DDD vs EBD

[Pierce89]

This is incredibly difficult to compare. Each car is optimized for the current set of rules. Different tires get in the way, different car designs and wings optimized for DRS cause trouble too. And then some teams just seem to get it right with one particular design and others do not.

exactly.So i use the small amount of aero knowledge I've gained at school so far. With that limited knowledge, I feel that the DDD would ultimately be the more powerful device, IMHO.

[hardingfv32]

Your opinion is fine, but how about some details into the logic you used to form your opinion.

We can't learn or discuss anything from opinions that are not supported with reasoning.

Brian

[raymondu999]

I seem t remember someone saying that the double decked aspect of the DDD itself is not actually a good thing. A single deck with similar volume and other measurements would actually be more efficient. Given that the EBD would probably allow you to create an air wall, allowing you increased rake, would it not then give you potentially more downforce?

By the way, for argument's sake, are we or are we not taking into account fuel and reliability issues of the EBD?

[Lycoming]

reliability issues with the EBD seem to be effectively nonexistant, except for renault, but thats more of a FEE thing than an EBD thing. and by unning more rake and using an air skirt, isnt that similar to the DDD in that they are increasing the effective height of the diffuser beyond what the rules enable you to have in terms of hight above the referance plane?

[MIKEY_!]

Is the EBD height greater than what the DDD height was?

[Byronrhys]

I think this is a great question, by the way, although I think it will be almost impossible to answer. My first thought was to compare this years RB7 lap time at Australia to last years MP4-25 fastest qualifying lap. Now I compare these two because the MP4-25 had a non-blown second-gen double diffuser and (importantly) the f-duct which could be seen as equivalent to DRS (for qualifying). The RB7 is the best example of an EDB car in 2011. So the results

RB7 (2011): 1:23.529
MP4-25 (2010): 1:24.675

Note, also, that the blown DDD of the RB6 set a lap time in 2010 of 1:23.919 for pole.

Also interesting is that this years EDB cars are faster than last years DDD non-blown and blown cars. The caveat to that is that you'd probably expect (with static rules) that the cars would gain a second a lap over a years development. So you could argue that the DDD MP4-25 would have set a 1.23.5 (ish) in Australia after a years development.

Then chuck the new tyres into the equation and who knows!!!

Like most people say they are very similar but very different in some aspects, the Tyres, DRS, Kers and weight throw of the comparison.
I don't think Albert Park is the best circuit to compare either, for instance at Catalunya a more downforce demanding circuit:

MP4-25[Bridgestone] : 1:20.829 DDD,F-duct only
MP4-26[Pirelli] : 1:21.961 EBD,KERS,DRS only
Fastest Lap 2010:1:24.357 on lap 59 [Lewis]
Fastest Lap 2011:1:26.727 on lap 52 [Lewis]

Just throwing numbers around won't do much but I'd still pick the DDD.

[Mr.S]

DRS & KERS combined are so much more efficient than F-duct. KERS on an average gives around 1 full seconds more or less which decreases & increases track to track. KERS about 0.2-0.4 depending on manufacturer & circuit.

How much did the F-duct contribute???? 5-6 km extra speed when DRS gives 20 km extra speed for some cars. I dont hink F-duct gave more than 0.5-0.6s.

So just KERS+DRS adds 1 full seconds to that laptime compared to F-duct.DDD was massive. EBD is very powerful too but nowhere near as DDD.

[DM0407]

@perce: being the flat floor leading edge rule limited, I think that also the potential downforce from DDD is limited (you can see it as a bottleneck at the front of the flow). A for Toet quote, it is about 2010 vs the past, whereas here we are discussing 2010 vs 2011, so it is not relevant.

I think the bottleneck at the front would just create a faster flow as the DDD would still need to be fed. A bottleneck at the front would just create a bigger vacuum to make up the difference, no?

Also worth considering is the lay out required for each setup. The EBD makes for a much neater package at the rear and a lower CoG. Wasn't the gearbox very high above the floor in last years design?

[Skunk0001]

It really has been amazing how much downforce the blown diffusers have generated, as the teams have perfected them; probably 20% more than was envisaged by Pirelli when they designed their tyres and certainly more than enough to take the cars back to and beyond the levels of downforce in the double diffuser days.

Source: http://www.jamesallenonf1.com/2011/10/r ... designers/

[shelly]

Interesting quote -I agree with the estimat, but it is a shame that james allen has not provided a good source for the downforce level information.

[Pierce89]

It really has been amazing how much downforce the blown diffusers have generated, as the teams have perfected them; probably 20% more than was envisaged by Pirelli when they designed their tyres and certainly more than enough to take the cars back to and beyond the levels of downforce in the double diffuser days.

Source: http://www.jamesallenonf1.com/2011/10/r ... designers/

this says the CARS are making as much downforce as last year or maybe a little more not just the DIFFUSER. To me, when you take into account the speed of development in F1 which is roughly 2 seconds a year in a good team(we'll ignore tire because i think ultimate pace in first few laps is roughly equivalant if you disagree with this sorry this MY assumption), it seems they've done alot of work with MUCH MORE DEVELOPED AND REFINED CARS than 2010 to equal or slightly better a MUCH LESS REFINED AND DEVELOPED CAR from 2010. All James is saying is that Pirelly thought the ddd AND ebd had been outlawed so they thought 2011 would have less downforce even with all the development, but the teams all found a loop hole to bring back the ebd and combined with another year's devepment equaled the 2010 downforce.

[Byronrhys]

The cars aren't making more downforce than in 2010 though, James Allen must just be talking ish.

[raymondu999]

I don't buy it. I think the cars of last year still had more downforce. This year possibly has more mech grip; but less downforce

[PlatinumZealot]

I think Double diffusers were slightly better. EBD is only a small area, with a knock back effect which you have to get right - sometimes giving 0.5 seconds to 1 second a lap. Doudble deck was just raw unadulterated expansion zones - some slots running 1 meter in length like on the RB6.

The two are independent effects and can acutally work together.

[Pierce89]

I think Double diffusers were slightly better. EBD is only a small area, with a knock back effect which you have to get right - sometimes giving 0.5 seconds to 1 second a lap. Doudble deck was just raw unadulterated expansion zones - some slots running 1 meter in length like on the RB6.

The two are independent effects and can acutally work together.

This is the exact point I've been banging on about. But overall, I would definitely say the DDD had more ultimate potential.(It literally more than doubled diffuser volume)