Sunday, September 16, 2018

Landing Gear Blues and Summer Doldrums

     I just finished writing the AirVenture 2018 post, almost two months late, and now I'm back to writing about progress on the airplane.  Or lack of it.  Doing the initial research for this post has been rather depressing.  My last post on aircraft progress here was July 16th; the last Kitlog Pro entry covered was July 12.  After OSH, I didn't work on the airplane until August 2.  The most recent entry was September 7.  In the space of that month, I only worked 47 man-hours and several of those hours were accumulated by helpers.  Lots of gaps and two-hour days.  There are reasons for that, both good and bad.  But the bottom line is that kind schedule won't get this airplane finished when I wanted it to be finished... and I have to be honest with myself about that, address it and hopefully correct it.  I have allowed a lot of distractions to break my work flow.  AirVenture was the first distraction; trip preparation, attending and getting caught up afterward took up three weeks of my time.  A three-day trip to Gatlinburg somehow managed to gouge ten days out of my work schedule.  There were flying days, airshow days, photo and video production days, appointment days, chore days, all chipping away chunks of time.  The most recent distraction was a trip to Traverse City from September 10 to September 13.  My last work day on the plane was September 7, and I haven't worked on it since.  This isn't good, and I only have myself to blame.  I keep coming up with more distractions.  Even this blog is keeping me away.  I've got a recording session tomorrow that will involve audio and video and I'm sure that will eat up more time.  Do I have to do a lot of these things?  Some yes, some no... but I want to do them, and apparently I want to do them more than work on the airplane.  Why?  Because working on the aircraft is getting harder, and sometimes a lot more frustrating.  The latter stages of building an airplane involve working around a lot of Catch-22s and Chinese puzzles.  If I do this, it will make it harder to do that... but if I do that first I'm not sure I'll be able to do this at all.  Agonizing over the "correct" sequence of work has eaten up a lot of my shop time.  It's also common that if work on a large project like this is interrupted, it's harder to get back to work again... especially if the work has made me feel like I've been bashing my head against a wall and getting nowhere.  I know this is a hump that all builders must get over, and I won't let it defeat me.  I'm just on top of that hump now, and to be honest it's a scary place.  I just have to keep telling myself that every builder goes through these times, and most have come out of it all with a wonderful aircraft that is the joy of their life.  If I want this airplane - AND I DO - I have to keep going.  If I keep going, it will get done and I will experience the joy I've wanted to feel for decades.  I also know that even when the airplane is flying, there will be ups and downs, literally and figuratively.  I have to be prepared to face it all to get the joy out of it that I seek.  Now that I think of it, it's a lot like parenthood... a job that may never end, sometimes a source of frustration, but ultimately a source of pride, joy and love.  Maybe I'm better trained for this than I thought... but enough of me and my angst.  Let's talk about what progress has been made.
     When I got back to working on the plane after OSH, I started with small tasks.  I finished the mounting holes in the fuselage bottom for the com antenna.  I had started with pilot holes through a template from the inside when the fuselage was upright, but the template shifted during the process and I wasn't happy with the alignment.  I waited until I could work from the bottom with the fuselage inverted and very carefully enlarged the screw holes by hand with a jeweler's file until they would align properly with the holes in the mounting base and reinforcement plate.  I enlarged the cable hole with a Dremel tool because it would work more gently and accurately than using a large drill bit that might tear up the hole and pull itself out of alignment.  I really wanted to mount the antenna, but the fuselage bottom should be painted first, so after test fitting I removed it.
     There were other small jobs that could be done now.  I dimpled the flap fairings and the new seat ramp that will replace the one I had to mangle to get that stripped floor screw out.  The ramp also needed to be deburred and smoothed, along with the damaged area of the left console cover.  Then I prepped, wash primed and primed the seat ramp, flap fairings, landing gear covers and part of the console cover.  I sprayed the top coat of interior green on the seat ramp and console cover.  I did my best to mask and match the console; the new paint didn't blend as nicely as I had hoped, but it doesn't matter to me.  Most of the repaired area will be covered by the replacement seat ramp anyway; at least it's protected from corrosion and should reinstall well enough.  Once the seat ramp was painted, I riveted on new nut plates after checking them to make sure they wouldn't strip out new screws.  I don't want to go through that again.  With some assistance from Naomi and Andrew I got the rivet holes in the fuselage for the flap fairings dimpled and plugged the unused step rivet holes.  After discussing it with Van's builder support it seemed that using round head rivets would be the best way to do it, since dimpling or countersinking those holes on the already assembled quickbuild fuselage would have been risky.  The holes did need to be final drilled to size for the rivets to fit.  I'm not going to worry about the added drag of six round head rivets per side; they're downwind of a big lap joint in the belly skins anyway.
