Go "pedal" your sob story somewhere else, fella

It's kind of hard for me to believe, but I'm actually a little choked up. Tonight I installed the rudder/brake pedals. That doesn't seem overly significant, I suppose, but as I was tightening up the bolts to hold the pedal assembly in place (temporarily - it will all come back out once the brake lines are done to aid accessibility for other stuff yet to go in) I realized that I had just finished installing my first flight controls. It's really starting to become an airplane! And what's more, it's really starting to become my airplane.

On the occasions when I have shared the idea that I'm not sure which airplane I will sell (the RV-6 or this RV-12) when the time comes, I've been told that the decision is already made. I will be too emotionally involved with the RV-12 to sell it, they said. I didn't believe it, thinking for some reason that I'd be able to keep a business-like detachment about the whole thing, but I now know that to not be even remotely possible. If the simple act of bolting a collection of tubes to a frame of aluminum nearly brought me to tears, I don't see how I could ever sell this thing after we have shared a moment as deeply profound as its first flight as an airplane and my first flight in a machine that I assembled by myself. Those, my friends, are emotional bonds that won't be easily broken.

And, ignominiously enough, it all started with grease. The brake torque tubes need to pivot nicely inside the rudder pedals, and for that we need lubricant. Nothing fancy; just plane plain old grease.

Here's a free hint: you don't need to grease the whole length. Fully half of the thing is going to hang out the other side and have a brake pedal bolted to it. Just grease the half closest to the flange.

The pedal part of the rudder pedals then get bolted on. They're just little rubber grippy things to give some traction to your feet. Notice the arrow pointing at what appears to be a missing flange? Well, I didn't. Not until later, anyway.

To be fair, it was enough trouble holding tools and parts in place with grease all over my fingers - it's no wonder that I missed that!

The brake master cylinders go on next. There's a washer that sits between the clevis bolt and the cotter pin that holds it in. It's not a particularly easy washer to get into place.

I got those tweezers at the dental tools section of Harbor Freight. One really has to wonder about a dentist that buys his tools at Harbor Freight. [shudder] I got as far as the second cylinder before I realized I had a little problem:

Over the months that I've been working on the plane, I've developed a highly tuned sensitivity to things that don't look right, no matter how subtle the hint may be. In this case, I don't think an inexperienced builder would have seen anything wrong, but my finely tuned senses immediately detected the whiff of a problem here. Something just didn't look right. But what could it be???

Quick fix, although it might have been easier if my hands weren't so greasy and I hadn't gotten that bolt so tight.

Then there was more dental work required to bend the cotter pins.

Finally, time to install it all into the fuselage! Which, I'm here to tell you, is a royal pain. You see, the plastic blocks holding the whole thing together were only in place temporarily. They have to be removed to put the pedals in the plane. Note the relationship between "holding the whole thing together" and "removed." What happens when you remove the blocks should be pretty obvious: everything falls apart. You then get to try to put it all back together under the shelf of the firewall. Tricky!

They sure do look good, though!

Taking a "brake" from the fuel system

Well, a "break," too. A break to start on the brakes, if you will. It's 90+ degrees outside with a humidity level to match, so I need to keep myself busy down in the shop. The fuel system fittings haven't arrived yet, so I thought I'd try to get started on the brake/rudder pedals. For those unfamiliar with the relationship between the two, here's a quick synopsis.

An aircraft is normally steered on the ground by use of the rudder pedals. The rudder pedals are attached via some linking mechanism to the nose wheel. Application of left rudder pedal will cause the aircraft to turn left, and vice-versa for the right. Braking of the aircraft is accomplished with differential braking. This means that the left or right brake can be applied individually, which enables the aircraft to turn about on its axis. In the case of the RV-12, there is no linkage between the rudder pedals and the nose wheel. All ground steering is therefore accomplished with differential braking until such time as sufficient airspeed is attained (typically during the takeoff roll) for the rudder to become effective. The differential braking is accomplished with "toe brakes." The rudder pedals either swivel at their base or have a separate pedal at the top that is activated by the top of the pilot's foot. In the case of the RV-12, each rudder pedal was a separate brake pedal.

