Monday, January 18, 2010

The dream lives

There are days like I wrote about the other day when nothing goes right. Then, there are days when some time on the RV airplane project can get you back on track and feeling chipper. Today was one of those days.

It being the Martin Luther King holiday, I had the day off, so I headed to the hangar this afternoon to get a few things figured out. The antenna run for the transponder was one of them. The run for the push-to-talk switch on the yoke was the other.

It was 34 degrees at the hangar and thanks to Mr. Carhart and a small kerosene heater, it was relatively springlike. The radio was pumping out NPR (and MPR), which gave me the opportunity to listen to the entire "I have a dream" speech from King, when I realized -- and I'm ashamed of this -- that I've never heard the entire speech.

You neither? Well here.



One thing I like about building at the hangar is I can get smarter about so many things while I build. The speech was followed by a discussion about what "post racial" looks like in the real world. But I digress...

I've spent a lot of time trying to figure out the best way to run the transponder antenna. I was going to run it up the small bulkhead where I've mounted the headphone/mic jacks, but eventually I decided to run it down the center channel, somewhat away from other electrical connections.

I don't have a lot of buttons on the yoke, so the push to talk wiring run was a little easier. Both end up in the same bay.



The push-to-talk wires have an adel clamp, then a tie-wrap, and then a terminal strip. I have a ton of Adel clamps and I use them religiously. Another wire comes down the from the mic/headset jacks (I'm using black snakeskin and a dark gray interior so nobody will notice).



I'm very conscientious about not letting the wiring turn into a rat's nest, and being a little -- or maybe it's a lot -- OCD, I will put an Adel clamp in when I run one wire, then remove it and put a larger size in when a second wire comes along.



The wires here are the transponder antenna, the push-to-talk switch wire, and a wire for left nav light, which will terminate at a terminal strip. After they go through the main spar, the push-to-talk wires go straight to the bulkhead and then up to the jacks, the antenna wire follows the wiring run forward of the spar, and then down the left side of the center channel. I added a bushing in the forward heater cover to bring it up the firewall and -- at some point -- to the transponder.



It's a good thing I'm a relatively thin guy because getting in and out of the small space in the cabin takes a ladder and some contortion. I also stumbled across other things that needed fixing. The cotter pin hadn't put in the yoke bushing nut, and the control assembly was hitting -- slightly, but it counts -- several of the ribs. I fixed both.

You wouldn't think all of that would take four hours, but that's how long it took. Lots of in and out of the cabin, and lots of swapping of tools, and lots of pulled hamstrings.

But it got me back on track and I got some decisions made.

Onward!

The RV Dream

This video has been around for awhile, I guess, but I haven't seen it until now. The RV scenes are great, but the last "surprise" is the best.



Someday my RV will be finished. There are a growing number of people who've passed on that I regret will never get a ride in it.

Sunday, January 17, 2010

Being stupid



I was at a meeting at my workplace on Friday. A group of the "best and brightest" were charged with coming up with a likely scenario for what my industry would look like in the post-Broadband-initiative world. About 20 minutes into the conversation -- in the break-into-small-groups stage -- I found myself thinking, "I should've gone to grad school instead of gone into radio." That was a moment after I found myself thinking, "Man, these people are way smarter than me. What am I doing here?"

As you advance in your working years, you reach the point where you realize that the working world has passed you by, and you're just trying to hang on. I've reached that point. I had no business being in the room.

So a trip to the hangar on Saturday -- the temperature reached the summery 30s -- offered the opportunity for some "therapy" against the psychological ravages of a week at work. Unfortunately, for people like me, an RV airplane-building project can also make you feel stupid from time to time. Saturday was one of those days.

I had hoped to run an antenna cable from the transponder antenna to the transponder, but I struggled with the BNC connector. I couldn't figure out how to crimp the small pin on with the crimper I've got. One ruined BNC connector later, and feeling stupid -- I moved on to putting the new alternator on.

"Disconnect the battery," the instructions said. I knew I was supposed to remove the ground cable first; I really did. But I put the socket wrench on the positive stud first anyway. I don't know why. When the wrench hit the firewall, sparks flew. A minute later, I noticed the hole (above) in the firewall. I might as well have been welding. Stupid.

I drilled the hole out to a ragged #30, and added a new item to the "to do" list on the whiteboard: "Fix hole in firewall." I'll have to make a doubler plate and cover it. Just something else to do.

I moved to the alternator and, funny, I couldn't figure out how to mount it properly. Stupid. Three strikes, I'm out.

