« Posts tagged landing gear


7 hours.

Put the pants on, one leg at a time.   I’m about to head back into my regular work schedule, which means days will become weeks.   So a task that will take a couple of days, will become a couple of weeks, because I’ll only get to it on weekends.  And the fun part coming up:  Wet fiberglass!  But this is what I got done today:

People’s exhibit A:  The right side wheel pant with the intersection fairings test-fit.



Left wheel pant.IMG_1966



Getting there.   Today was all about installing the mounting hardware for the fairings  Since we did the tweaky measuring stuff on Friday, today was all about just putting everything together.   Lots of platenuts to replace the clecoes from the position-locking drill ops.   But it is actually pretty cool how sturdy these things become once they’re put together and installed.   They’d better be.   They’re going to get the crap beat out of them.

Next is the wet work.   The intersection fairings will have to be taped on, then have a couple of layups of glass put on them to thicken them and make them conform to the exact shape of the fuse, gear leg fairings, and wheel pants.  I’m still working out the best way to do this, but I think it’s a two-day job.   One side per day.    Then the whole kerbang comes apart and I take the parts home and paint them.

Gear Leg Fairings Continued

6 hours.

I found my missing length of piano hinge (hidden inside a piece of PVC to keep it from getting damaged), and took it and my intersection fairings up to OXR to see what I could get done.   I got up there and spent a lot of time pondering the instructions and plans.  I spent a lot of time doing that because this is real work about to be done here, and it involves fiberglass, and the cutting of things that affect the flight characteristics of the airplane.

The first thing I did was put the wheel fairing attach brackets on.   This is a stupid process if ever there was one.  I had to wrangle the engine hoist from down at the EAA hangar, walk it halfway across the airport, then lift each side of the plane  by running a strap around the engine mount so I could get the wheel off   I’m not shelling out a couple hundred bucks for some weird attachment, this seems to work just find.  With the wheel off, I could attach the bracket.

The gear leg fairings, on the surface, are not that complex.  They’re teardrop-shaped covers for the round gear legs.  The only tricky part is that they have to be built with no twist in them.   There’s a full-scale section of a drawing that needs to be cut out and used as a template.   This lets you know where you can cut the fairings, and the fairings are the same ones used for all Van’s aircraft except the -8 and the -8A.   They are attached by means of a couple of hose clamps and secured by a piece of piano hinge running up the trailing edge.   So they have to be cut straight, then there’s the hinge installation, then the alignment to the fuselage.   I got one part of one leg cut, and had to move brake tubing out of the way and cut clearance divots where that wasn’t feasible.

Other time was taken up by moving the late Jim Ayers’s RV3 (with the Walter LOM engine) out of the EAA hangar and down to his private hangar waaaay at the other end of the airport.   Ron and I rigged up a way to lash the tailwheel to one of the forks of the old propane forklift and he towed it, driving backwards, really slowly.   I followed him in his VW.  After we got back from that, we went for a ride in the Pacer.

Starting on gear leg fairings and wheel pants

6 hours.

My pre-molded intersection fairings arrived from Van’s this week, but of course I forgot to take them up to the hangar.    The last major bit of fiberglassery is the landing gear stuff, so I tried to get started on that today.   There’s a .063 plate that bolts on to the brake caliper and its job is to hold the two halves of the wheel pants together, on each wheel.   I made them, cut all the spacers, and installed them, then took them off, anticipating that I could just put them  back on as needed. But it’s impossible to access the bolt head on the inside of the brake caliper without taking the wheel off.   I made two attempts to bend a 7/16 wrench 90 degrees at the open end, one resulting in a broken wrench, the other a wrench with too wide a bend to fit inside the rim and access the bolt.

So I figured taking the wheel off would be the best option.  I searched the hangar in vain for a floor jack.   Those guys don’t have one.   The engine hoist I used before is down in the EAA hangar, but it was all locked up and I couldn’t get to it.   So that was out.

I did get the plans and the manual out so I could begin working on cutting the leg fairings to fit.    That didn’t take long, so I went up to the aviation department of O’Reilly Auto parts and picked up another tube of red RTV.   I finished the front baffle bead and the left mag duct, and also isolated a couple of things from chafing via the RTV Blob method.


5 hours.

Today was about putting things back together and getting a handle on some of the chaos.   The first bit of good news is that the oil temperature probe works fine.  I pulled it out of the engine and hit it with a heat gun and sure enough, it gave me a reading.  So I’m not going to worry about that anymore.   I secured the wires back in their bundle and i’m calling that squawk done.

