Paul Eastham's RV-9A: Flying, Maintaining, and Hacks to go with it

Petaluma / Wine Country

2008-12-29T07:43:00.001-08:00

Better paint job photo

2008-11-16T21:55:00.001-08:00

Airplane back together, back home after paint shop

2008-11-10T17:58:00.000-08:00

At the paint shop

2008-11-02T07:55:00.001-08:00

Disassembled all the control surfaces, fairings, wingtips, inspection panels in about 4 hours.

Trip to Burning Man

2008-09-01T20:40:00.000-07:00

More photos here

Cheap and easy O2 bottle mount

2008-08-03T15:11:00.000-07:00

Two small chunks of .063 aluminum and two large hose clamps from OSH. Seems plenty sturdy.

Flight to Half Moon Bay

2008-07-27T09:26:00.001-07:00

High speed serial with Arduino / Protoduino

2008-07-27T07:36:00.000-07:00

Sadly, Arduino is not capable of high speed serial -- by that I mean 115200 or even 57.6k baud.

Most Arduino boards have a 16MHz crystal, which does not mesh well with the common baud rates above 19.2K, causing frequent dropped/garbage characters. It actually doesn't mesh very well with any common baud rate, but it's worst above 38.4K. It's a horrible choice of clock speeds.

(The crystal is that silver thing in the middle. Look close and you'll see "16.000" printed on it)

My Dynon EFIS transmits data only at 115.2K, and I would love to do something with that data...what to do? The ATMEGA chip at the core of Arduino can do it, but that crystal is all wrong. From the ATMEGA168 data sheet:

This 2-3% error is enough for you to get a handful of characters through ok, but after that you'll start getting garbage.

Fortunately, there is a pretty easy solution. You can go to an electronics store, or go online, and purchase a 11.0592Mhz crystal (with 20pF load capacitance -- part X1103-ND from Digikey works). This is a special "UART crystal" whose frequency is exactly what you need for these higher baud rates. Observe:

If you're feeling brave you can de-solder the crystal from an existing Arduino board, or buy a seperate standalone board and install the slower crystal instead.

(If you're concerned about the slower processing speed at 11MHz, there is also another good UART frequency at 18-MHz-and-change, but to use it you are supposed to set the ATMEGA fuses to run the clock at a higher power setting, leading to reduced battery life. I didn't find that setting to be necessary, but your mileage may vary.)

The other piece of the equation is that you need to inform the software you'll be running of the different clock speed, otherwise all your timing (including the serial operations you're trying to get working) will be way off.

To do this, you'll need a machine capable of running Makefiles and gcc. That means downloading Xcode if you're on a mac, or cygwin on Widnows. Linux boxes can just install Make/gcc packages if not installed already.

Then go here to get a standalone Makefile for arduino programs:
http://www.arduino.cc/en/uploads/Hacking/Makefile

Put your .pde program in the same directory of the Makefile, then follow the directions in the Makefile to get it set up. Lastly, modify the F_CPU line in the Makefile to the new clock speed (11059200). Note that you need to "make clean" anytime you change the clock speed so that everything gets rebuilt with the new constant. Then "make" to build and "make upload" to upload to the board.

When combined with an MC1489 receiver and a Protoduino board, the result is a multi-LED bar-graph that speaks flawlessly at 115.2Kbps:

AOA Protoduino flies

2008-07-19T19:13:00.000-07:00

I have this nice Dynon EFIS in my airplane. It does just about everything all those old-fashioned airplane instruments do, all in one package, as well as some fancier things like an angle-of-attack readout (lower left colored bar)

While that AOA readout is great for making smooth landings, it's tough to see with a quick glance away from the runway that's approaching at freeway speeds.

So after getting Arduino to speak serial at 115.2Kbps by replacing the crystal and hand-compiling the binary images, I was able to connect my Dynon EFIS to a Protoduino board and set up a nice angle-of-attack and rotation-speed readout, right in my line of sight on top of the glareshield.

ATMEGA168 on the left, MC1489 on the right. Switch in the middle controls brightness.

Here's a view of it installed, from outside the airplane.

The 9 LEDs create a "bar graph" of the current angle-of-attack -- I have it set up so that any less than 3 LEDs is closer to stall than I want to be during the landing sequence. On takeoff, it will flash a few LEDs at rotation speed and Vy. The display dims with each press of the pushbutton in the middle.

