Update on ducting:
Yes, it helps to increase the velocity by reducing the area, but not too much. If I find the magic number I'll post.
Gregg
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Update on ducting:
Yes, it helps to increase the velocity by reducing the area, but not too much. If I find the magic number I'll post.
Gregg
Quote:
Originally posted by grega:
Hell, consider, for example, relative newcomers Southwest Airlines and JetBlue's method of doing business versus Delta and American. total different mindset, total different culture.
Actually Jet Blue and the other newcomer's advantage is that they don't pay out hundreds of millions of dollars a year in pension because they haven't been around long enough to have pensioned retirees.
That will change in time and my prediction is that regulation will come back lest the industry become unsafe as corporate entropy kicks in.
[This message has been edited by Prince Makaha (edited October 21, 2004).]
OK so what happened to the wheel fans in this discussion? They are certainly legal, and they can move a large amount of airflow over the caliper, rotor and bearing housing. They also remove air from under the car. Lots of advantages here IMO.
They are allowed specifically per the GCR. They are not part of the wheel width, as they are not part of the wheel (removeable). I know that at least one ITA VW used to run them in the early 90s.
Just wondering why now we are only discussing the ducting options. Possibly the availability, or difficulty to fabricate wheel fans?
Chris
I know, a total hijacking.....sorry.
"Actually Jet Blue and the other newcomer's advantage is that they don't pay out hundreds of millions of dollars a year in pension because they haven't been around long enough to have pensioned retirees.
That will change in time and my prediction is that regulation will come back lest the industry become unsafe as corporate entropy kicks in."
AND most of the new airlines don't have to pay the same landing fees as established airlines, and many times they have their plane lease costs deferred up to two years. Many predict that the future of all airlines will be roughly a ten year run, before they have to file for bankruptcy because their costs "catch up with them".
Having to watch my wife take her third pay cut as a flight attendent in 10 years I think that some basic regulatory action needs to be put into place. In most cases it is now cheaper to fly across country than to drive or take Greyhound. And my wife still has to listen to all the passengers bitch, whine, and moan about everything!
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Tristan Smith
Buffalo's Southwest Cafe
ITA Nissan 240sx #56
It is an interesting situation, possibly without a solution (like my brakes). We tried regulation for nearly 50 years and it seemed to work. We junked that, and initially it seemed to work.
But now, it just looks like the existing economic model for airlines doesn't work. Costs are too high and revenues too unpredictable and on average too low.
I think you hit the unfortunate nail on the head. The discounting and other incentives given to non-business travel are probably going to have to come to an end. Air travel has been artificially cheap for nearly two decades, and that probably has to stop.
Interesting economic dilemma.
I just look at the airline situation and sigh. They keep asking for concessions from the pilots, attendants, and mechanics, (and getting them, because everyone figures it's better than no job at all) but we never hear anything about the top executives giving up any of their pay, and they're making alot more than the ones giving the concessions.
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Lesley Albin
Over The Limit Racing
Blazen Golden Retrievers
I am not a CPA dealing with the airline business, but as an accountant, I'm am 99.99% confident what we are talking about here is a deferment of payments. This is NOT the same thing as cost. The costs must still be recorded despite the fact no payments have been made.Quote:
Originally posted by Tristan Smith:
...many times they have their plane lease costs deferred up to two years.
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Quote:
Originally posted by OTLimit:
I... but we never hear anything about the top executives giving up any of their pay, and they're making alot more than the ones giving the concessions.
The classic ENRON situation....of course those guys screwed their people willingly and knowingly, but really, isn't America famous for overpaid executives who get all the free perks, and still make bonuses even when the company goes under??
When was the last time we heard a top executive say that his companies big guys were all going to take a 15% cut in base and bonus? Maybe I'm just hearing all the (negative) headlines!
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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
Note that the caliper is partially insulated from the piston by the fluid as well as by the problem seals themselves. Ducting may remove heat from the caliper, but keeping the heat away from the piston in the first place seems to be the main requirement here (unless the problem rubber seals can be replaced with something having a higher melting point, maybe silicone -- my guess is that the British rubber is more natural than other possible sources).
Pad insulating shims have been discussed. The shims must be heat insulators (like ceramic) rather than heat conductors (like metal, and maybe carbon -- can someone check me on that? -- it's been nearly 20 years since RPI engineering school).
You might also consider the heat transfer properties of the pad material itself. In your particular situation (piston seal heat failures), you should probably try a pad material that is *not* a good heat conductor. Thus, choose high ceramic content rather than high metallic content.
Just some race-only advice from one lawyer to another. http://Forum.ImprovedTouring.com/it/wink.gif Cheers!
I've never tried them, but I did know someone who tested them on a World Challege Corvette. They tried pulling the air from the inside as well as pulling the air from the outside. The unacceptable (to them) disadvantages were that the wheel fans caused huge aerodynamic drag at higher speeds, cooled the tires more than desired, and didn't cool the brakes enough at lower speeds. Sort of like the non-linear boost problems of a turbocharger versus a supercharger.Quote:
Originally posted by shwah:
OK so what happened to the wheel fans in this discussion? ... Chris
Since this subject has been revived...Quote:
Originally posted by gsbaker:
[B]...If I find the magic number I'll post.[B]
There is no "magic number" for reducing the area of ducting to increase the velocity in an optimal manner. However, there is an equation that requires measurements from flow meters and pressure sensors, but I don't believe anyone wants to go that far.
When I complained to my ME friend that this was becoming too complex for the weekend amateur he said, "Look at the end of a leaf blower. That's about right."
He also reminded us not to miss any hot surface area, e.g. if you can get to, say, 12 square inches of hot material you wish to cool, don't pinch the duct exit area down to less than that.
Now where is that leaf blower? http://Forum.ImprovedTouring.com/it/smile.gif
Gregg