Why were “periscope” air intakes on Formula 1 cars banned in the 1970s?

[LDO]

Yes, I recently watched the movie “Rush”. I cheered for Niki Lauda; the analytical problem solver. Not the bull in a china shop. 

[CabDriver]

I’m not sure why they were banned, I’d like to find out more about that…will research!  Some of them were RIDICULOUS though:

Maybe something to do with the engine specs of the cars changing from naturally aspirated to turbo’d in the eighties meant that they didn’t need to be quite as large as they were too?  It’s an interesting question.

To Google!

[1930fordpickup]

Safety maybe it blocked drivers view of trouble ahead?

[LDO]

I believe the ban went into effect for the 1976 season, hence the reason for the Ferrari 312T2 intakes on the front sides of the body, vs Periscope for the 312T

 

[Bill Eh?]

I believe that this was done in an attempt to reduce speeds by reducing the amount of air getting to the engine. Did it work? No. As Lee has shown with the pictures of  Ferrari's adaptation in the 312T to the 312T2. No tall airbox, but clever thinking still got the same volume of air to the engine. The McLaren M23 also went from a tall airbox to a design where the air intake snorkles protruded horizontally behind the driver's head. James Hunt, won the '76 Championship with his revised McLaren M23. My first attendance at G.P.s happened that year. I went to the Canadian G.P. at Mosport and the United States G.P. at Watkins Glen. Both races were late in the season, and the low air boxes were in use at that point. The Lotus 78 adopted the same design feature that McLaren used, with the horizontal snorkles behind the drivers head.

[CabDriver]

So I did a little reading last night, and apparently a rule was brought in to stop the air boxes extending beyond the top of the roll hoop, reasoning that having anything much higher than that hoop was a safety issue.

Once the turbo cars started coming in, the turbos were mounted low on the cars, so the air intakes moved down accordingly - generally into the side pods.  

[Bill Eh?]

It is true that FIA stated that safety was the motivation. They have to provide a plausible reason for the ban after all. However, the banning of the airboxes was simply a means of the FIA clamping down on the "ram-air" effect they created in an effort to reduce engine performance. The bigger the opening, the more air - and thus, intake pressure - you had going to the engine. The higher you had the intake, the better chance you had of capturing cleaner and cooler air. Engines prefer cooler air. So, the FIA came up with new rules stating a maximum height for all bodywork and just like that, put the kibosh on the tall intakes.

Not much different from the 1994 season, when the FIA demanded holes be cut in the airboxes to reduce performance after Senna's death.

[Big John]

the Ligier Matra was just So French!  Thanks guys, good information about that transition in formula.  I went to the Long Beach GP in spring of 76 and they still had the snorkels.  I think they changed over within a race or two later.

Edited November 18, 2021 by Big John
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[LDO]

29 minutes ago, Big John said:

the Ligier Matra was just So French!  Thanks guys, good information about that transition in formula.  I went to the Long Beach GP in spring of 76 and they still had the snorkels.  I think they changed over within a race or two later.

I had never heard of that car, so I did a quick search. Holy cow, that thing looks like a caricature!

 

[Bill Eh?]

My favourite car of that era was the Brabham BT-44

 

[Baraczknowicz]

Airboxes were first "banned" after the 1976 spanish GP, safety being the main reason behind it. These airboxes were responsible for the ram-air effect (annex 1), which acted as a forceful feeding of air caught in the airbox intake into the carburettors, similar to a forced induction system, but passive instead of active (like turbos and superchargers). Furthermore, it was not uncommon for ariboxes (specially in back of the grid teams) to fall off after a small shun or if the mechanics didn't screw the bolts that held the airbox tight enough. They'd be first limited in height and intake area, later being discontinued due to low benefits in speed and adding drag to the cars (annex 2).

The airbox would make a return to F1 in back of the grid cars in the mid 80s though, as leyton house march showed up in 1987 with the march 871 chassis running a Ford DFZ 3,5L engine, which appeared more often than not with a big airbox that'd bifurcate and present an intake either side of the driver (annex 3). Later, in 1989, the FISA (FIA) would "unban" the airboxes, with not so many teams presenting them later in the season, but making an appearance in pretty much every car of the 1990 season (annex 4 & 5)

[sfhess]

On 11/17/2021 at 6:44 PM, LDO said:

I had never heard of that car, so I did a quick search. Holy cow, that thing looks like a caricature!

 

The "teapot" Ligier.