The board is a Protoduino trimmed to remove the top half which wasn't needed for this project, and to keep the size small and inobtrusive. Since there's no need for outgoing serial communications, there's no need for a MAX232 or anything like that -- I just used a MC1489 quad-receiver which translates the incoming RS232 signal to TTL levels.

Here's a view in flight. You can just barely see the multi-color AOA display in the lower-left corner of the Dynon. The LEDs are quite a bit easier to see!

Early Photos from Yuri's Night

2008-04-11T19:56:00.001-07:00

Yuri's Night

2008-04-10T07:26:00.000-07:00

I will be displaying the airplane at Yuri's Night Bay Area 2008, at Moffett Field, this Saturday April 12.

For first-time visitors to this site, here's a link to the airplane construction page.

Relocated to RHV

2008-03-30T19:38:00.000-07:00

My new hangar is closer to home, costs the same but is worse in every way. Water has already leaked in and ruined some of my stuff, and the oil-stained asphalt floor is the pits. Oh well, hopefully I'll be able to fly more often.

Here's my "fiberglass taco" aileron stop. I'll stick that cloth in there permanently, and add a bungee to attach it to the aileron weldment.

Some flight tracks from my GPS logger

2008-02-22T20:20:00.001-08:00

Made from an Arduino Diecimilla board, a SparkFun Protoshield, a MAX232 for serial interface, and a Serial i2c 32KB EEPROM also from SparkFun. With some simple compression of the lat/long and altitude data I can store about 10 hours of flight data on the rather small eeprom.

Trip to L.A.

2008-02-06T20:19:00.001-08:00

A few more bay tour photos

2008-01-20T10:01:00.001-08:00

Bay Tour

2008-01-17T20:18:00.000-08:00

Nice day for a bay tour, but everyone else had the same idea -- was dodging traffic the whole way.

Harris Ranch

2007-11-23T17:16:00.000-08:00

Some of the SoCal RV guys organized a small flyout to Harris Ranch, we had about 15 RVs show up, including a formation arrival and a smoky fly-by.

The winds were pretty wild -- we might have felt 25 knots on the ground, and I saw a 45 knot headwind on the way over.

Nice to finally put a face to all the SoCal-RVList names!

I also tried out a new camera mount. Need to run the camera in higher-resolution mode next time! Add in my compression and YouTube's compression and you get a whole mess of pixels. Well, at least it was a good on-the-numbers landing.

B-25 at South County

2007-10-27T20:48:00.001-07:00

A strange visitor appeared at South County a few weeks ago...a huge and very weathered B-25 parked out in the weeds by the fuel island. It's been drawing a steady stream of gawkers from the highway.

As you can see it still seems to be wearing it's original paint -- so much peeling that it's hard to believe it can get airborne. Lots of buckets to catch leaking oil too.

Apparently the owner plans to restore it and display it at South County, and seeks volunteers to help. There's a note to this effect on the airplane but it's now illegible due to the brief rains we had.

We've also had a lot of RVs buzzing around, and strange helicopters...

Dynon update, Watsonville again

2007-10-27T20:45:00.000-07:00

New software on the Dynons shows percent-engine-power, winds aloft on the EFIS screen, and all sorts of other screen-cluttering goodies.

Flew over to Watsonville and ran into some fellow EAAers. The enchiladas draw people from all across the state...

Moving Don's Airplane, Watsonville

2007-10-21T21:03:00.000-07:00

Harris Ranch and misc flying

2007-10-15T08:24:00.000-07:00

Flew to Harris Ranch on saturday, but forgot the camera. Too bad, I was dodging cumulus all the way down there.

On Sunday, I set out to do some maintenance and found my brake fluid reservoir was leaking all over the inside of the firewall and my soundproofing foam. That fitting has leaked before -- I tightened it and forgot about it. Now it was loose again, even though there's no way it can rotate. I suspect that nylon fitting just isn't up to the job, and will need to be replaced.

I also added a trim tab for my rudder, made of two pieces of stacked AEX wedge, taped on with aluminum tape.

I had planned to fly over to Watsonville for cheap gas, but it was fogged in. So I cruised over to RHV for the first time instead.

San Luis Obispo

2007-10-07T18:33:00.000-07:00

Hills in the King City area

There's a small commuter terminal at SBP -- yet it is the biggest airport that this airplane has been to!

