First F1 car with flat underbody and diffuser

[Xwang]

Hi everyone,
I know that until 1982 F1 cars had Venturi channels and some of them had those channels that ended at the front of the rear wheels.
Then, in 1983, the rule dictated that the underbody had to be flat and some cars didn't have a diffuser and some didn't even have a covered engine (my 1:24 scale Ferrari 126c4 bburago model has the bottom of the engine uncovered and I suspect that the first Ferrari to have a diffuser was the 126c4m introduced in the second half of the 1984 season).
So which car was the first to have a diffuser similar to those currently in use?

[Jolle]

I would say every car in 1983, because the rules said so.

[jjn9128]

Hi everyone,
I know that until 1982 F1 cars had Venturi channels and some of them had those channels that ended at the front of the rear wheels.
Then, in 1983, the rule dictated that the underbody had to be flat and some cars didn't have a diffuser and some didn't even have a covered engine (my 1:24 scale Ferrari 126c4 bburago model has the bottom of the engine uncovered and I suspect that the first Ferrari to have a diffuser was the 126c4m introduced in the second half of the 1984 season).
So which car was the first to have a diffuser similar to those currently in use?

An interesting question. I'd always assumed when the flat bottom (between front and rear wheels) rule came in all the teams ran with a rear diffuser from the outset, e.g. this is the McLaren MP4-1 diffuser - it's even exhaust blown.



The Brabham BT52 diffuser seems to have been a bit smaller. I recall Frank Dernie talking about the Williams car going from L/D>6.5 to lift in their first 1983 wind tunnel runs before they started optimizing the diffuser.

[Xwang]

I've seen some Giorgio Piola's drawings of Ferrari 126C2b, 126C3 and 126c4 and they all had only small diffusers which seems to end before rear wheel center line and do not cover the engine bottom.

[jjn9128]

I've seen some Giorgio Piola's drawings of Ferrari 126C2b, 126C3 and 126c4 and they all had only small diffusers which seems to end before rear wheel center line and do not cover the engine bottom.

The bottom of the engine or the gearbox? Can't imagine any team would leave the bottom of the engine exposed after 1979. The drag saving just too valuable.

[Xwang]

I've seen some Giorgio Piola's drawings of Ferrari 126C2b, 126C3 and 126c4 and they all had only small diffusers which seems to end before rear wheel center line and do not cover the engine bottom.

The bottom of the engine or the gearbox? Can't imagine any team would leave the bottom of the engine exposed after 1979. The drag saving just too valuable.

Both in the model and in Giorgio Piola drawing have the bottom of the engine exposed.

[jjn9128]

Both in the model and in Giorgio Piola drawing have the bottom of the engine exposed.

Well the "old man" was quite outspoken on his views on aerodynamics Can you link the drawing?

[Xwang]

Both in the model and in Giorgio Piola drawing have the bottom of the engine exposed.

Well the "old man" was quite outspoken on his views on aerodynamics Can you link the drawing?

The drawing is in a printed book covered by copyright so I cannot post those images.

[jjn9128]

Fair enough. These are all the piola images I can find for '83.

[Xwang]

Thanks!
For example from this drawing:of 1983 126C3 car:
https://www.motorsport.com/f1/photos/fe ... /11446688/
It seems that the diffuser is short and do not cover engine and gearbox.
For what it is worth, this is how the 126C4 was made by BBurago:

[JordanMugen]

Thanks!
For example from this drawing:of 1983 126C3 car:
https://www.motorsport.com/f1/photos/fe ... /11446688/
It seems that the diffuser is short and do not cover engine and gearbox.
For what it is worth, this is how the 126C4 was made by BBurago:
https://postimg.cc/jntbrqTr

It seems a most unwise design indeed! This Ferrari does not appear to using ground effect to the full extent, especially given you would presume the designers would be keen to recover any bit of ground effect they could being quite experienced with the concept by this time.

I would say every car in 1983, because the rules said so.

It seems like every car apart from Ferrari then.

PS. There are so many version of Ferrari 126C, it is super confusing! Have I got this right:

Ferrari 126C3 early version



Ferrari 126C3 late version



It seems Ferrari preferred to rely on bolting on a whopping great big rear wing!

Ferrari 126C4 early version

(the 'organic' sidepod shape is terribly modern for 1984!)

Ferrari 126C4 late version