The plans call for regular AN365 nyloc nuts here, but I've already decided to use only all-metal locknuts forward of the firewall, no exceptions. AC43.13 only forbids nylon nuts where temperatures exceed 250°F, but since I'm not in a position to measure peak temperatures in various locations forward of the firewall, I'd rather just outlaw nylocs entirely.

I set up Scott's hoist and attached it to the fuselage, using sections of clear vinyl hose material slipped over the engine mount tubes to keep them from getting crunched up by the chains.

"Not to be used for aircraft purposes" – hmm.

Having one end of the the fuselage suspended several feet in the air and the other end supported by a single little wheel induced a certain degree of nervousness.

I had to grind off some of the excess powder coating on the gearlegs to get them to go all the way into their sockets. I also ground a very slight chamfer at the top to keep the rod from getting hung up inside the socket.

Since Mary had other things to do, I had to call and beg Scott to come help me steady the fuselage while I persuaded the gearlegs into the engine mount. The first one went in relatively easily, but the second one was a real pain, especially the last half-inch or so.

I used a low pressure in the rivet gun and a brass-tipped rivet set to drive the bolts home. This worked very well and seems to have resulted in some nice tight-fitting bolts. I need to pick up some AN363-524 metal locknuts, but in the meantime these bolts aren't in danger of going anywhere.

With both gearlegs installed, I put the wheels on the axles so the plane would have something to sit on when lowered to the ground:

The fuselage is on the gear! Suddenly, the airplane is much taller.

Big milestone today. Also, big thanks to Scott for his assistance and the use of his hoist. Don't tell China that I used it to lift an airplane, or they might come take it away.

I've repacked many an aircraft wheel bearing in my time, but I've always done it the low-tech way – globbing in new grease by hand. This time I wanted to try out one of those fancy bearing packer tools. I picked up one of these at Sears, but its plastic housing broke almost immediately. Then I bought one like this, which worked better. It's pretty crudely constructed, but at least it's made of metal. It didn't eliminate the sticky-fingers problem, but using it was somewhat easier than packing bearings by hand. It probably does a more thorough job of getting grease into the bearing, too.

The old-timers' approach is to use Aeroshell #5 for wheel bearings, and #6 for everything else (pivot bushings, etc.). I'm too lazy to keep two different kinds of grease around, so I've always used Aeroshell #22 for everything. (specifications here) It costs a couple bucks more, but one tube is enough to do a half-dozen annuals.

Seven AN960-416 washers stacked up gives you the required 1/16" clearance between the bracket and the brake disc. By the way, my U-810's are actually aftermarket replacement jobbies, made from stainless steel. I'm not sure this is really necessary, but I've had them laying around for a couple years (impulse purchase, again) so I decided to use them. They're heavier than the stock aluminum brackets, but I guess they ought to be pretty much indestructible.

Here are both gearlegs with all the bracketry mounted:

I installed the elbow fittings in the brakes, although I haven't gotten around to mounting the brakes for good just yet. I gooped Bakerseal (teflon paste) on the threads before installing.

Then I dug the tires and tubes out of storage so I could assemble the wheels. The red dot is opposite the heavy side of the tire, so you line up the valve stem with the dot. One trick I learned somewhere is to put a couple psi of air into the tube after you get it into the tire, before you try to mount the tire on the wheel. When it's just slightly puffed up, it's much harder to accidentally pinch the tube between the wheel halves and ruin it.

One other thing I want to mention about tires… the tradition is to put talcum powder inside the tire, to keep the tube from sticking to the tire at high temperatures – this is supposed to make it easier to remove the tube later on. I'm not sure if I believe this is really a problem, but when changing tires on my airplanes I've always done it anyway. This time, I decided to go looking for unscented talcum powder so my wheels wouldn't smell like baby. I went to three or four different places looking for it, and here's the thing: What is up with hot babes obviously checking me out when I'm shopping in the baby aisle? This never, ever happens during a normal day, but I swear it happened at least twice while I was looking for airplane supplies between the diapers and those little jars of strained carrots. I mean, attention women of North America: Doesn't it seem logical that if a guy is standing next to the Pampers, he's probably less likely to ask you for your phone number?! Women.

Not to mention, in the end I could only find the baby-fresh kind so that's what I bought. Anyway, I torqued the bolts holding the wheels together to 90 inch-pounds, which is higher than normal but that's what it says on the sticker. I also had to enlarge the hole in the rubber grommet to get the valve stem through without resorting to pounding on it.

