DRS downforce numbers.

[hardingfv32]

Has anyone seen anything on estimated downforce numbers, open to closed, with the new DRS system? I know the flap sizes vary among the teams.

Maybe as a work around, any data on the flaps as used in a standard two element rear wing?

Brian

[Tozza Mazza]

I have a model of aerofoils closed and open. If anyone wants to CFD em feel free. Used real aerofoil shapes in a common F1 layout, so should give fairly decent results.

[hardingfv32]

Is this a big challenge Ringo?

Brian

[shelly]

IIRC Hamilton has said in an interview there are 30 points difference in downforce between DRS open/closed

[gridwalker]

What does 30 points mean anyway? Is it a percentage? Is it just an arbitrary number? PR speak? Does anyone actually know? Scarbs, can you translate?

[hardingfv32]

In the Bond market 30 points is .30 of 1%. Hopefully here it is 30%, but I'm not sure. Funny how every trade/activity likes to develop their own meaning for certain words. Are you in or are you out kind of a thing.

Brian

[hardingfv32]

Maybe there is a way to back into this.

The FIA advertised or simulated gain from DRS in 10-12 KPH.

Just saw a RB video that states KERS is good for .3 sec per lap but a 1.5 gain is required to make a pass. KERS is good for 80 HP. Can we say that DRS is good for 1.5, since it can allow a pass? Saying DRS in worth 400 hp in drag reduction would seem a stretch.

IF the engines produce 800 HP (round number), how much in used up by aero drag on average, 700 HP?

Brian

[thisisatest]

so you start with 800hp, probably made at or near the 18k rpm limit. road cars quote 10-15% drivetrain losses when tested on rolling roads. I can imagine the F1 cars are better, with advanced coatings and treatments on gear and bearing surfaces, thinner lubricants, much lower-pressure seals... so maybe half? 7%? that's 744hp left.
i thought Hamilton was closing up on Vettel with something like a 20kph difference, and I understood Lewis was on the limiter. He kinda pegged the limiter at about halfway down the straight.
it seems you have to know what Lewis' terminal velocity would have been with tall enough gearing. or estimate his acceleration before topping out.
my head hurts.

[shelly]

What does 30 points mean anyway? Is it a percentage? Is it just an arbitrary number? PR speak? Does anyone actually know? Scarbs, can you translate?

It was discussed some time ago in the thread "how much is a point of downforce".
The most common convention in teams is 1 point = 0.01 in terms of SCz (with SCz being dowforce coefficient times reference surface).
So if you multiply: points * speed^2 *air density/2 you get downforce

[alelanza]

Interesting, i always thought it was just a scale each team used, and where 30 McLaren points didn't necessarily equal 30 RB points

[shelly]

Most of the teams use the same convention

[Tozza Mazza]

I'm open to any study on this, could well be interesting to do a basic comparison between the data from the teams and data from a basic CFD study.

Below are some images of my rear wing models. The aerofoils themselves are very detailed, as in the mostpart, are the endplates, but the actuator is a bit slap-dash. It should be more than good enough, however, to give promising results.


Whole wing - DRS closed

Whole wing - DRS open

Slot gap - DRS closed

Slot gap - DRS open

TM.

[PlatinumZealot]

hamilton said 30 points as said above too. So at varying speeds that 30 points represents different levels of downforce.

[hardingfv32]

Here is a 2010 study by Lockheed on a rear wing where each half of the rear wing flap can be actuated seperately. Who would have pad to have this done? They seem to provide downforce and drag numbers.

GOFAST-1 Final Report, AER E 462: Design of Aerospace Systems

http://seniord.aere.iastate.edu/reports ... report.pdf

Brian

[machin]

That is an interesting article.... I couldn't see any info on drag for a wing with the complete upper tier in the "flat" position (aka today's DRS system)...??? Or maybe I missed it?

I've had my own go at working out the difference in drag the DRS provides... using a base "typical" f1 car model and the general observation that DRS gives a car 12 to 15kph top speed advantage I've worked out the car's TOTAL drag reduction needs to be in the region of 10 to 15%!!! must admit I was quite surprised by this difference....

The simulation below assumes the DRS activation point is 100mph.