FR-S vs Lexus RC-F

[HunterGreene]

Originally Posted by richardM

We are not talking about in a vacuum. Eyeballs boil.

No, they don't.

To the larger point, I think you are thinking of stuff in terms of momentum rather than mass. As has been pointed out as well, you are discounting the overall fact that the FR-S is generally going to be more "slippery" in the air (smaller surface area, lower drag coefficient), which, given our atmosphere, could actually help the FR-S move faster than you expect. This is getting into levels of math I have no desire to attempt, but the question is would the competing factors cancel each other out or make the difference negligible?

Originally Posted by babydriver

Not sure about your point, Sarlacc. To me the underlying assumption is that the Lexus, due to its greater weight, will have a higher terminal velocity. However, this is dependent on A, the projected area, Cd, the drag coefficient and the mass of the object, m. Acceleration due to gravity (g) and rho (fluid density) are effectively fixed. "A" will favor the FR-S, Cd will favor the FR-S, since they are in the denominator. Only mass (m) will favor the Lexus.

It will have a higher v(T), if the two objects are the same size and shape. Which they aren't, hence my point above.

[babydriver]

OK, I finally "did the math". Here is what I calculated:

The area assumed (A) is based on the height and width of the two vehicles, if they are falling nose first:

RC-F
Area (inches^2) - 3971
Area (meters^2) 2.56

FR-S
Area (inches^2) - 3537
Area (m^2)- 2.28

Based on a flat drop, the terminal velocity of the Lexus is 57.54 m/s. The Vt of the FR-S is 51.62 m/s. Clearly the Lexus will have an advantage here. However, if the drop is vertical (nose first) and the cars do not tumble, then we obtain the following: Lexus - 184.4 m/s; FR-S - 180.33 m/s. Much closer and it will then depend on the height from which the two cars are dropped. If it is say 30 meters, then they will hit more or less simultaneously. If from a great height, the Lexus will hit first, about 2.2% of the total height sooner. So from 1000 meters, the Lexus will hit 22 meters sooner. From 30 meters, it will be 30*.0022= 0.06 meters or about 2 inches sooner.


Someone else may wish to check my math, but I believe that these are correct. Let me know if not.


ADDED: Converting m/s into miles per hour, 58 m/s is roughly equal to 130 mph. That looks reasonable. Nose down and with no deviation from the trajectory due to turbulence, the Lexus' terminal velocity would be a screaming 411 mph and the FR-S would reach Vt of 402 mph.. I strongly suspect that both vehicles would begin to tumble long before reaching that velocity. Well, at least now we know how to get an FR-S above 200 mph. :-)

[ScoobsMcGee]

I'm pretty sure this was the perfect direction for this thread to take.

[richardM]

Originally Posted by HunterGreene

No, they don't.

To the larger point, I think you are thinking of stuff in terms of momentum rather than mass. As has been pointed out as well, you are discounting the overall fact that the FR-S is generally going to be more "slippery" in the air (smaller surface area, lower drag coefficient), which, given our atmosphere, could actually help the FR-S move faster than you expect. This is getting into levels of math I have no desire to attempt, but the question is would the competing factors cancel each other out or make the difference negligible?



It will have a higher v(T), if the two objects are the same size and shape. Which they aren't, hence my point above.

I'm assuming the cars fall pancake style, because if they go nose down, they are basically a crude airfoil shape and will generate a pitching moment and tumble. Or assume they both tumble randomly...

here's a cute little app from NASA...

http://www.grc.nasa.gov/WWW/k-12/airplane/termv.html

[swarb]

Originally Posted by raven1231

Unless you were to drop both of the cars out of a plane and see which would land (crash) faster. This is why you need the parachute

Look what you started!

[swarb]

So who wins this race from a plane?

[ScoobsMcGee]

Originally Posted by swarb

So who wins this race from a plane?

The pilot.

[babydriver]

Originally Posted by richardM

I'm assuming the cars fall pancake style, because if they go nose down, they are basically a crude airfoil shape and will generate a pitching moment and tumble. Or assume they both tumble randomly...

Either way, the cars eventually will tumble about their centers of gravity given enough height. Seems like the right time for this video:

http://topgear.wikia.com/wiki/File:V...Gear_-_BBC_Two

That was a flat drop from one mile and you can see that the VW began tumbling fairly quickly. I laugh every time I see the VW pancake a full three seconds before the Porsche crosses the finish line!

[BlueDubbinTDI]

[babydriver]

No, no, these are smartass comments.

[shu5892001]

Originally Posted by poptopclk

My thoughts are that Lexus RC-F must have been somewhat "inspired" by the
FR-S design. When I look at them some of the lines look awfully similiar.

However the specs lead me to think the FR-S is likely more fun to drive since the Lexus is so heavy 3,958 lb vs 2,806 lbs. w AT

Price $72,000 vs $31,000 (series 10)
Horsepower 467 HP vs 200 HP
0-60 4.4 Sec vs 5.9 sec
length 185.2 in vs 166.7
Tire 19" vs 17"
Fuel cap 17.4 gal vs 13.2 gal
Top speed 168 mph vs 149 mph

I just wonder if paying an extra $41,000 for 1.5 seconds faster to 60 mph and an extra 19 mph at top end are worth it.

It would seem all that extra weight might take some of the "fun" out of driving it.

IMHO

lol base on your theory, best car to buy is GTR hands down. Tones of cars costing way more but has even slower 0-60

[alexisfire02]

A big difference is the audience. Most of the people that are going to buy an RC-F aren't the same people that are considering an 86. They are the people considering buying an M4. There will always be buyers that won't even consider an 86 just because it is too cheap.

[HunterGreene]

Originally Posted by alexisfire02

A big difference is the audience. Most of the people that are going to buy an RC-F aren't the same people that are considering an 86. They are the people considering buying an M4. There will always be buyers that won't even consider an 86 just because it is too cheap.

I don't want those type of people owning an 86 anyways. They'd just b*tch all day long.

[Tcoat]

Originally Posted by HunterGreene

I don't want those type of people owning an 86 anyways. They'd just b*tch all day long.

And that is different then half the people on here in that...?