It's not supposed to happen this way.
I flew N500F for about eight years, and was in charge of its maintenance for most of that time. The Fly Baby prototype had a lot of miles under its wings. Yet, for being a 30+ year-old homebuilt with over 1500 hours, the plane gave very few mechanical problems.
My own Fly Baby, Moonraker, is different. It's but 14 years old; with only ~140 hours total time, and 50 hours total on the C-85 engine. It's not *supposed* to be having the kind of problem that turned up during the annual. The A&P who's been doing the annual for the past five years (for the previous owner as well as myself, this year) wrote in the log, after his first annual of the airplane: "This is the nicest Fly Baby I've ever seen."
Well, like the saying goes: "Even a man who is pure at heart, and says his prayers at night...." Just goes to show one that even the peachiest of airplanes can have a werewolf's heart, beating inside.
Getting ahead of myself, though. Like mighty rivers, the most turbulent stories should start out in placid calm.
Can't do it for this one, though. That's part of the problem. Calm in my life has been in short supply, this summer, and that lack of calm has contributed to a very tense experience. I don't normally talk about my life "outside the net", but in this case, it's an intrinsic part of the story. I'll try keep it short.
I had been scheduled to start a new task at work in June, but due to problems in the old one, didn't come over to the new job until the first week in July. The Fly Baby's annual was due at the end of the month. The new job started out rough...I had a rather pivotal concept development job, and it didn't get done while I tried to work out the problems in my old program. Worst still, we had a customer presentation due in mid-July, and my section was in real bad shape.
Plus, I had committed to covering the Arlington Fly-In for a magazine. I regretfully informed my new boss that I wouldn't be available to work that weekend (one of the two between my starting the job and the customer meeting), but would work evenings to catch up.
The morning before Arlington started, I had to take my wife to the Emergency Room. They operated on her that evening. She's fine, now completely recovered. But I lost a couple of days of work, in addition to the time I had to spend at Arlington. The next several weeks were insanely busy at work. Even so, I also had to take some additional time off. I was on the planning committee for the Auburn Antique/Classic Fly-In in mid-August, and the meetings were on Monday afternoons.
So I didn't have much time to think about the Fly Baby until the end of the month drew near. Around the last week of July, I started the pre-annual process.
Since I didn't build N45848, an A&P has to do the annual condition inspection. Ed's been doing my Fly Baby annuals for years, starting with N500F in the mid-80s. I clean and inspect the plane, repair everything I find wrong, then Ed comes through to inspect. He points out any problems, I fix them, and then he comes back to check and sign off the inspection.
The first step, as ever, was to wash the airplane. After taxiing back from the wash rack, I met a friend and his wife, just going over their Long-EZ prior to a flight. "That's sure a nice-sounding engine," said Maureen. Appearances...and sounds...are deceiving.
I knew a couple of items Moonraker was going to need. The ELT battery was out of date. That took just a few moments...and led to the discovery that the ELT antenna *wasn't even hooked up*. Hmmm. Hook up the antenna, check the time, hit the "on" switch for a moment. Everything OK.
Pull off the old Bracket filter, install the new one. Spray the hinges and control linkages with LPSIII. Scrub the small amount of dirt off the belly with Simple Green.
One interesting discovery. The 'Baby has a long steel axle. On the gear legs behind the axle, I found gouges on both sides. These were like an arc of a circle, getting deeper toward the trailing edge of the legs. The builder had wiped the gear off about a year after finishing the plane; I suspect the gouges are from when the axle collapsed backward. Surprising the gear legs themselves are still good enough to use, but hey, Fly Babies are way overbuilt...
Look through the logs, see what maintenance the previous owners did, and whether the bird had any recurring problems. Surprisingly little data...though the last owner, at least, hardly flew the airplane, so he probably didn't have to do much for the annual. In his five-year ownership, the plane got only about 20 hours total flying time.
No mention of greasing wheel bearings. That suited me; greasing bearings is the kind of dirty, smelly, simple job I like. Besides, the tires were both getting worn along the inside, and pulling the wheels would let me flip the tires around for equal wear.
