Gear Radius Plate alignment

The new steel plates for the gear came back from the laser cutters. I had them resized to fit the radius plates from Grove, which were 1.5″ wide, not 1″ wide. The first thing was to trim the radius plates themselves down to the right length, clean up the edges, and then drill holes to line up with the steel plate. I read somewhere that the radius plates are not strong enough on their own, since they are aluminum, and since there’s a lot of load here, I decided to just double up and use the original steel plates as well. This might be overkill (and sure it heavy), but it will work for now. I went slightly thinner on the steel plate – 6mm instead of 6.35mm but that will make no difference really. This should be plenty strong.

Drilling the holes in the radius plates to match the steel plates was easier than I thought it would be. I clamped them in the drill press, added some cutting oil, and just pushed the drill bit through – came out well, although was time consuming. I then brought out the gear and hoisted on a ladder and tested the new system out. Fitted perfectly.

After this I did they tough looking drill hole through the spring gear itself, aligning up with the thin aluminum clamp plate. It was tough as hell, but after I decided to runn a small pilot hole through, it went quick and easy as well.

Time expended: 2.5 hours. Total time: 461.7 hours.

Stabilizer Support Brace Tubes #2

Dean came over and we welded up the thread ends of the brace tubes. I bought the forks from Spruce to measure up the distances just right, and trimmed the ends to fit. The welding went fine. I also trimmed the trailing edge to make it look better and malletted the ends together and welded them closed. I think it came out pretty well. Afterwards, I checked the threads were still intact – they seem fine, although I ran the tap through them one more time to pick up any slag that may have developed on the inside.

After this, we tackled the spacing problem I discovered between the elevators and the stabilizers. After welding on the spacer tabs, they seemed to pull away and not touch the elevators or give them support. We spend about 2 hours trying to fix this. I heated the tabs and tapped them outwards to try and create distance again. Unfortunately I had trimmed them too short before, since when they fanned out I thought they were too long since they touched the elevator hinges.

This didn’t really work. Eventually we tried to heat up the tabs and malleted a thick walled tube up against the tabs to create the right shape. Fiddling endlessly, we finally decided we had it close enough, and stopped for the night. Afterwards, looking at it, I felt pretty unhappy with the fit, and decided next time to create a new spacer tab, and grind off the old ones and do it properly. I will feel much happier during those tailslides…!

Time expended: 4.2 hours. Total time: 459.2 hours.

Threaded Stabilizer Bushings

I am waiting for new landing gear clamp plates to arrive from the laser cutters. The radius plates from Grove are 1 1/2″ in width, and my previous clamp plates were 1″, so I need new ones cut, Until then, I can’t install and test the gear with the new wheels, but that’s just as well since it is a lot of work. My revised forward wing attachments, however, have arrived, which is good. Instead of .080, I’ve opted for .100, and removed the lasercut bolt hole since I’ll need to leave room for adjustment when the wing is fitted.

Of the things left, the stabilizer brace tubes are the main things  other than the forward wing attachments. I purchased a higher quality tap 1/4″ UNF 28 thread, so I decided to tackle them. What a difference proper tapping fluid makes. It went a lot easier than I thought. I cut and trimmed both bushings, and trimmed the stabilizer brace tubes back as well, but stopped short of trimmed to actual size, since I have no idea of the length of the AN161-32RS fork. I’ll get those next week, and do a final measure up before welding the bushings into the brace tubes, since the thread on the fork is not very long, so I’ll need to get it pretty accurate. As per the bulletin notes, the brace tube is not supposed to pull or push the leading edge of the elevator, rather just support it.

 

Lastly, while I was removing the bearings from the control stick for powdercoating, I managed to damage one of the KP4 bearings, and it was turning a bit rough. I ordered a replacement, and opened it up to check it out inside (see pic above). Not every day you look inside a Fafnir bearing, so what the hey

Time expended: 3 hours. Total time: 455 hours.

Powdercoating Torque Tube, Control rods, Pedals

Had a bit of fun getting the control parts powdercoated over the past few days. I decided to try a certain method and see how it came out before doing any of the bigger parts. After a lot of research I had decided on the following strategy:

1) Sandblast parts. The local blaster uses some fine crystals (don’t recall what offhand),  but he reckoned a 2-3 micron effect. I was not expecting the bright gray colour it would come out in – was expecting shiny silver, but it was dull gray and sightly rough to the touch.

2) 2 coat/layer powdercoat process using Orica’s PacficGold product range (New Zealand based):

   a) Undercoat of PacificGold Zincshield

(see http://www.oricapowdercoatings.com/tds_files/990%20Zincshield.pdf for a technical specification). This is a pretty tough zinc based epoxy based thermosetting powder.

   b) Topcoat of PacificGold Armourspray EP

(see http://www.oricapowdercoatings.com/tds_files/910%20Armorspray%20EP.pdf for a technical specification). This is tough as nails thermosetting powder used for anti-graffiti application on things like bus shelters, telephone boxes, foodcourt benches, etc. and is the only powder I could find that was completely MEK resistant – important for fabric covering.