I also wasn’t real happy about the weird way I had the fuel pressure sensor set up.  The Adel clamp holding it was maybe a size bigger than it should have been, and this way seems more secure:


As I mentioned last time, I flipped the governor arm over and it seems to work just fine:


My biggest problem with doing it this way was where the injector line was going to go.   A piece of angle solved that.   Now it’s out of the way, and less likely to be heat-soaked down near the cylinder.  I still haven’t safety-wired the screws yet, or put the cotter pin in the cable attach nut, But I think this is how it’ll stay.

Last week, Owen recommended tightening up the tailwheel chains.   Van’s recommends a half an inch of slack, but if you ask ten different people how they like their tailwheel chains, and you’ll get at least five different answers. But my chains had an inch of slack, and if I took a link out, I’d have none.  But I did take a link out of each side, and while there isn’t really any dangling slack, I can move the chains up and down by about a half an inch, and I’ll tell you, based on today’s test, it taxis just fine:


That little gap in the rudder fairing is kind of annoying.   Not exactly sure what to do there, except put nutplates in there and hope for the best.

Today’s test was all about seeing how things went with the cowl on.  First, I wanted to make sure I could actually get the cowl on with the flipped-over governor bracket making the cable rise a bit more than it did before.   Turns out, I’ve got about 1/8″ of clearance between the cable and the top cowl, which is good enough.   And from what I remember, the cowl inflates a little in flight, so that 1/8″ becomes a little more.   And that’s fine.   I just don’t want to have to put a clearance wart in the cowl to accommodate the cable.


But before taking it out for another test, this adjustment had to be made to the baffle material on the lower cowl.  I had to cut it back a bit, because it was covering up about 6 square inches of air intake.   Bad.   So with this mod in place, I put the top cowl on, and pinned it down.   Then I put a few of the floor panels in, and you’d be surprised how much the plane stiffens up with the reinforcing action of the panels.   I ran it up, then shut down the left mag.  Engine died.   Started it again, repeated.   OK, right mag dead.   Grr.   Still runs fine on one though.

So I said screw it, let’s taxi it around.  The new tailwheel chain tension was much better.  Now it’s more like Mickey’s Citabria, and the ground handling is nice!  I took it to the end of the hangar row, turned right, went down the next row, turned right again, then went back to the barn.  CHT’s never got above 210.   As soon as I get this mag situation sorted out, it’s time for ground runs.

\Last time, shutting off the left Mag made a lot of popping and missing, which I attributed to timing.   This time, I’m pretty sure the timing’s right, but now shutting off the right mag shuts off the engine.  Now, it might have something to do with the fact that I left the pop-rivet I was using for a timing pin in the hole when I pulled the prop through, but I can’t say for sure.   What I do know is that before, on the right mag, I had backfiring.   Now I’ve got squat.


More odds and ends.

2 hours.

I’m waiting for parts from the Mothership, so it’s all about what I can find to do while I’m waiting. Mostly I sat out there puzzling out wiring runs. The floor panels are in already, so I might have a nice game of Go Fish to look forward to when it comes to running wires for 2 GPS antennae (yes, 2, in case I get hold of a GNS 430W), trim servo, strobe unit power, tail light, then strobe wires forward for the wingtip strobes. What I did actually get done was finally rivet the reinforcing angle that the tank brackets attach to just forward of the main spar. I can’t believe I forgot to do that during wing mating, but I think I probably had other things on my mind at that point. So that’s done, and there are little blobs of torque seal on the accompanying thru-bolts to tell me I don’t have to worry about it anymore. Oh.. remember this thing? F-697?

It’s the canopy jettison bracket. I put it on the subpanel because I was just following the directions. Then I realized I’m not going to install the canopy jettison system (weight, complexity, etc). Now I realize that thing might get in the way if I have to chop holes in the subpanel for some deep avionics, like a GNS 430W or some other surprisingly large piece of gear I think I need. So I took it out. You can never have too much practice drilling out rivets.

After that, I fiddled around with the fiberglass rudder tip, and worked on the mounting system for the tail position/strobe. This is genius. At some point, I bought a length of 1/4″ aluminum dowel from the hardware store. What I did was cut 2 half-inch lengths of it, which I’ll drill and tap to 4-40, the same thread as the tail light mounting screws. I’ll put some dimples in the sides of them, then sink them into blobs of flox in the rudder bottom. At that point, they’ll be permanently affixed and I’ll still be able to unscrew them to change bulbs. OH, thumbs down on the build quality of the rudder botttom. The two halves of the rudder bottom don’t exactly line up along the seam, so I’m going to have to clean it up with micro and sandpaper. If I was exceptionally skilled with sheet metal, I’d make my own out of aluminum, but I’m not, so I’ll deal.

