Adjustable Rear Wing (DRS)

[ringo]

No i'm hearing you man.
Keep in mind the wings have to pivot at the trailing edge.

Having only Rotary motion from a motor would mean it has to be located where the pivot is. Unless the motor has a cam or a lever arm.
It's not evident that Mercedes have a motor at the leading edge.
It can't be placed anywhere else. The motor also needs to be able to hold it's torque without rotating.

The next best electrical device is a solenoid.
About 200lb need to be exerted.

This may need a thread indeed. A shot of the front wing motor would also be a guidance, and also the tf09 hydraulic front wing.

[xpensive]

So, the flap must pivot no further than 20 mm forward or below the trailing edge of itself? This makes it a little more difficult for pneumatics, but let's try and see what we are talking about in terms of forces;

- Imagine the flap being 700 mm wide and 250 mm high, travelling at 300 km/h.

- The object above will generate a drag of 500 N at a Cv of 0.7 and an air-density of 1.2, acting 105 mm below the pivot.

- If the actuator is placed 230 mm below the pivot, it means that it has to carry 500 N times 105/230 = 230 N

- Over two actuators with a pressure of 7 Bar, you need an area of 1.6 cm^2 per actuator, meaning ø15 mm pistons.

Rough numbers I know, but it should perhaps give us an idea of which forces we are dealing with here?

[WhiteBlue]

Hydraulics always have a much higher energy density than pneumatics, plus the fluid is incompressible which gives more precise control. IMO teams would be dumb not to go for the much more compact hydraulics. They have a lot of expertise on that from the gearbox.

[The FOZ]

Similar to the ones used in the front wing?
How fast where those things. Any body Got a video?

No video, but I do remember the adjustment being quite quick - under 1 second or so over the full sweep.

Another solution could be a pinion gear at the pivot, with a rack gear mounted on a rod, driven by a solenoid. This would allow the solenoid to be located lower on the wing endplates, lowering CoG.

Then again, the actuation could come from a hydraulic or pneumatic actuator as well...

[Richard]

Either way, it is interesting to see how some are huge (RB) while others are hidden in the endplate (Merc).

I can't help thinking that big RB lump is either an aberration by Newey, or it is hiding something clever.

[747heavy]

maybe some find this interesting

http://www.moog.com/literature/ICD/News ... ssue10.pdf

to give some ideas about the size of some hydraulic actuators & control valves

[xpensive]

Indeed Jumbo, micro-hydraulics are impressive size-wise and so is the precision and force through Moog servo-hydraulics.

However, in this case none of the latter features really apply the way I see things, the flap simply moves from one end-position to another with a comparably low force, why I can't shake my inclination towards pneumatics for this application?

Pneumatics ar fast, light, dirt cheap (not that it counts in F1 though) while xtremely clean and neat to install.

[raymondu999]

One question which will be very stupid: Where do all the cars get the energy for the moving of the rear wing?

[747heavy]

I agree with you X, that pneumatics would be well up to do the job (and technically a possibility).
I guess, teams use hydraulics, because they have the pressure "on tap" anyway, most likely steeming from the diff control.

The additional weight of either a compressor unit or a tank for pressuriezed air (gas), will perhaps offset the slighly higher weight of the hydraulics - IMHO.

I can imagine that teams which run a central pillar (such as Ferarri) have the actuator mounted down low (short lines etc.) and use a "pull rod" or high tensile fibre as connection to a lever mechanism in the main plane.
This would be possible for a endplate mounted system as well, think about an high tensile(carbon) fibre running inside the endplates.

[WhiteBlue]

I can't help thinking that big RB lump is either an aberration by Newey, or it is hiding something clever.

The air behind the air box is disturbed anyway. So they may be going for a clean flow over the end plates and have fitted the actuator at a spot where they have dirty air by design.

[xpensive]

I agree with you X, that pneumatics would be well up to do the job (and technically a possibility).
I guess, teams use hydraulics, because they have the pressure "on tap" anyway, most likely steeming from the diff control.

The additional weight of either a compressor unit or a tank for pressuriezed air (gas), will perhaps offset the slighly higher weight of the hydraulics - IMHO.

I can imagine that teams which run a central pillar (such as Ferarri) have the actuator mounted down low (short lines etc.) and use a "pull rod" or high tensile fibre as connection to a lever mechanism in the main plane.
This would be possible for a endplate mounted system as well, think about an high tensile(carbon) fibre running inside the endplates.

Your arguments for sticking with hydraulics are rather convincing Jumbo, while a centrally mounted actuator would probably be of the "push-rod" kind, when the flap pivots around its trailing edge, no? Guess a single-action cylinder, possibly with a spring-loaded return stroke, would do as aerodynamic drag will see to the closing sequence of the flap?

But I think I would try to integrate miniature actuators in the endplates anyway, if nothing else for the sheer looks of it.

[WhiteBlue]

This looks like an activation by hydraulic cylinder moving in the vertical direction. The flap is probably connected by a roller to the activation blade.



pretty much the same solution at McLaren

[Ciro Pabón]

Just to add that this development was planned since 2007. I've been asking people to read this in a separate thread, but here you might find more time.

http://www.paddocktalk.com/news/html/mo ... mework.pdf

The relevant paragraphs, in page 4, say (written in June 2007, year when the "chassis framework for 2011" had to be approved by all teams):

...

b. Front and rear wings being constrained to fit within defined ‘boxes’ and consist of a
fixed number of elements. The purpose of this is to constrain the designer from
producing overly complex assemblies. The rear wing will be the main mechanism by
which adaptive drag is achieved, while the relatively small (compared to today) front
wing serves as a trim to achieve balance. The front wing ‘box’ will be close to the
ground to minimise the affect (sic) of wake turbulence.

c. Front and rear wing settings maybe electronically controlled, but within set limits
defined from time to time by the FIA. This is to allow much reduced drag along the
straights to improve fuel efficiency and yet retain the downforce required around
corners, under braking and under acceleration so as to retain overall lap times. Failsafe
design, as used on aircraft, will be mandated.

The "failsafe design" could explain the size of some things. I'd say this implies not one but two hydraulic cylinders.

Anyway, teams had 4 years to be prepared...

I'm intrigued by the Plasma Generation (already mentioned in an old thread) and MEMS (same thing) that the document proposes for drag reduction. I'm also intrigued with what happened to the adaptive cooling systems (another way to reduce drag and downforce at the same time, the ultimate goal of FIA these days, as you can easily deduce if you read the document).

I am also very intrigued with what happened with this point (page 5):

6. Improving the show: A turbulence sensor complete with an aircraft type back up system (for robustness) will be supplied by the FIA. When travelling in high turbulence levels such as those generated by the close presence of a leading car, the ride height of the car, both front and rear, must be altered in response to the output of this sensor (within a set range, at a set rate, and with appropriate hysteresis, determined from time to time by the FIA) to compensate for the degradation in performance. In free stream the car is to return to a baseline ride height. The purpose is to allow for full compensation for downforce losses due to being in the wake of another car.

[WhiteBlue]

The "failsafe design" could explain the size of some things. I'd say this implies not one but two hydraulic cylinders.

or one double acting

[xpensive]

I hazard a guess that "fail-safe" means that the flap should be in "down-force position" if manouvering means are lost, such as a hydraulic, electrical or pneumatic failure, sounds like a single-acting cylinder with integrated spring-return?

Beholding the Ferrari and McLaren solutions, pneumatics could certainly do that, but the proximity to the gearbox speaks for hydraulics of course.