Brakes

Brakes and BRS Bridles

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Awhile back I ordered some black plastic clips from AliExpress.com to hold the bridles for the parachute in place. This weekend I decided to put them to use. When I got started I also decided to tackle the brake cables since it looked like I could route those with the bridle clips too.

FC-30 3M Selfadhesive Nylon mounting flat pole wire cable clamp
FC-30 3M Selfadhesive Nylon mounting flat pole wire cable clamp

The brake cables exit the fuselage near the front of the landing gear on each side, I added a small grommet to this hole to reduce chafing.
Grommet for brake cable
Grommet for brake cable

To keep the cables from flapping in the breeze I added a couple of rubber lined cable clamps to the landing gear bolts. The cable routed through the clamps then down the landing gear leg along the bridle that is secured with the plastic clips.

Bridle and brake cables secured with clips
Bridle and brake cables secured with clips

The grade cable the runs around the from of the gear into the caliper.

Break cable into caliper
Break cable into caliper

I also used the bridles clips inside the fusealge so they don’t get tangled up with other things. These clips are a little too tall so they don’t clamp the bridle. I put a small piece of foam on the top on in the picture below. Next time I’m at the hardware store I plan to get some self adhesive black foam weather striping to use in the few places where this matters.

BRS bridle secured with clips in cockpit
BRS bridle secured with clips in cockpit

I plan to add maybe one or two more clips inside the fusealge but I need to climb in and make sure I don’t place them in a position that my elbow might hit. Right now the seat is covered with parts for electrical wiring so I’ll do that some other time. If the 3M sticky tape does not hold up I plan to secure the clips using a couple of tiny wood screws but so far the 3M tape seems adequate.

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Disc Brakes

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I have thought about adding inexpensive and lightweight bicycle disc brakes to my Minimax for a long time. The main stumbling block is fitting the rotor to the AZUSA Tri-star 6″ wheels. On http://www.lonesomebuzzards.com Walkabout posted a brilliant, cheap way to mount the rotor. More about that later. With the most difficult part resolved it was time to get started.

Finding inexpensive rotors that did not look like something out of the movie Saw was a little difficult but since there is a nearly infinite selection I did finally find a set I liked. I settled on the Gymforward YD-ZXC-SCP001 160mm rotors.

I could have bought two of nearly any bicycle caliper but I wanted something a little unique. If I used the same caliper on the right and left one side would require a longer cable, look odd and possibly cause uneven braking. Finding a set of right/left calipers was difficult until I searched for scooter calipers. Ordered these calipers for $20 from a Chinese seller and it only took about a week for them to arrive. I’ve seen these sold on other sites but this model is the only right/left set of calipers I’ve found.

The mounting bolts on bicycle calipers are spaced 51mm apart. These scooter calipers use a 50.5mm spacing. To figure out all the measurements I used a free on-line CAD application OnShape. After finding a drawing for bicycle caliper mounting bolt measurements I designed the caliper mount in OnShape altering the measurements just enough to account for the 0.5mm difference. The mount is fabricated from 2″ x 2″ x 0.125″ aluminum angle.
Also used OnShape to design the rotor adapters. I knew with the proper bolt spacing the rotor would be perfectly centered. Using OnShape assembly I was able to verify the design before drilling a single hole. 

I used 1.25″ x 1.25″ x 0.125″ aluminum square tubing. Each wheel needs three adapters and each adapter requires two cuts and three holes. Very simple to make.

One of the main reasons I am doing this is to have a parking brake. With that in mind I started looking for a brake lever that has a locking mechanism. Found the perfect lever that allows me to set the lock with my pinky finger. Simple, elegant solution.

Brake lever
Brake lever latched

The final result looks great, I hope they perform just as good!

Caliper mount
Caliper mount

If you want to build these parts yourself you can download the plans: Caliper-mount-drawing.pdf