trouble!
Reproducing wind tunnel performance on the track is the key and, in the end, is what it is all about."
Is there anything that can be done in a wind tunnel that can't be done using computer software (Computational Fluid Dynamics packages)?
"Far from competing with wind tunnels, CFD has made them significantly more efficient. CFD is, in essence, an equation that governs the flow of air and the effects of turbulence can also be modelled with a degree of approximation. New development parts aren’t made at random anymore – they're designed on computer and run through CFD simulations to get a feel for their effectiveness before manufacture.
Aero parts then still need to be checked in the wind tunnel because the wind tunnel can give the ‘right’ results against a modelled one. Wind tunnels are also more productive when it comes to the number of planned cases developed in a given cycle. But wind tunnel time is highly expensive, and CFD is a vital tool in making sure new developments have a good chance of working before they enter the wind tunnel."
How busy do you expect the wind tunnel to be when fully operational?
"Very! For the initial period we will run 24 hours a day when full-scale testing and 18 hours a day when scale testing. This is on top of the 24-hour running of the scale tunnel. The expectation is that we will move to consistent 24-hour testing in both facilities."
Will the team be employing more aerodynamicists when the wind tunnel opens?
"The second tunnel effectively doubles our aerodynamic testing facilities. As part of this programme, we are recruiting a number of positions including senior aerodynamicists, wind tunnel technicians, model makers and machinists. These opportunities can be explored within this website."
Is this wind tunnel the missing piece of the Honda Racing F1 Team jigsaw?
"Absolutely, yes. With the completion of this facility in the summer of 2006, we will have a fully integrated site here in Brackley and all of the main building blocks required to support our World Championship ambitions."