Moonraker has Goodyear wheels and brakes. I wasn't familiar with them, but the operation was pretty obvious. The brake disk has points in its periphery like a gear, the wheel drum has matching teeth on the inside. The disk is held inside by three spring-loaded clips on the outside. Obviously, the clips had to be held outward so the wheel could slide off the disk. Where the three clips engaged the disk, small square slots were cut in the disk. Pretty obvious.
I slacked off on the master turnbuckle, disconnected the flying wires at the left wheel hub, and jacked up the tire. Removing the bolt through the axle and spacer took but a moment. I'd cut three wooden wedges. They slipped under the clips, and with a little wiggling and shaking, the wheel came off the airplane.
It was a bit reluctant to come apart, but I finally split the wheel. Out with the inner tube, shape talcum powder into the tire, back in with the tube the other way, and reassemble the wheel. Pump it up and back to the axle. Write down the part number of the bearings in the logs (for future reference), put a big dollop of grease in the palm, then work it into the bearings. Lift the wheel up to the axle.
The brake disk refused to engage the drum.
I couldn't understand it. I had the same clips in place. I hadn't marked the pre-removal orientation of the disk to the drum, but there were only three possible ways it could go...and it wouldn't go for any of them.
I worked for hours...literally. I even took the disk off the wheel and sat with the wheel in my lap. It simply would not slide into the hub.
I ended up leaving the plane up on blocks and taking the wheel and disk to my shop. I never did figure out *why* it wouldn't go...but trimmed down some of the edges of the clips and managed to get it to engage relatively easily on the workbench.
The next evening, after work, I brought the wheel out to the airplane. After just a moment's fiddling, it slid back into place. Five more minutes, and I was done with that wheel.
I looked at the other wheel with a sense of dread. The tire wasn't that badly worn...I didn't *have* to take the wheel off. The bearings on the left side hadn't been too dry. Did I want to go through the entire process again?
No choice, really. Would I rather go through the problems there, in a nice warm, dry hangar, or try to fight a reluctant wheel on a cold, wet, far-from-home ramp? I *had* to take the wheel off, just to be sure it could be reinstalled easily.
One thing I did this time: I took a marker and drew a reference line between the disk and drum. At least I'd know what reference it was *supposed* to go.
Need I mention that this wheel came off...and back on...easily?
That was on the last Wednesday night of July. The annual would expire the next day. That weekend was a major local fly-in. I wanted to take Moonraker there. Could Ed do the annual on Saturday, so I could make the fly-in's second day?
Nope...turns out he was out of town. Oh, well, that let me work late during the evenings and denote all weekend to spiffing up the plane.
I'm a putterer
at heart...I like nothing better than to take covers of machines and go
through them with a cleaning rag and a set of wrenches. I indulged myself
that weekend. One work buddy came by to look at airplanes, and shot a picture
of me happily working away on Moonraker's engine.
It wasn't all make-work, though. The carb heat control was stiff, for one thing. I tried to pump LPSIII through both ends of the sheathing. No improvement. Nothing for it than to take the wire out and lube it separately. After pulling it out, of course, it wouldn't go back in. I had to disconnect and straighten the sheath itself. While I was at it, I did a minor bit of rerouting to eliminate one sharp bend. Worked fine.
I cleaned off the engine with paper towels and Simple Green, tightening any lose nuts or screws on the way. I studied the generator...I've mentioned my electrical problems, and it's almost certain the field of the generator has almost a dead short to ground. Unfortunately, it appears that I'd have to remove several items from the firewall to get the generator out. I'll save that one for a long rainy weekend this winter.
Ed called back Sunday night. He'd be able to do the inspection (including a compression check) Monday night.
Monday itself was...interesting. I got a call from a former co-worker. He's a former Army Mohawk pilot, and is currently working on development of a small satellite imager. They had a test version of the sensor mounted in a company-owned Helio Courier, and he handled navigation and traffic watch for the pilot.
Unfortunately, he had to go on a business trip to Europe. Would I be willing to fly right-seat in the Helio?
The temptation was irresistible. The customer review for my own job had gone off OK, but we had another one scheduled in three weeks. But I just couldn't turn down the opportunity.
Later Monday afternoon, I attended the final planning session for the Auburn Fly-In. "Ron, are you bringing your little Fly Baby to the Fly-In this year?" asked the Manager.
"You bet," I said. Last years' Auburn Fly-In was the "Fly Baby Debut" I posted about last year, and I was looking forward to bringing it again.