Spent ages watching the process and the big ovens, and thoroughly had a good time annoying all the staff who probably hate people wondering around their floor, but anyway, these parts are like my babies..  It all came out pretty good in the end. And I was pretty chuffed with the gloss finish and the tough feel to them now. Amazing what a single colour does to cover a really ugly set of dirty greasy tubes.

I’m too scared to try scratch them, so next time I’ll take through a spare tube or two so I can bash them around afterwards and see how good they are, The guy literally beat a sample piece with a claw hammer 30-40 times to try an get the surface to crack, and he couldn’t, so I was well impressed. A friend made a good observation, that I would be unlikely to lean over and beat the side of my torque tube with a claw hammer 30-40 times, but hey, it’s nice to know the stuff is tough.

Also bought a inch-pound torque wrench (only had a foot-pound one) and a better tap 1/4″ NC 28 for threading bushings for the stabilizer support tubes.

Time expended: 2 hours. Total time: 452 hours.

Linking Torque Tube to Elevators

Bit of a milestone tonight. I connected up all the push pull rods up to the elevators. Didn’t have all the bolts I needed, so robbed boxes and other parts, but got it all hooked up.

I had to grind away the spacers on the horizontal stabilizer to get the elevators on, and now they no longer touch the elevator – they must have deformed from welding, so I will heat them and tap them back to create the right distance between them of 1/4″. Didn’t matter for tonight, so I just wanted to see if I could get the stick to work the elevators… and..

Awesome. It works.

With the elevator stop bolts in place, I eyeballed a 25 up/down degree deflection off the elevators, and then saw that the shear binding problem on the rear idler doesn’t occur any more. I’m assuming this is all normal then, but I will still check it out.

Time expended: 1 hour. Total time: 450 hours.

Torque Tube Fitting

Tonight was all about tweaking and adjusting. First off, Dean and I heated and flattened the insides of the fairings against the longerons with a mallet. Looks better this way. Also then installed the torque tube to see how it fitted now that the base has been straightened.

This took ages. The torque tube itself takes quite a bit of time to install in the blocks. First was the need to straighten and adjust the bushings that hold the blocks in place. After welding the bushings they had moved slightly at the top so that the bolts were real tight inside the torque blocks – shear force. We heated and carefully tapped the bushings, not expecting much of a difference, but it worked well. Then after installing the torque tube again, found that the rear bushings/washers somehow were aligned in the horizontal slightly off, and so the blocks clamped the forward part of the torque tube more than the rear. We again heated and tapped the bushings, this time not to space them, but to align them in the perfect vertical by tapping themto the rear. After endless adjustment, the bolts then seemed to slide inside more easily.

We then drilled down through the bushings with the blocks installed to clear open the hole for the bolts. Didn’t have a reamer of the right size, but a drill bit seemed to do the job just fine. After this the bolts fitted fairly easily inside the blocks and bushings.

After tightening up the bolts, the torque tube now still slides around easily, so I am now pretty comfortable that the torque tube is aligned and will not wear against the blocks.

At the end of the night, I noticed that the when the control stick reaches the bottom right most position (without the stops) the idler lug that holds the two push/pull rods up seems to be bind, almost as if the idler lug is not in alignment correctly. Checking it again and again, it seems to be fine. I even heated and malletted the idler left and right a bit to see if it would improve things. It didn’t, and all that happened was that the push/pull rods now rub up against the fuselage diagonal. I reheated and straightened it again, but continue to have a twisting resistence at the stops – almost as if the bearings don’t turn enough in – although they do. Something not quite right, and I’ll have to check this later.

For now at least, the torque tube slides around beautifully inside the blocks, so one thing out of the way.

Time expended: 4 hours. Total time: 449 hours.

 

Front Fairings, Tailwheel Release Bushings, Misc Welding

Been a month since I did anything – house going on auction in a month and a new job have kept me completely out of the workshop, as expected.

Dean came over and we started welding the last bits and pieces. We first did the horizontal stabilizer support tubes – came out rather nicely. I’ll do the difficult end later when I have access to a better set of taps. And will take photos of both ends then. I then got him to weld on the ends of several push rods – now complete, so next step is to test the rudder control system from the stick!

Thereafter I drilled a hole through the tailpost for the tailwheel release cable. I installed a long guide tube through the tailpost which bends around the tubes at the back and guides the cable onto the right side of the fuselage. Then made up a bunch of little bushings to run along the right side of the fuslage much like the trim cable bushings on the left side. I chose right side, since there’s more space on the right side, and I’ll only be using it when my right hand can swap with left on throttle – so not concerned here.

Dean and I welded on the various odds and ends to make this work and line up. Took a bit of time gettig it lined up nicely, but came out fine in the end.

