RCR Offers Canards for the GT40 (and other cars)

[Lynn]

Please talk about the RCR canards here.

Thank you,
Lynn

[Big-Foot]

Maybe Ron can make a copy or hurl the thread from the Superformance area to this one..

[WesS]

fran,
can you send two if the small ones to ken?
yeah, i know; the kitchen sink. it'll never end. quit coming up with things, and i'll quit asking for them!
thanks,
wes

[Howard Jones]

Do we have a price on these?

[Joe T]

Hi Fran

Got any pics of them on the Lola..................

You know what I am gonna ask next dont you...

[Chris_K]

Just to save linking back, here are the pics:









for some reason I can't get them to appear as images.

[Bill D]

Fran-
Where are you buddy? Are you ignoring us? We need canards.

Now I'm undecided on whether to get the small ones or the larger ones as shown on the blue GT40 that he posted.

GOD!! Decisions, decisions!!

[John Lowe]

Has anyone researched the downforce contributed by canards? Unless the benefits are great (and even then track time v road time is worth feeding into the equation) I think they spoil the purity of the original shape. Fran, do you have any torsional rigidity figures for your monocoque? Proper figures, not like CAV's bolt one end rigid etc etc. I am talking to Chris in the UK and look forward to the arrival of his demo car

Grow old disgracefully

John

[Fran Hall RCR]

Wes,...no problem

Peter....yes for your RCR70 MK3b and others

Joe...I will take some for you tomorrow.

Bill D...buy them both and save the big ones for Sunday Best..

Howard...how much are they worth????

John...I am unaware of any race team ever having telemetry refined enough to test the Canards in the 60's or 70's...although some drivers had some pretty sensitive hands and seat of the pants results for sure....
I know Ford ran lots of telemetry in the J/Mk4 cars but I doubt anyone has bothered too much with the other cars.....You also have a PM.

[Johan]

The canards are as much for keeping air out of the wheel wells as for downforce. They grow in importance at 100mph and become critical for 5th gear corners, but to remove them is not a big deal if vents are cut into the fenders.
Race cars need canards, street cars do not. Track day cars need them if the driver wants to run high speed corners at high speed.

[Howard Jones]

Fran, They are of course worth as much as you can get for them. But I would think you have about $35 worth of 6061 and about 2 hours worth of labor if it is all done by hand one set at a time. You do good work and I live in Calif so lets say $75 hour shop rate. Call it about $200ish the set in cost for a one off. Mark them up 10%, how about $225 or there abouts the set?

If you make a lot at one time, maybe a little less, but I have no idea if you intend to recoup your R & D or how much you have into that.

If I'm way off, I don't mean to insult. They do LOOK like they are exotic and expensive.

Oh... and I have some that are very much like yours. They make very little difference if any at all. Nothing like the rear spoiler. It does make quite a bit of downforce that can be felt above 80 or so. I like them because they make for a balanced areo look.

I suspect the real effect of the front canards is a couple of dozen pounds of downforce at 100 or so. Maybe more at much higher speeds. I'll never know. Anything above about 125 or so on the road, and in a corner, isn't really cool and the time spent at 150 or so on a track, and in a corner, is so little that it is really hard to quantify any performance gain.

Besides I don't drive good enough to tell anyway.

Still saving for the P car. Gonna be a couple of years though.

[Richard O'Clery]

I don't have my copy of 'Competition Car Suspension' by Staniforth close by, but I remember him saying something like canards will produce a little downforce and lots of drag, but the performance gain of cars with them fitted seemed out of proportion with the expected results from the canards alone. He says that a massively beneficial by product was that the vortices created behind the canards would actively depressurise the undertray by pulling air out from under the car along the sides.

I guess the effect would be more pronounced with rounded sill cars like the MkIs, MkIIs, P4s and Lolas etc than the later square edged sill cars as the transition is smoother allowing the vortex to roll more easily down low along the side of the car, but I could well be wrong about this!

[Dalton]

To add a few comments from my reading of books on the GT40's, originally in 1964 the Mk 1 GT40's were getting 700 lb (total front and rear) of lift near top speed. This was described as an aerostability problem causing a rotary motion of the rear end which increased with speed and was accentuated on a wet road, so that eventually the rear end lost adhesion. The Lola GT had suffered similar problems. Earlier wind tunnel work had "proved" that a spoiler would be superfluous, but practical know-how and test driving at the MIRA proving ground lead to the addition of a rear spoiler. The stability of the car was described as transformed. Then later in 1965, when the Mk2's (without spoilers) could exceed 200mph, they were horribly unstable at Le Mans at speeds approaching this. Spoilers and stabilising fins (and canards) were hastily improvised and added. Finally, the rear anti-roll bar was dispensed with (removal presumably increased the understeer) and handling became acceptable at Le Mans.

All a bit academic for road cars, but obviously an interesting subject for those forum members who race, or for those trying to replicate a particular car configuration.

Incidentally, original design estimates had suggested a maximum speed (Mk 1) around 210 mph. But in practice 76 rather than the estimated 30 bhp were absorbed in ducting to brakes, radiator, and engine, so that the true still-air maximum was 197 mph, according to one source.

Dalton

[John W]

Dalton, from your books did they only remove the rear ARB for LeMans ?

The reason I ask is that all mkIIs I've seen have a rear ARB. Granted there are different types (most notably between H&M and Shelby cars), but they still have them...

[Dalton]

John, Unfortunately the information is a bit patchy. But the implication is that they were only removed for Le Mans. All the photos I have seen certainly show rear ARB's on Mk II's, so maybe they quickly found a better combination of high front roll stiffness and lower rear roll stiffness, by varying the lever arms and/or diameters.

I wish there was better data on all of this, plus the aerodynamics.

Dalton

[John Lowe]

Thanks to all who responded. Since my current machine is a Gardener Douglas Cobra replica Aerodynamics is a bit of a mystery (I think origanal Cobra's went very light on the steering above about 155mph). Fran, appreciated your call and RCR is my current front runner for when I move to a GT40, a beautifully engineered product. Bills excellent website also very helpfull for future reference.

Grow old disgracefully (and mostly sideways!)

John