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Snorkel Again, and Exhaust.

April 8, 2012 / posted in Firewall Forward / No Comments

5 hours.

Today I did some more work on the snorkel, this time trying to shape the throttle body side to allow for smoother airflow, fill in some voids in the opening, and generally beef the thing up where the interface is.


This is looking into the relief hole I made for the alternator. You can see that the demoisturizer container serves as a perfect plug in place of the throttle body and the tape wrapped around it is exactly where the lip on the TB would be. The dark bit on the right inside the hole there is a void that didn’t get filled on the last glassing pass. I roughed up everything, cleaned it out, and went to town.


This is looking in from the top, where the air filter will go. It looks pretty anatomical, I know. The thing I have to fix now is where the opening bulges up, which will create a turbulent airflow.


Weapons of the trade. That’s the Builder Shield plastic on the left, and West System 206/105 epoxy resin on the right with the pumps sticking out. Living 3 miles from Marina Del Rey, I’m fortunate to have a West Marine store where I can buy this stuff. I wanted to get the 206 hardener, because I needed more pot life from the epoxy. I can wait the 10-15 hours for it to cure.

The photos stop for a bit, because of the whole resin/iPhone thing again. The next step was mixing up a bunch of micro to fill in some voids and take a crack at shaping a more gradual transition inside the snorkel where that burble was going to be. The first thing to figure out was how to fill in the voids around the actual opening itself. What I wound up doing was fairly genius (assuming it comes apart properly tomorrow). I wet down a strip of glass cloth, put it on the inside of the opening ring, then jammed the plug through it. It should form a perfect shape around the plug, and I can easily cut/sand off the excess on either side.


Here, it’s about done. There’s micro in there, and a couple of layups of glass around the burble and the rest of the edges go hold everything down. I also put a couple more layups on the outside to thicken up the interface ring.

With that curing, I went hunter-killer on some of the smaller items that I’ve been blowing off. First thing was reclocking the prop governor cable bracket.


This bracket also goes on the IO-540 in the RV-10, but the -7’s cowl doesn’t have enough clearance to let that happen. I’ve seen one or two examples of putting a bump in the cowl to allow the bracket to clear, but since I want to do as little fiberglass as possible, I decided to reclock the bracket. That just involves drilling two offset holes. The bracket will stay on just fine with two screws. I didn’t need to do much, that’s maybe a quarter-inch of distance between those hole, but I managed to bring the end of the arm down enough to where there won’t be any interference issues with either the cowl or the #2 injector line.

Since it’s time to think about things like control cable and wire routing, I decided I should probably put the exhaust system back on. The more things that are actually on the airplane, the fewer guesses I’ll have to take when deciding where to run things. Forward of the firewall, the name of the game is keeping things from picking up too much heat, and the primary source of that is the exhaust. The recommended distance between the exhaust and anything else is half an inch. Anything comes closer than that, and it needs to be shielded.


What you see here is the 4-pipe Vetterman exhaust I had to purchase to replace the crossover 4-into-2 type I had before. With the Crossover exhaust, there’s absolutely no way to get control cables to the throttle body without a horribly complex series of bellcranks and other things I really don’t want to mess with. The 4-pipe setup has a nice wide space up the middle where I can route the mixture and throttle cables without getting them too close to the pipes.


Since the right aft baffle is already on the engine, and finished enough to matter, I thought it might be a good idea to get the two-pipe cabin heat muff set up, along with the suspension by which the aft sections of the pipes hang. I’ll admit, I can’t find the instructions or drawings right now, but it really only makes sense to put it together one way. This is all about making sure I have all the parts, which I do, except one of the nuts is defective. There are no threads in it. I don’t even know what that type of fastener is called, to be honest, so I’m going to tap it for whatever threads the connecting rods between the brackets are. Like the crossover version, the pipes hang from stainless steel tubes connected by sections of rubber oil hose, so that’s no mystery. But with this and the baffle in place, I’ll be able to hook up the cabin heat system.

Snorkel 1.

April 3, 2012 / posted in Firewall Forward / No Comments

7 hours.

Saturday and Sunday. The snorkel fit fine with no modifications. April Fool’s! Seriously, this thing is the biggest POS in the whole inventory. There’s no way it will fit without mods, ever. It doesn’t even fit well with the engine Van’s sells. It is a black hole of suck, no two ways about it. Firstly, I hate fiberglass. Second, I have the AFP fuel injection system. Third, this thing has to line up in at least three places before it can be said to ‘fit.’ Let’s have a look.


What you see here is an attempt to make a plug in the shape of the throttle body intake. To do this, I make a ring out of .032 aluminum, then riveted it to another ring just inside that one, with the shop heads sticking out. This slipped over the throttle body intake and the idea was that I’d tape it off, fill it with spray foam, and have a perfect foam plug from which to form all my fiberglass and use as a sanding block later. No such luck. The foam can I used had probably been sitting on the shelf for about 6 years or so, and never quite cured. Mess. And before you ask, yes, I taped up the throttle body so no goo would get down inside. Back to square 1.

I don’t have a lot of pics of the snorkel in its totally hacked up form, because I didn’t want to get fiberglass dust all over my phone. Basically, I had cut away pretty much everything near the flange of the snorkel, leaving a hole big enough to get the throttle body into. A lot of people cut the snorkel in half and re-glass it back together after fitting each half, but I didn’t want to do that, for some reason. Since I was committed to glassing a whole new flange on it, I didn’t see the need to cut it in half. So that led to the next process:


When fitting this thing, not only does it have to line up on the throttle body intake, the filter end has to line up on the left front inlet ramp, and it has to do it while clearing the #2 oil line, the governor baffle, and the front side baffle. Plus there needs to be enough meat around the edge of the air filter hole to attach the supports and meet any riveting edge distance requirements involved. The only way to get it into position is to take off the inlet ramp and try to fit it that way. surprisingly enough, this does work. I wound up suspending the snorkel in a cat’s cradle of PVC pipe tape (all hail pvc pipe tape, that sh*t rocks!) in the position it would eventually be in once everything is glassed and cut.

I also found my new best friend for fiberglass work: Contractor’s carpet guard. This stuff comes on a roll like Saran Wrap, and it’s the stuff contractors lay down on your carpet before they start trudging in with muddy boots and taking out old sewer pipes. It has a mildly adhesive backing, and it clings to itself and smooth surfaces like crazy. Think of the blue stuff that comes with Van’s kit parts, but clear. It leaves no residue behind either, although they do recommend you don’t leave it on for more than 30 days. Anyway, this stuff became the new throttle body condom, as well as a wrapper for anything else I didn’t want to get stray resin on. I took the alternator off, because it was seriously in the way, but I just wrapped a bit of this stuff around the starter and the alternator bracket. Oh and all over the throttle body. Like so:


Here’s a mostly side-on shot of the opening in the snorkel next to the throttle body. As you can see, it’s not even close. But with the TB protected, I can slap glass on this thing until the cows come home.


From the back.

Now the photos stop, because I’m not about to get resin all over my phone. I used two layups of the same stuff I had when I did the canopy. I’ve got a crap-ton of it left, wo a few pieces got me through. I was able to make a decent connection between the TB and the snorkel, the end result of which is this:


A perfectly-shaped snorkel-to-throttle-body interface. OK, not perfectly shaped, but close enough to keep going. This is after 8 hours of cure. There are some voids where the plastic wrinkled around the throttle body opening, but that’ll get fixed in the next couple of days or so. I did find a perfect facsimile for the throttle body opening though. At the hardware store, they sell this demoisturizing stuff. It’s basically little balls of salt, but what’s of interest to me is the container. The container is smooth plastic, and it’s exactly 3.25″ in diameter, same as the throttle body. Half an inch up from the bottom, I wrapped about 1/8″ thickness worth of pipe tape around it to simulate the lip of the TB, and I was able to use that as a plug for the next 3 layups of reinforcement of the opening.

The inside is a different story. I’m going to be in there with micro, shaping a smooth guide for the airflow around the parts that indent too far into the snorkel chamber and will cause turbulence rounding the corner into the throttle body. That’s when I squidge some micro between the plug and the interface there to fill the voids as well.

Baffles: To Do.

March 20, 2012 / posted in Firewall Forward, To Do / No Comments

If you don’t know what any of the terms or parts are, this won’t make a damn bit of sense to you. This is more for me to have a written plan of the order of operations to hopefully avoid some future FUBAR. So I’m going to lay out what I think is the proper op order for getting the baffles on and trimmed, the cowl finished, and the airbox done.

See, this is an interlocking puzzle, kind of like a Rubik’s Cube, but none of the pieces are square and there’s no colors to tell you when it’s right. You just need to end up with a shape that meets certain requirements, i.e. everything fits without rubbing on something else and nothing makes the prop stop spinning.

First thing to do: Clean the shop. I swear, sometimes I don’t even know why I bother having a tool box. Everything winds up strewn all over the place anyway. It’s reboot time, because when something I’m looking for is buried under crap I should have put away and it takes me 10 minutes to find it, it’s time to fix that.

So, the baffles:

1. Order new front left inlet ramp. This is because I may have already trimmed too much off the front edge to get the thing to fit inside the cowl. Have to check. I can still use the old one for lineup and getting the shape right, but there might not be enough meat on the front of it to brace the air filter.