"Good...we're mentioning it on the radio ads."
Gulp. Celebrityhood, forsooth.
But that evening came Ed's inspection. The airframe and engine inspection went well...Ed only found that a tip of a cotter pin had scratched the paint on one bellcrank.
Compression test time. "Hold the prop, Ron."
I held a blade as Ed applied the pressure to the first cylinder.
"Ummm," he said.
With Ed, "Ummm" is *bad*.
He turned the gauge in my direction. 60 PSI...right at the limit. We could hear a snake-like hiss from the bowels of the engine.
"Y'know, this engine has always been real reliable and repeatable. That's why I always test it cold. This isn't a good sign, Ron." He fiddled with the test setup and turned the prop slightly. No change.
"Let's do the others." The other three cylinders came out at over 70 PSI.
"Let's run it up and see if the pressure comes up." I ran the engine for about ten minutes. We hooked up the compression set-up.
40 PSI.
Ed put his hand over the exhaust pipe. This hissing changed tone. "Exhaust valve. Pull off the rocker covers, let's stake the valve."
I pulled off the cover, and Ed tapped the exhaust rocker arm with a rubber hammer in case it was locked down by a piece of carbon. No change. We pulled off the rocker arms, in case the pushrod was holding the valve open. No change.
"Bad valve, Ron. Guess you're gonna have to pull the cylinder."
Gulp. Pulling a cylinder was one of the things I've always been scared of. I borrowed a set of cylinder wrenches and an overhaul manual from Ed. "One thing to watch out for," he said. "Careful when you pull the cylinder off, so the piston and connecting rod doesn't drop down and hit the case."
OK. I called Cecil, the EAA Counselor who has saved my bacon time and time again. "I think I can get it off myself, Cecil, but can I get you to watch over me when I put it back on?"
"Sure. Oh, when you take it off, make sure you don't let the connecting rod drop and bang on the hole."
"Oookayyy. Where do I take it to have someone look at the valve?"
He gave me a name of a man based near Boeing field. "He's a bit hard to get hold of, though," said Cecil. "Works weird hours."
Boeing Field? Perfect. I had to fly the Helio the following Friday. I was travelling to LA for a two-day trip the following Monday and Tuesday, and the Auburn Fly-In was the Sunday after that. I'd take the cylinder off on Thursday, take it in Friday, pick it up Wednesday, and get it reinstalled by the Auburn Fly-In.
Wednesday, I decided to visit the cylinder specialist to get a feel for whether my plan would work. The shop Cecil described was unmarked, in a rather seedy part of town. I stopped by the shop during lunch. There was no one there. The door was locked.
Oh-oh. I tried calling the man's listed number. No answer.
Thursday, I drove up at 2:30 in the afternoon. No change. Ulp. Who the heck would I get to work on my cylinder? I stopped by the office where the Helio sensor work was being done, to get my last briefing. I happened upon Mike, my former Stinson partner. I told him my woes.
"Why not use the same guy I used when we had to get the Stinson cylinder fixed?"
Hope dawned. I flew the Helio mission Friday, and called up the cylinder guy. "Ummm, well, I'm trying to get it ready for the Auburn Fly-In next weekend and I'm going out of town Monday..."
"That's all right...just bring it in Saturday." Turns out he works out of a shop behind his home. "Oh, and when you take the cylinder out, make sure the connecting rod...."
Saturday morning, I reported to the airport bright and early. Off with the ignition harness, off with the eyebrow fairing. The pushrod tube boots were held one with stiff wire clamps. A pliers skidded right off them. I improvised a hose clamp to squeeze the ends of the wire clamps. I tried to remove the intake cup, but the stud twisted off. I loosened the hose clamps on the rubber tube on the intake, which is the way it was *supposed* to be done.
Last to go was the exhaust. The system on my Fly Baby is all one piece. I was hoping to be able to loosen it from the right side (the one with the bad cylinder) and flex it enough to drop the ends down far enough to clear the cylinders. I was deathly afraid of twisting off one of the studs, especially since I had to remove the exhaust from the good cylinder on the same side. I splattered the nuts with penetrating oil, then slapped a socket wrench on the first nut as eased back.
The wrench slipped off the nut, rounding its corners.
