Ah yes, the DeltaWing...

[gixxer_drew]

The main purpose of the design is low drag and you can see it in use everywhere including F1 wishbones where for any given surface area you just have a lot less drag when the surface doesn't need to expand to full width right away like a squared plan view layout does.

Sorry, wrong.

F1 wishbones, also called A-Arms are not delta shaped, they are triangular because triangles provide for better load bearing, since it's members are always under tension/compression, never bending or tortion.

http://static-bc.blogcritics.org/wp-con ... 00x197.jpg
Low drag wings, like those of sail planes and low powered planes, are long and square.

Delta wings primary reson of use is supersonic flight, since said wings will not touch the sonic boom. Same goes for sweepback wings, like the used on modern airliners, which can cruise up to around mach 0.85.

Delta wings in fact produce a lot of induced drag due to their small aspect ratio.

I think you may have misunderstood me. When I said "The purpose of the design" I was referring to the DeltaWing, not a delta wing. I understand the reason for its use in aircraft, but obviously the DeltaWing is not super sonic, the purpose of its design is low drag.

As for the A arms I can tell you without any doubt that the design of A arms is changed significantly based on aerodynamic feedback and drag reduction, including but not limited to the forward tube angle in relation to the trailing being more of a "delta" shape. I cannot speak for every team/design though.

[gixxer_drew]

The delta wing shape of the so called DeltaWing car has nothing to do with groud effect. Which is achieved by the underbody ventyry tunnels, not the leading edge of the side pods.

That is not true, the topside shape has a major effect on what happens underneath. Unfortunately that is the limit of what I can say.

The delta wing resembles a delta winged plane, that's where it got it name from. It has nothing to do with it's aerodynamic characteristics. The delta wing has no wings. Body and sidepods fairing are not wings.

Yes, I think I agreed with that.

[rjsa]

The delta wing shape of the so called DeltaWing car has nothing to do with groud effect. Which is achieved by the underbody ventyry tunnels, not the leading edge of the side pods.

That is not true, the topside shape has a major effect on what happens underneath. Unfortunately that is the limit of what I can say.

The top shape might have a saying on the groud effect performance -like beam wings or the McLren buterfly suspension - but I really don't belive that the sidepods having a triangular shape have an influence on that.

You can try to convince me though.

[rjsa]

As for the A arms I can tell you without any doubt that the design of A arms is changed significantly based on aerodynamic feedback and drag reduction, including but not limited to the forward tube angle in relation to the trailing being more of a "delta" shape. I cannot speak for every team/design though.

The great aerodinamical change was the adoption of airfoil shaped elements instead of tubes. Angle of the elements relative to the transversal axle has no influence at all when you have simmetric profiles like the rules mandade.

As for the angle bein more delta shaped I don't get it. See below, suspension elements are placed according to spce avaliable:

(image from the 2014 comparison thread)

[gixxer_drew]

As for the A arms I can tell you without any doubt that the design of A arms is changed significantly based on aerodynamic feedback and drag reduction, including but not limited to the forward tube angle in relation to the trailing being more of a "delta" shape. I cannot speak for every team/design though.

The great aerodinamical change was the adoption of airfoil shaped elements instead of tubes. Angle of the elements relative to the transversal axle has no influence at all when you have simmetric profiles like the rules mandade.

As for the angle bein more delta shaped I don't get it. See below, suspension elements are placed according to spce avaliable:
http://www7.pic-upload.de/01.02.14/wteyhhr1t6jk.jpg
(image from the 2014 comparison thread)

Regardless of the section shape... there is still a major effect on drag by the angle, I think we can agree there. Over the years other compromises (including regulation) have forced the shapes in different ways but it is well known that there is a compromise against aero if when you move away from that. Ideally (for drag and only drag) you want the leading section to be laid back at an angle and it has been done like that in the past for that reason. That is all I will say on this topic.

[DaveW]

The top shape might have a saying on the groud effect performance -like beam wings or the McLren buterfly suspension - but I really don't belive that the sidepods having a triangular shape have an influence on that.

You can try to convince me though.

Probably not convincing, but the atmospherics shown in this amateur video might, perhaps, provide a bit of a clue.

[rjsa]

The top shape might have a saying on the groud effect performance -like beam wings or the McLren buterfly suspension - but I really don't belive that the sidepods having a triangular shape have an influence on that.

You can try to convince me though.

Probably not convincing, but the atmospherics shown in this amateur video might, perhaps, provide a bit of a clue.

It's condensation due to lower pressures (and consequential low temperatures) on top side of the wing, caused by the rough 3D manouvering. That's a wing attached to a flying aircraft. Nothing to do with cars, sidepods and ground effect.