To drill the axles for the cotter pins that keep the nuts in place, I ignored the plans and followed the Tony Spicer method. Basically, it goes like this:

1. Install the wheel and tighten the nut to where you want it.
2. Use a 12" #30 drill bit to mark the location of the first hole with a small dimple.
3. Remove the nut and wheel.
4. Grind away the threads on the axle in an area about 1/8" in radius, centered on the dimple you made. I used a small hemispherical stone in my Dremel.
5. Replace the wheel and tighten the nut back to where it was.
6. Use the 12" #30 bit again to re-mark the dimple for drilling.
7. Remove the nut and wheel.
8. Use a sharp #30 bit to drill the first hole through the axle, using the dimple as your guide.
9. Replace the wheel and nut.
10. Put a drill bit through the hole you just made, to keep the nut from rotating.
11. Repeat steps 2-9 for the second hole.
12. Use the 12" #30 bit to clean out the two holes so a cotter pin will go all the way through.

You end up with nice-looking holes and you don't have to worry about splitting the threads and getting the nut jammed on the axle, which can happen if you use a center punch like the plans tell you.

I installed the wheels and nuts but didn't bend the cotter pins yet, since I'll need to remove the wheels again to pack the bearings.

Here's two gearlegs with wheels installed (but no brakes yet) ready to go on the airplane.

Scott was nice enough to loan me his engine hoist, which I will use to lift up the fuselage for fitting the gearlegs (not to mention for hoisting the engine). I just need to get a few things in order and then it will be gear-attaching time.

]]> http://www.rv7blog.com/2008/01/20/wheels-and-tires/feed/ 0 http://www.rv7blog.com/2008/01/13/gearlegs-misc/ http://www.rv7blog.com/2008/01/13/gearlegs-misc/#comments Mon, 14 Jan 2008 03:19:48 +0000 Matt http://www.rv7blog.com/2008/01/13/gearlegs-misc/ The first thing I did on the airplane this weekend was to finish riveting the tricky rivets that I hadn't been able to finish last time I worked on the subpanel/firewall area. While setting the bottom-most rivet on the starboard side, I screwed up the shop head bigtime and had to drill it out (which I didn't do a great job of either, sigh). I discovered that I also managed to crack the very edge of the dimple – from whacking it with the bucking bar, maybe – and decided to drill out the hole to get rid of the crack and use a bolt instead. So now I have this mystery bolt on my firewall:

I fished the gearlegs out of storage and got to work getting them ready to go on the airplane. These things are about the size of golf clubs, but are made out of solid steel and weigh something like ten pounds each.

Here are the Cleveland wheels and brakes. This stuff is all made of magnesium… light but expensive!

I swapped the pressure and bleed ports on one of the brakes so I'd have one left and one right.

These are the U-403 brake mounting flanges, bolted to the gearlegs. It took forever to get these on here, since I had to grind away all the excess powder coating and then polish the outside of the axles with emery cloth to get the flanges to slide into place. Then I needed to ream the pre-drilled but undersized bolt holes up to 1/4". I'm glad the holes in the gearlegs were already there, or else I'd be taking these things to a machine shop… I looked up the properties of 6150 steel, and it doesn't sound like drilling through an inch of the stuff with hand tools would be a lot of fun.

I swear that two hours elapsed between the last photo and this next one. See, the plans for the wheel/brake installation aren't exactly clear. It took me a couple hours of fiddling, head-scratching, and web-searching to realize that if you follow the instructions as they're written and bolt the U-403 flange to the gearleg first, it's impossible to get the brake mounting plate installed because the bolt is in the way. Of course, it wasn't obvious to me which way around things were supposed to go, so I wasted a lot of time trying to get things to fit the wrong way. An exploded view would have saved me a lot of time here, but oh well.

I can't believe that's all I got done on the airplane all weekend. Blah.

Oh yeah, somebody told me I need to take more big-picture pictures so the casual reader might be able to have half a clue what I'm rambling about, so here you go, a photo of the fuselage… soon to be converted from a metal canoe to a real live honest to goodness airplane fuselage on wheels. I hope.