     It was time to get ready to bolt on the landing gear legs.  I had asked the Grove reps at AirVenture whether or not the part of the gear legs that are held by the brackets should be painted or left bare and they said they should at least be wash primed and/or primed.  So I prepped the legs for paint (including having to wash them in our bathtub) and sprayed them with wash primer and primer.  I decided that as long as the legs were already in the booth, I should go ahead and give them their top coat of Neutral Grey.
     While the paint dried I patched a couple errant fuselage holes with aluminum epoxy putty.  One has adequate edge distance; the other is an overlap but it's not a complete hole, it's a notch in the skin and it's backed by an intact longeron and will be also squeezed together by the fuel tank bracket.  I also started working on the lower brake lines that connect the fuselage lines to the built-in gear leg lines.  I had made up one set earlier, but during initial test fitting I realized I needed to make up new ones with different bend locations.  It also began to dawn on me just how difficult it would be to get the lower brake lines installed.  I had to temporarily fit the gear legs to the fuselage with brackets and bolts and finish fabricating the brake lines around them to the correct shape.  Then the gear legs and brackets had to be removed.  I attached the brake lines to the fuselage lines and tightened the fitting nuts down at this stage because they could only be accessed without the gear in the way.  Later, when the legs and brackets were installed permanently, the other end of the brake lines would need to be attached to the gear leg fittings and tightened.  But before all that could occur, the wear plate installation had to be done.
     Before the landing gear could be mounted, the inner and outer wear plates would have to be bolted down and torqued to spec; it couldn't be done later because the legs and fuel lines would block access to the bolt heads.  I fitted the brackets with bolts in place to make sure the hole alignment would be correct before the wear plate bolts were tightened.  This was where things started getting really difficult.  You'd think that bolting down the wear plates would be very simple; four steel straps held down by eight bolts, washers and nuts should be simple, right?  Not if the fuselage is upside down.  Not if the reach into the fuselage from below is a nightmare, trying to reach from a floor crawler with as much arm and body extension as I can muster through spaces obstructed by braces, baggage bulkheads, instrument panels, avionics and the windscreen support.  Not when trying to fit a washer and nut onto a bolt from the bottom upwards onto a bolt with only two fingertips, an almost impossible reach and other adjacent bolts and nuts blocking access to the target bolt.  Not when dropping a washer means it disappears into catch places that are impossible to access with the fuselage upside down.  One nut and washer in particular gave me absolute fits: the messy-looking one you'll spot in the photos below.  The bolt holes for these wear plates are infamous to RV-8 quickbuild fuselage owners because they should be drilled before the bottom skins are put in place but they aren't.  As a result they need to be drilled through pilot holes in the skin.  It can be done, but it's hard to guarantee perfect hole placement through the longerons underneath.  One of my holes was slightly off... acceptable and usable, but awkward to get the nut and washer on given the conditions I've described.  To make matters worse, there was a quickbuild rivet adjacent to the bolt hole, which meant I need to make a notch in the washer to fit around it so everything would tighten down correctly.  Because of that, I couldn't use the tactic of sticking the washer to the nut;  I had to  trying to get it to stick to the longeron, and in this situation gravity was working against me.  I tried gasket sealer, but it proved ineffective.  I finally had to stick it to the nut with a tiny dab of grease, get the nus started, then rotate the washer so that the notch would fit around the rivet.  It was almost impossible to do and I spend hours struggling with it, but I eventually succeeded.  Even the relatively easy inner wear plates were a nightmare because although getting the washers and nuts onto the exposed bolt ends was much easier, the only way to reach them was to crawl under the inverted fuselage and into the aft cockpit bay, squeeze onto the workstand supporting the fuselage under the forward cockpit bay, painfully roll onto my back and scoot forward until I could reach the bolts protruding from the gear tower weldments.  Getting out of that position was even more painful and having to repeat the process many times left bruises on my ribs, back and legs.  I eventually got all eight nuts and washers onto the bolts.  With Amy holding the bolt heads with a wrench and using different combinations of sockets, extensions and crowfoot wrenches, I was finally able get all eight nuts torqued to spec.  All together it took seven man-hours of work to get those four wear plates bolted down with eight bolts, washers and nuts.  As I said in the Kitlog entry: Ridiculous.