Damn. *Now* what? I looked at my socket. A good Craftsman 12-point ½" socket. 12-point. I dug in the tool box and found a cheap ½" socket... *6* point. It went on, grabbed, and the nut came off.
One of the nuts brought the stud out with it (from the good cylinder, of course), but the process went smoothly enough. I pushed down on the exhaust stack, and it slid down far enough to clear the cylinder.
Up with the cylinder base wrenches, and in a couple of minutes I had the cylinder ready for pulling.
First, get ready for the connecting rod. Cecil had recommended some rags on the bottom of the cylinder opening as the jug came off. Seemed too hap-hazard for me. I prepared a roll of safety wire.
I eased the cylinder out. It held, then slowly started to slide. I kept it coming until the base cleared the case. Then I slid a piece of wire under the connecting rod, pulling it tight and tying it off on either side.
Pull the cylinder some more...and there it was, hanging in my hands.
I had a plastic bag and a cardboard box ready. In went the jug. The cylinder guy wanted to see the piston too, so I slid off the piston pin and slid the piston into a plastic bag.
I couldn't leave the engine open for the week or so before the jug would be ready. I wrapped a clean shop towel around the connecting rod, and covered the opening with plastic bags.
To the cylinder shop. I arrived at the man's address, and went to his backyard shop. I knocked. No one there. I went to the house. No one there, either.
Now what? If I didn't get him the cylinder today, I wouldn't have the engine ready for the Fly-In the following weekend.
I drove to a shopping mall a few blocks away, and called his number. He answered.
"I...uhh, I think you gave me the wrong address."
"Nah, I was just out for lunch."
Whew. He took me back into the shop, and within 30 seconds had the valve out. "Look there," he said. On the valve seat, I could see a discolored place. "That's where it wasn't seating," he said. "You caught it early, there's not much damage."
Why did it happen? The best explanation: Insufficient lubrication, as in a lack of lead.
The engine has only 50 or so hours since it was overhauled in 1988 (and 35 of those hours are in the last year). The stock valves used on Continentals need lead for lubrication...which they weren't getting on the unleaded auto fuel I was running on.
"I'd put another 50 hours on it with 100 LL, then alternate...three tanks of car gas, one of 100 LL."
What do with the current valve and seat, though? I had an older model valve in it, ground at a 45-degree angle. The replacement seats were ground to 30-degrees. My valve could be ground, but that wouldn't leave much "meat" on the valve. AND the stock Continental units needed lead; I'd be pretty much stuck with 100 LL.
Superior has an improved valve and seat, and it's OK'ed for both auto and 100LL fuels. I opted for the Superior valve...it was just $100 more.
(Note: I'm not relating this part of the story very well...I was trying to take in masses of cool information at once. This man is VERY well thought of locally...he wasn't ripping me off.)
On the good news department... he looked at the piston, and declared that the rings were OK. Not only did I not have to replace the rings, I wouldn't have to run a break-in period once the cylinder were reinstalled.
So anyway... I drove home, feeling pretty well assured that I'd have the engine back together for the Fly-In a week hence. I didn't have to be *flying*...all I had to do was taxi in.
I took my trip, got back Tuesday night, picked up the cylinder Wednesday. Total bill: $325, including two new exhaust gaskets. "Metal gaskets?" I marveled.
"It's all the EPA will let 'em make. Can't use the asbestos ones any more."
I mentioned the difficulty I had with the wire clamps, and he showed me the specialized pliers required. I stopped by an auto-parts store on my way home and picked up a set.
Saturday morning, I met Cecil at the airport. He watched over my shoulder as I reinstalled the piston, applied the ring compressor. He kept things clear as I slipped on the cylinder. Off with the ring compressor, and slide the cylinder back into place. Yippee!
"Now, we gotta make sure we get the torque right," said Cecil. "I brought an overhaul manual."
"That's OK, I brought Ed's too."
We compared the torque listings. They were *200 in-lbs different*.
NOW what?
I decided to use the ones from Ed's manual, since his manual was dated in the '60s and Cecil's was 1945.
[Note: Subsequently to this, I found that Continental had issued a service bulletin that updated and verified all torques for their engines. If you've got a Continental, get a copy of the bulletin. The values we used on Moonrkaer were close enough to the new bulletin values.]