]]> http://www.rv7blog.com/2008/01/13/gearlegs-misc/feed/ 0 http://www.rv7blog.com/2008/01/12/upgraded-tailwheel/ http://www.rv7blog.com/2008/01/12/upgraded-tailwheel/#comments Sun, 13 Jan 2008 02:00:41 +0000 Matt http://www.rv7blog.com/2008/01/12/upgraded-tailwheel/ I finally received the Doug Bell tailwheel fork that I ordered a couple years(!) ago. I was one of the first RV builders to place an order for one of these upgraded forks, but since the one-man production shop's output is limited, I kept giving up my delivery slot to people who were closer to flying than I was. But now that I actually need to get the airplane up on its wheels for good, I told him to go ahead and ship it to me.

Much has been said about the Bell tailwheel before, so I won't repeat it. Suffice to say that it is well made, easy to install, and way ahead of the stock Van's tailwheel when it comes to ground clearance. Not to mention that Doug has a payment policy of "I'll ship it to you so you can try it out, and you can either send it back or send me a check." You don't see that very often.

I also received my tires from Desser Tire today. These are Michelin Aviators with Airstop tubes – much higher quality than the tires Van's supplies (which I deleted from the finish kit). I used these on my last RV and they lasted forever and hardly ever needed airing up, which is a lot more than I can say about the cheapo Van's-supplied tires and tubes that airplane previously had. I figure it's worth it to spend the extra money here.

And for some reason, my cat loves them:

]]> http://www.rv7blog.com/2007/01/06/nuts-and-tires/feed/ 0 http://www.rv7blog.com/2006/08/12/finished-empennage-attach/ http://www.rv7blog.com/2006/08/12/finished-empennage-attach/#comments Sun, 13 Aug 2006 03:49:10 +0000 Matt http://n709mb.com/?p=173 Today I took the empennage stuff completely apart yet again, deburred and cleaned everything, and primed the various parts that needed it:

I also vacuumed out the tailcone and smoothed and spot-primed a few places where there were scratches and tool marks.

Once the primer was dry (it doesn't take long in Kansas in the summer) I riveted the up elevator stop to the top deck:

I also riveted the forward attach plate and shim to the vertical stabilizer spar:

Scott came by to check out the project and I put him to work bolting the tail back on yet again.

Since all the bolts are in now, I attached the tailwheel. Once I'm done with rigging the control surfaces, I'll take the tail off and put it back in storage, but I should be able to use some shorter bolts and a temporary doubler of some sort to keep the tailwheel fastened to the aft bulkhead.

I installed the F-790 aft elevator pushrod and rigged it so when the elevators are clamped in trail with the horizontal stabilizer, the elevator bellcrank is exactly vertical. This happens when a 3/8" socket placed over the lower bolt head is perfectly centered in the access hole, like so:

Just for grins I also installed the F-789 forward elevator pushrod to see how it would fit. Something seems to be wrong, though… In this photo the elevators, bellcrank, and control sticks are all in their neutral positions, and even with the rod ends backed out as far as I dare, the forward pushrod is way too short. I promise I made it the exact length called out in the plans, so I'm not sure what the story is. It may turn out that I have to re-make that pushrod, which is no big deal since the end fittings are not terribly expensive and the tube stock is available locally – no expensive shipping of long pieces, hooray.

I also spent some time cleaning up the garage, which was a mess. It's still a mess but at least most of the tools are put away now.

After repairing the "damage" and then thinking about it some more, I decided to remove the tailwheel and let the aft end of the fuselage rest on some 2" styrofoam insulation instead. Although I got the go-ahead from Van's before I put weight on the tailwheel in the first place, it's obvious now that it was never meant to hold up the airplane with only two of the five the bolts in place. The fuselage can go back on all three wheels once I get the vertical stabilizer fitted, but for now it will sit on the foam.

I temporarily bolted on the tailwheel, so that I can use it to make moving the fuselage around the shop easier.

I also knocked together these little legs for the fuselage, and attached them to the wooden spacers that are bolted to the center spar carrythrough:

At approximately 10AM on February 25th, RV-7 #72324 made its first landing! It now sits nice and low so I can just lean into the fuselage to work on stuff. I think those stubby little legs make it look kind of like a KR-2.

