Poll to decide whether a spoiler actually serves a purpose.

[DeusMR2]

>

Any one ever seen an Escort Cossie race away?
The back slams to the ground for traction.<
BUT - take the spoiler off and the top end INCREASES.
Downforce actually isnt as good for top end as previoulsy suggested in certain designs.

WTF

when you design a spoiler, you have to make a compromise between drag and downforce. The more downforce you have, the more drag it exerts and vice versa. The same principle is used in plane wings with landing/taking-off flaps, except this time they're used to create lift. So again, when there is more lift there is more drag, which is why they're closed when at cruising speed.

[Andy F]

>

Any one ever seen an Escort Cossie race away?
The back slams to the ground for traction.<
BUT - take the spoiler off and the top end INCREASES.
Downforce actually isnt as good for top end as previoulsy suggested in certain designs.

WTF

when you design a spoiler, you have to make a compromise between drag and downforce. The more downforce you have, the more drag it exerts and vice versa. The same principle is used in plane wings with landing/taking-off flaps, except this time they're used to create lift. So again, when there is more lift there is more drag, which is why they're closed when at cruising speed.

I don't need a lecture......i was referring to this

>Any one ever seen an Escort Cossie race away?
The back slams to the ground for traction.<

And a spoiler does this????

[jonb-]

A lowrider spoiler, hell yeah =D> =D>


boing, boing, boing.

[Andy F]

A lowrider spoiler, hell yeah =D> =D>


boing, boing, boing.

Thanks Jon......i thought it was just me

[DeusMR2]

>

when you design a spoiler, you have to make a compromise between drag and downforce. The more downforce you have, the more drag it exerts and vice versa. The same principle is used in plane wings with landing/taking-off flaps, except this time they're used to create lift. So again, when there is more lift there is more drag, which is why they're closed when at cruising speed.

I don't need a lecture......i was referring to this

>Any one ever seen an Escort Cossie race away?
The back slams to the ground for traction.<

And a spoiler does this????

sorry, i obviously thought you were refferring to the other bit

[Simarshy]

The Mode is solid in 3D terms, as in it's made up of polygons.

The model was originally used in a RealTime simulation so, the pieces to the car we're saved as items such as. The Bonnet, The FrontBumper. Thats why it's possible some holes have appeared in the model.

What i'll do is check over it for gaps, and convert it to a single group. i.e. mr2body

Oh also the floor to the car is totaly flat. I'll try and make a gap for the engine bay, and stuff a few polygons in there to simulation the engine and bits and pieces.

I'll have to look into parasolid format. At the moment I should be able to do DXF, ACIS (sat), Lithography(stf), Encapsulated PS (eps), Metafile (wmf). DXX extract (DXX). Do you know the filename extention for the parasolid format?

[Dave_Gat]

Would it be possible for me too have a copy of that CAD model.... have been wanting to do a CFD model of the car for a while. Intended to take lots of measurements of my car but as I have mentioned before am lazy and not got around to it yet.

Regards

Dave Gatland

MkII (NA) rev4

[Davidbeaven]

Had a word with a mate at work he can drive 3d fx program that you use, so could you email me the model and il put a little sumulation together!!

Ta,

Dave

[Simarshy]

Ok guys, i'll try and tart the model up and give you a copy hopefully in the next couple of days.

If the model works, i'd love a copy of your results, to add to my portfolio (Graduate looking for a job)

[Dave_Gat]

Should probably put im my tuppence worth on spoiler.... I suspect that the rev 5 spoiler may do something cause it is up higher and more likely to be out of the dirty recirculating air over the rear deck.... the earlier spoilers.... pass but probably not a lot. Will wait to see what we can do with CFD and find out what the airflow is like.

Whatever happens, is not likely to be that effective till you get to high speeds

Dave Gatland
MkII (NA) rev4

[Harry]

good topic,

since i have fitted engine cover,gt style,it covers the rear window,fits flush
also lets out hot air through the post box type lourves,rear stability at speed is much improved.
when my front under bumper tray came loose,hanging off,i noticed a lot of
bouncing and poor front performance,

but as i have gone along i have noticed the differences....
full bodykit-all round-better
ganador mirrors-better
rev5 carbon wing-better
gt louvre-better
shaved off general weight where ever i could-lighter tyres/rims-better
includes-carbon bonnetfront& rear carbon gt engine cover...

finally tein coilovers arrived...lowered to about,mm,...maybe 2 inches off
ground,could just fit foot under front bumper,just,....was a pain though,

this really pulled all the tuning/aerodynamic together....

as now being right near the ground/road the vacum creates a suction
which makes downforce,also apparently,a lot of downforce issues relate
a lot to the sides of car,abit like a boat in water,the force of boat pushes great surges past the sides,air no different here.