     Once the wear plates were in place I could address getting the gear and brackets in place.  Test fitting the legs allowed me to finally finish the lower brake lines and get them tightened down to the fuselage fittings.  Test fitting the gear legs also revealed that additional refinements would be required.  For some reason things didn't quite fit the same way they did when the initial gear alignment was done.  The fuselage bottom skins needed further relief to clear the oversize Grove outer brackets; so did the right gear leg cover, after which the  wash primer would need to be reapplied to the modified edge by hand.  Some bolt holes needed a bit of light reaming before the bolts would go in without binding.  The left outer bracket didn't seem willing to fit the way it did before, possibly due to paint on the legs.  I had to very lightly relieve a contact area, then touch up the paint to protect the relieved area from corrosion.  The left gear leg also wasn't sitting quite flat on the outer wear plate either, even though it had during initial fitting.  At this point I decided to go ahead and spray the clear coat onto the gear legs, rather than wait until the fuselage bottom was painted and doing it all at the same time.  I masked off the mounting section of the legs to avoid adding extra thickness in the bracket areas.  When the clear coat was dry the gear could be fitted to the fuselage permanently and the lower brake lines could be attached to the leg fittings.  None of the fitting nuts on the lower brake lines could be torqued with a torque wrench because there was absolutely no way to use a clawfoot wrench in the tight quarters.  I had to use a standard open-end wrench at a sharp angle over two sides of each nut and turn the angled wrench with a pair of pliers, tightening carefully until it felt right.  I won't know for certain if it is right until the brakes are installed and tested.  I'm keeping my fingers crossed, because as you are about to learn, removing and reinstalling the gear to fix any leaks will be practically unbearable.
     The torquing sequence called out in the manual also gave me cause for concern. Van's Aircraft recommends tightening down the outer bracket first, then tightening the inner bracket.  Getting the nuts and washers onto the outer bracket bolts and tightening them down is generally accepted as being one of the most difficult tasks in building an RV-8.  It isn't quite as bad during initial fitting, but at this stage of assembly there are fuel lines, vent lines and wiring cluttering the inside of the gear towers.  The instrument panel, avionics and windscreen support are also obstacles to access.  This is also complicated by the fact that I'm using Grove airfoil landing gear legs and bracket, which fit differently than the stock ones.  I was hoping I could torque down the relatively easy inner brackets first and flip the fuselage before torquing down the outer brackets.  Access would still be difficult, but at least I'd have gravity working for me.  Consultations with Grove and Van's Builder Support convinced me that I should torque the outer brackets first and then the inner brackets before flipping the fuselage and resting it on the gear.  Grove added that when torque was applied to the left gear leg bracket bolts, they should pull the gear leg down onto the wear plate and everything would align without creating any undue stress.  I spent a lot of time pondering just how I was going to get the washers and nuts onto those outer bracket bolts.  The combination of bad access, obstructions and working blind seemed impossible.  But it had to be done, and I had to figure out a way to do it.  I started by gluing the washers to the special 12-point nuts supplied by Grove so that I didn't have to worry about losing them in the gear towers during the attempts to get the nuts started.  I could solve the problem of working blind by using a borescope camera that could connect to my cell phone with wi-fi, so I ordered one.  When it arrived, I had to figure out how to use it, then I realized I also had to figure out how to set up my phone as a hands-free monitor while laying on the creeper underneath the gear tower.  I took the bass drum mic stand off the drum set in my house, brought it out to the shop and figured out how to mount a bracket that would fit the belt clip on my cell phone case.  It still wasn't easy, by any means.  Making the wi-fi connection could be troublesome at times; the camera battery wouldn't hold a charge for very long and finding a way to fish the flexible camera tube into the gear tower and tape it into an orientation where it was viewing correctly without being another obstruction was a very frustrating process.  But at least I knew it was possible, so I pressed on with testing and experimenting until I felt I was ready to actually make the attempt at getting washers and nuts onto the outer bracket bolts.
     Around this time period I had read an account written by another VAF builder who had his RV-8 on the gear without the empennage attached.  He was moving the fuselage by lifting the tail and rolling it on the gear, and he made the mistake of dropping the tailwheel instead of setting it down gently.  He heard a loud bang inside the tail; investigation revealed that without the vertical stabilizer bolted in place, the tail spring support bracket was only fastened to the aft bulkhead with two flush head rivets, seen just below the upper washer in this photo.  When he dropped the tail, the rivets sheared and the bracket put a slight dent in the bulkhead notch.  I learned from his mistake and promptly went out to the shop and placed temporary bolts and washers in the bolt holes to stabilize the assembly and prevent doing similar damage.
