Archive for the ‘Main Landing Gear’ Category

A Tale of Two Suppliers – 9 hrs

April 27, 2014 Leave a comment

Sunday April 27, 2014

This is a tale of two suppliers. The first is which is a maker of data plates. I found in a Google search on the web. They advertise plates for aviation and other markets like classic cars.I liked the look of their plates and the price was attractive so I ordered one. It arrived in less than a week and I was even more pleased with how it looked when I saw it in person. I installed it a few weeks ago and was happy until I read in a DAR inspection checklist that it had to be fireproof. The plate I ordered was aluminum and clearly would not survive a fire. In frustration, I fired off an email to the company complaining that they should have told me it was not a legal data plate and it should be steel. To my surprise I received a response from the owner of the company within a day saying I was the first to call this to their attention, he had done some research and found that the FAA had changed the regulations on data plates a few years ago and they had missed it. They would send me a refund and were investigating new materials. I told Scott the owner that I was interested if they could make it fireproof. To make a long story short, I received a replacement data plate in about a week in a brass plated steel material. I actually like the look with a brass background color in a field of black anodize (see below). I commend for how they responded to my complaint and could not ask for more. I’m not sure how the DAR inspector will respond to this material. It’s not like other data plates I have seen. Scott claims it is fireproof but the anodize looks like it could be a painted surface which would burn off. I asked Scott if he could send me a report on the flame testing he has done on this material. I have not heard back on that yet but it would be handy if the DAR asks. All in all, I would recommend but stay tuned to find out if mine passes inspection.


The second supplier is ACK Technologies. They make the E-04 ELT I installed behind the baggage compartment. I bought my ELT for just under $600 in November of 2012. I needed it at that time to make a custom shelf to mount it but I wasn’t going to install it until further in the build process. I wired it up recently and I did not test it until two weeks ago when I found it was completely dead. I checked the battery voltage and it was only 0.2 volts, not 12V as it should be. Not good. So I called the company and the representative I talked to said mail it in and they would repair it under the 2-year warranty. I packed it up and sent it to the factory in San Jose and three days later I got a call telling me I must have triggered the ELT at some point and let it run dead. It was going to cost me $65 for a new battery.  But I argued I never turned the ELT on because I had not registered it until two weeks ago and since it was switched off I can’t see how I could have triggered it. The switch was still off when I went to test it two weeks ago so I hadn’t accidentally turned it on. The only thing I can think of is it may have been dead when I received it in 2012 from Chief Aircraft. Since I did not test it then I never realized it. After talking to the technician for a few minutes he agreed to put a “used” battery in it with the same shelf life as my old battery and send it back to me at no charge. That’s more than fair and I appreciate ACK Technologies standing behind their product. The lesson I learned for next time  is to test the ELT as soon as I receive it. And I’ll do that when I replace the battery in 2017.

This weekend was the time to charge the brake system with fluid and bleed it. I purchased a quart of Mobil 1 synthetic automatic transmission fluid on the advice of many on VAF instead of the typical Royco 782. I also bought a pump-type oil can off Amazon along with some vinyl tubing from Home Depot. In short I connected the oil can to the brake bleeder valve via the vinyl hose and started pumping fluid into the lines from the caliper to the reservoir. The right ride was easy. The fluid flowed in quickly and in a minute or two I had pushed fluid into the reservoir. When I closed the bleeder valve and check the firmness of the right pedals they were rock hard. Charging the left side was much harder. The fluid did not want to flow easily with significant back pressure for unknown reason. It took a lot of slow pumping to get the fluid all the way through and it was hard to push out the bubbles visible in the lines. When I closed the bleeder valve and check the firmness of the left pedals they were a little squishy. And when I pumped them I saw bubbles come out of the master cylinders. I disconnected the hose at the top of the landing gear and pumped fluid through that line and the brake caliper but it was still hard to pump. It must be some restriction in the caliper. I reconnected the hose and pumped the brake pedal with the bleeder valve open to push fluid backward through the caliper hoping to discharge anything that might be in the line. That seemed to help a little. So I pumped more from the bleeder valve to the reservoir and after more time than I expected all the bubbles were gone and both sets of pedals are now very hard.