View of the airplane from the Spirit of San Luis restaurant. The food was good, though not cheap.

Quick flight out to the coast from there with Nick, who met me for lunch.

Current temps

2007-10-01T09:58:00.000-07:00

Long hot climbout...still hotter than I'd like.

Cruise at 5500, 75% power

Columbia

2007-10-01T09:09:00.000-07:00

Bumpy ride into Columbia today. Cool terrain nearby really chops up the air.
Winds got very high by the end of the day -- really had to struggle to keep the controls straight while taxiing.

Columbia was...Columbia. I had been here about 6 years ago. There was a rose show going on, though, and they had some really amazing miniature roses.

Phase 1 complete

2007-08-26T20:00:00.000-07:00

3 hours left!

2007-08-25T19:36:00.000-07:00

Spent the morning attaching this little mini-fairing to the nosewheel. I had to cut it down quite a bit so that it wouldn't get knocked off when the nosewheel pivots, but it turns out to be worth it: I think I gained at least 3 knots from this little guy. And it's not even sanded down yet, and I think I can extend that little tab at the top a little higher as well.

I wasn't planning on going out to the hazy central valley today, but I ended up doing it to get away from all this traffic. It got worse after I took this picture...

Not even at 75% power, but getting closer to Van's published 75% cruise at 162 knots (showing 157 knots here, I think I got it up to 158-9 at 75%)

5 hours left in Phase 1

2007-08-22T20:29:00.000-07:00

Did some flying on Sunday and Tuesday morning; airplane is running pretty well right now. Looks like the next area of attention will be cylinder temperatures. They are a bit warm, despite glassing in the inlet ramps on Monday.

Worst during the climb, pushing 450. They hover around 400-410 in cruise.

.8 hrs: Fuel pressure finally fixed

2007-08-18T21:32:00.001-07:00

After a failed attempt to fix the sky-high fuel pressure with a new fuel pump, I tried a bunch more things today and one of them worked. I suspect the problem was that the faston tabs on the (Dynon-supplied) pressure sender are a bit on the thin side, so they don't make good contact. This only became apparent when I tried to pull the fastons off to replace them. Even brand-new fastons didn't grip that well, so I soldered them on.

I also enlarged the restrictor fitting to the sender (on the theory that the fuel was boiling in the line, and couldn't vent the pressure), and filled the sender line up with fuel (larger volume harder to boil)...I guess these could have fixed it too.

3 PSI, I think the only time I've ever seen this in the green! It's always shown 6 or higher, sometimes as much as 20. No more wondering if fuel is spraying out the carburetor throat! (Supposedly the needle valve starts to leak at 14 PSI, but I guess I never really had 14 PSI...)

2.0 hours: Haywire fuel pump

2007-08-14T21:52:00.000-07:00

My mechanical fuel pump, which has been reading somewhat high since the first flight and has been well above redline for the past few flights, got really bad today. At one point I saw 20PSI (redline is 8PSI, supposedly the carb starts to overflow at 14PSI). I've previously checked that the gauge is calibrated, so Aerosport offered to send out a new pump under warranty. I paid them to overnight it to me, so hopefully it will be installed on the engine tomorrow with the help of the local FBO.

No interesting photos today, sorry. Was too busy gathering glide data while not worrying about the fuel pressure.

1.6 hours: mostly pattern work

2007-08-13T22:04:00.001-07:00

Some nice morning flying over the Monterey Bay. Nice to have the sky to myself for once, though I think I heard Bill Randolph take off from Watsonville in his around-the-world RV-8 as I departed for Hollister.

I found a corn maze! Right near Hollister airport.

3.6 hours: Pattern and salinas

2007-08-12T19:52:00.000-07:00

Winds were howling today, leading to some real rough landings. At least I know the fairings are sturdy now!

Hazy over the central valley today.

I found a good use for my backup GPS -- by leaving it on the "NRST" page, it constantly tells me where to head in case the engine quits. It also has field elevation and distance so I can tell if I'm in gliding range.

First clear day over Monterey I've seen ever.

On the ground at Salinas (first time here, mainly as a bathroom break). Line guy rolled up with a cold bottle of water within seconds! Gas was overpriced though.