     The first attempts at getting those outer bracket nuts onto the bolts led me to change the way the fuselage was supported to allow better access to the gear towers from inside the fuselage.  I placed the small workstand back under the aft cockpit bay and used the engine hoist to raise the front end of the fuselage, remove the large workstand from the forward cockpit bay and lower the engine mount onto jackstands to support the front of the fuselage.  Now I could crawl under the fuselage, sit up into the forward cockpit bay and reach into the gear towers to access the aft outer bracket bolts.  It was still very awkward and difficult, and I was still working by feel with some slight assistance from the borescope cam, but at least I had hope that it might work.  The forward bolts would still have to be accessed from the crawler using long extensions with a universal joint just under the socket to allow the nut to thread onto the slightly angled bolts.  I put masking tape on the universal joint to help stabilize it and prevent it from flopping to one side and dropping the nut.  This actually worked rather well, and after numerous tries I was able to get one started on the left forward bolt, which was not obstructed by the fuselage screws and nuts protruding nearby.  The right forward nut was another matter; it was more obstructed by the screws and nuts that surrounded it.  I had to swap to a smaller diameter extension and universal joint and instead of using a socket I had to put fine line tape on the square stub of the universal joint thick enough to engage the threads of the nut.  I gently threaded the nut onto the fine line tape and secure it lightly on the outside with masking tape.  This allowed me to thread the nut and washer onto the right forward bolt without anything catching on the protrusions.  More numerous tries later, they were on.
     From the photo above you can see just how difficult it would be to get the nuts and washers onto the aft bolts.  Analyzing the photos and feeling with my fingers, I realized I could probably get a nut onto the right aft bolt without having to move the bolt sticking in through the aft tower bulkhead.  On the left side it was too tight; I would have to at least back out the bolt to get clearance for the left aft bracket nut.  And of course, the head side of the offending bolt was blocked in by a fuselage screw, nut and washer.  I had to tape an open end wrench to the nut inside the fuselage to hold it in place while I removed the screw from the outside.  Removing the wrench, nut and washer allowed enough clearance to back off the protruding bolt just enough to get the nut and washer onto the left aft bracket bolt.  I really didn't want to remove that protruding nut if I could avoid it.  Just backing out the bolt was hard enough; trying to get the nut and washer back onto that bolt after removing them would have been another nightmare and I was facing enough nightmares at that point.  I tried over and over to get that left nut/washer on.  Access was too tight to use my fingers in the normal way; I could only use certain fingertips to try to get the nut started on the bolt.  I could get the nut and washer around the protruding and over the top of the bracket bolt, but I couldn't get the threads to catch.  I tried rigging up another special tool that would allow me to spin the nut easier with two fingers.  Again, I could get the nut and washer onto the top of the bolt, but couldn't get the threads to engage.  I pulled out the bolt and checked the nut on the bolt, making sure the threads weren't damaged.  I chased the first few threads ever so slightly with a die to make sure it was physically possible to get the nut to thread on by hand at least one turn.  The nuts Grove supplies are much stronger than the stock Van's nuts, which have broken on a few aircraft.  They are slightly pinched at the outer edge, not unlike a nut plate, to make sure they grab the bolt and resist loosening.  I knew that they would take some effort to tighten, and I didn't want to change that.  I just wanted to get the nut started at least one full thread before the effort was required.  I put the bolt back in and tried again... over and over and over, working blind because I couldn't use the borescope cam without blocking it with my hand.  I tried using the tool I fabricated; I tried with my fingertips; I tried until my left arm bore the imprints of many near-lacerations from squeezing into the access port.  I tried until the frustration almost drove me to tears... and I stopped.  I climbed out from under the cockpit, sat on the floor and took many deep breaths.  I couldn't do this job alone.  I needed help.  I got off the floor, turned out the lights and locked up the shop.  Time for a break.  I went inside and discussed the situation with Amy over a couple of beers.
