Page 1 of 1

Brake master cylinder mountings

Posted: Mon Sep 14, 2020 10:20 am
by Richard Roller
Good morning everyone. I'm sure most are aware that N34KP was damaged a year ago July. At that time it was the latest incident due to not having brakes, and there are many.

So, I'm putting brakes on the old bird this coming winter. I've bought a set of Matco wheels and brakes that will suit my needs.

I've taken many photos over the years of various master cylinder installations. I'd like builders/pilots to post pictures of your installations, tell me your thoughts behind what you did and maybe what you might change with experience.

I have ideas of my own, but I'd be a fool if I ignored others experiences.

Thanks.

Re: Brake master cylinder mountings

Posted: Mon Sep 14, 2020 3:07 pm
by taildrags
Richard; do you have any preference as to whether you go with heel or toe brakes?

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power
"Bill Rewey style" toe brakes

Re: Brake master cylinder mountings

Posted: Mon Sep 14, 2020 8:01 pm
by Richard Roller
No preference. I have toe brake actuators on hand, but I have no problem with heel brakes.

Re: Brake master cylinder mountings

Posted: Mon Sep 14, 2020 8:02 pm
by Richard Roller
What would be Bill Rewey style brakes?

Re: Brake master cylinder mountings

Posted: Mon Sep 14, 2020 10:46 pm
by taildrags
Richard; see photo of the toe brake setup on Bill Rewey's Piet. Mine were fabricated after the same fashion. They sit pretty much on each side of the passenger's thighs, on the sides of the fuselage. Simple and effective. Bill's actually have parking brakes, which are the metal tabs on top of the cylinder shafts. You apply the brakes firmly, then pull on the parking brake knob which lifts the tabs such that they 'jam' the shafts and hold the brakes. I had them on my brakes when I got the plane but they never held and never worked right, so I took them off.

I have some pix of one or two nice heel brake setups as well, one which uses the Matco masters laid on their sides. I'll try to find that picture.

-Oscar
Rewey_brake.jpg

Re: Brake master cylinder mountings

Posted: Tue Sep 15, 2020 6:38 pm
by Richard Roller
Thanks Oscar. The picture is similar to one I've taken of Lowell Franks Piet.

Re: Brake master cylinder mountings

Posted: Wed Sep 16, 2020 3:03 pm
by Spark6
I'll try to get a photo of 5TM's brakes next time I'm out at the plane (may be next week), but the guy who installed them did a pretty clever thing, in my opinion - and no, I'm not the builder! The master cylinders are under the box formed by the passenger seat, with the heel brake levers extending out from either side. It's a very neat packaging solution, and nothing gets hung up on the cylinders. The heel brakes took about a few minutes of taxiing to get used to, but I'm very happy with them.

Re: Brake master cylinder mountings

Posted: Wed Sep 16, 2020 9:23 pm
by KenBickers
Richard,

Like the heel brakes described by Barrett, mine are located under the front pax seat. I used Airheart small master cylinders. I designed mine to as flag pole levers. The attached photo shows them from above with the front seat removed.

They are never in the way in flight. I have to pull my heels slightly under the front seat to actuate the brakes on the ground. They work fine for runups and for navigating in close quarters on the ramp.

Cheers, Ken

Re: Brake master cylinder mountings

Posted: Thu Sep 17, 2020 10:24 am
by taildrags
Ken: what's the nylon braided hose running down and out the bottom of the plane?

-Oscar Z.
Medford, OR

Re: Brake master cylinder mountings

Posted: Thu Sep 17, 2020 11:31 pm
by KenBickers
Oscar, I used the braided nylon hose as conduit for the wires from FWF to run up to the aft instrument pod. Not visible from the top-down photo is a small hole drilled in the hose at the low point when the airplane is sitting on the ground to act as a drain for any rainwater that might find its way into the hose. Cheers, Ken

Re: Brake master cylinder mountings

Posted: Fri Sep 18, 2020 10:16 am
by taildrags
Ken; got it. So you used the TSO'd braided nylon electrical flex conduit from Aircraft Spruce for that electrical wiring? ;o) :lol:

-Oscar

Re: Brake master cylinder mountings

Posted: Fri Sep 18, 2020 2:24 pm
by Richard Roller
Ken. I'm not sure I could use your set up. I have the rudder bar. It is a sharp looking installation!

Re: Brake master cylinder mountings

Posted: Sat Sep 19, 2020 11:49 pm
by KenBickers
Oscar, I'm pretty sure that came from the aviation aisle at Home Depot. I've found lots of certified-ish items there. :roll: Cheers, Ken

Re: Brake master cylinder mountings

Posted: Wed Sep 30, 2020 9:13 pm
by Richard Roller
wood piet brake master installation.jpg
This is what I've come up with for the brake master cylinders. These are Cleveland master that I happened to have, model #10-55. I bought these back in the 80's, for another project that never came off.

I got my wife into the rear cockpit and had her put her feet on the rudder bar so I could take measurements for the pedal location.

Re: Brake master cylinder mountings

Posted: Wed Sep 30, 2020 10:55 pm
by taildrags
Richard: I think you're getting it! If it would help, I'd be happy to take measurements of the triangulated fuselage framing space where my brakes are mounted, as well as where the mounting points are located on the diagonal, to give you a point of reference to see if we're close to what you've come up with. It's easier to erase and redraw it in a CAD program than it is to plug drilled holes in your fuselage framing and make new holes if it needs adjusting later ;o) My setup may not be perfect or ideal, but it works fine and has done so for quite a few flight hours, under the feet of various pilots since it was first flown. I have a rudder bar in the rear cockpit.

-Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Re: Brake master cylinder mountings

Posted: Thu Oct 01, 2020 7:51 am
by Richard Roller
I would appreciate the help Oscar. It is better to measure twice and drill once!

Re: Brake master cylinder mountings

Posted: Sun Oct 04, 2020 12:23 pm
by taildrags
Aha. I knew I had a thread going somewhere on this subject. Here are the measurements of my setup, as well as a photo of the starboard side brake showing the welded-on tab on the pedal to make it easier to reach with the toe.

-Oscar
brake_dims.jpg

Re: Brake master cylinder mountings

Posted: Sun Oct 04, 2020 8:09 pm
by Richard Roller
Thanks Oscar. I appreciate the help.

Re: Brake master cylinder mountings

Posted: Sun Oct 04, 2020 10:35 pm
by taildrags
Richard; not saying "do it this way", just putting additional food for thought out there. I'm a bit curious about your leg length. Looking at my brake pedal location fore-and-aft relative to yours, either our cockpits are differently configured by a couple of inches, or my legs are shorter than yours because my brake pedals appear to be about 2" aft of where yours are in the drawing. I wear pants with a 32" inseam. Are yours by any chance a little longer, like 33 or 34"?

-Oscar

Re: Brake master cylinder mountings

Posted: Mon Oct 05, 2020 1:55 pm
by tom kreiner
Oscar,

Have you thought of replacing the L shaped bracket that mounts the pedal with a U shaped bracket? There appears to be an eccentric load on the angled fuse member along with the bracket itself.

Tom

Re: Brake master cylinder mountings

Posted: Mon Oct 05, 2020 9:01 pm
by Richard Roller
We seem to vary from .5" to 1.0" between what you measured and what I drew. The drawing is of the Piet plans. I did put my wife in the rear cockpit to get the measurements that I used. I'm sure it will work out okay.

Re: Brake master cylinder mountings

Posted: Mon Oct 05, 2020 11:42 pm
by taildrags
Richard; I'm sure it'll work out OK... I just thought it might inspire confidence if you had some measurements off another airplane. Sounds like you and I are mighty close on ours so get busy fabricating those brake master mounts and actuators. You'll like having brakes.

Tom: looking at the geometry of the brake masters, the pedals where the braking force is applied, the brackets and their mounting configuration, there are of course a number of eccentric loadings in the picture. I haven't given it much thought because there are others out there flying with the same setup. The main thing I don't like about it are the 3/16" holes through the framing members to mount the brackets, but I had no choice in the matter so there it is. Corky built the plane; I just fly it, break it, and modify it ;o) Regarding the braking force applied by the pilot's feet, there is an unintended but definite restraint that prevents the application of too much force to the pedals: the front support for the front seat. I know this because I have twice broken it loose from its mounting point at the cabin floor when I pressed a brake pedal "energetically" a time or two. The last time it happened, I removed the entire front seat frame, scraped everything back to flush clean wood on the cabin floor, and reinstalled the seat support using a crossmember the full width of the floor, from longeron to longeron, and made it the full size of the longerons to give the seat support plenty of glue area to attach it so as to resist breaking loose if I overdid it with the brake again. The rudder bar has its own stops (a la Mike Cuy's blocks), but the brake pedals were hitting the seat support. Incidentally, when I took the existing seat support framing apart to rework it, I found that it had apparently broken loose before I had the airplane and had been 'repaired' using Gorilla Glue. I hate that stuff! It foams up and fills the gap alright, but it's not structural... the hardened foam glue snaps like peanut brittle. I know why it was done that way... out of convenience and to get a feeling that a poorly-fitted joint could be gooped full of stuff that foamed up to fillet across an ugly gap and look like a real glue joint when it dried, but it wasn't. I think it is now though.

-Oscar

Re: Brake master cylinder mountings

Posted: Sun Nov 08, 2020 8:58 am
by Richard Roller
I'm ordering extrusions for the brake installation. I have considered putting restrictions in the brake lines, to slow down the application time a little. The reason is that I don't plan on reworking the landing gear V's at this time and N34KP is built to the plans. Which means the wheels are to far aft for normal brake application, I'm pretty sure I could put it on its nose with to much brake application. I plan on using them only while taxiing on the ground.

Any comments?

Re: Brake master cylinder mountings

Posted: Sun Nov 08, 2020 10:59 am
by KenBickers
Richard, restrictors might be prudent. You might wait, though, until you've had a chance to do some ground testing. Depending on the mechanical advantage (or lack thereof) of the pedal assembly, you may find that things are okay without adding additional bits to the braking system. Good luck with this. Cheers, Ken

Re: Brake master cylinder mountings

Posted: Mon Nov 09, 2020 9:10 am
by Richard Roller
Thanks Ken. I have done something similar in the past on another project for a friend. We just used a steel fitting (brass would work) out of the master cylinder, soldered shut, then drilled a hole through with a #50 drill.

Re: Brake master cylinder mountings

Posted: Wed Jan 13, 2021 12:52 pm
by Richard Roller
brackets.jpg
I made a set of brackets for the master cylinders. The piece of 1" key stock is the drill guide from the tail longeron repair. I added an extra hole to match the hole spacing for these brackets. It'll be clamped in place and the holes back drilled through the station diagonal.

Re: Brake master cylinder mountings

Posted: Wed Jan 13, 2021 3:23 pm
by taildrags
Looking good! Progress photos are good for those who might be considering the same setup.

-Oscar

Re: Brake master cylinder mountings

Posted: Thu Jan 14, 2021 11:21 am
by tom kreiner
FWIW — The use of a restrictor will not reduce the braking force, but it will slow down the rate at which the force is applied.

Re: Brake master cylinder mountings

Posted: Thu Jan 14, 2021 3:52 pm
by Richard Roller
Very true.