« Archives in September, 2008

WD-409 and F-712

3 hours.
Going through the construction manual and looking over all the steps sometimes reveals things that weren’t done by the quickbuilders, which is why it’s a really good idea to check their work as if it was your own. For one thing, I ran into the fun and exciting process of setting up the tailwheel spring mount, WD-409. This device comes partially assembled in the QB kit. The mount and spring are match drilled and the tailwheel fork is matchdrilled to the spring. What’s not done for you is installing the mount between the F-711 and F-712 bulkheads, a process which was definitely not easy, for such a simple task. First I had to heat up the mount to get the spring loose. I gave it a few licks with the propane torch and finally managed to twist the spring out of the mount. AFter the mount cooled down i was ready to try fitting it in the fuselage. Well, guess what. You have to drill out a bunch of temp rivets and take the F-712 out so you can drill the holes for the two keeper rivets that hold the mount in place while you drill the holes for the verticle stab bolts. And then, friends and neighbors, you have to get the thing back in. This is not easy. And there is a trick to it. For one thing, if you rivet the mount to the F-712 bulkhead first, you’re hosed. You won’t be able to get the bulkhead into the magic position that lets you get all the tabs inside the skins. Even then, it’s a really tight, nasty fit. Cutting the “mouse hole” where the tube sticks out of the lower aft skin makes it even worse. I wound up drilling off the rivets on the side between the F-711 and F-712 bulkheads, which helped a little, but it was still a royal pain. Methinks nobody brought this up when the qb kits went into production, and even if they did, it’s not like there’s much you can do about it. The WD-409 has to distribute its load between two bulkheads, because just one wouldn’t stand up to the stress of 3-point landings and taxi-ing down force for all that long. Of course, me being the dumbass that I am, misread the plans for the keeper rivets and wound up using 1/8 rivets instead of 3/32. No big deal, I’m sure, but those keeper rivets are going to stay kept.

Here’s the F-712 bulkhead clecoed back into place after my tender attentions with the drill.

This is the WD-409 mount after a coat of paint. The hole in the top is where the bolt goes through to hold the spring. It’s extremely important to get this vertical, because side forces on the tailwheel fork suck.

Here’s a shot down through the top deck. You can see the mouse hole down there in the lower skin, which is cut to clear the mount tube as it angles down and outward.

This is the section of the drawing that shows how it all goes together. One of the notes off to the side is “Some parts removed for clarity.” I wonder why.

Drilled aft top skin

1 hour.
Aft top skin is now drilled. Tomorrow, i’ll take it off and deburr everything, as well as check out the F-788 clip that seems to be a little too close to one of the holes for comfort, in such a way that I won’t be able to have a properly expanded shop head in that area when I put the skin on if I don’t do something about it. It’s going to be easier to puzzle that out when the skin’s not clecoed on, so I’ll tackle that after the deburring process.

Seats are done.

4 hours.
Got the right seat finished, everything seems fine, so I started in on the aft top skin, the forward one. This thing is a bit difficult to work with, especially when you forget to drill out all the temp rivets the QB kit has for you. I spent some quality time with the soldering iron and removed the blue plastic along the lines of holes, then clecoed it on to the fuse. It looks like this will be the second part of this project where I will need some help riveting. I can’t reach deep enough in there to buck all the rivets, and since I forgot to deburr the edges before I started messing with it, even evaluating the process is risky. But I’m not about to take all those damned clecoes out. I’ll drill it, then unhook it and deburr everything right before I dimple it.
I still have a couple of details to finish on the flap actuator, like drilling out a slot for the servo bolt on one of the covers, and drilling the actuator arm to final size for bolting to the rod-end bearing on the end of the servo arm, but I was just so geeked to see everything bolted into place, I didn’t feel like unbolting everything again to finish up.. Maybe I’ll do that tomorrow morning.

Finished Left Seat

3 hours.
Finished, as in, flyable but not pretty. All this interior stuff is going to get a coat of paint anyway. Deburred, primed and riveted the parts for the left seat, which have been sitting around clecoed together for a couple of months. Also finished up the flap actuator stuff, except the bolt connecting it to the servo. Baggage floors are riveted in, and yeah, i’ve just cut off access down there, but to be honest, I really don’t think it’s worth the effor to put them on with nutplates or make access doors. Maybe I’ll feel differently when it comes time to mount the strobe pack and ELT, who knows.

Seat in place.

Seat back adjust assembly. seems a little hacky, design-wise, but it works great.

Seat back retaining assembly.

Flap actuator and riveted baggage floors.
Pictures are a little blurry.. I’m using my iPhone as a camera, and when the light gets low, the pics get bad.

Some new stuff

4 hours.
Well, i went and did it.. I got an engine.. A Lycoming O-360-F1A6 with 951 hours on it. After getting it home, I realized some work will have to be done to make it viable, if I may understate the case a bit. Right now, it’s sitting on an engine stand with about 7 gallons of oil in it, bathing the internals so it doesn’t turn into a hunk of rust. It’s a little frightening, since it’s really big, and really heavy, and I don’t know any A&P’s. The guy I was going to call is… unavailable. It will need a forward-facing sump so I can throw on an AFP FI system and I’ll need to get a governor that matches my prop. I hope this doesn’t turn out to be a nasty, expensive mess. Until now I had no idea how many places one of those damned things could leak from, and part of it’s my fault. I just HAD to pull off a rocker cover and get a peek at the valves, which, as advertised, were wet with oil.
So I whacked together an engine stand based on Mike Snook’s design. It was a logistical nightmare, renting the hoist, taking delivery, and actually mounting the thing on the stand. Until you’ve done it, you have no idea how awkward an ungainly a 200+ pound block of inert metal can be, especially when it must be treated with extreme care and be manipulated a certain way. What I would have given for a Caterpillar PWL. Then there was the whole oil issue. 7 gallons of oil tries to squeeze out every hole and crack. It runs out the hollow crank in front, it runs out of the magneto gaskets, it runs out of the rocker cover I took off, it runs out of the cooler fittings. I really didn’t think about all that when I flipped it over on the rotisserie and started funneling the Texas Tea into the inverted sump. So I had to find and plug every leak. As it is, I’ve still got a funnel under the rocker and a rag under the centerline of the engine on the T-bar of the stand. It’s scary. I took the ring gear off and sealed up the front with a 2″ jim cap from the aviation department at B&B hardware, but it’s not as nice as one of those little red caps on the TMX-360 on the Mattituck site. I searched high and low for one of those to no avail.
Meanwhile, here are some pics of the engine in the days of and after its arrival:

First day I was able to mess with it. Got the thing hoisted up in preparation for mounting on the stand. Simba is very curious about this heavy thing emanating all the strange odors in his backyard. Here it still has all the Cessna 172RG baffles on it, which will be removed later.

Right now, Simba’s had enough of this thing but he trusts it well enough to turn his back on it.

On the stand. I know it looks like it’s sagging, but it’s not.

From the front.