To catch any overflow from the reservoir I attached a straight AN fitting in place of the vent screen on top. To that I attached a short aluminum tube with a flaired AN fitting and a vinyl hose going into a clean water bottle. This worked perfectly to prevent an overflow. When I was done I opened one of the bleeder valves and pumped the pedal enough to drain any excess in the vinyl tube back into the reservoir so it would not spill out when I took the AN fittings off. Then I pumped enough out of the reservoir with a syringe to leave the fluid level about an inch below the vent screen.


I had a couple of plastic lines that are close to rubbing against the braided stainless steel lines so I put some split vinyl tubing on them for protection.


My wife helped me remove the canopy one last time (I hope) to install the rubber seal strips and to make it easier to rivet the front top skin on.


Intersection Fairings – 20 hrs

March 2, 2014 Leave a comment

Sunday Mar 2, 2014

I was out of town last weekend with the wife and for a couple more days this week on business so progress was delayed.

With the gear leg fairings aligned it was time to start installing the lower intersection fairings on the wheel pants. I purchased mine from Cleaveland Aircraft but they are actually made by RVbits. These are supposed to be better quality than the Vans parts. After aligning them to the leg and wheel fairings I match drilled a set of #40 holes to cleco them in place. I then marked a line to cut the intersection fairing into three pieces so it can split with the front and read wheel fairing sections. After wrapping the gear leg fairing with packing tape I mixed up some epoxy with heavy flox and bonded the three pieces back onto the wheel fairing as well as bonded the aft edges of the intersection fairing together. I did this all in place on the gear leg to make sure everything was fitting well. Here is one clecoed together and set up to cure.


After the epoxy was set I  sanded the surfaces to remove excess epoxy. I applied more packing tape over the aft section of the intersection fairing and laid down three layers of fiberglass overlapping the seam between the front and rear sections to make flaps attached to the front section that overhang the aft section along the gear leg fairing so the air stream cannot get under the aft fairing and lift up the forward facing edge. I took this picture after I removed the fairing sections from the landing gear and clecoed them back together. Here you see the raw fiberglass layup.


With the two sections separated you can see the fiberglass is bonded to the front section and simply overlaps the aft section. The edges of the layup are still raw.


After trimming the edges to leave 1/2 inch overlap and sanding the surfaces the parts look like this.


Here I put it back together again to show the finished overlap on the bottom edge.


When I was happy with the flaps on the left side fairing set I mixed up more epoxy with micro and smeared it on to smooth out the transitions between the parts including the front and rear wheel fairings which are not very flush along the seam. This photo is before sanding the micro.


I received two hoses I ordered from TSFlightlines for the brake lines down the landing gear legs. I installed the left hose to verify the length. It looks good so I installed it using three short pieces of plastic tubing and electrical tape to strap it to the leg.


I sanded the micro on the left wheel pant and intersection fairing using several coats of epoxy to get it well blended and smooth. I also sanded the entire exterior of the both the left wheel and leg fairing. Then I installed K1000-6 nutplates on the aft wheel pant section for the screws that hold the two sections together. After more hours of work than I expected this set is finally complete including the lower intersection fairing and is ready for primer. I just need to get the right set up to the same point.


Another task on my list was to run a 1/4 inch tube from the firewall to the right fuel tank for the Airflow Performance fuel purge line. I had been dreading this task because there is no easy way to do this. The routing from the firewall to the tank is anything but direct and I knew bending the tubing would be difficult in these tight quarters. I decided to go through the right longeron with a snap bushing and get the line behind the right interior side panel trim as soon as possible, then go downward under the right rudder cable into the area of the right gear weldment which is covered by the carpet. You can see my final routing in this photo before I installed the side panel. I bent the section in front of the longeron first. Then I inserted the free end of the tube through the snap bushing and bent the remainder of the tube run to the tank in situ which was a big pain. I used a coil spring tube mandrel to prevent the tubing from flattening during bending. One of my goals was to keep the tubing away from the copilot’s feet and this accomplishes that goal.


The tubing comes through the side of the fuselage with a rubber grommet and points straight at the access cover of the right tank. I will have to line up and partially install the right wing to locate the correct spot to install a bulkhead fitting for this line so that will have to wait a while. For now I left the tube a little long so I can cut and flair it to length at that time.