I added another set of 2 tabs as additional support to the heel trays, and then proceeded onto the hard job of installing the front fairings. Without the firewall complete (v3 now required) I had to guestimate a little where the fairing should go out to – but in reality there’s a fair bit of play here, so I can adjust the fairing by pulling out later. We also heated and welded the insides of the fairing and softly tapped them flat down onto the longeron so there is less gap on the inside – looks much better.

At this stage, we are very nearly complete, and I am getting excited to powdercoat some parts. I had a brief look at the to-do list and it now looks thus:

My to-do list is getting shorter every time. It now looks like this:

7) Weld on the side and lower stringer attachment tabs.

8) Weld on the front wing attachment brackets.

13) Tailwheel lock release bushings from front to back, and through the tailpost.

16) Elevator push/pull control tube (the shorter one needs a rod end welded on).

17) Stabilizer support tube – streamline tube, left and right sides. (HALF DONE)

18) Weld tabs on right side of seat to hold tailwheel release spring mechanism. (NEW)

19) Heat and straighten torque tube block bushings on fuselage. (NEW)

I’ve added 18) and 19). The last one is since I have realised my bolts through the torque tube blocks come out the other side slightly narrower than they should – which makes fitting the torque tube hard. Needs to heated and adjusted (if possible).

Time expended: 3.5 hours. Total time: 445 hours.

Stabilizer Support Brace Tubes

I’ve been trying to work out how to make the brace support tubes for the horizontal stabilizer. These are the detachable ones – optional. Some guys sent me some pics from theirs, but it was difficult to see, and the bulletin notes are very blurred as well, so I just decided to go ahead and work it out myself. I got the top ends done today – and it came out much easier than I thought!

First, I cut a line down each end of the streamline tube. Aviat mention their special “former”.. so I decided my former would be a vice!, and then simply bent it over and then trimmed the edges around to make it oval at the end. I’ll clamp them before welding and then put a hole through (possibly with a bushing – still to decide.).

In addition, my radius plates for the spring gear and the hydraulic fluid cannister arrived from Grove in good order. I’ll need to trim the radius plates and new steel plates made up to match the new size. The old steel plates are a lot smaller – as per the Steen plans.

Time expended: 1 hour. Total time: 441.5 hours.

Wheel, Brakes & Tires #3

I spent some time grinding away the brake calipers to provide some clearance between the calipers and the spring gear to allow the caliper to move easily on the troque pins. The easist was to use my dremel and go gently by hand. It went pretty quickly as the casting is pretty soft.

I ended up eating a way slightly off where I wanted to – grr – but it’s no biggie, and finally got it all done. The clearance is now very tight – about 1/32″ I think, but at least the caliper moves freely. I’ll eat away more later after I have painted the spring gear and can recheck the clearance.  

I got both sides done, and then installed the whole kit as per how I intend to install them finally. Firstly, I installed the torque pin bushing back plate onto Axle and put both onto the spring gear – forward/down position. Bolted them on.

Then I added the inside axle spacer onto axle.

Then I added the wheel and brake disc set onto the axle. You can see how they fit with the axle spacer:

Then I added the outside axle spacer onto the wheel in the same way the inner one went on, and then tightened the axle nut on after the spacer to complete the wheel installation.

After this I moved over to the other side and slid the brake caliper onto the torque pins, ensuring that the brake pads/linings were installed first, and then installed the back pressure plate and torqued the bolts to 80 inch/pounds.

I then did the other side and checked that the wheels moved easily. I noticed the one side clatters a lot more than the other when the gear is dropped onto the floor, so I’ll investigate that later. I finally hung the gear, with it’s wheels, up on the wall, and will attach them after the new radius plates arrive and are installed.

Time expended: 3 hours. Total time: 440.5 hours.

Wheel, Brakes & Tires #2

Axle nuts and spacers arrived from Griove. I was amazed that US Postal Services took literally 3-4 days to get to New Zealand. I thought it would take weeks! With this, I now have enough to actually install the wheels and brakes onto the spring gear which will be great so I can get the aircraft finally onto it’s three wheels for the first time. Also, the control stick grip arrived – yay – time to play

After a trial fitting, I discovered a real problem. First off, the calipers only fit onto the spring gear in the forward/down position. This is because the gundrilled hole is at the bottom, and that prevents the brake installed underneath. This is not a problem, since I don’t want to have a problem scraping them if I get a flat. The axle hole positions also make the rear position impossible. The problem now, is that … the forward position, it seems, has a clearance problem. The spring gear and the caliper on the lower front don;t have enough space together where the torque pin housing is i.e. they touch and rub. This means the caliper’s torque pins will be unable to move in/out the torque place bushings when in use -i.e. no brakes!

Yikes! This shouldn’t occur, so I am a bit baffled. I contacted Grove to find out what they reckon, and Robbie said that the clearance should be at least 1/16″, and if not, I should remove some material from the caliper casting. This I will do next time, but I am wondering why this has happened? It’s possible that the calipers have changed shape slightly over the years – they are from 1980, after all.

Time expended: 1 hours. Total time: 437.5 hours.