Back from a few days in Green Valley (near Tucson) with my folks. It was good to see the sun again.
I worked a bit more on trimming the baffles to the ramps and the side ramp seals that I made. It looks pretty good. Hopefully that is the end of the baffle trimming.
I thought I was done with the baffle trimming a few weeks back, but I forgot about the ramps. I did several iterations of installing the top cowl, marking the baffles, removing the baffles, trimming on the band saw, and re-installing the baffles. The ramp extensions I made are working perfectly. I’ll probably add a few more strips of fiberglass along the exposed forward edges just to beef them up a bit.
The cowl is now to the point where it sits in the correct position again. I still need to trim a bit more to get a 3/8-1/2″ gap. Just a few more work sessions and I think I’ll have the baffles mostly done. I don’t know if it’s the nice weather we’ve been having or the prospect of moving past the baffles, but I’ve been enjoying the project more lately. It was getting to be quite a grind for the past month or so. Unfortunately, I won’t be able to put in any time for the next few days. And then I’ll really be driving hard to finish it up.
I worked more on riveting the baffles together. It’s slow going due to all of the weird angles. It’s very cool to finally be putting these things together. I can’t wait to install them on the engine for the last time.
I worked some more on riveting the baffles together. The left aft section is really complicated with the oil cooler doubler and the little box I made to avoid the baffle jog. I’ve swapped the squeezer sets at least a dozen times already, and there’s still a few I’m just going to have to buck.
I also spent some time trying to figure out the attachment of the throttle quadrant to the panel. Bill has some good pictures of how he mounted his. Scott also posted a picture on the VAF forum of his mount.
Also in the news are the new EFIS systems from Advanced Flight Systems. They look like sweet systems. They claim that the EFIS interfaces to the VOR and GPS. If it can act as a CDI, that would be sweet. AFS/ACS has a great reputation with their AOA and EMS.
The ramps turned out great. I sanded off the excess epoxy. I can see that it made a great bond and it’s plenty strong. I’ll probably add a bit more filler and sand one more time.
Today was my first adventure with fabricating fiberglass. In order for the front baffle bulkheads to have something to seal against, I decided to seal off the inboard edge of the intake duct ramps. I followed this great tutorial on fiberglass. This is my work area after I was done.
I laid up two layers on each side that was shaped like a trapezoid, 5″ along the bottom, 5″ high, and 2″ wide at the top. It’s a little hard to see, because it’s mostly transparent. It turned out great! (Doh! My birkensocks got into the picture.)
I started out trying to use duct tape and saran wrap and mold over the top of that. It was a bit of a mess, so I quickly ditched all that, cleaned up the cowl, and just laid the fiberglass right onto it. Luckily I had already roughed up the surfaces of the cowl with some sandpaper. I followed the tutorial above to the letter, except I didn’t bother with the Dacron peel-ply. I’ll try that next time. I’m using bidi fiberglass, so it’s really pliable. I was able to fit it actually how I wanted it.
Fiberglassing isn’t too bad. Hopefully my buddy Steve doesn’t read that. He’s got a fiberglass sailboat and a nasty sensitivity to epoxy. I’ll be conscripted into helping on his plastic boat!
I spent a few hours out in the yard. The grass is growing again unfortunately. Around Seattle, the grass stays nice and green all winter without growing. It’s great. And then Spring hits and it’s a half foot tall in 2 weeks with tons of moss.
While the fiberglass set up, I worked on riveting together some of the baffles. It seems like there are 100 parts. I riveted on the right side stiffener, and most of the oil cooler doubler. I was lazily following the rivet call-outs on the plans for the doubler. Big mistake. The rivets along the bottom need to be 426 with the flush head forward. On the bright side, I got some extra practice at drilling out rivets. Thanks Vans.
Well, it’s all finished. First flight was today, and it went great. (I wish.)
Last night I took 4 kids from the Math Team to a competition. (I’m the Math Team coach this year.) They did pretty good. It went pretty late, so I didn’t have any time for the plane.
I mixed up some epoxy, added some flox, and permanently attached the ramps to the upper cowl.
I put a heat lamp on them for a little bit to help kick off the reaction.
I also cut the hole for the prop oil line a little larger in the right front floor. I have a rubber grommet that fits pretty well. While I had the floor out, I also added a diagonal bend. I never quite figured out how it was supposed to work, but now it’s obvious. I didn’t bend it too much so that everything I already drilled still fits.
I also drilled the little box I made for the baffle jog.
I was re-arranging stuff on the shelves to make room for the harnesses and noticed the cowl intake ramps. These things are attached to the underside of the top cowl in order to smooth the air flow. Since the baffles are trimmed to the ramps, I decided it would be a good idea to install them.
The first step was to do the final, final trim on the cowl inlets. I figured I might as well to the top and bottom and long as I was donning all the safety equipment. I trimmed the bottom inlets back from the baffles 3/8″ and used a sanding block to finish them up. I left as much material as possible along the top of the inlet and just drew a straight line in between. It turned out quite well.
