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si_civic said:
Does it matter which way they are installed?

which way should they be on ?
Yes, it matters. As for the proper orientation, the bottom of the "swirl" (i.e. the portion of the swirl nearest the hub) should be forward (i.e. lead the swirl arc around the rotation).
 

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manufacturers, i believe, have "designed" cross-drilled rotors both ways...arc forward or arc back....it doesn't matter, they serve no purpose anyway.

NOW - if your internal vanes are arc'ed, then that's something different, and is important.
 

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LucasBlack said:
manufacturers, i believe, have "designed" cross-drilled rotors both ways...arc forward or arc back....
I've mounted lots of cross drilled rotors and I have yet to see a set that was designed for a swept forward arc. Check every manufacturer of aftermarket rotors, check every new vehicle manufacturer that mounts drilled rotors from the factory, you'll see the same thing, swept back arcs.

LucasBlack said:
...it doesn't matter, they serve no purpose anyway.
Well then your opinion doesn't line up with the scientific analysis of the efficacy of drilled and slotted rotors that I've read, the most recent from no less than a scientific authority than NASA.

Believe what you want (you will anyway, regardless of what I write), however, there is a huge body of both empirical and scientific evidence that proves that drilled rotors do in fact have an advantage over non drilled (or slotted) rotors.
 

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shipo said:
Believe what you want (you will anyway, regardless of what I write), however, there is a huge body of both empirical and scientific evidence that proves that drilled rotors do in fact have an advantage over non drilled (or slotted) rotors.
yes it keeps it cooler but you reduce the amount of rotor to brake pad contact. also the cross drilled get rust colored and look stupid after a while. get slotted and be done with it.
 

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...those arcs seem to conflict one another...unless i'm seeing something you aren't.

and when NASA starts working on cars, you let me know, and I'll consider it, kthnxbye ;)

and you're correct, I'll most likely keep believing what I believe. I tend to favor truth.... i could be wrong,
but i haven't seen the evidence yet...maybe you have it. please share if you do...
 

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^ Just because somebody mounted aftermarket rotors on the wrong side of the car doesn't mean that's the way they're supposed to be mounted.

As for NASA, they do LOTS of scientific studies on stuff other than sattellites and space shuttles. Think about it this way, aircraft (and even the Shuttle) need to stop once they reach the ground and brakes are still one of the preferred methods of performing said stops.
 

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shipo said:
^ Just because somebody mounted aftermarket rotors on the wrong side of the car doesn't mean that's the way they're supposed to be mounted.

As for NASA, they do LOTS of scientific studies on stuff other than sattellites and space shuttles. Think about it this way, aircraft (and even the Shuttle) need to stop once they reach the ground and brakes are still one of the preferred methods of performing said stops.
when i fly the preferred method is to reverse engines. plus i thought that the space shuttle used a parachute to stop. they prolly use brakes some but not as much as u think. they are too worried about not killing the people in space and not about the final 200 feet of runway.
 

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GlxyGry06Si said:
when i fly the preferred method is to reverse engines. plus i thought that the space shuttle used a parachute to stop. they prolly use brakes some but not as much as u think. they are too worried about not killing the people in space and not about the final 200 feet of runway.
What plane do you fly? I ask because I've flown lots of small recips and they all use brakes as their only method of braking. As for turbine and jet engine motivated aircraft, yes, reverse thrusting is one means of slowing, however, the primary means of braking is from brakes on the wheels. That holds true for the Space Shuttle (the parachute(s) is(/are) a secondary drag device), 747s, A380s and Dash 7s and virtually every other kind of private, commercial and military aircraft flying these days.
 

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shipo said:
^ Just because somebody mounted aftermarket rotors on the wrong side of the car doesn't mean that's the way they're supposed to be mounted.

As for NASA, they do LOTS of scientific studies on stuff other than sattellites and space shuttles. Think about it this way, aircraft (and even the Shuttle) need to stop once they reach the ground and brakes are still one of the preferred methods of performing said stops.
ok, examples aside, how about that scientific evidence that proves your point?
and a shuttle (which does use methods of stopping beyond a caliper/rotor braking system) coming to a stop once on a long runway is not exactly what i would use as the backbone of my argument for performance automotive braking systems....
 

