GT90 Info

well the GT90 was/ is at RCR and they build replica's...hmmmm my guess is the car is fully measured ,moulded and in the wings to supply a kit.....
 
People watching the GT90, posted just a day ago. Looks like a sort of workshop:
l8yUK5e.jpg


Anyone know where this is? I would love to get better detailed pics or get info about certain items on the car.
l8yUK5e
 
Hans,
The pictures in your link were taken at RCR/Superlite cars in Detroit. Most of those 'other' cars are replicas made by them.
 
Hans,
The pictures in your link were taken at RCR/Superlite cars in Detroit. Most of those 'other' cars are replicas made by them.

Okay, thanks. Cool and expensive stuff they have there. I heard from another Ford forum the GT90 had been scanned in Detroit. So most probably the car was scanned by RCR to prepare the design and build of a replica GT90. That would be extremely exciting.
 
Sorry Hans no scanning done and no replicas planned

Okay, that's a pity. On the other hand, the design is basically aerodynamic flawed. Flipping up the spoiler at speed would mean losing the back end and I suppose you don't want to sell such cars and be liable for claims.
 

Randy V

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Okay, that's a pity. On the other hand, the design is basically aerodynamic flawed. Flipping up the spoiler at speed would mean losing the back end and I suppose you don't want to sell such cars and be liable for claims.

...and you know this how?
 
...and you know this how?

I made a scale model of the spoiler system based on pictures available.
This is a good pic of the original:
4TqCamg_zps7lm1pwcj.jpg


What you see is the half of an hydraulically operated L-shaped swing arm. The pivot point is about over the rear axle. The remaining (not present) part of the arm is fitted on the spoiler itself and the 2 parts are assembled with 2 bolts each.
On my model I made it as follows:
IMG_0081_zpsjaai8r7p.jpg


The spoiler has a positive camber because it follows the rounded bodywork. On itself this is already a bad thing. To make matters worse because of the pivot system, when the spoiler is lifted it starts of with a positive aoa (angle of attack). I estimate the spoiler is rotated about 50 degrees to its full up position so this is the full up position:
IMG_0101_zpsorix5jva.jpg


Only at full up position the spoiler has a negative aoa generating negative lift at the cost at high drag because of the shape of the wing. So flipping up the spoiler at speed on the prototype would generate positive lift until the last 10 degrees when the aoa goes negative.
On a real production car the pivot system should be replaced by a system like on the Veyron with a hinge point at the forward edge of the spoiler. The spoiler would then be tilted to a negative aoa while still in contact with the bodywork. A higher speed it would be transversal raised by an hydraulic actuator to create a slot. To counteract lift of the rounded bodywork there should be gurney flaps.
 

Randy V

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Very impressive exercise but there are a couple of other things that need to be taken into consideration -
1) Are you certain that there is not a recess in the body below the wing that may allow for a different wing-chord than your model had? I've not seen a GT90 with the wing deployed.
2) Relative wind and angle of attack - it may not provide downforce from inverse lift like most wings, but it is a spoiler which may provide downforce as well as aerodynamic braking.

Frankly, I think #2 may have been their goal.

It would be interesting to see if you could put your model in a wind tunnel to determine the areodynamic effect.
 
Very impressive exercise but there are a couple of other things that need to be taken into consideration -
1) Are you certain that there is not a recess in the body below the wing that may allow for a different wing-chord than your model had? I've not seen a GT90 with the wing deployed.
2) Relative wind and angle of attack - it may not provide downforce from inverse lift like most wings, but it is a spoiler which may provide downforce as well as aerodynamic braking.

Frankly, I think #2 may have been their goal.

It would be interesting to see if you could put your model in a wind tunnel to determine the areodynamic effect.

Here is a good pic of the GT90 with the spoiler deployed:
1449762534571769002.jpg_zpsrohgaazm.jpeg


You can see the foil shape and curve of the rear body. The model is a good match in general shape.It differs just that the spoiler on the 1/18 model is a bit thicker and therefore that the recess in the body is deeper.
It will generate negative lift at full up, but at a cost of top speed due to its inefficiency. I don't think it was ment as an airbrake because of the dangerous transition phase. But with a Veyron like system this would be quite easy to implement.
 
At last got building again after the summer break. Finished the interior, chassis and engine should be a doddle. Exterior will need more work, esspecially the front and tail lights. Possible will improve the mirror struts as well.
IMG_1095_zps9umzlbdi.jpg


IMG_1094_zpsijndscm2.jpg
 
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