Active aero

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OO7
OO7
171
Joined: 06 Apr 2010, 17:49

Re: Active aero

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trinidefender wrote:
Tommy Cookers wrote:
bhall II wrote: ......I tend to think a front wing equipped with what would almost be ailerons is sensible, because there's no reason for a car to carry peak downforce along straights. It's counterproductive for a formula that strives for greater efficiency.
yes, some planes have used this
(both wings) ailerons could be selected to 'upset' slightly above the neutral position, in cruise
so the outermost wing section has 'cancelled' camber/incidence effect equivalent to zero AoA/zero Cl (or close to that), and less drag

(though the benefit for the aircraft is reduced or zero lift far outboard, so reduced bending moment throughout the wing)
eg this was used on elderley UK RAF aircraft eg the VC10 and Victor to conserve their wing life

similarly, by extension, Tristar 'active ailerons' and modern equivalents alleviate outer wing gust loads (if not steady load)
Having both ailerons set above 0 degrees to reduce outer wing loads and reduce induced drag is inefficient and something that a designer would add in only if they needed to as a result of problems found in testing when it is to late or costly to change the design. It is inefficient as it increases form drag, parasitic drag and you get some weird drag inducing flows from permanently offset ailerons while in cruise instead of being flush with the wing. If the problem is caught early enough then they will generally design some more washout into the outer sections of the wing. This will achieve many positive results over the method proposed by TC. It has the same benefit of reducing load on the outer sections of the wing and helps reduce induced drag (to a certain level), at low alpha levels it helps keep the outer part of the wing stable and reduces turbulence felt by the aircraft. Washout helps the outer part of the wing to stall at higher alpha levels than the inner portion, this maintains airflow over the ailerons and helps maintain control when flying the aircraft close to stall speeds (very important for safety and something every pilot will thank you for). Lastly with washout on a swept wing when the inner, more forward parts of the wing stall first the centre of pressure moves aft and drops the nose of the aircraft helping it to recover from a stall.

Before somebody states the obvious and says that it is rare that the ailerons would be flush with the wing that often because they will constantly have to adjust slightly let me say that at cruise speeds commercial airliners rarely use the ailerons for roll control. Above a certain speed the aircraft uses the airbrakes on the wing of the side of the plane that they want to roll to. The flight computers (whether they be analog on older aircraft or full FBW {fly by wire} on the modern Airbuses and such) decided how much roll input and deflection to put on the airbrakes of the wing to control roll. Using the airbrakes on the inner wing of an aircraft in a turn means that the rudder has to be used less as drag is already on the inside wing, this helps keep the turn coordinated.

TC for the Tri-star are you referring to the DLC (dynamic lift control)? It is a brilliant piece of kit and I've yet to meet a pilot yet who has flown that aircraft and didn't love it. It allowed very stable approaches and just made the pilots life a breeze even with autopilot off.

Note: alpha used here means angle of attack

P.s. Sorry for the OT, I'm just trying to give some context to some information presented in another post.
trinidefender, for aircraft that spend most of there time cruising or loitering e.g airliners, cargo planes, refuellers, then perhaps you are correct. For fighter aircraft that are required to operate over a wide range of flight conditions, the described alleviation techniques aren't band aid fixes, but fundamental design principles I believe.

What you say about the Tri-Stars DLC is correct. I remember reading posts from a few pilots on an aviation forum and they absolutely loved it.

livinglikethathuh
11
Joined: 15 May 2015, 23:44

Re: Active aero

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Washout and varying airfoils are better ways to adjust lift distribution on the wing. But especially for supersonic aircraft, both washout and differing airfoils can potentially introduce a lot of wave drag and flow separation, so it's not fair to look at them the same way. Thus, designing the wing for minimum supersonic drag and later adjusting lift distribution by symmetrical aileron deflection might be a better way to go.