The rudder pedals are a push type of control. You push on the right pedal for right rudder, and the left pedal for left rudder. Pushing on a pedal causes a tube to rotate. Flanges on the tube are connected to the rudder with steel cables. The upshot of all of this is that the tube needs something to support it yet allow it to rotate. This "something" is a set of plastic blocks. The first step is to cut them in half. The band saw had no trouble at all getting though them.

Because neither the band saw nor its operator is genetically capable of cutting a perfectly straight line, I marked each block half so that I'd be able to match them up again. Any deformities resulting from my poor directional skills with the saw would net out to a perfectly matched edge. Or so I like to think, anyway.

The two rudder pedal tubes are identical. Each has what the plans call a "short end" and a "long end." I set the two parts on top of each other with their short and long ends together.

Then I simply flipped one over to get the pair of them properly oriented to each other.

The two parts then get temporarily assembled into the plastic blocks. The plans show the need for washers to get the nuts to fit correctly on the bolts, but don't specify what size. I had a bag of the AN960 washers that eventually get used during the final installation lying around, so I just used those.

As it sits on the bench, the rudder pedal assembly is actually upside down. When it eventually gets installed into the airplane, it will get turned over and the blocks will be on the top.

To install the brake pedals, the tubes that support them are slipped through the rudder pedals. It is important to note here  that the "pedals" are actually just horizontal steel tubes. The picture below shows two of the rudder pedals with the brake pedal supports inserted.

The brake pedals (which are also tubes) will pivot on the bare steel parts of the rudder pedal tubes. Trust me, it's all going to make sense soon. The brake pedals are going to be slid onto these tubes and match drilled for a bolt to hold them on. When a pedal is pushed, it will rotate the tube it is bolted to. That will move the flanges  that you can see on the ends of the tubes, between the rudder pedals. The flanges will be attached to brake master cylinders. It's really quite clever.

To lock the pedals into place to aid in the drilling, one of the brake support tubes is inserted through the rudder pedals on the other side

It was a bit of a tight fit. The pedals didn't line up perfectly up & down, so it took a bit of twisting and turning to the brake support through both rudder pedals.

Back to the other side, two brake master cylinders need to be temporarily installed. I marked the 'L' and 'R', but these are parts that I don't think will fit in the wrong way if you lose track of which is which.

Here they are installed:

Now you can start to see how they're going to work. Once the actual brake pedals are bolted onto the bare steel part of the rotating tube, you can see how the rotation of the tube will activate the brake master cylinder.

The idea is for the brake pedals to be perpendicular to the rudder pedal assembly, so I used a square to get them as well lined up as I could.

It's hard to see what's what in that picture (the replacement photographer is much better about making sure my bald(ing) spot is out of the picture, but his overall composition skills are weak)  so I added arrows to show the two parts of the brake pedal. Those are the two points that are used to ensure a close approximation of perpendicularity. I say "approximation" because 1) the rudder pedal tubes block good access for the square to align the inner brake pedal, and 2) because I had a great deal of trouble in keeping the pedals from moving as I clamped them in place. Oh, and 3) I also had trouble keeping them from moving as I was drilling them because my clamps suck. Hopefully the alignment isn't super critical.

The holes get drilled #30, then #12, then 1/4". There is not a single one of those sizes that wasn't an absolute bugger to drill. My little 12 volt lithium drill is wonderful for almost every situation, but drilling through hardened steel is not one of its strong suits. And quite painfully, there are eight holes to be drilled. With three separate sizes for each, it was a good two dozen holes to drill. I was mighty glad when it was done. At one point I got a 1/4" bit well and truly stuck, and I think I came very close to stripping the gears in the drill.

What with these being match drilled holes, the odds are enormous against them ever actually matching. That said, it's prudent to mark each part in order to aid in getting them back into position after removing them for deburring.