Sunday, May 15, 2016

Sunday, May 15th, 2016 panel, parking brake, finish fwd, cowling, misc

I've put off posting since I had no way of linking pictures in now that Google has finally shot Picasa in the head and linking from Google Photos is just way too painful.

Finally decided to give SmugMug a rip. We'll see how that goes.

 I'm going to try to organize tage his a bit differently and put things by subject rather that chronologically.

I originally planned to go completely per plans and not have a parking brake.  After some consideration of some fields I've been into and talking to folks I realized there are some spots where stopping just wouldn't be an option without a parking brake.  Steve Solomon gave me an idea about how he mounted his - I realized I could just remove the stock Van's bracket and put another in it's place that would make the whole thing pretty seamless, so I decided to do that.

Just for grins I dug up the picture of when I was just getting started on the firewall.  Here's the image:

From Fuselage
The brake bracket is on the lower left.

The Matco unit I got from Aircraft Spruce is pretty compact.  The most logical mounting for me (and with the best fluid line routing) is where the brake side is down, the actuator lever is on the right (facing forward) and the input side from the master cylinders is on top.

The position of the lever determines when the valve is closed and the brakes are locked on.  The way the unit is made you can close the valve, then apply the brakes.  There is a one way valve that will pressurize the brakes but will not release the pressure until the valve is opened again.  The required angle is about 90 degrees or so.

I tried making a side bracket from 1/2" angle to do that.




The final mount looked like this (first attempt):



It was very sturdy and the angle worked great, but there were some position problems - I didn't like how closely I could get the pedals to the bracket.  I couldn't hit it, but it was very close and was unnecessarily beefy.

As happens a lot of times, I decided to take a detour to mount the rudder and connect it up so I could be sure where the pedals would fall in the forward most holes, and as part of that I decided to fabricate and install the stops so I could get the dimensions correct.

That lead to try two (after some googling and Steve Solomon sent me a pic of his)

Version two features a single stop/cable support on the inboard side and a much narrower mount.

Here's the stop/bracket before riveting. The way it works is the part with the rivet holes mounts to the bracket so the longer "arm" is perpendicular to the firewall and provides a place to secure the cable with an adel clamp. The arm also serves as a stop to the actuator lever so it doesn't open too far and go over center. I decided there was no need to have a stop on the closed side because the cable couldn't move that far anyway.




The components after bending in my cheap Harbor Freight brake and before assembly.  I had a bunch of fittings I tried before settling on  a 45 and a 90 on the bottom.




I was able to use most of the holes from the previous mount.  I had to make a couple of more holes and had to fill 2 holes with rivets.

Nut plates on the backside allow mounting the valve with AN3 bolts.




Here's the mount with the valve installed.  The height of the mount allows the lines from the two brake cylinders to clear the angle on the firewall with just straight fittings on top of the valve.




Just used a plain old ACS friction cable for the brake.  The only downside to the way it mounted is pulling on the knob opens the valve and pushing it closes the valve and sets the brake.  It's backwards from what you would expect, but since it is tucked away there is no way to accidentally actuate it and there will be clear labels to make sure it's obvious which way it works.




Mounting the Dynon GPS 250.

I had originally planned to mount the Dynon GPS unit on the glare shield under the canopy.  After thinking about it I just decided to mount it under the cowl.  Fiberglass is transparent to GPS signals.

Here's the mounting.  Two pieces of 1/2" angle back to back with a hole in the middle, then two #14 Adel clamps to hold it on the engine mount.  Very simple and rock solid.



Side view.




We had a project visit in early April and Pete Pearson (very experienced builder who is one of our Chapter Tech Counselors) came out and was kind enough to go over everything and give me tips.  He's just recently flown off the hours on his RV-9A and is also working on a Sonex Onex.  I think the Onex will be his 10th project. :)

He said everyone he knows has cracking at the oil cooler mounting behind #4 cylinder, regardless of the model (-7, -8, -9, -6  they all do it).  He suggested adding additional reinforcement.  Here's my solution: