 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
|
 Posted: Tue Oct 28, 2008 5:48 pm Post subject: Question On Low-Pressure Brake Lines... |
 |
|
Dear Listers,
I spent a lot of time staring at those plastic brake lines for the low pressure side and just didn't like a thing about them. Just imagine if one were to break and what a mess all the brake fluid all over the cockpit would be like.
After some thought, I came up with the following system for the low pressure feed. I used standard AN 1/4" fittings and aluminum tubing to bring the fluid from the reservoir to a tee fitting and then to bulkhead fittings that connect to standard Aeroquip hoses to the master calendars. Yeah, it was a little more weight, but the peace of mind is worth it.
But here's my question. Notice that on the back side of the second bulkhead, I kind of looped the tubing up and around the hole for the vent. This also positioned tee fitting nicely to feed the left and right sides. The top of that loop is maybe 4 to 5" higher than the top of the reservoir, though. Is the flow from the reservoir to the master cylinders suppose to be basically "gravity fed" or is the "pump" action from the master cylinders all that is necessary to keep the tube and master cylinders full?
Matt Dralle
RV-8 #82880 N844RV (res)
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
| Description: |
|
| Filesize: |
101.3 KB |
| Viewed: |
245 Time(s) |
|
| Description: |
|
| Filesize: |
85.42 KB |
| Viewed: |
253 Time(s) |
|
_________________
Matt Dralle
Matronics Email List Administrator |
|
| Back to top |
|
 |
Dale Ensing
Joined: 11 Jan 2006
Posts: 571
Location: Aero Plantation Weddington NC
|
| Posted: Wed Oct 29, 2008 3:32 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
Matt,
If a leak develops anywhere in the system that could draw air into the
lines, the air will migrate to the highest point in the system which is that
loop. The air would displace fluid in the loop and could allow fluid to leak
from the air vent on the top of the reservoir. May never happen but the
system should allow fluid to gravity feed from the reservoir to the
cylinders and any air bubbles to the reservoir..
Dale Ensing
---
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
_________________
Dale Ensing
RV-6A
Aero Plantation
Weddington NC |
|
| Back to top |
|
|
Charles Heathco
Joined: 10 Jan 2006
Posts: 201
|
| Posted: Wed Oct 29, 2008 4:10 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
I believe you need the reservour above the lines, but this looks like a question for the Vans guys for sure. Also havent heard of the "plastic" lines ever breaking. Chas
[quote][b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
| Back to top |
|
|
pbesing(at)yahoo.com
Guest
|
| Posted: Thu Oct 30, 2008 7:34 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
Yes, Matt, it's supposed to gravity feed to the cylinders. I did not like the plastic lines, but I have also not heard of them leaking. I like to see the plastic lines (working on the brakes of an RV-6 right now) and can clearly see air (or lack of fluid in this case!) in the clear lines to the cylinders. Van's resevoir has the breathable cap so that you can allow the air to escape to the high point in the system (although there are many times this just doesn't happen, unfortunately)
Paul Besing
From: Charles Heathco <cheathco(at)cox.net>
To: rv-list <rv-list(at)matronics.com>
Sent: Wednesday, October 29, 2008 5:09:30 AM
Subject: Re: Question On Low-Pressure Brake Lines...
I believe you need the reservour above the lines, but this looks like a question for the Vans guys for sure. Also havent heard of the "plastic" lines ever breaking. Chas
[quote]
[b]
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
| Back to top |
|
|
Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
|
| Posted: Sat Nov 01, 2008 5:03 pm Post subject: Question On Low-Pressure Brake Lines... |
|
|
Dear Listers,
After some head scratching and a couple more tries, I think I came up with a new design for the low pressure side of the brake lines. With this design, there is a steady slope downward from the reservoir to the master calendars. Seems to be pretty substantial. My only concern is that right feed line going through that candy cane piece isn't really supported anywhere. Its pretty short and solid to the touch, but vibration might cause a issue. Since the bottom floor of the baggage area goes over the top, there's really nothing permanent I can attach it to short of making a bracket of some kind (yuck).
So what do you guys think?
Matt Dralle
RV-8 #82880 N844RV (res)
At 06:48 PM 10/28/2008 Tuesday, Matt Dralle wrote:
| Quote: | [snip]
But here's my question. Notice that on the back side of the second bulkhead, I kind of looped the tubing up and around the hole for the vent. This also positioned tee fitting nicely to feed the left and right sides. The top of that loop is maybe 4 to 5" higher than the top of the reservoir, though. Is the flow from the reservoir to the master cylinders suppose to be basically "gravity fed" or is the "pump" action from the master cylinders all that is necessary to keep the tube and master cylinders full?
Matt Dralle
RV-8 #82880 N844RV (res)
|
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
| Description: |
|
| Filesize: |
120.71 KB |
| Viewed: |
244 Time(s) |
|
| Description: |
|
| Filesize: |
104.02 KB |
| Viewed: |
230 Time(s) |
|
| Description: |
|
| Filesize: |
107.51 KB |
| Viewed: |
258 Time(s) |
|
| Description: |
|
| Filesize: |
110.33 KB |
| Viewed: |
255 Time(s) |
|
| Description: |
|
| Filesize: |
118.64 KB |
| Viewed: |
232 Time(s) |
|
| Description: |
|
| Filesize: |
125.65 KB |
| Viewed: |
257 Time(s) |
|
| Description: |
|
| Filesize: |
123.03 KB |
| Viewed: |
248 Time(s) |
|
_________________
Matt Dralle
Matronics Email List Administrator |
|
| Back to top |
|
|
Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
|
| Posted: Sun Nov 02, 2008 9:20 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
Thank you for the feedback John. To run it parallel with the high pressure line above it, I would have had to go up a couple of inches as it relates to the reservoir since I have to go under the baggage floor. I was trying to make sure that all of the run was at least slightly downward to keep gravity pulling the fluid toward the master cylinder. Am I mis-understanding your comment?