Leg Fairings Aligned – 9 hrs

February 16, 2014 Leave a comment

Sunday Feb 16, 2014

The gear leg fairings need to be aligned to the nominal airflow when the aircraft weight is off the landing gear. So while the wheels were off the ground I aligned the fairings using the method described in the manual. I hung a plumb bob from the aft edge of the fairing and measured the distances of that point vertically from the floor and out from the centerline. In this photo you can see the plumb bob marking the distance out from the centerline.


Then I set up a stool to establish a point the same distance up off the floor and out from the centerline under the horizontal stabilizer. I strung a piece of string from the stool to and around the fairing at the aforementioned point and pulled it tight. This represents the nominal air flow direction. I then adjusted the fairing until the aft edge bisected the two legs of the string and then tightened the hose clamp that secures the fairing to the leg. It took longer to set this up than it did to adjust the fairing.


After finishing the left main gear fairing alignment I set up to do the right leg but I realized I still needed to install the hinge for that fairing so I did that before I stopped working on Saturday for the night.


In the morning I installed the right leg fairing and aligned it to the air stream in the same way I did the left leg fairing. After that I realized I didn’t really need the airplane up off the ground on jacks any longer so I lowered it down and got the jack stands out of the way. I’m glad to have that done.


For a small diversion I decided to install the seat belts next. I have the Crow harnesses with camloc releases in black with black anodized hardware. Denise picked out the color. I like it because it accents the black instruments on the panel and the stick grips.


Right Main Gear Fairing – 2 hrs

February 13, 2014 Leave a comment

Thursday Feb 13, 2014

Tonight I went through all the motions to align the right main gear fairing and drill it to mount to the fairing brackets.


I also trimmed the opening for the tire to provide about 1/2 inch clearance all around and sanded the edges smooth.


Fitting Gear Leg Fairing Clamps – 2 hrs

February 10, 2014 Leave a comment

Monday Feb 10, 2014

Still plodding along on these landing gear fairings with fiberglass dust in my hair and dried out hands. Tonight I cut the notches in the main leg fairings for the hose clamps that secure them to the leg struts. These are cut on the inboard side and will be under the intersection fairings so they will not be visible. A straight notch did not provide full access to the clamp screw so I opened it up a little with my dremel tool.


Here is how it looks installed on the left leg. I followed the instructions and heated the fiberglass up with my hot air gun before tightening up the clamp to make the fiberglass more pliable and help it form to the cylindrical leg.


Here is a view from the inboard side so you can see the hose clamp screw.


I sanded the fiberglass on the inside of the wheel fairing where the brackets mount in preparation for liquid shimming the fairing with epoxy/flox. I put packing tape over the surfaces of the brackets then gooped up blobs of epoxy/flox on the inside of the fairing in the area of bracket contact. Then I put the fairing on the wheel, clecoed in place to cure for tomorrow.


Categories: Main Landing Gear

More Fairing Work – 8 hrs

February 9, 2014 Leave a comment

Sunday Feb 9, 2014

This nose wheel fairing is turning out to be more work than I expected. This weekend I wanted to try to wrap up the job of fitting it to the wheel brackets. I needed to drill three holes in the fairing; two for the two bar access and one for access to the air valve. To locate the proper location for the air valve hole I set up a laser level at the height of the valve and I pointed it directly at the end of the valve. You can see the red glow in this photo.


Then I put the fairing back on. The laser now shines directly on the fairing in line with the valve so that is where I drilled. I started out small and worked my way up to almost a inch diameter to fit the camloc access door I bought at ACS.


This next photo shows the fairing after I had installed the access door and drilled both holes for the tow bar.


I did a final trim of the cutout for the wheel to make sure I had adequate clearance then I mixed up some epoxy and painted on a layer inside the fairing to seal the surface with a non-porous layer. Then I set this out to cure.


I resumed work on the main gear leg fairing by installing the hinge which is used to close up the aft edge. This was basically the same process used on the nose gear leg fairing. I also cut the notches for the hose clamp that will hold the fairing to the gear leg.