On with the nuts, working the torques gradually to the manual limit. On with the pushrod boots, fumbling with the cheap auto-shop clamp pliers, which finally broke. On with the intake tube. On with the metal exhaust gaskets, and finally, on with the new brass exhaust nuts.
By this point, Cecil had left. I rolled the plane out of the hangar. "Clear!"
She caught, rolling into a smooth Continental idle.
Clean up, cowling back on. It'll taxi tomorrow, even if the annual isn't signed off. Back home, leave a message for Ed telling him it's ready for a compression check and final signoff.
He calls back at 6 PM. "Wanna do it now?"
Ninety minutes later, Moonraker is fully legal again.
The next morning, I taxied to the Fly-In. Last year, I did a couple of low-passes prior to parking. This year, though I was marshalling airplanes for Young Eagles and too bloody busy to go aloft. Besides, I *didn't* want to make the first flight with the new valve in front of a crowd...just in case. I was too hot and worn to want to fly after the Fly-In, so I waited until the following evening.
As the plane lifts off, I stiffen. What's that low whistle? Was the intake open? Then I noticed: The landing wires (atop the wings) are slacker than normal, and shaking at what appears to be the same frequency as the whistle.
I remember... I had trouble re-tightening the master turnbuckle after slacking off the wires to take off the wheels. It just needs to be tightened with a decent tool rather than the old nail I used....
After landing, I inspect the engine. A thin puff of soot stains the cowling just aft of the cylinder I pulled. The metal gaskets weren't sealing too well, apparently. I tighten the nuts a bit more.
The following weekend, our EAA Chapter supported a "Sport Aviation Weekend" at Seattle's Museum of Flight. It was my first time to fly Moonraker into a controlled field...Boeing Field, one of the fifteen busiest airports in the US. I made it without a hitch...and found more soot behind the exhaust.
Those bloody metal gaskets. I picked up a fresh set, but couldn't do much for a week or so. Had another customer presentation; another trip to LA.
I went to the airport yesterday to see what I could do. I pulled off the exhaust...and noticed the flanges were a bit warped. THAT was why the metal ones weren't sealing.
Fiber gaskets weren't available anymore, though Continental. I decided to buy some gasket material at the local auto-parts store and make my own.
I go to the store. I can't seem to find the material itself, but there are a number of pre-cut header gaskets on the wall. I look at the ends of one... a hole 1 ½" in diameter, two bolt holes....
I run back to the car, where I have one of the metal ones. I bring it back in.
Sure enough. The exhaust holes and the bolt holes in both ends of the gasket match.
Five minutes work with a pair of borrowed scissors, and Moonraker now sports a set of exhaust gaskets made from a small-block Chevy set.
In an ideal world, the leaks would have stopped dead. Not in this case, but it's sure better. There are soot marks on the edges of the gaskets themselves, but the cowling wasn't stained after a ten-minute flight.
Like the electrical problem, this is probably something I'm going to fight during the non-flying season. There are several options...the best is to take the whole exhaust manifold off the airplane and grind the flanges flat again. As the paint job on the manifold is pretty bad, I can get a powder-coating at the same time.
Or...I may just use high-temp epoxy to build up the edge of the flange (NOT using it to seal the gap...just build up the flange so that the gasket can do its job).
In retrospect, the entire process wasn't as bad as I feared it would be. Cylinder work was always a bugaboo of mine; like most fears, when directly faced, it turns out to be not as bad as one's imagination makes it.
It wasn't fun, of course. But Moonraker is operational again, with a couple of small problems I can tinker on over the upcoming months. The pressure of the last two months is off...I'm leaving on vacation in a couple of days, so Owen, I'll flame you when I get back. :-)
All in all, I guess Moonraker is still a pretty good ship. Ed probably best summarized it with his last entry in the logs for this years' annual:
"This is STILL the best Fly Baby I've ever seen."
[The following follow-up was posted October 6th, 1997]:
Just a quick note to close out the saga of my first annual of "Moonraker," my Fly Baby.
At the time of my last posting, the plane was back together and flying again. However, I had a bit of exhaust leaking from the stack on the side where I'd had to remove one cylinder for a valve replacement. I'd first used the "No Blow" metal gaskets that are sold for Continentals, then replaced them with fiber gaskets from a 283 Chevy.