I stopped by an RV-building neighbor on the field and looked at his set-up, then returned to the hangar and loosely bolted the alternator on (not sure which way the belt goes). I had to get something out of the day.



But it was one of "those" days, a day when every step not only feels like two steps back; every step is two steps back.

Around 4 this morning, I found myself tossing and turning and thinking about the hole, and the doubler plate, and the BNC connectors, and all the other things I have to do on the engine and panel before the plane flies. And the fuel line has to be punched through the firewall. And the heater box cable. And the mixture and throttle controls. And... and... and... on and on. I tossed-and-turned more because it was starting to feel like it might be too much for me.

At 6 on a Sunday morning, unable to sleep, I got up to let the dog out and grab the paper and read about the people of Haiti.

I might be stupid, but if a ruined BNC connector and hole in a firewall is the biggest problem I've got, I'm pretty well off.

Update: I slapped a doubler on the inside of the firewall. Some poorly driven rivets there but I'll Pro-seal around the edges. I'm not going to drill these out and risk further woes. It's just that kind of weekend.

Saturday, January 16, 2010

Installing BNC connectors

If you're an airplane homebuilder, you should start to get in the habit of going to the EAA video tips for homebuilders before wasting a lot of time searching all over Googleland. EAA has produced hundreds of videos over the last few years and they're indexed well enough to easily find what you need.

Today, since the temperature his 30, I'm heading out to the hangar to run some antenna cable to the transponder and transponder antenna. I spent some time looking on AeroElectric Connection for a "comic book" on BNC connector installation, and I'm sure it's there somewhere but the search and navigation function on the site isn't really very good.

In some degree of desperation, I went to the EAA site. Guess what the newest video is? BNC connectors, taught by Dick Kohler, who taught the SportAir workshop on avionics that Warren Starkebaum and I went to a few years ago.



By the way, the Web site Matt's RV-7 Project, also has a good step-by-step.

Wednesday, January 13, 2010

Land it on the... err... numbers

I'll be honest with you. I live in a metropolitan area. The runways are wide and long and sometimes it still seems like I battle to execute a good landing.

So I can only admire the kind of piloting talent that goes into something like this.

Sunday, January 10, 2010

Two killed in RV-8 crash



From the Peninsula Daily News: (Washington state)

Two Sequim men killed in a single-engine plane crash north of Sequim Valley Airport on Friday were experienced pilots who were well-respected in the aviation community, the airport president said Saturday.

Carroll "Jeep" Larson, 68, of Sequim was the owner and pilot of the Van's RV8 aircraft that crashed into a muddy field about a half-mile from the west end of the runway.

Robert "Bob" Reandeau Sr., 61, also of Sequim, was a passenger in the two-seat, low-wing experimental aircraft that was built in 2008.

"He was active in the aviation community on all fronts," said Andy Sallee, president of Sequim Valley Airport and a close friend of Reandeau's.

"If you're a pilot in Clallam County, you probably know Bob."

Tuesday, January 5, 2010

The hardest part about building an RV airplane

Learning to rivet properly was hard. Making the canopy for the RV-7A was hard. Coming up with the money to buy tools and kits was hard. But you know what the hardest part of building an RV airplane is? Keeping from looking beyond the next thing you have to do on the plane.

As many of you know, this is year 9 of the great RV project and for years when people would say, "When will you be done?", I'd say, "About $30,000 from right now." Funny stuff, but it buttressed my discipline to not let others pressure me in the build. It will be done when it's done. It will be built right; except, of course, for the parts of the plane I didn't build right.

When you get nearer to the end of the project than the beginning, I've found it's difficult to keep that sensibility.

I made the mistake a month or so ago of doing some calculating . If I can get the panel completed this winter and if I can get some engine work done this spring, I can have first engine-start by fall. If I can start the engine for the first time this fall, I could be flying some time in 2011.

Let's hit the Wayback Machine. It's 2001, and I've just taken delivery of the tail kit. "If I can finish the tail kit this year, I can build the wings next year," I said to myself and, thankfully, nobody else. "If build the wings next year, I can complete the fuselage the year after that. If I complete the fuselage the year after that, I can finish the finishing kit and be flying the year after that."

Sure, it was possible to be flying by 2005; lots of people have built an RV in four years. But that was them and their schedule and resources; not mine.

Fortunately, I altered my thinking early on and went with the "it'll be done when it's done" mantra.