4 hours and a jittery video

2007-08-05T20:39:00.000-07:00

Just barely hit 20 hours this weekend, and using an improvised camera mount made from Shapelock plastic attached to my canopy handle, I took this video. Need to work out the vibration somehow. The mount itself is solid but the canopy/handle seems to vibrate a little.

Did some sanding of the wheel pants, now cruising at about 160 knots TAS (184 MPH), a few knots short of Van's numbers. I have some pretty big gaps at my intersection fairings and some other rough spots -- hopefully fixing those will get me up to full speed.

2.7 hours: local flight then circuit of the test area

2007-07-29T20:18:00.000-07:00

Did some trimming on the lower cowl to increase exhaust clearance. I think the exhaust may have been hitting the low cowl on startup, causing the hinge breakage.

I flew the entire outer boundary of my test box today -- in about 50 minutes. Not too much going on.

Marine layer over Watsonville

New Dynon firmware images

Fairing wrap-up, debugging lightspeed

2007-07-28T21:52:00.001-07:00

I drove down to the airport in the early morning several times throughout the week to debug the lightspeed ignition, no luck so far. I also laid up some fiberglass over the intersection fairings to keep them from falling off.

Today I sanded down those intersection fairings...now they're at least airworthy, but lots of touch-up, filling and painting remains.
I also repaired the hinge at the bottom of the cowl -- it had lost 3 eyelets (possibly from the exhaust pipe rubbing on it, or maybe just from vibration. The repair was actually not too bad. I excised the broken hinge section with the dremel then it pried right off after the rivets were drilled out.

Flying again!

2007-07-23T20:04:00.001-07:00

The fairings make quite a difference in flight. I gained more than 20 knots in cruise at the same power settings, and climbout now feels less like an airplane and more like a rocket. RPMs have changed a lot -- I was worried this airplane was overpropped as I couldn't really get the RPM above 2400. Now 2600 is no problem (limited by prop placard).

Landing is quite a bit trickier as well, it just keeps on floating. Need to reduce approach speeds and idle RPM (again).

Unfortunately, my "half-RPM" indication from the Lightspeed ignition happened in flight for the first time, so I really need to get that fixed. It has been happening usually only the first 60 seconds after engine start. I have done much debugging of this but it looks like there's more in store.

Virga south of Hollister

Just stayed around the home patch (lower left) today -- looking north up toward San Jose.

Fairings done, finally!

2007-07-22T21:06:00.001-07:00

What a cruelly huge amount of work for Van's to leave you to do after you get your airplane flying. I must have spent at least 60 hours on these guys, and I even bought pre-made intersection fairings from fairings-etc.

Well, they're finally done, and I can get back to the important business of getting that 40 hour test period flown off.

The only advice I've got for the fairings: don't be afraid to use your heat gun -- liberally. There are lots of places where things won't line up right, and thankfully this non-structural fiberglass can be abused with heat without too much worry.

Here's an alternative to drilling a big hole to fill up the nosewheel: this is two air valve extenders from the auto-parts store epoxied together. It fits through a 1/4" hole in the fairing. If you can find some that are threaded on both sides then you can skip the epoxy.

Intersection fairings

2007-07-16T21:06:00.001-07:00

The intersection fairings from Fairings-Etc fit pretty well -- installing the bottom intersections only took a few hours. It's the gear and leg fairings that take forever.
I spent a full 8 hours at the hangar today and still not done...

Dynon update, getting close on the fairings

2007-07-14T20:27:00.001-07:00

Looks pretty much the same, I know, but they're getting closer -- honest!

Dynon released a new firmware with a whole bunch of new features, including more modern tape-style readouts on the sides. Looks good!

Still working on fairings

2007-07-07T22:29:00.000-07:00

I've got the leg fairings mostly done, working on the wheel fairings now. Maybe flying by next weekend? I've been trying to take bits and pieces home to get a little bit of work done during the week.

Airplane down for final construction

2007-07-01T22:06:00.000-07:00

I found a minor problem with my exhaust hangars the other day, meaning I need to de-cowl the airplane yet again. While I'm at it, it's time to bite the bullet and actually finish this airplane, gear fairings and all.

Leg fairing construction under way
The worst part about the fairings is that you need to get the airplane completely off the gear, and levelled at the same time. I'm going to try lifting by the engine mount while propping up the tail.