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c-130H3
 

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LucasBlack said:
ok, examples aside, how about that scientific evidence that proves your point?
and a shuttle (which does use methods of stopping beyond a caliper/rotor braking system) coming to a stop once on a long runway is not exactly what i would use as the backbone of my argument for performance automotive braking systems....
In the July 2007 issue of NASA Tech Briefs there was an article titled Simulation of Heat Generation in Analyzing Thermoelastic Instability in Disk Brakes written by University of Miami scientists Eltoukhy, Asfour & Almakky. Unfortunately the above referenced article is not available online (although I believe you can contact NASA for reprints), there are a couple of quotes that I can provide from said article:

"Both the perforated and the notched disks provide better results as far as the temperature distribution and the heat flux as compared to the standard design, despite the fact that the maximum temperature is the same."

"It can be also concluded that the perforated disks give better temperature distribution and heat flux compared to notched disks."

Temperature distribution is the key here, the better the rotor can evenly distribute the heat generated from braking, the better the braking and the longer lasting the rotor. To summarize the article, undrilled and unnotched (i.e. standard center vented disk rotors) are inferior to both cross drilled and notched (i.e. slotted) rotors, and of those two, cross drilled are more effective than notched.

For more on this subject, you can order the following documents from the SAE archives:

Document Number: 2006-01-0691 -- Title: The Effect of Rotor Crossdrilling on Brake Performance

Document Number: 973016 -- Title: A High Aerodynamic Performance Brake Rotor Design Method for Improved Brake Cooling

I could go on as there are MANY more articles in the SAE archives on this subject, but you get the point.
 

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Discussion Starter #14
Hercules! Hercules! Hercules!

What has my thread turned into !!?

Those three pictures are conflicting. 2 / 3 have the rotors facing one way.

Now, I see pictures where the arc is aimed to the rear of the vehicle, but the caliper is on the front. Next I see pics where the arc is aimed to the front, but the calipers are in the back of the rotor.

eeerrk !!
 

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caliper front or not...the rotation and interaction with the face of the rotor is the same....just at a different point of the rotation....
 

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si_civic said:
Hercules! Hercules! Hercules!

What has my thread turned into !!?

Those three pictures are conflicting. 2 / 3 have the rotors facing one way.

Now, I see pictures where the arc is aimed to the rear of the vehicle, but the caliper is on the front. Next I see pics where the arc is aimed to the front, but the calipers are in the back of the rotor.

eeerrk !!
I'm not sure what you're looking at as all three pictures that I posted all have the cross drilling arc oriented the same way. What you may have missed is that the only visible portion of the cross drillings on the Lamborghini are on the bottom, however, if you just mentally picture that same cross drilling swirl as the rotor rotates, you'll "see" that it is orientated the same as the others.
 

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shipo said:
You aren't suggesting that the HerkyBird generates more stopping power from the props than from the wheel brakes are you?
no but you dont wanna heat your brakes up. thats a big problem. when we do assault landing we raise hell on the brakes but normally we will just reverse engines and just run it out. saves money for brakes and we dont want a wheel well fire.
 

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GlxyGry06Si said:
no but you dont wanna heat your brakes up. thats a big problem. when we do assault landing we raise hell on the brakes but normally we will just reverse engines and just run it out. saves money for brakes and we dont want a wheel well fire.
Makes sense given a long enough runway. I guess you haven't shot any landings on the USS Forrestal recently huh? ;)
 

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shipo said:
Makes sense given a long enough runway. I guess you haven't shot any landings on the USS Forrestal recently huh? ;)
nope but in the sandbox you wanna get off the runway really fast because there are lots of other planes. i see where you are coming from but im sure nasa will land their shuttle on a long ass runway with no one around. they will run the plane out the whole way. i think they have better things to do than worry about rotors. just my .02
 

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shipo said:
Makes sense given a long enough runway. I guess you haven't shot any landings on the USS Forrestal recently huh? ;)
also they dont use brakes while landing on aircraft carriers. they use they drawcord and max out engines. no need for brakes. no need to reverse engines either.:thumb:
 
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