So, about a month ago, when I was talking to someone at work, I speculated that I could be flying in 2011. That was a mistake. Why? Because now it put me on something I've steadfastly refused to be on -- a timetable. And once you're on a timetable, you put pressure on yourself to adhere to it. Again, good for some people; not me. I've got plenty of things in my life that have to be done by a certain date; this project is my therapy, not another thing that has to be done by a certain date.

This week provided two examples. On Sunday, I finished installing the PS Engineering 1000II intercom. It was time to plug it into the Vertical Power VP-50 system. When I checked my load-planning worksheet, however, I realized I'd made a mistake. I attached a power connector, assuming I'd assigned it to a 5 AMP switch on the VP-50 unit. I hadn't. I actually had assigned it to a 2 AMP pin, which is a different connector on the other side of the VP-50 control box, requiring a DSUB pin.

What to do? It didn't make any sense to waste an open 5 AMP pin on a 2 AMP circuit, but the wire was too short to simply cut off the connector and install the correct one, and I didn't want to splice in extra wire. I'd have to take the wire harness for the intercom apart, pull the wire out and replace it.

"Screw that," I said on Sunday.

On Monday, I started on the next part of the panel: installing the transponder (a Garmin GTX 327), so that I can then install the ICOM A210 radio and be done with all the radio work. That's when I made another discovery. I hadn't cut through the subpanel for the transponder unit because it's shorter than the A210 radio. Why would I need to? Because, I learned Monday night, there's no room to attach the wiring harness to the transponder without doing so.

I did cut through the subpanel for the A210, but I placed a piece of angle across the bottom of the cutout, and that now presents a barrier for cutting through the subpanel to make room for the connector for the transponder.







Did I mention it was 4 below at the hangar last night?

See, that's the problem; It's entirely uncomfortable at the hangar; it's far too cold to be working on metal parts with bare hands. And now I've put pressure on myself to get the panel done over the winter, so I can move on to the engine, so I can start it by fall, so I can be flying by next year.

"Screw that," I said to myself after a night of tossing and turning.

The plane will be done when it gets done. The VP-50 needs to be removed, the intercom needs to be removed, and the cutout solution for the subpanel needs to be taken care of. If it's too cold to do it now, I'll just have to do it later. But it has to be done right.

So, sometime this spring, I'll resume work in the hangar, and get the panel done.

But not until I rewire that intercom harness.

Saturday, January 2, 2010

Mysteries of push-to-talk (PTT)

I've been wiring up the headphone and microphone jacks for the pilot and co-pilot positions via my PS Engineering 1000II for the last few weeks (yes, I said weeks. It's -14 today.). Now I'm thinking I've been confused into doing it wrong. Yes, I used passive voice there.

Here's why.

I'm using the PS Engineering wiring harness tutorial, which you can find here, if you have Powerpoint.

Here's one of the slides.



It appears to tell me to connect one push-to-talk wire to the tip and one to Audio Lo, the barrel... ground, as I understand it. OK, fine.

Another slide shows this schematic:



So far so good? Good.

Notice that it says connect PTT to tip. Now look at this slide:



Notice the difference? In the first two schematics, it has the PTT wire on the top, indicating that it's the "tip." On the last schematic it identifies the tip as the middle.



Based on the last two images, it suggests one wire comes off the same pole as the ground (Audio LO) and the other comes off the same pole as the audio (AUDIO HI). It appears to me that the schematics in one indicate that audio_hi is the tip and on the other it seems to indicate audio_hi is the ring. In effect -- if you compare image #1 with image #3, it appears to identify a location as a "tip" in one schematic, and then as the "ring" in the other.

Or am I reading it incorrectly?

So, which is it? Let's look to Bob Nuckols of Aeroelectric Connection for help (click for larger image).



To me, that shows the AUDIO-HI wire attaching to the jack without any other wire. Which is too bad because, of course, that's not the way I did it. It's interesting to note that this particular schematic also connects at shield at the jack, which PS Engineering's tutorial says is a no-no. But that's another story for another day.

Update 7:39 p.m. - Armed with the knowledge that there are no electrical symbols here, only a physical reference, I went out to the hangar and got the jacks rewired properly. The -3 temperatures be damned.

Friday, January 1, 2010

RVers scramble in wake of engine cylinder warning



January 1, 2010) -- An expanded FAA airworthiness directive on cylinders manufactured by ECI Titan has RV airplane builders scrambling to find out if their engines are covered.

According to ECI, the problem is posible fatigue cracking and head separations on specific replacement cylinders. (Read more)