Oil Change

2007-06-30T19:51:00.001-07:00

Forgot my camera today, sorry!

At 11 hours on the hobbs and 7.5 on the tach, I decided it was time for an oil change. The draining went smoothly (I have a quick-drain from Van's), but the filter removal was not so good. Lots of oil was still in the filter, and the 45-degree adapter made sure it all drained out all over the fuel pump, engine mount, and floor. This was after a short flight to warm the oil -- maybe I need to let it drain overnight next time?

Prospective RV builder Steve flew in and checked things over. He's just >< this far away from pulling the trigger, I bet.

The Airwolf filter cutter made quick work of cutting the filter open, no metal found.

After getting cowled up again, I flew out to the last unexplored part of my test box: Watsonville and Salinas. Watsonville (where I am not allowed to land) sounded busy -- to be expected at an airport with a restaurant on a nice Saturday. Salinas (towered, where I am allowed to land) was dead, and had hundreds of empty tie-downs waiting for a visitor. I will try landing there tomorrow for lunch.

Back at South County, I found that the fuel island is out of gas. Now I really have an excuse to get to Salinas tomorrow!

First 10 hours

2007-06-24T21:06:00.000-07:00

The plane is running pretty good right now. I cleared some squawks off the list, some other problems disappeared (the high fuel pressure, in particular), and I finally felt like the engine was broken-in enough to try some pattern work which went pretty well.

I've landed at Hollister twice now, and although the food is good, the air is bumpy and I have seen runway conflicts both times I've been there. One of the two included me making a go-around while a glider landed on the crosswind runway. The weekend is especially busy there...lots of gliders inbound and outbound, parachute jump planes, and just a few spam-cans. And I'm pretty sure some RC aircraft buzzed me on takeoff...the AFD lists a RC field nearby.

Parked on the ramp at CVH

Ding-A-Ling Cafe at CVH

And despite being confined to a fairly uninteresting test box, I've seen a few interesting things...

Castle Air Museum, from the air

Some Yaks departing E16

CDF spotter aircraft departing CVH

35 squawks and counting

2007-06-24T19:26:00.000-07:00

Well, the early days of N42PE have been marked by lots and lots of small problems. Enough that I had to start keeping a detailed list, lest I forget them all.

You RV owners can click the photo and read the whole list if you're curious.

Out of all those, there have been five problems that have been more significant.

#1: Super-high fuel flow. The first time I flew the airplane, the EMS started beeping as soon as I leveled off in cruise -- Hmm, 20 gallons per hour...that's either an incorrect reading or there's 10 gallons an hour dumping into the cowl somewhere. I turned back to the airport, but then noticed I forgot to turn off the fuel pump. That dropped it down to 10 gph. Once back on the ground, a quick web search told me that apparently the Facet boost pump can send pulses through the sender that confuses it.

#2: Cowl hinges breaking off. After only a few flights, the cowl attach hinges started shedding eyelets at the bottom near the exhaust. Apparently this is a common problem, but so soon? That whole area was vibrating like crazy...I've since dropped the exhaust pipes down a lot so hopefully it will get better.

#3 Electronic ignition gets confused at engine start. I've had the prop off several times now trying to debug this -- right after engine start, the indicated RPM drops to half of what it should be, and the electronic ignition is clearly only firing on two cylinders. But then it goes away within a minute. It's nice that I've got a backup magneto, but I thought this electronic ignition was supposed to be MORE reliable than a magneto...

I've been on the phone with Klaus at Lightspeed multiple times but the debugging is going slow and hard.

#4 Gear shimmy. Initially I think just the nosewheel would shimmy on landing, now I think all three wheels are doing it. I've checked all the parameters on the nosewheel and it's all set to spec, although it is still not rotating very freely as Van's promised it would. There are many ways I can go to try to fix this, but so far all I've done is played around with tire pressures, to no avail.

#5 High fuel pressure. This only showed up once, but high fuel pressure is bad because it can flood the carb -> fire or engine-out. I think it only happened with the boost pump on, so I can turn it off if it happens again.

First flight photos

2007-06-24T18:30:00.000-07:00

No writeup yet, but you can see some photos here.

Welcome!

2007-06-24T18:04:00.000-07:00

Following on from my RV-9A build log, this is where I will write about what's going on with the airplane now that it's built. Travel, maintenance, upgrades, etc.