The volume of fluid required to be moved is dependent on the facial area of the slave cylinder and the distance it must move to place the pad on the brake disk. It's got nothing to do with the diameter of the line.
Also if you apply 10 pounds of weight to a plate that is 10 square inches in size your pressure applied is 1 pound per square inch of plate. If you apply it to a plate that is 100 square inches then it is only 0.1psi. Consequently the pressure on a small diameter tube per unit of pipe wall area is greater than it would be in a larger pipe although it is still spread evenly in both cases according to physical laws for incompressible fluids. Small pipes also experience a proportionately greater loss in pressure over distance due to frictional effects and you have to push harder to move the same volume of fluid in the same period of time. It is the need to move a certain volume, as determined by the first paragraph above, in a defined time that dictates the pipe diameter. The change in volume due to a large diameter tube flexing out under pressure is not necessarily any greater in proportion to the total volume of the pipe than it is in a smaller pipe thus size is not necessarily an indicator of braking efficiency. To take it to the extreme an infinitely small pipe would prevent any transmission of force irrespective of how strong or stiff its walls were. John Martindale 29 Jane Circuit Toormina NSW 2452 Australia ph:61 2 6658 4767 m:0403 432179 email:john_martind...@bigpond.com -----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Nerobro Sent: Thursday, 13 September 2012 12:36 AM To: Craig Williams; KRnet Subject: Re: KR> What material for lines from the toe brake masters to thebrake? The volume of fluid doesn't really matter much. The fluid, for all intents and purposes, is incompressible. However the diameter of the line, that makes a huge difference. For a given wall thickness, if you halve the size of the tubing, you're going to end up tubing that's several times more resistant to pressure. (I can't be bothered to do the exact math right now) But the stiffer brakes (read improved braking) comes from the stiffer (to pressure) tubing. On Wed, Sep 12, 2012 at 9:06 AM, Craig Williams <kr2seaf...@yahoo.com> wrote: > Yes, small line = less volume of fluid to move. I have heard of several instances of people moving to the 1/8" line and getting much improved braking. I too will use 1?8" plastic with my Tracy O'brien brakes. > > Craig > www.kr2seafury.com > > > > ________________________________ > From: Dan Heath <da...@windstream.net> > To: 'Corvair engines for homebuilt aircraft' <corvaircr...@mylist.net>; 'KRnet' <kr...@mylist.net> > Sent: Wednesday, September 12, 2012 4:29 AM > Subject: KR> What material for lines from the toe brake masters to the brake? > > Joe, > > I have Matco brakes and master cylinders. I use 1/8" plastic line that I > got from Matco, for the entire installation. My plane is fast and I have to > brake hard often. This is a replacement installation, so I got lucky. The > old installation used 1/4" line, and I was able to feed the new line all the > way from the Master to the Slave. This can come in real handy if the line > ever needs to be replaced. So, this is a hint to install the 1/4" line > first as a conduit for the 1/8" line, if you decide that is the route you > want to take. > > Another interesting thing is that with the old type installation, which I > had on this KR and my first KR, I could not hold the plane during run-up. > Now that is not a problem. I think the 1/8" line does not expand like the > 1/4" did. > > See N64KR at http://KRBuilder.org - Then click on the pics > See you at the 2012 - KR Gathering in Mt. Vernon, Il ? MVN ? 40th > Anniversary > There is a time for building and it is over. > Daniel R. Heath - Lexington, SC > http://www.krbuilder.org/MyUSA/ > > > _______________________________________ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html > _______________________________________ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html _______________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2437/5264 - Release Date: 09/12/12