Matt
At 08:54 AM 11/2/2008 Sunday, you wrote:
[quote]Your workmanship is exceptional and a thing of beauty to behold.
However, when I am performing Tech Inspections, I would caution builders
on the use of a long continuous run as in your picture (2). I would
have created the same sweep as the line above and run the straight line
more parallel to the upper line.
John Cox
A&P, IA
EAA Tech #5242
--
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
_________________
Matt Dralle
Matronics Email List Administrator |
|
| Back to top |
|
|
Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
|
| Posted: Sun Nov 02, 2008 9:28 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
Ah! I understand. But those are the low pressure side so there really isn't any "pressure" to speak of, is there? I do see your point from a best-practices stand point and it was something that I didn't know.
Thanks!
Matt
At 09:23 AM 11/2/2008 Sunday, you wrote:
[quote]No, however any line containing pressurized fluid contracts in length
and expands in diameter, hence the need for flex by routing other than
the "shortest distance between two connection points. It is spelled out
in the AC43.13.
John
--
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
_________________
Matt Dralle
Matronics Email List Administrator |
|
| Back to top |
|
|
Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
|
| Posted: Sun Nov 02, 2008 9:53 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
Thanks for the tip, Mike. I actually did try these babies out. The problem on the RV-8, though, is that with the adjustable rudder pedals at full "tall-person", the mini-reservoir doesn't clear the firewall when the brakes are applied. Here's a picture with one on the right master cylinder and full right rudder applied, but no brake action. Notice that there is only about 1/16" of clearance to the firewall. I wish that Grove had used a different fitting design instead of just slapping a NPT M-M on the side. Its way too long. Anybody know of a similar fitting that is about half as long?
Matt
At 06:46 PM 11/1/2008 Saturday, you wrote:
| Quote: |
Hi Matt,
You've created a plumbing masterpiece but it's a ton of complication and cost. Have you thought about just mounting the brake reservoir right on the brake master cylinders?
This is similar to the set up that I've used. $22/ea.
Good luck.
http://www.aircraftspruce.com/catalog/lgpages/remoteFluidReservoirs.php
>Dear Listers,
>
>After some head scratching and a couple more tries, I think I came up with a new design for the low pressure side of the brake lines. With this design, there is a steady slope downward from the reservoir to the master calendars. Seems to be pretty substantial. My only concern is that right feed line going through that candy cane piece isn't really supported anywhere. Its pretty short and solid to the touch, but vibration might cause a issue. Since the bottom floor of the baggage area goes over the top, there's really nothing permanent I can attach it to short of making a bracket of some kind (yuck).
>
>So what do you guys think?
>
>Matt Dralle
>RV-8 #82880 N844RV (res)
>
Matt G Dralle | Matronics | PO Box 347 | Livermore | CA | 94551
925-606-1001 V | 925-606-6281 F | dralle(at)matronics.com Email
http://www.matronics.com/ WWW | Featuring Products For Aircraft
|
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
| Description: |
|
| Filesize: |
142.89 KB |
| Viewed: |
250 Time(s) |
|
_________________
Matt Dralle
Matronics Email List Administrator |
|
| Back to top |
|
|
retasker(at)optonline.net
Guest
|
| Posted: Sun Nov 02, 2008 11:30 am Post subject: Question On Low-Pressure Brake Lines... |
|
|
If you don't mind a non-AN fitting, you can get a close nipple from
McMaster-Carr in a variety of materials. Just go to
http://www.mcmaster.com/ and search for close nipple.
They will not have a hex section so you will have to screw the two parts
together with the nipple between them, but since this is no-pressure
connection the final torque is not critical.
Dick Tasker
Matt Dralle wrote:
| Quote: | Thanks for the tip, Mike. I actually did try these babies out. The problem on the RV-8, though, is that with the adjustable rudder pedals at full "tall-person", the mini-reservoir doesn't clear the firewall when the brakes are applied. Here's a picture with one on the right master cylinder and full right rudder applied, but no brake action. Notice that there is only about 1/16" of clearance to the firewall. I wish that Grove had used a different fitting design instead of just slapping a NPT M-M on the side. Its way too long. Anybody know of a similar fitting that is about half as long?
Matt
At 06:46 PM 11/1/2008 Saturday, you wrote:
>
>
> Hi Matt,
> You've created a plumbing masterpiece but it's a ton of complication and cost. Have you thought about just mounting the brake reservoir right on the brake master cylinders?
> This is similar to the set up that I've used. $22/ea.
>
> Good luck.
> http://www.aircraftspruce.com/catalog/lgpages/remoteFluidReservoirs.php
>
>> Dear Listers,
>>
>> After some head scratching and a couple more tries, I think I came up with a new design for the low pressure side of the brake lines. With this design, there is a steady slope downward from the reservoir to the master calendars. Seems to be pretty substantial. My only concern is that right feed line going through that candy cane piece isn't really supported anywhere. Its pretty short and solid to the touch, but vibration might cause a issue. Since the bottom floor of the baggage area goes over the top, there's really nothing permanent I can attach it to short of making a bracket of some kind (yuck).
>>
>> So what do you guys think?
>>
>> Matt Dralle
>> RV-8 #82880 N844RV (res)
>>
>>
>>
>>
>
> Matt G Dralle | Matronics | PO Box 347 | Livermore | CA | 94551
> 925-606-1001 V | 925-606-6281 F | dralle(at)matronics.com Email
> http://www.matronics.com/ WWW | Featuring Products For Aircraft
>
>
>
> ------------------------------------------------------------------------
>
|
--
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
--
| | - The Matronics RV-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