I then checked the fit on the gear leg. I made another trim cut on the bottom edge and now this looks good to go. Not shown here are some reinforcement patches I laid up inside the left main wheel fairing in the areas where the brackets mount. I put down two or three layers of fiberglass to even out the surface of the fairing and make it more parallel to the bracket surface. I’ll still have to form epoxy/flox shims between the fairing and the brackets later to get the fit I want.


I also went out to Corona to look at hangars on Saturday. My search for a home base has officially started.

Preparing to Install Main Gear Fairings – 8 hrs

February 1, 2014 Leave a comment

Saturday Feb 1, 2014

This weekend was my first chance try out the jack stands I built to lift the fuselage and take the weight off the landing gear. This is needed to install and align the main gear fairings (pants). I used the engine hoist to lift the engine mount to level the longerons so the aircraft support is on three points. It is quite stable and I don’t have any concerns about the stands tipping over so I can leave the airplane this way for a while.


First thing I needed to do was install the wheel fairing support brackets. I fit these to the wheels a long time ago but I found that I needed to trim down the three tubular spacers about 0.1 inch to get the gap to the bracket set in the .032 -.094 range called for on the drawing. That took a while but I got everything back together again with the brackets installed and ready to receive the fairings.


I dropped a plumb line from the center of the firewall and another from the tie down ring on the tail and snapped a chalk line between them to mark a centerline for the aircraft. Then I measured out about 40.25 inches in tow places and snapped another chalk line parallel to the centerline but passing through the centerline of the tire where it touches the ground. I did this on both sides of the aircraft. These are my lines to which the wheel pants will be aligned.


Back on the nose gear fairing, I mixed up some epoxy with flox and I gooped it up in between the nose gear fairing and the brackets. These brackets don’t sit flush on the fairing surface and the epoxy is to form a shim that makes the connection solid without distorting the fairing. After installing the wheel fairing I checked the alignment and then left it alone for about 3 hours while the epoxy cured. I switched out the clecos after that to make sure I did not epoxy those in place and let it cure another 2-3 hours.


After that I took off the leg fairing and started fitting the hinge that holds the rear edge together. Here you see it drilled and cleco’d to the fairing. I trimmed the hinge to length but I left the hinge pin long for now.


Drilled Right Main Gear Axle for Cotter Pin – 1 hr

December 14, 2012 Leave a comment

Friday Dec 14, 2012

Tonight I drilled the right main gear axle for the cotter pin. The process was just like last night except on the opposite gear leg. No pictures.

Drilling Axles for Cotter Pins – 2 hrs

December 13, 2012 Leave a comment

Thursday Dec 13, 2012

The nose gear has a couple of big belleville washers that preload the vertical pivot bearing axially. This eliminates slop but more importantly causes frictional damping to prevents the nose wheel from doing the shimmy at high speeds. The level of preload is set by adjusting the pivot bearing nut until the breakaway drag on the pivot bearing is about 22 lbs measured along the wheel centerline. The scale for measuring this does not come with the kit so I went on Amazon and found a digital luggage scale that measures up to 75 lbs. It was only about $7 so I ordered it about a month ago anticipating this day. I can also use it to weigh luggage.

Here is my setup for measuring the breakaway friction of the pivot bearing. I used safety wire to make a loops that attach to the nose gear fairing brackets on each side. The nose wheel is off the ground in this photo about an inch so the pivot axle is vertical. I adjusted the nut until the breakaway force was about 22 lbs in each direction then I rotated the wheel through +/-30 or so about fifty times to make sure everything was seated and rubbing surfaces were broken in. Then I readjusted the nut for 22 lbs again. In repeated measurements the results varied somewhat but in the end I measured about 22 lbs in one direction and about 24 in the other direction with each measurement varying about +/-0.5 lbs from one measurement to the next. Then I drilled the holes in the axle for the cotter pin. That was a pain in the neck. The axle is steel and it is pretty hard. Going at low rpms and using plenty of lube it took quite a while to drill through each side and I broke one drill in the process. Nevertheless I got the holes drilled and deburred and the nose gear is now permanently mounted to the axle with the cotter pin installed.