Anyways, we're way OT.

trinidefender
317
Joined: 19 Apr 2013, 20:37

Re: Active aero

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Blaze1 wrote: trinidefender, for aircraft that spend most of there time cruising or loitering e.g airliners, cargo planes, refuellers, then perhaps you are correct. For fighter aircraft that are required to operate over a wide range of flight conditions, the described alleviation techniques aren't band aid fixes, but fundamental design principles I believe.

What you say about the Tri-Stars DLC is correct. I remember reading posts from a few pilots on an aviation forum and they absolutely loved it.
I was never referring to fighter aircraft. I was referring to mostly commercial aircraft and the aircraft TC had referred to here "this was used on elderley UK RAF aircraft eg the VC10 and Victor." One is a long range bomber and the other is a military personnel transport (very similar requirements as a commercial airliners).

Fighter aircraft design is completely different. They use vortex creation, heavy use of active leading edge slots (if you look at a video of a typhoon or pretty much any delta wing aircraft you will see the leading edge slats moving in and out all the time), leading edge blowing, and yes flaperons are heavily used for ginger aircraft. I still don't see why a fighter aircraft would set an above zero setting in cruise though. I know when landing many times the ailerons ailerons will drop when landing flaps are set though.

Btw that aviation forum wouldn't happen to begin with "airliners" would it?

trinidefender
317
Joined: 19 Apr 2013, 20:37

Re: Active aero

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Back on topic.

If they want to introduce active aero then I think it should be done in stages so that the output can be measured and adjusted to suit. I would say start with active suspension. I consider active suspension as active aero for obvious reasons. Active suspension is commercially viable, it can be relatable to future road car technology, it can make cars seconds faster. Last but not least, the amount that chassis builders spend on trying to work around the silly limitations of a totally passive suspension doesn't make sense. The active suspension can actually work out to be cheaper.

This train of thought of progressive rule changes can also be applied on a bi-annual or tri-annual case instead of this large rule change every 6 or 7 years.

OO7
OO7
171
Joined: 06 Apr 2010, 17:49

Re: Active aero

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trinidefender wrote:I was never referring to fighter aircraft. I was referring to mostly commercial aircraft and the aircraft TC had referred to here "this was used on elderley UK RAF aircraft eg the VC10 and Victor." One is a long range bomber and the other is a military personnel transport (very similar requirements as a commercial airliners).

Fighter aircraft design is completely different. They use vortex creation, heavy use of active leading edge slots (if you look at a video of a typhoon or pretty much any delta wing aircraft you will see the leading edge slats moving in and out all the time), leading edge blowing, and yes flaperons are heavily used for ginger aircraft. I still don't see why a fighter aircraft would set an above zero setting in cruise though. I know when landing many times the ailerons ailerons will drop when landing flaps are set though.

Btw that aviation forum wouldn't happen to begin with "airliners" would it?
I understand.

When you say ginger aircraft is this auto-correct gone crazy or another term for fighter aircraft? :D

The Hornet doesn't utilise a >0 aileron or flap schedule during cruise. The flaps start to deflect downwards at low AOA 2-3 degrees and the ailerons are scheduled to 50% of the flap setting.

I think there may be some occasions when the F-16 will deflect its leading edge flaps upwards by a degree or two. I believe this occurs at high speed and is for load alleviation.

I used to read posts from airliners.net but was never a member. The forum I'm talking about was pprune.org. :)

livinglikethathuh
11
Joined: 15 May 2015, 23:44

Re: Active aero

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trinidefender wrote:Back on topic.

If they want to introduce active aero then I think it should be done in stages so that the output can be measured and adjusted to suit. I would say start with active suspension. I consider active suspension as active aero for obvious reasons. Active suspension is commercially viable, it can be relatable to future road car technology, it can make cars seconds faster. Last but not least, the amount that chassis builders spend on trying to work around the silly limitations of a totally passive suspension doesn't make sense. The active suspension can actually work out to be cheaper.

