Gordon Murray Automotive T.50 'rear fan'

[botsapper]

Almost 30 years ago Gordon Murray designed the legendary McLaren F1, to become the ultimate benchmark for supercars for years to come. Driver sat in the middle of a three-seat configuration, carbon-fiber monocoque construction, a 627-hp V-12, six-speed manual transmission but with no ABS, traction control or power steering. It went over 240 mph and first entered & won the 24 Hours of Le Mans. Gordon Murray wanted to celebrate his 50 years in automotive engineering and created the T.50, he wants it to the be the last great 'analog' supercar. It would also have the same tri-seating configuration, naturally aspirated V-12, manual gearbox and weighing only 980 kg but he will be using his unusual aerodynamic system. He will be using the same idea in the Brabham BT46B electrically-powered fan system, which won its first & only Formula 1 race before it was banned. The T.50 uses a 48v fan to only remove dirty air from the disrupted boundary layer, not to suck the air down but to make the diffuser more efficient in creating downforce. It would have multiple adjusting valves for an auto aero mode and a high downforce mode that would assist in braking mode. It also assists with the ram induction for the engine. The 400-mm fan exhaust can also create a 'virtual longtail' that would reduce drag by 12%. The fan system's total weight would be less than adding a large adjustable rear wing and its hydraulic actuators.

https://www.youtube.com/watch?v=FSaI6STYIQA

https://www.youtube.com/watch?v=mphk-VP0chY

[cRiPpLe_rOoStEr]

Gordon Murray is a genious, usually ahead of his time, but the average Joe often doesn't want to try too hard.

[AeroMcAeroFace]

There was an F1 car that managed to stall the diffuser on straights to get reduced drag, not quite sure how it worked though.

I don't understand the virtual long tail? Is this a bit like that morelli tail thing?

[Piotrsko]

Originally Posted by AeroMcAeroFace

There was an F1 car that managed to stall the diffuser on straights to get reduced drag, not quite sure how it worked though.

How does stalling lower drag? Every instance I see drag is max at stall

[AeroMcAeroFace]

I don't know, they lowered the car on the straights using clever suspension. Presumably increasing the pumping ratio, lowering the airflow under the car. How it works, why it works I don't know

6:34

https://www.youtube.com/watch?v=sRB9T2ACPRI

[deluxx]

[QUOTEAeroMcAeroFace;638663]https://www.youtube.com[/url][/QUOTE]

Wow It jumped by its self?! What car is that?!?

[serialk11r]

Originally Posted by AeroMcAeroFace

There was an F1 car that managed to stall the diffuser on straights to get reduced drag, not quite sure how it worked though.

I don't understand the virtual long tail? Is this a bit like that morelli tail thing?

I believe the way the T50 works is the diffuser is stalled without the fan (too steep), so that if the fan is sucking the boundary layer away, the diffuser produces both lower drag and more downforce. The car sits high enough that you can send quite a bit of air under the car without creating too much drag.

On F1 cars, I think the car is set up to pull a lot of air quickly under the car to produce high downforce at the expense of drag (ground effect is probably the main contributor). Stalling the diffuser reduces the airflow through the bottom of the car, and cuts both drag and downforce.

[freebeard]

Haven't watched the videos, but yes the real magic is in the roof of the diffuser.

[aerohead]

Originally Posted by freebeard

Haven't watched the videos, but yes the real magic is in the roof of the diffuser.

That's my take, at least on supercars. Ferrari has flaps that lower to a less radical angle on the straights, where cornering force isn't as important, then on approach to turns, the flaps lift, increasing the ramp angle, allowing low base pressure to communicate under the diffuser. Online, there are photographs of a Lamborghini configured for this and the tufts indicate forwards airflow down and under the car, heading for the suction peak at the venturi.

[JulianEdgar]

Originally Posted by aerohead

That's my take, at least on supercars. Ferrari has flaps that lower to a less radical angle on the straights, where cornering force isn't as important, then on approach to turns, the flaps lift, increasing the ramp angle, allowing low base pressure to communicate under the diffuser. Online, there are photographs of a Lamborghini configured for this and the tufts indicate forwards airflow down and under the car, heading for the suction peak at the venturi.

That is NOT how diffusers work! In fact, it is 100 per cent wrong.

Refer to Chapter 6, Race Car Aerodynamics (Katz) - and numerous other references.