Delta wing car concept

[machin]

Sounds good and fair to me.. I'd go along with that... then we'd see which is the better solution....

(Is there any reason why you think the "flying away" issue would be any worse than the current rectangular cars? Certainly some articles in Racecar Engineering by people way more knowledgable than me on the subject suggest a full ground effects car would be less prone to "flying away" than the current flat bottomed cars)

[machin]

I agree there is a natural weight advantage of the Delta-wing layout, although personally I think its small

Here's how I come to that conclusion, showing the stages of converting the Delta wing to a "rectangular car":-



Picture 1 -We start with the Deltawing @ 450kg, with its 28:72 mass distribution, wide rear wheels and narrow front wheels.

Picture 2 -We then space out the skinny front wheels on long suspension (pic.2), adding perhaps 3 or 4 kg per side? .... so 458kg total.

Picture 3 -We re-arrange the existing components to achieve a "conventional" 40:60 mass split front:rear. No weight change.

Picture 4 -We add carbon fibre composite shrouds around the skinny front wheels which attach to the wheel uprights. The shrouds are "open" on the outside so the weight is pretty low; 2 or 3 kg per side? Total Now 464kg.

Picture 5 -We take some of the material from the rear wheels/tyres/shrouds/brakes and "move it" to the front weels.. making the front wheels/tyres/shrouds wider and the rear wheels narrower, in accordance with the new 40:60 weight split as opposed to the original 28:72 of Deltawing. No weight change. Total still 464kg.

So I conclude that the weight increase to go from Delta to Rectangular would only be somewhere in the region of 14kg... or about 3%...

[Scania]

you think there is really only 14kg more?

assume you are right @ first, the arm & cover are 14kg more

we can see the front end in the videos, the left & right arms are installed nearly on the same point, that means we only need 2 stronger point to located the arms(1 for up & 1 for low).

if u expo it on formula style, that means you need 2 more stronger structure to located them & more weight

also, when the wheel is far away frony the chassic, u'll need 2 rods to connected the wheel & damper

and then, I don't know y but they said that there are nearly no stress on the chassis during turning. that means if you make it to normal, we all know is normal car got that and you will need a stronger chassis to support the extra load & gian more weight.

[Scania]

your design is more suitable on a Deltawing concept road car---more drag& weight, but easier to drive(specially park in car park), more comfortable, still very light weight & low drag for a road car.

[machin]

if u expo it on formula style, that means you need 2 more stronger structure to located them & more weight

With the "footbox" area of the chassis moved forward as shown, and the suspension attached to this I don't think you'll need any additional structure....

they said that there are nearly no stress on the chassis during turning. that means if you make it to normal, we all know is normal car got that and you will need a stronger chassis to support the extra load & gian more weight.

I can see that the repositioning of the weight (and downforce centre of pressure) nearer the rear wheels would mean that for a given chassis bending moment the weight of the chassis would come down (simplistically thinking of the chassis as a beam, since the loads on the deltawing would be nearer the supports (wheels) rather than acting in the middle of the "beam" as with a conventional car). However, the difference in weight distribution isn't actually that much (rear weight bias of 72% on the Deltawing vs 60% on a conventional car... so 12% difference).... But lets say for argument the chassis on the Deltawing could be 20% lighter...

The Aluminium Chassis on an Elise weighs 65kg... the carbon monocoque on an F1 car (designed for very high downforce loads) weighs approx 35kg... (The bare chassis of a Caterham 7 is <20kg). For argument's sake lets say the chassis on our Deltawing is carbon composite and weighs something like 50kg. 20% weigh reduction from 50kg is 10kg. So lets add that to the Conventional car we've built from our original Deltawing... so now we're up to 474kg (or 5.3% higher than Deltawing).

also, when the wheel is far away frony the chassic, u'll need 2 rods to connected the wheel & damper

I had assumed 5 lengths of steel tubing (2 per wishbone and a spring/damper push rod) per wheel, each 500mm long and 25mm diameter, 3mm wall thickness resulting in a weight of 4kg per wheel increase to space the wheels outwards as shown. So an increase of 8kg total for the two wheels.

your design is more suitable on a Deltawing concept road car

There is no "Delta" shape in the conventional design shown so I would drop the "Deltawing" tag altogether

---more drag& weight

Slightly more, as discussed, But better cornering dynamics. Without wanting to sound like a broken record... Even if you don't believe my calculations and diagrams in preceeding posts showing the fundamental effects at play, history has shown that a delta layout with a very high rearward weight bias is good for straight line events such as dragsters and top speed records, but the rectangular layout has better cornering dynamics and results in a faster race car around a circuit with corners, despite the drag and weight penalties. Naturally there will be a switch point where the circuit in question favours one design or the other... is Le Mans "straight enough" to favour the Delta Design? That's the question....

but easier to drive(specially park in car park)

Eh? Why?

more comfortable

,
Again, why?

[Scania]

but easier to drive(specially park in car park)

it is always not a easy thing to park a long car

more comfortable
Again, why?

the cock pit is too narrow’！

before DW launch in 2010, I had think aboit a eco sports car for a 21st centry concept of a Super 7 would be, and it is 90% look like yor wing car!

[GSpeedR]

I'll jump back in this thread to counter two points that keep returning:

1.) The deltawing is not a tricycle. It's a 4 wheeled vehicle and it's behavior will more closely mimic that of a 4 wheeled vehicle than a 3 wheeled. Simply the fact that there are 4 tires makes this pretty obvious.