     I took the next day off from working on the RV-8 and went flying in the Citabria at Ann Arbor Aviation Center.  They finally had an available tailwheel instructor, William Burtless.  I combined the tailwheel recurrency flight with a Biennial Flight Review.  It was probably the most enjoyable BFR I've ever gotten.  The morning weather was ideal, and I got a special surprise that morning.  Will gave me a simulated engine failure and told me to choose my landing spot carefully.  I got the glide set up, talked through a check list and looked around... and realized I was right over a private grass strip!  Honey Acres Airport ran east/west and the winds were coming from the east.  I was gliding a crosswind leg northbound directly over the center of the field, so I did a gradual 270 degree turn to set myself up on final for Runway 27.  I slipped the aircraft to lose some altitude, and brought it all the way to touchdown, right where I wanted it.  I was really proud of that, and the best part was that it was my first landing on a grass runway.  I told Will that as I taxiied back for takeoff and he gave me the option of remaining in the pattern for a few more, which I did.  We did one more full stop 3-point landing and one wheel landing that was touch-and-go.  The other two landings were ok, but the simulated engine failure landing was the best by far.  When we went back to Ann Arbor to land, the Citabria got a little squirrelly on me, but I reigned it in.  I'll need more paved landings before I feel truly comfortable in this particular Citabria, but overall it was a great flight.  The ground portion of the review was casual and comfortable, and Will and I shared experiences as he reviewed my knowledge.  I look forward to flying with him again, and he said he'd be happy to fly up to PTK and pick me up at my hangar so I wouldn't have to drive down to Ann Arbor.  Yep... best BFR ever... and a welcome break.  I was having so much fun flying, I forgot to take any photos.  I grabbed this selfie right before we locked up the hangar.
     The morning after my day off, Amy came out to the shop with me.  I got her set up with a ratchet on the left aft bracket bolt.  I got underneath, got situated and got the nut and washer over the bolt end.  I held it there with my thumb while Amy rotated the bolt from above.  It worked.  The nut threaded onto the bolt.  Hallelujah!  We repeated the process on the right side with similar success.  The nuts and washers were already on the six inner bracket bolts.  Now it was time to torque everything down.  The Grove 12-point nuts would require a special tool for this.  Clearance issues prevented the use of a 12-point socket; likewise a 12-point box end wrench wouldn't clear the obstacles.  The nut wouldn't accept a six point socket, crowfoot wrench or open end wrench.  So I modified a 12-point box end wrench to clear the obstacles and hold the nut while torque was applied on the bolt head above.  I taught Amy how to use a torque wrench and set it to the proper setting.  I got in position underneath and we got to work.  We drew the left bracket down until they were even and then torqued the back, then the front, back and forth until the proper torque was applied and the gaps between the bracket ends and the were plates were even.  Grove was right; torquing the outer brackets pulled everything together nicely.  We repeated the process on the other side and the nightmare was over... for now.  By the way, I had forgotten to take any photos of Amy during the work, so I had her come out and pose for her photo.  I asked her to look like she was putting a serious torque on the bolt.  When I looked at the photo later, I realized how staged it looked with her grimacing... but when you look at her hands she's obviously doing nothing with them.  That made us both laugh.
     Later that day, Naomi helped me torque the inner bracket bolts.  For the inner brackets, I torqued the center nut from underneath while Naomi held the bolt from above with a 6-point socket and a long handle.  The forward and aft inner bracket bolts had to be torqued from above; the proximity of the gear tower weldment webbing prevented the use of a socket or clawfoot wrench.  I set the small torque wrench to the correct in/lb setting, taught Naomi how to use it and she tightened the bolts down while I held an open end wrench on the nuts.  Then she helped me tighten down the loose gear tower bulkhead bolt and refit the fuselage screws, nuts and washers I had removed to gain the clearance needed for the bulkhead bolts.  I torque marked all the nuts I could reach; the inner nuts will have to wait until they are retorqued after flight.  But the landing gear legs are on... hopefully to stay forever.
     Very little work has happened since.  I got the fuselage back on both workstands and stowed the jackstands and engine hoist.  I did some homework on getting the axles, wheels and brakes on the gear and proper alignment methods.  I took a measurement from the bottom of the gear legs to the bottom of the fuselage so I knew how far the fuselage stand would have to be raised to be used in aligning the gear.  The final number was a bit shocking.  To get the bottom of the gear legs one foot off the ground as recommended by the plans, the fuselage stand would have to be at least 38 inches of the ground.  Man... that's tall!
     I'm still not sure what to do next.  The flap fairings will need to be riveted on before the fuselage is flipped, but I need to wash prime and prime the skin below them before I do that.  And if I'm doing that, I may as well wash prime and prime the belly.  So I'll probably be erecting the paint boot later this week.  I'm glad the weather is holding up so far this fall.  I also need to do the next round of preservation this month.  I was hoping I'd have it on the fuselage before doing that, but no such luck.  I'll have to investigate the best method of turning the engine over as it sits in its foam throne.  With the desiccant plugs removed, I won't have to fight cylinder compression... but it still might take some leverage.  I'll call Barrett and see what they think.  Stay tuned... I'm hoping to report a lot more progress in the next post.