[rjsa]

Regardless of the section shape... there is still a major effect on drag by the angle, I think we can agree there. Over the years other compromises (including regulation) have forced the shapes in different ways but it is well known that there is a compromise against aero if when you move away from that. Ideally (for drag and only drag) you want the leading section to be laid back at an angle and it has been done like that in the past for that reason. That is all I will say on this topic.

No we can't. The effect of an A arm element being square to de side of a car or assembled at an angle is negible regarding drag.

[DaveW]

Probably not convincing, but the atmospherics shown in this amateur video might, perhaps, provide a bit of a clue.

It's condensation due to lower pressures (and consequential low temperatures) on top side of the wing, caused by the rough 3D manouvering. That's a wing attached to a flying aircraft. Nothing to do with cars, sidepods and ground effect.

I thought not....

[Psyclone]

Probably not convincing, but the atmospherics shown in this amateur video might, perhaps, provide a bit of a clue.

It's condensation due to lower pressures (and consequential low temperatures) on top side of the wing, caused by the rough 3D manouvering. That's a wing attached to a flying aircraft. Nothing to do with cars, sidepods and ground effect.

I thought not....

Same effect as seen on an F/A-18 from its leading edge root extensions.

From wikipedia

On a modern fighter aircraft LERX provide usable airflow over the wing at high angles of attack, so delaying the stall and consequent loss of lift. In cruising flight the effect of the LERX is minimal. However at high angles of attack, as often encountered in a dog fight or during takeoff and landing, the LERX generates a high-speed vortex that attaches to the top of the wing. The vortex action maintains a smooth airflow over the wing surface well past the normal stall point at which the airflow would otherwise break up, thus sustaining lift at very high angles.

Not sure how that relates to your current argument though.

[gixxer_drew]

Regardless of the section shape... there is still a major effect on drag by the angle, I think we can agree there. Over the years other compromises (including regulation) have forced the shapes in different ways but it is well known that there is a compromise against aero if when you move away from that. Ideally (for drag and only drag) you want the leading section to be laid back at an angle and it has been done like that in the past for that reason. That is all I will say on this topic.

No we can't. The effect of an A arm element being square to de side of a car or assembled at an angle is negible regarding drag.

Negligible is not a relative term to F1. It is a known value. This is at least 10x that number in drag reduction. I did a quickie CFD just to verify this between two shapes --> /| and |\. I really dont know what else to say. I dont know how you can look at a car littered with tiny little devices to reduce drag by four decimal places (and smaller) but call this negligible.

[rjsa]

And what exactly is 'this'? Can we have some numbers?

And while you are at it, can we have the horizontal beam with the same chord length and cross section relative to the airflow as the angled one?

[DaveW]

Same effect as seen on an F/A-18 from its leading edge root extensions.

Not sure how that relates to your current argument though.

Good image. I was merely trying to point out that what your reference calls "LERX", which rjsa wold dismiss as "bodywork", can (and indeed does in modern agile aircraft) have a fairly dramatic effect on characteristics of a lifting surface. With some imagination the vortices shown in your image are analogous to the Y250 vortices of F1.

[rjsa]

Same effect as seen on an F/A-18 from its leading edge root extensions.

Not sure how that relates to your current argument though.

Good image. I was merely trying to point out that what your reference calls "LERX", which rjsa wold dismiss as "bodywork", can (and indeed does in modern agile aircraft) have a fairly dramatic effect on characteristics of a lifting surface. With some imagination the vortices shown in your image are analogous to the Y250 vortices of F1.

But you know LERX works on wings while under high AOA, delaying stall. That's a situation that will never happen in a car, with ground effevt tunnels, rolling on pavement.

Delta shaped winggs do have delayied stall characteristics due to the angled leading edge, LERX will just add to it. But it adds induced drag insted of reducing it.

And the whole mess started after a statement that delta shaped wings will reduce drag, which is wrong.

[Tommy Cookers]

the LERX style vortices effect was originated decades earlier, in the Saab Draken 'double delta' wing
(its huge afterburner was an accident, they didn't know the CoP position better than 1m so left engine wiggle room to adjust the CG)
now the Swedes love a big afterburner

the F 4 Phantom (designed for small AoA missile-only use) shed alternate 'Karman' vortices off the nose at high AoA
this impeded its later evolution into gun use air-to-air
the F 5 had a chisel (lifting ?) nose and small LERX, replacing the alternating Karman vortices with steady vortices
and allowing a higher maximum AoA from the rather straight wing
(btw the F 18 and many others show like the F 104 that a swept wing was never needed supersonically)

if a wishbone is swept back eg at 45 deg the drag must be somewhat lower even at F1 speeds
as its 'aerodynamic thickness' is 41% less (than a 'straight' design) the Cd would be less
though today's designs when angled would presumably need to be physically thicker for buckling resistance, so would benefit less
though the drag saving would anyway have been greater (ie worthwhile) in the days of round tube wishbones