This train of thought of progressive rule changes can also be applied on a bi-annual or tri-annual case instead of this large rule change every 6 or 7 years.
Totally agree.

How would failures in the active suspension system affect the car? Sudden loss of downforce? Can it limp back to pits, at least?

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turbof1
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Joined: 19 Jul 2012, 21:36
Location: MountDoom CFD Matrix

Re: Active aero

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livinglikethathuh wrote:
trinidefender wrote:Back on topic.

If they want to introduce active aero then I think it should be done in stages so that the output can be measured and adjusted to suit. I would say start with active suspension. I consider active suspension as active aero for obvious reasons. Active suspension is commercially viable, it can be relatable to future road car technology, it can make cars seconds faster. Last but not least, the amount that chassis builders spend on trying to work around the silly limitations of a totally passive suspension doesn't make sense. The active suspension can actually work out to be cheaper.

This train of thought of progressive rule changes can also be applied on a bi-annual or tri-annual case instead of this large rule change every 6 or 7 years.
Totally agree.

How would failures in the active suspension system affect the car? Sudden loss of downforce? Can it limp back to pits, at least?
In all probability there needs to be a standard ride height to which the car gets back to in case if the system fails.
#AeroFrodo

trinidefender
317
Joined: 19 Apr 2013, 20:37

Re: Active aero

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turbof1 wrote:
livinglikethathuh wrote:
trinidefender wrote:Back on topic.

If they want to introduce active aero then I think it should be done in stages so that the output can be measured and adjusted to suit. I would say start with active suspension. I consider active suspension as active aero for obvious reasons. Active suspension is commercially viable, it can be relatable to future road car technology, it can make cars seconds faster. Last but not least, the amount that chassis builders spend on trying to work around the silly limitations of a totally passive suspension doesn't make sense. The active suspension can actually work out to be cheaper.

This train of thought of progressive rule changes can also be applied on a bi-annual or tri-annual case instead of this large rule change every 6 or 7 years.
Totally agree.

How would failures in the active suspension system affect the car? Sudden loss of downforce? Can it limp back to pits, at least?
In all probability there needs to be a standard ride height to which the car gets back to in case if the system fails.
Not necessarily. When I finish eating I'll make a longer post explaining why it won't always be able to revert to a standard ride height.

P.s. Apple autocorrect is terrible.

Update. From my knowledge of servo systems (mainly based on helicopter control hydraulic systems) whether they are electric or hydraulic, what happens when they fail depends on what exactly fails and what kind of system failure it is.

I'll mainly deal with electrical servos for now as I can't imagine F1 cars using hydraulic servos. With electric servos the type we have only move if an electrical current is applied to it. These servos can fail and freeze in place or can fail to an extreme where they will go to maximum or minimum displacement and stay there. In helicopters we call this a hard over. The trim servos on the control systems (how the autopilot controls the helicopter and what we use to take control forces and trim the helicopter in a turn/level flight/climb etc) are fairly reliable though and don't fail often. Applied to an F1 car it means that if a similar system is implemented then it is possible although highly improbable that a system can fail and push one of the corners off of the ground and remove downforce mid corner. There must be a way to ensure that it doesn't fail and go full ride height mid corner though. For all the suspension guys what are your thoughts and ideas?

This was discussed heavily but it also depends how the active suspension is set up. There is a whole other thread talking about the differences between series and parallel active setup suspension systems where a spring is included.

riff_raff
132
Joined: 24 Dec 2004, 10:18

Re: Active aero

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I would love to see active aero devices adopted by F1, in stages. I don't see how failure of an active aero device would present more of a hazard than structural failure of a passive aero device. Would failure of the actuator of an active trailing edge flap on the front wing be any more hazardous than loss of the front wing from contact at high speed?
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

Pingguest
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Joined: 28 Dec 2008, 16:31

Re: Active aero

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bhall II wrote: Despite DRS, rapidly-degrading tires, and a refueling ban - all measures taken to increase overtaking - the sport is in the midst of the sharpest decline in overtaking in the last 35 years.
Evidence suggests the decline is the result of a convergence of design philosophies that make it difficult to exact enough of a performance differential to regularly facilitate overtaking. This happens in (mostly) spec-series, too.
Just out of curiosity, what is your source and does that graph only include on-track passing?

bhall II
473
Joined: 19 Jun 2014, 20:15

Re: Active aero

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Clip the Apex wrote:Methods & Credits

The data for 1981 and 1982 has been compiled by KekeTheKing using lap charts and video footage.