2.) I agree that the design is disadvantaged to a typical rectangular-track rear-engined circuit racecar, if all elements besides wheel location were equal. However, a rectangular wheeled racecar is disadvantaged to an eight-wheeled racecar...or a twin-engined racecar...or a racecar with electric motors at the wheels...or a racecar with active suspension/traction control/ABS...

The rules will be set to make various platforms competitive. If you want spec chassis, then watch a spec series. This is a great opportunity to see a real engineering challenge in the making.

All my opinion of course. =)

[P.S.]

... a rectangular wheeled racecar is disadvantaged to an eight-wheeled racecar...

I was thinking exactly same.

... somewhere in the region of 14kg... or about 3%......

I don´t want to interupt your enthusiam in weight calculations... however I still like to do

If you gain 14 kg with the chassi, then something comes to roll...
The car needs less brakes which reduces weight again. And it reduces the needed cooling which will reduce the aerodynamik drag. With less weight and less drag the car needs also less engine with less cooling. This again reduces weight and aerodynamik drag. And oh, I forgot the tires. The car needs less tires and this will safe weight and aero drag.... Again!

When you saved all the weight from the added componets, you can reconstruct the chassi and safe... weight.... again ! At that point you can go back and restart with reducing weight and drag with smaller brakes....

This little example I haven´t squeezed out of my brain, but it is very well known in aviation business. All in all, the potential of weight reduction with coupling to aerodynamik drag is an heavy subject.

[Scania]

... a rectangular wheeled racecar is disadvantaged to an eight-wheeled racecar...

I was thinking exactly same.

... somewhere in the region of 14kg... or about 3%......

I don´t want to interupt your enthusiam in weight calculations... however I still like to do

If you gain 14 kg with the chassi, then something comes to roll...
The car needs less brakes which reduces weight again. And it reduces the needed cooling which will reduce the aerodynamik drag. With less weight and less drag the car needs also less engine with less cooling. This again reduces weight and aerodynamik drag. And oh, I forgot the tires. The car needs less tires and this will safe weight and aero drag.... Again!

When you saved all the weight from the added componets, you can reconstruct the chassi and safe... weight.... again ! At that point you can go back and restart with reducing weight and drag with smaller brakes....

This little example I haven´t squeezed out of my brain, but it is very well known in aviation business. All in all, the potential of weight reduction with coupling to aerodynamik drag is an heavy subject.

there is a phrase in Chinese said: when you make 1 thing wider, there are 3 things will go bigger

[machin]

When you saved all the weight from the added componets, you can reconstruct the chassi and safe... weight.... again ! At that point you can go back and restart with reducing weight and drag with smaller brakes....

Oh, I totally agree.. these are what I refer to as "second order effects", and resolving them is what I call "the design spiral"...

OK, so if the increase is estimated at 5% weight increase for a conventional car over the Deltawing, for the purposes of our first pass at re-speccing the brake components lets say these knock-on effects of the initial weight estimate is an additional 5%... i.e. doubling the weight increase of a conventional car over the Deltawing (from 5% to 10%)...

In braking a 10% heavier car from one speed to another in a given time frame means dissippating 10% more energy (KE=(1/2 mv1^2)-(1/2 mv2^2)) than the Delta-wing... so that is going to mean brake discs roughly 10% bigger/heavier... so how much is a typical brake disc for a light-weight race car such as this... something in the region of 5kg? so we may add an extra 2 kg to the car (5*0.1*4)... (so 0.4% further increase on the 474kg figure).

...Once we've calculated thess small increases for all the other knock-on effects I'm pretty sure we'll find that the inital estimate of an additional 5% (on top of my original 5%) was way over the top, so we go around the design spiral again, based on the new lower estimate and start again, getting closer and closer to the final result until we get to a point where any further reductions are simply not worth the bother....

[rjsa]

Just imagine MS driving this thing, not being able to adjust brake bias every corner...

My big issue with it is trying to push it as a race car. It isn't. It's a racing something.

Given a set of rules, like maximum track, length and minimum weight, this thing is losing every single time.

The original proposal was to turn Indy racing into this. Then it wouldn't be a disadvantage, everyone the same crap.

Would you? Would you really bet the farm and make a dozen or more teams go with a layout that never faced a race track? The cars like they are, being raced for 100 years, still can pull some nasty surprises on everyone.

Now they go to LM and play with a very high handicap. It will mean nothing, if it even finish in one piece.

But then stays the question: Why not sidecars? Or bikes? Or six or even eight wheeled cars like mentioned here?

Makes as much sense IMHO

[machin]

Now they go to LM and play with a very high handicap.

I don't think they're playing with a handicap -I think they're playing with an advantage -they're allowed to run at half the weight, but more than half the power... I think they'll put in a fairly good (unfair) performance....

[rjsa]

Now they go to LM and play with a very high handicap.

I don't think they're playing with a handicap -I think they're playing with an advantage -they're allowed to run at half the weight, but more than half the power... I think they'll put in a fairly good (unfair) performance....

I guess they also fall out of the dimension rules don't they?

But that's what I meant by handicap anyway. Handicap as in Golf.

[machin]

It's a 4 wheeled vehicle and it's behavior will more closely mimic that of a 4 wheeled vehicle than a 3 wheeled. Simply the fact that there are 4 tires makes this pretty obvious

Don't you think that the relative positions of the tyre contact patches (which determines the overall load transfer) on the Deltawing more closely resemble a Trike than a conventional car?

[machin]

I guess they also fall out of the dimension rules don't they?

ooo... not sure about the overall dimensions...?

But that's what I meant by handicap anyway. Handicap as in Golf.

What's wrong with the VW golf? Oh, I see what you mean... that game which "ruins a good walk"!