As of that point, the leakage was down, but still there.
The flanges on the exhaust had a bit of a warp, sort of in a "U" shape. I decided to take some gasket material and try to match the shape of the gap...one normal gasket to which I RTV'd a washer-shaped gasket just around the opening in the middle.
I put them in place, then started to tighten-down the nuts. One nut didn't want to get tight. I started fiddling with it with my fingers...
...and the whole stud dropped out. I'd stripped the threads on the aluminum cylinder.
A moderate amount of cursing ensued. Badwater Bill's name was invoked several times.
Obviously, I needed to get a helicoil installed. I could either pull the cylinder again and take it to the cylinder specialist, or could pull off the exhaust stack on that side and have a coil installed in place.
The later was the simplest, of course. And since I was going to have to remove the stack anyway, I decided to do things right and get the flange area resurfaced, one way or the other. Not only were the flanges themselves warped, but the pipe itself stuck ABOVE the level of the flange in some places. I had no idea how the thing had sealed before, but it obviously wouldn't seal NOW. So I was going to get the durn thing fixed right, instead of trying to kludge up some funky gaskets.
Getting the stack clear was interesting. It looked like just a clamp held it to the center section of the exhaust. But even with the bolt removed from the clamp, the pipe refused to release.
But then, the clamp didn't move, either. I took a closer look. There was a smooth bump on one spot on the clamp. I shoved a screwdriver underneath...and found the bump was the top of a rivet. I managed to wedge up the clamp high enough to get the rivet clear. Out came the stack.
I brought the stack to an EAA meeting, where it met a lot of long faces. Many were skeptical about the thickness of the flanges. Several recommended I cut the flanges off and install thicker ones.
But doggone it, the thing had sealed adequately before. My buddy, the A&P who annuals the thing for me, suggested I bring it by. He'd use a welding torch to straighten out the flanges.
When I mentioned that some folks thought the flanges were too thin, he pulled out an extra stack for comparison. The flanges on HIS stack were even thinner.
He heated my flanges cherry-red, then bashed on them with a hammer. They straightened out pretty well...but it still left a low spot in the middle. He laid a bead of welding along the low spots, then we ground down the whole thing on a belt sander. Left a BEAUTIFULLY flat pair of flanges.
I called the on-field FBO and made an appointment for one their mechanics to install the helicoil. I met the guy at the office and took him to the plane. I expected him to print a toolbox full of equipment, but all he had was a portable drill and a little wooden box. Buzz, buzz, turn, turn, and it was in. Cost me $24.
Anyway, I reinstalled the pipe a week ago. Instead of using the Chevy gaskets, I decided to try the No-Blows again. The FBO's mechanic had recommended using red RTV to seal them, even though the RTV was rated at 600 degrees and the exhaust gets a lot hotter. I bit the bullet and used the RTV.
I carefully tightened the nuts, then let it cure for 24 hours. A fifteen-minute flight the next day left no soot on the cowling or around the gaskets. I flew for a half-hour today; still no sign of leakage, and the RTV squeezed out around the gaskets is still apparently unaffected by the heat. Even a thin smear on a lower part of the pipe is still intact. Guess the temp isn't as high as I thought.
So my annual is done. Finally.
Major cost elements:
My most expensive Fly Baby annual ever. Ed did the inspection for free, but I usually get him a nice aviation book for Christmas.
This year was pretty expensive, as Fly Baby ownership goes. Here's a try at remembering everything I shelled out money for:
Pretty steep...but next year, there shouldn't be $500 in radio expenses, $175 cockpit cover, or (hopefully!) another $325 valve job. I could save $400 by carrying liabilty insurance only, but consider the peace-of-mind being worth it.
Anyway, last year my total hourly rate (for my 40 hours flown) was about $70/hour. Without the big maintenance expenses, that should drop below $50/hour.
However, I do have some things planned for this year. My generator needs to be rebuilt, as I've mentioned in previous postings. Removing it looks sporty; I'm waiting for a spell of bad weather before taking a crack at it. My airspeed indicator needs a rebuild as well (it indicates 40 MPH at rest). So there's $200-$300 worth or work, right there.
Yet another excuse to keep writing articles... :-)