The data for the years 1983 to 2003 are as published in Michele Merlino’s 2007 Autosport.com article Passing Thoughts: F1 Overtaking Analysis, using Brian Lawrence’s methodology of recording passes (as listed below) made from lap charts of those races. We are grateful to Michele and Brian for their permission to include this data.

Data since 2004 has been compiled by Galahad and includes overtaking moves shown on TV coverage as well as from lap charts.
From 2010 to 2012, KekeTheKing has also contributed with additional video footage and analysis.

As such, it is not possible to draw anything other than the broadest conclusions from analysing across all data sets since the methodologies used to collect the data are different.

The overtaking figures for each race (across all data sets) do not include:
  • Position changes on the first lap of the race
  • Position changes due to drivers lapping backmarkers
  • Positions gained in the pits
  • Positions gained due to drivers yielding
  • Positions gained when a car has a serious technical problem; e.g. puncture, accident damage, etc.
The final criteria involves subjective judgements and consequently figures can never be regarded as ‘definitive’. Gaps in the available data, such as moves missed by TV cameras or obscured on lap charts by pit stops or retirements, mean that the data do not lend themselves to detailed analysis at the micro level, but are indicative of general trends.

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godlameroso
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Joined: 16 Jan 2010, 21:27
Location: Miami FL

Re: Active aero

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Would this be completely illegal in F1?

Sorry bit of a shameless plug.

Saishū kōnā

OO7
OO7
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Joined: 06 Apr 2010, 17:49

Re: Active aero

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godlameroso wrote:Would this be completely illegal in F1?

Sorry bit of a shameless plug.

https://www.youtube.com/watch?v=b1Zqv5-AaX4
The McLaren MP4-X concept mentions the use of plasma for aero control over the rear wing/s. It has no moving parts so it can't be categorised as a movable aero device. However fitting the hardware on the wings may fall foul of the bodywork regs, as well as the power system regs.
Last edited by OO7 on 14 Feb 2016, 22:27, edited 1 time in total.

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djos
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Re: Active aero

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Blaze1 wrote:
godlameroso wrote:Would this be completely illegal in F1?

Sorry bit of a shameless plug.

https://www.youtube.com/watch?v=b1Zqv5-AaX4
The McLaren MP4-X concept mentions the use of plasma for aero control over the rear wing/s. It has no moving parts so it can't be categorised as a movable aero device. However fitting the hardware on the wings may fall foul of the bodywork, as well as the powering the system.

And let's not forget how anal the FiA can be, e.g. Tuned mass damper gate!
"In downforce we trust"

federicobernabei
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Joined: 14 Feb 2016, 21:59

Re: Active aero

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Hi Guys,
I'm an engineer and an automotive enthusiast from Italy.
I made a concept about an active aero device for race cars and I would like to know what you guys think about this.
The idea is centred about one or more vertical wings mounted on a vehicle which can produce lateral forces (left and right) over the center of gravity of the car. The force generated whilst cornering counterbalances part of the inertia force of the vehicle and reduces the total rolling moment.
With 2 vertical wings it is possible also to generate drag whilst braking and reduce the longitudinal load transfer.
The core of the idea is the controlling of the angle of attack of the vertical wing to keep the aerodynamic force always proportional to the inertia force of the vehicle.
How can I post some pictures or a presentation in PDF of my concept, can you help me?

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