For the main landing gear I had to raise the nose of the fuselage slightly with the crane to get the weight off the gear. I started with the left main gear. These use tapered roller bearings with seals that offer a fair amount on rolling resistance (at least until the seals wear in a bit). The objective here is to tighten the axle nuts enough to remove all axial play in the bearings but not so tight as to cause excessive loads on the bearings. The Matco instructions say to tighten the nut until the seals no longer rotate with the wheel as it is turned then tighten to the next cotter pin position. Well, there are no cotter pin positions yet because they are not predrilled so I tightened the nut about 15-20 degrees past where the seal stopped turning. I also checked to make sure there was no freeplay in the bearings at this preload. Then I started drilling with a 12 inch #30 drill through one of the pin holes of the nut. Once I drilled far enough that the hole center was well established I took the nut and wheel off the axle and finished drill through the first side with a new 1/8 inch cobalt drill bit. I cleaned up the burrs and reassembled it to set up to drill the opposite side. To make sure the hole I just drilled was aligned to the hole in the nut I pushed a 1/8 inch solid rivet though the aligned holes in the nut and the axle to key them together before drilling on the other side. Then I repeated the drilling process for the opposite hole starting with the 12 inch #30 drill until the hole center was well established. After I took the wheel off again and had drilled through the axle I ran the drill through both holes at the same time to make sure the cotter pin could pass through both sides. Then I just cleaned up the burrs with a tiny jewelers file and put it all back together again. The cotter pin is currently slipped through but I won’t bend it until I am satisfied the wheel is staying on.


This Bird Has Legs – 8 hrs

December 1, 2012 Leave a comment

Saturday Dec 1, 2012

Today was one of those rare days where a bunch of significant things were completed. I started this morning working on the ELT mount. The parts needed to be primed so I scrubbed all the parts with Simple Green, rinsed and dried them. The weather was not great this morning and the humidity was kind of high but I was able to get a decent coat of primer shot onto the parts in the paint booth. After drying a while I riveted them together with the nutplates for the ELT tray. Here is the bracket by itself.


And here is how it looks with the ELT tray installed. The ELT traps are clamped down under the tray by the mounting screws.


I installed the bracket with the tray attached into the fuselage using CS4-4 pop rivets and installed the ELT to the tray. I’m guessing it is stiffer than the Vans bracket because it ties directly into those stringers without the large flat surface of the Vans bracket. This mount sure seems stiff. It also does not interfere with the rudder cable and it keeps the center of gravity as far forward as possible.


Next I installed the Dynon remote transponder unit. It also has a tray which I mounted with three screws to the center rib behind the pitch autopilot servo. I drilled the holes in the rib and used locknuts to install it. This did not take long once I got my less-than-flexible body back there where I could reach this area. The transponder just snapped into the tray with a wire retaining clamp on the aft end. Next step with the ELT and transponder will be making coax cables and running wiring.


Several months ago I purchased an engine crane at Harbor Freight in preparation for hanging the engine. Today was the day that I opened the crate and assembled this thing. It took about 45 minutes to put all the pieces together and get it operating. I have to say I am impressed with the quality of this thing. It lists for $200 but I bought it with a HF coupon for $100 and at that price it is a steal. It is perfect for this job and it looks pretty good too. I just wish I had more space to store it.


I didn’t really plan this in advance but since I had the crane operating I lashed it to the engine mount and lifted the front end of the fuselage. That gave me enough clearance to insert the nose gear which has just been sitting in the corner anyway. I had to jiggle it quite a bit to get the bolt hole aligned but I got it in. At that point I had to decide to go ahead and put the two main gear legs on or remove the nose gear for another day. I thought, “It’s time to give this bird some legs.” With the crane attached I just lifted the front a little further and I could slide the main gear legs into the sockets and bolt them in. Wow, it is cool that this is done – it’s a major milestone.


One lesson learned – I buggered up the threads on one of the gear leg bolts trying to get it in before the holes were perfectly lined up. After that I got smarter and went to the hardware store a picked up a 3-inch long, 5/16 diameter bolt that I ground down to make a tapered drift pin (see below). Once I got the holes close I tapped this pin in to center everything up before installing the real bolt. I will have to order a replacement for the one bolt I buggered.