the mr2 has been designed with good undertrays to make smooth air work
aerodynamics from under,like sides the under is a big part of it too.

i tested my full set up on a special track/circuit,not public roads,@clock
speed reading.@167mph,and you really felt very stable and safe,but
at flat out it was mental,when i asked my partner what she thought how it felt, ,described it as just before lift off in an aeroplane...

conclusion....
the wing is a part of the solution...other items mentioned above has an influence as well as outright initial design by the makers 2.

i would rather drive 150bhp perfect...brakes,suspension balance,aerodynamics,lightweight,power to weight ratio,than just say outright bhp,

when c clarkson put full brakes on in a straight line,with a 4x4,think it was
a range rover type,being so far off the road,high centre of gravity..
it fliped and cartwheeled....vvv very dangerous them

[Andy F]

I used to have the big MRD combat spoiler on my car, when you got to 110mph ish i used to line up the spoiler in the rear veiw mirror with the heated rear window lines, the spoiler would bow dow about 5mm!! which would indicate down force but .......you could bend the spoiler down 5mm with your little finger. So unless that much downforce makes any difference (NOT) i think its all in the mind

[tamiyauk]

Spoilers definately make a big difference at high speeds, a nice safe demonstation can be had with a Radio control car, the dynamics translate to these little beasts and on the few occasions I have crashed and lost the rear wing the high speed corners are impossible to take at the same speed, especially in the wet!
As with big cars you can still go fast with just mechanical grip like the early F1 cars but they really started to speed up on the corners when wings were introduced. When Turbo's came into F1 things got even faster: http://www.f1-grandprix.com/history5.html http://www.f1-grandprix.com/history4.html#Wings

the original high-mounted, manually adjustable rear wings tended to fall off, causing tremendous shunts

Imagine the carnage with a Turbo F1 car and no rear wing!

As for the MR2 I think that for normal use a wing is not necessary but I'd want one if I was driving it fast or on a track! I think alexwainwright's got it about right in his post

[Andy F]

Narrrr
Just think of the weight of a MR2 back end, how the hell do you think
a bit of plastic can push that down, it may do it on your RC car but that weigh's feck all.

[michael]

Deja vu?

Anyway late to the party as usual but I thought I'd throw this in:

http://www.mulsannescorner.com/aerodata ... mkiii.html

Does anyone remember the chap from the Yahoo list that built a full on downforce MK2? It wasn't pretty but it was designed to stick to the ground If I could be bothered I'd search the archives for info.... but I'm lazy

What you really want is for the underside of the car to be even flatter and get a decent rear diffuser in combination with the usual batch of mods up top, the problem you have is that the base design worries about minor things like cooling too so you can't mess too much

Mmmm, I remember going to pick up the car this started life on and having it follow me back up the motorway, different.... but not for me....

[Andy F]

Arr now i can see it helping at the front Michael, i think a very low lip to stop it from lifting, but you ain't gonna hold the back down

[tamiyauk]

Narrrr
Just think of the weight of a MR2 back end, how the hell do you think
a bit of plastic can push that down, it may do it on your RC car but that weigh's feck all.

A bit of plastic can make a massive difference, wings and spoilers are often adjusted by adding or removing Gurney strips which can be real thin strips of plastic or carbon. F1 wings do move around like your wing on your MR2, it pushes the rear tyres to the tarmac and the faster you go the more it pushes!

[Andy F]

Narrrr
Just think of the weight of a MR2 back end, how the hell do you think
a bit of plastic can push that down, it may do it on your RC car but that weigh's feck all.

A bit of plastic can make a massive difference, wings and spoilers are often adjusted by adding or removing Gurney strips which can be real thin strips of plastic or carbon. F1 wings do move around like your wing on your MR2, it pushes the rear tyres to the tarmac and the faster you go the more it pushes!

Of course it does!!

It will on the back of a F1 car...........but not your 1 ton back end!!

[johnwoo]

As far as I know, the spoiler on the MR2 is not for downforce (as said, with the weight of the engine in back, the back is going to stay down all by itself), but to reduce drag...

It has to do with the cooling of the engine bay. Because of the straight rear window, a low-pressure zone is created above the engine lid, "sucking" the hot air out of the engine bay. But although this is good for getting out the hot air, it also disturbs the airflow (for a better airflow, the rear window should slope down over the engine bay to the rear of the car, but that would mean less hot air could be evacuated from the engine bay, and we all know it can get pretty hot in there anyway). To my knowledge, the spoiler was meant to help decrease the drag caused by these turbulences.

[luthor1]

My mate and I did an experiment on this... he has a Rev2 Mk2 tubby, and we opened the boot, the rested it down but not clicked shut, then we went down the motorway at 120mph. It did not even produce enough downforce to close itself.

Totally cosmetic.