Borrowing Walter’s idea, I marked on the cowl where the side and inner baffles line up. I then used that to align the ramps. I held it in place temporarily with duct tape and then drilled a few holes for clecos. The ramp will be held in place with epoxy. The clecos are just used to hold it until it dries. According to the instructions, the ramps will stiffen up the top cowl and essentially fix its shape. Thus, I installed the cowl on the plane to drill the holes. I just need to rough-up the surfaces and then it’s ready for epoxy.
It seems that I’ll need to extend the ramps inboard in order for the front baffles to have something to seal against. I’ll investigate the situation on some builder logs.
I worked more on bending and fitting the custom-made piece for the baffle jog. It fits pretty well. It ended up being kind of close to the oil cooler hole, but I want to make sure it’s at least an inch tall to provide enough material to attach the baffle seal.
I wasn’t quite ready to drill it, so I picked up something else. I was looking at the FAB and noticing how rough it was inside. I spent a few minutes sanding the inside smooth. That’s not exactly easy on such an ackward part.
Also today, I received the Princeton capactive fuel sender converters and Hooker harnesses. The harnesses look great. They’re a little heavier than I expected, but they look extremely well built. The colors were black for the belts and dark gray pads with black edging.
The Princeton units look straight-forward. Comparing them to the units Dan C described, they now leave off the cover from the BNC connector to make it easier to get them through the side of the fuselage. That’s an improvement. However, in retrospect I wish I would have just installed the float fuel senders in the tanks.
I’m finally back at building after our trip to Sun Valley. We had great weather and a great time skiing/snowboarding.
I’m still wiped out from the trip, but did a tiny bit of work after dinner. Using some scrap sheet, I did a first cut at the box that will fill the jog in the left rear baffle. I bent the box following my cardboard template, but it just didn’t fit well. It was too long and too wide. Instead of trying to unbend and rebend, I just made a new one from scratch. This time, I’ll be a bit more careful about how I bend it.
I’ve also been trying to make some final decisions on the avionics. Until I place the order, I guess I’m going to keep waffling. I’m pretty set on the Dynon EFIS/EMS. I looked again at the transponder. Using Stark’s prices including wiring and shipping, the GTX-327 is $1750 cheaper than the GTX-330. I’d love to have traffic display, but it’s only going to last another year or two because the FAA is too cheap to pay for it as the terminal radar sites are upgraded. I’d rather save that money and apply it to an ADS-B system, which is better and should continue to be supported in the future.
The next decision is between the GNS-430 GPS and GNS-480. The 480 has more flight management functions and is WAAS capable, allowing precision GPS approaches. The difference in price is $2400. I’ve downloaded both simulators. It’s really cool to be able to interact with the user interface for both units. Personally, I find the 430 much easier to use. It would be nice to have WAAS, but I doubt I would use it very often. I don’t plan on flying IFR approaches on a regular basis, and if I did I could always find a nearby airport equipped with a localizer/glideslope. Also, Garmin is supposedly working on a WAAS upgrade for the 430.
Next up is the SL-30 vs. SL-40. The only difference is that the -30 includes a VOR receiver. Actually, they’ve done the interface so well it’s like two VOR receivers. However, the 430 includes VOR, so the -30 would be redundant. Especially since the 430 can automatically tune the VOR receiver from the database. Plus, I expect I’ll use the GPS 99% of the time. The VOR is just a back-up. The difference in price is $1800.
All of those combined add up to $6000. That’s a big chunk of change. I might be giving up little things here and there, but for 99% of my VFR flying and even 90% of my IFR flying I don’t think I’ll notice the difference.
I deburred all of the parts that I drilled yesterday and cut out a hole in the back baffle for the oil cooler. I drilled the corners to get a nice radius, connected them carefully with the jig saw, and then filed with the Vixen and sandpaper.
A common customization that I’ve seen is to make a little box for the area above the oil cooler so that it’s easier to attach the baffle material. I’m also hoping that the box reinforces the area a bit. The back left baffle doesn’t attach to the cylinder like the back right does. I made a trial box out of some cardboard from a shoe box. I’m glad I did this as I would have screwed it up a few times trying to make it first out of aluminum. I want the box low enough that the baffle seal has plenty to grip, but high enough so that it doesn’t disturb the air flow into the cooler. It’s a little difficult to see, but here’s a picture anyway.
I also sent back some changes for the panel layout to Ross. I decided to ditch the vertical card compass, and to try to move switches around a bit to make a clear area under the EFIS for a portable GPS like the 396.
I also decided to go for the throttle quadrant. At one time I was going to install it, then decided against spending the time on it. Now that I’ve seen Dan’s install, I want it again. The standard knob set up is just not intuitive. I remember when I was first training actually moving the knob in the wrong direction. It seems weird to push it in to go faster. The levers on the quadrant make much more logical sense and look 1000% cooler. For “only” $180, it’s worth the mony and should only take an hour or two to install.