Rf 117

[Iain]

Dennis,

Thank you for taking the time to provide such a detailed reply, if I understand your opinion the single "wide" snorkell will direct the air over the top of the car rather than the effect generated by the "twin" snorkell that tends to divert it around the sides. The rear "Duck tail" (with the optional addition of an extra vertical fin) should suffice for rear downforce.

This lines up with some previous advice which I will send by email, its a bit too long to post on the site, (I am very happy to share this with any one else who is interested)

Regards

Iain

PS Have you ever had any experience with the effect of a very short but intense increase in air pressure from the inside of a high rise building, as caused by a dump of an inert gas powered fire suppression system ?

 

[dennism]

Hello again Iain
This question re fire suppression system dump was never thought of since this would affect only local areas, and at the most a single floor or two, where internal leakage would probably dissipate the slight increase in pressure
Hi rise concernss usually center around negative pressures developed on the building exterior, often due to reattached flow, that suck a window out, and any nearby occupant
The negative pressures developed are a great deal higher than building exterior wind induced positive pressures pushing windows, etc, inward
Best regards
Dennis

 

[dennism]

Hello again Iain
A few more bits and a mention that the ww.seriouswheels.com site should be looked at since they have some good GT40 pix, and a few that I will refer to here
The vertical fin was not at the rear of the car but in the center of the single nostril as shown on picture Ford-GT40-Mach II
This was used on both Mk I and II vehicles so would keep you within local regulations
The flying 230mph vehicle is, I believe, picture Ford-GT40-Mach-I-b, I hope that some old Ford wind tunnel fanatic can confirm this
The raised nostril sides for the Mk IV are seen on picture Ford-Mark-IV-Carroll-Shelby
The rear adjustable spoiler was used on the Mk II and IV and Mk I Gulf and Mirage vehicles
In addition to this rear spoiler were several openings above the rear brake lights to assist in relieving wheel well area pressures, the openings also in the spoiler
I can dig up a picture of this in a short time since my GT40 jpg files are presently on CDs while I rocover from a computer snafu if you so desire
Regarding a rear diffuser that might not be allowed by regulations, a flat pan might be devised running to the bottom of the rear clip as a minor downforce assistance
Hope that some of the above proves useful
Personally, I think that the aerodynamicist's email should be posted since it is extremely interesting and would help a lot of people thinking about going really fast
I'd even like to see the shots of the Supra mods
Best regards
Dennis

 

[dennism]

Hello Aian
There is a picture in seriouswheels of the rear spoiler wit openings above the rtail lights, picture Ford GT40-Red=Rear angle-Top
Went back to look at the GT40 hi def pix and found it
Dennis

 

[Bill D]

1076P

 

[dennism]

Hello Bill
Thanks for finding this picture
That was the one that I was thinking of
Dennis

 

[dennism]

Accidental duplicate submission deleted

 

[Iain]

Hi Dennis & Bill,

Thanks for digging out the picture, I had seen it, or a similar version on the forum before but this will now serve as a usefull reference. You may have already seen this but the car in MATECH-Concepts - Suisse is worth a look.

Iain

 

[Iain]

Er not sure what happened to the address but it should read www matech - concepts . ch

 

[Troy]

Iain, that chassis looks amazing. Excuse me if it was mentioned earlier, buy do you have any ideas on expected final weight as yet? Or maybe just the chassis weight?

Have you modelled the chassis design with Solidworks or Autodesk Inventor Pro?

 

[Iain]

Hi Troy,

We expect the complete package, without driver and without fuel to be about 1100kg, We will have added to the weight of the original chassis with the roll bars etc but we have saved a fair amount with the carbon body work etc. We have not put the chassis onto a software package but have put the chassis pick up points and suspension geometry through a package called "Susprog " We need to do a final run through once the car is finally on the deck, I am quite happy to share this information.

What suspension package to you plan for your car ?

Iain

 

[Troy]

Undecided at this point, still gathering information on spring rates used in these things. I've always set my cars up on the stiffer side, however that is with Triumphs that twist like a potato chip under hard acceleration!

The brake package is fairly business like, with 360mm / 330mm Harrop rotors and hubs front / back, Brembo calipers, so it would be a shame to let it down in the suspension area.

I'm open to (and would greatly appreciate) suggestions...

 

[Iain]

Troy,

I think your hardest decision is going to be in the selection of uprights front and rear, your brake hardware seems more than up to the job and the chassis can be engineered to provide a stable platform but you will need a sensible set of uprights with bearings to match if you are not going to throw away the benefits of the rest of the package.

Iain

 

[Russ Noble]

Plan is to register it, I muck about with a 5.2ltr Rover engined Triumph TR7 on the track.

I look forward to taking it down to Coles to do the shopping (if my shopping list was a packet of chewies and a chocky bar!)

Hope this isn't off topic on Iain's build thread but I thought
Troy's 40 was to be a road car.....So the benefits of the package are somewhat moot.....

Since you want suggestions Troy.....Wrong decision IMHO..... Use the TR7 as a road car, or flog it and buy a Corolla! Or another Herald! The 40 is a much better proposition for the track. Mind you I can imagine the state of development of the TR7.... But really, compared to a 40 you're pushing sh!t uphill with a pointed stick!!

Been there, done that with my 5.0 TR7!

Cheers,

 

[Jim Cowden]

I love it when you hold back Russ.

 

[Dalton Veitch]

A couple more rear end pix just for fun.

Dalton

 

[Troy]

Thanks for your honest opinion Russ!

I think we are a bit off topic, this is Iain's log, after all. I will be more than happy to take as much crap as humanly possible for admitting to owning more than one Triumph on my own log. Just look for the guy crouched in the corner of his workshop, sobbing - muttering something about dodgy english cars and the phrase "why me, why me, why me?"

By the way, how many gulf style (super-wide) rear clips are getting around? Iain, again I may have missed all this but, will you be running this bodywork?

 

[Iain]

We are using the standard RF rear clip that came with the car, no idea if it a gulf style or not !
I must also confess to having owned a Triumph, its favourite trick was to open the passenger door all by itself whilst negotiating roundabouts ! I may just have a picture of it that should entertain the troops, question is am I brave enough to publish it ?

Iain

 

[raca]

Do It ! :d

 

[Troy]

Hi Iain,

Any updates with pics on your build? I'm interested to see how it's progressing.