Finally, I messed around with the tailwheel springs. I’m going to need to order new chain. I should have looked at the plans. I remember them going together completely differently, and it took me some time to figure out that getting the chain directly on to the spring is no big deal. But the puzzle fooled this monkey, and I missed ‘Castle’ for nothing.

I’m going to pester Tim again this week and see what the deal is with my cylinders.

Fun with the Firewall

5 hours.

I can walk around that plane all day long and find things to not do because one of the ducks isn’t in its assigned row. Problem is, the days are getting shorter and I can’t wait for everything to fall into place. The firewall has been one of those things. I still need to make holes for wire pass-throughs, and bolt various things to it, some unknown as to their specific configurations and form factors. But sometimes, you have to make a move. Today I fire-sealed the cabin heat box and installed the firewall recess.

This is halfway through the process. The cabin heat box is done, and the battery box is in place. , All the gaps and openings need to be sealed up in case there’s an engine fire. A gasoline-accelerated fire in the engine compartment fanned by a 200mph gale would make every hole, crack, and gap a 2000-degree blowtorch aimed right at the occupants’ legs, something we’d very much like to avoid. I’m using 3M Fire Barrier 2000 in all those cracks. Hi-temp RTV is rated for 700 degrees, this is rated for 2000.

Hopefully this won’t be an issue. You’re not supposed to use rigid tubing from anything fixed to the airframe to anything attached to the engine. The reason for this is obvious: the engine vibration will fatigue and split a hard line in a fairly short amount of time. This is why you’re supposed to use braided steel and flexible, firesleeved hoses for fuel lines between the firewall and the fuel pump.

Since I was fire-sealing everything, I figured why not, let’s put the engine mount on. After sealing the lower firewall corners and the brake reservoir, I got the engine mount on, permanently. I considered being a showoff and putting the plane up on the gear, but then I realized I’d omitted a rather important detail: I’d forgotten to notch out a section of the lower firewall corners to make room for the gear legs. Not one of my prouder moments. But I was able to scribe out a section to remove, which I did, and it would have been really easy if it hadn’t been for the fact that stainless steel sucks to work with. It bites, so you have to file the edges down. It also hardens if you heat it up, with something like a Dremel burr. Finally I was able to get some notches done, but they’re not that pretty. That’s what gear leg fairings are for though, right?

Here’s the firewall recess all riveted in. There’s a bead of fire seal under the flanges in addition to the seams in the recess. I hope that goop doesn’t run too much before it cures.

What happens next? I don’t know. I have the rudder available to work on, maybe I’ll do the taillight.

Landing gear put together.

2 hours.

That’s not saying it won’t come apart again. It’s currently in this state:

I think I’m not kosher on the amount of threads showing on the bolts holding the wheel pant bracket on one leg, but I can sort that out tomorrow. But I have this theory: If things are assembled with all the requisite parts, those individual parts are less likely to grow legs and wander under appliances and places of storage to hang out with the dust bunnies. It’s like the Phantom Graveyard of Lost Hardware under there, like that scene in Heavy Metal when the B-17 crash lands on the island full of derelict planes, abandoned spaceships, and zombies. But instead of zombies, I have an assortment of fasteners and other hardware.

The gear is ready to rock, but I need to get fire caulk so I can finish up the firewall installation stuff and put the engine mount on. Then I can put the plane on the gear, just for a hoot . Tailwheel’s on, why not give it a test roll?

The engine is still at Tim’s. He’s backlogged, and my engine is all torn down, waiting for inspection. I’m not in a hurry, but I am in a hurry to find out how things cost, because I need to know what my avionics package is going to look like. The way my luck runs with engines, I’ll probably have enough left over to equip 313TD at about the same level as Kern and Rinker Buck’s Piper Cub.


2 hours.

Since Dave grew up racing go karts back in SA, it was only common sense that I ask him for some help putting the wheels and tires together. Airplane wheels are a lot like the old-style kart wheels. We made a decent mess with the tire talc, but we got the tubes in and the wheel/brake rotor assemblies back together and torqued. I put some air in them, and left them outside all night, and will check them for leakage later, but I suspect they’ll be fine.

After Dave took off, I started in on the landing gear, just to figure out the brake caliper assembly. The plans are pretty sparse about the actual caliper, which comes as part of the kit from Parker containing wheels and brake calipers. So I’m still puzzling out how to bolt the calipers to the gear legs. I think I got it, but there’s really no drawing showing how to integrate the caliper, gear leg, and fairing bracket. I need to dig into the plans some more, this is kind of important.