]]> http://www.rv7blog.com/2006/02/25/wheels-down/feed/ 0 http://www.rv7blog.com/2006/02/12/tailwheel-mount-continued/ http://www.rv7blog.com/2006/02/12/tailwheel-mount-continued/#comments Mon, 13 Feb 2006 00:59:24 +0000 Matt http://n709mb.com/?p=106 Here's the tailwheel mount back in the plane, after being cleaned, primed, and painted with some grey enamel to keep it from rusting. The aft bulkhead is also back in the plane, after lots of fitting, twisting, pounding, and bad language. I actually had to grind off about 1/16" from the top of it to get it to go back in – this is one area where the slow builders have an easier time, since they can just un-cleco the skins and put the aft bulkhead in and out all day long. I used some random 1/4" bolts to keep the mount in alignment with the forward bulkhead while drilling the holes for the two "keeper rivets" that keep (naturally) the tailwheel mount aligned with the aft bulkhead until the vertical stabilizer is bolted in place to hold all this stuff together.

Here's the same shot, but now it's mostly riveted together. In this and in the above photo you can also see the 0.040" shim I decided to add between the aft face of the mount and the aft bulkhead to take up some of the gap there. The plans say to add a shim between the mount and the forward bulkhead if necessary, but my problem here is that the lower part of the mount is fine, it's just the upper part of the aft face that doesn't perfectly match with the aft bulkhead. I think the aft part is actually welded a little crooked. Anyway, I jammed a piece of alclad down in there, and hopefully the bolts that will go through here later on will pull everything into alignment.

This little tab didn't lay down against the longeron like it should have, so I put a little shim in between and used a longer rivet:

The skin doesn't lay down over the bulkhead in a perfectly flat manner – it sort of tucks in a tiny bit and then bows back out, probably because the bulkhead flanges aren't 100% square with the skin. I guess I could have taken the bulkhead out, tweaked the flanges, and put it back in over and over until it was perfect, but I figured I'd risk bending something else in the process and decided not to mess with it. Anyway, this caused me to put a couple of light smiles in the skin when driving a few of the rivets, but once it's painted nobody will notice. Note that in the photo below I'm holding the light at an angle that exaggerates the dings and fingerprints – in real life you have to look closely to see this.

The tailwheel mount and aft bulkhead are completely installed, with the exception of four holes on each side where I plan to use Cherry Max structural blind rivets (there are five clecoes per side in the photo but one is for the rudder stop and will be riveted later). Three will go on each side below the tailwheel mount where you can't get a bucking bar to fit, and one will go through each of the little tabs on the forward face of the bulkhead where I can't get them to lay down on the longeron without a clamp, and I can't fit both the clamp and the rivet squeezer or bucking bar in at the same time.

I thought this was a neat view… I think it sort of looks like some kind of spiny deep-sea creature, what do you think?

]]> http://www.rv7blog.com/2006/02/12/tailwheel-mount-continued/feed/ 0 http://www.rv7blog.com/2006/02/11/working-on-tailwheel-mount/ http://www.rv7blog.com/2006/02/11/working-on-tailwheel-mount/#comments Sun, 12 Feb 2006 04:32:13 +0000 Matt http://n709mb.com/?p=105 This weekend's project is the tailwheel. There's a steel mount that bolts between the two aftmost bulkheads, and you have to cut an odd-shaped slot in the aft bottom skin to let it poke through. First I removed the aft bulkhead, which in the quickbuild kits is only held in with a few temporary pop rivets – it was still a pain to remove it, though, because of the way the aft fuselage tapers. I xeroxed the full-scale template from the plans, then aligned it on the inside of the skin by shining a light through the bulkhead rivet holes and lining the marks up. It worked out pretty well.

I marked the cutout and started the front end with a unibit:

Like with the landing lights, I rough cut with snips and then used drum sanders and files to enlarge the hole. I probably filed away at it for an hour before the mount fit through. I'll clean up the edges and make it look pretty tomorrow. The hole just aft of the bulkhead there is for a socket to go through later on when I'm installing or servicing the tail spring. It gets pretty close to the center rivet, but it's per plans.

Here's how the mount fits in:

Two 1/4" bolts secure it to the forward bulkhead. These were tricky holes to drill because the tailwheel mount is made of some kind of extra hard steel, and the shape of the mount makes it tough to get a drill in there – not to mention the fact that you have to locate the pilot holes by back drilling from the other side. You have to hold it square with one hand, hold the angle drill with your second and third hands, and hold the shop light with your fourth hand. These bolt holes came out fine though, and the tailwheel mount is straight.

The "mouse hole" at the bottom of the aft bulkhead is enlarged to fit the mount:

Reinstalling the aft bulkhead tomorrow is going to be a pain – it was hard enough to remove. Stay tuned.