2. Make the bracket that connects the ramp to the engine. With this in place, I’m not trying to hit a moving target as far as shaping the opening of the fiberglass snorkel/airbox, and also the angle of the front upper baffle that goes around the prop governor. OBTAIN PROPER BOLTS FOR BRACKET. Big, meaty 3/8″ Grade 8 bolts that connect to the pad just below the governor.

3. Find the rest of the airbox kit, especially the W-channels thqt hold the filter in place. I know they’re in there somewhere, I just have a filing system for parts that closely resembles the Sargasso Sea.

4. Make a collar for the opening of the fuel servo’s intake to assist in fitting/trimming the snorkel. Yeah, that should have FA to do with the baffles, but like I said, it’s an interlocking puzzle. The takeaway from this is that sorting out the snorkel before cutting any holes in the baffle means there’s no need to cut the snorkel in half and re-glass it.

5. Cut/grind off the extra ears on the starter so they don’t interfere with the snorkel.

6. Cut a relief into the snorkel so it clears the alternator bracket. This is a common mod. Why Van’s sells a part that doesn’t work out of the box with 90% of installations is a mystery to me.

7. Maybe not actual step 7, but finish the conical gusset, trimming, and fastening for the right-hand side, which seems to be working OK.

8. Glass in the top cowl inlet ramps. These will be necessary for the next step.

9. Begin the iterative process of trimming the top sides of all baffles down so the top cowl fits and the baffle seal strips will seal.

Baffles 5

March 20, 2012 / posted in Firewall Forward / No Comments

2 hours.

Continuing work on the front left inlet ramp. I had to puzzle some stuff out, because this one is a little different from the right side. On the right side, bending the inlet ramp at an angle lines it up to the cowl inlet pretty well. On the left side, you need a big flat spot for the air filter. Also, the amount of crazy you get to deal with when it comes time for the filtered air box is directly proportional to how well you line up the hole in the inlet ramp for the air filter.

Tonight I cut the big stupid flange off the FAB to make the opening somewhat resemble the AFP fuel servo intake. It’s still not even close, but it’s probably wide enough, there will be more trimming. I’ll also have to do two things: Cut a relief hole in it for the alternator bracket (why this isn’t in there from the get-go is beyond me), and grind off one of the ears on the starter. When that happens, I’ve got a fighting chance of lining up the FAB where it’s supposed to go on the inlet ramp.

The other thing about the left inlet ramp is that I have to fabricate the inboard bracket that attaches it to the engine. Fortunately there’s a big square pad with two 3/8″ threaded holes exactly where I need them to be to mount a support bracket for the inlet ramp. After some diggin on VAF and around the internets, I’ve found that even with the bend in the inlet ramp, the filter will still fit, because it’ll flex around the bend. Then the FAB just has to be trimmed to accommodate the shape, and it’s on.

Baffles 4

March 19, 2012 / posted in Firewall Forward / No Comments

5 hours.

Yesterday and today. I’ve been dreading this, mostly because the baffles are, uh, baffling. But with the cowl halves fit, it was time to seriously tuck into these things. Friday, I got a present from American Propeller, my new PCU5000x. I think they put the wrong spring on it, because the spring returns the control lever to the low-rpm position, but that’s no biggie, they can send me a new one. Either that or I pooched the order, which would suck, but it’s not a showstopper, I’ll just have to run the cable up from the bottom.


It’s a lot less bulky than the old McCauley that was on there originally, although I might have to reclock the bracket to clear the cowl. This is done by drilling a couple of offset holes in the bracket.

Yesterday, I farted around with the baffles for a while, putting them on in preparation for cutting the front ones to the cowl. I figured I’d be fancy with it this time and make some cardboard templates to get the shape right. This didn’t work out all that well. My plan to set it up like Bill Wightman’s installation didn’t work at all, because I couldn’t for the life of me transfer the shape of the governor pad onto the cardboard with any degree of satisfaction.


It seems simple enough, but it’s not, and I couldn’t quite make it work.

What I wound up doing was using the IO-540 baffles from the RV10 kit I’d ordered a while back. For some reason, this option dropped almost right into place. I had to modify the right side baffle to match the angle of the inlet ramp, but that worked out pretty well, once I actually figured out a good way to measure and cut it. The left front worked out fine, since the pre-cut hole was actually designed for a governor the size of the PCU5000X.

Today’s efforts consisted mostly of putting the bottom cowl on and taking it off again. A lot. I trimmed the front side baffles to clear the cowl, then worked on getting the proper shape for the right side.


This is the left front trimmed back enough to clear the cowl and nest in the spot just outboard of the cowl inlet.

Cutting the shapes was actually easier than I thought it would be. There’s a lot of extra metal on the front inlet ramps, maybe these things are designed to work with a variety of configurations, but the basic deal is that you have to trim everything so it tapers down to the rough opening of the cowl inlet. It takes several iterations.

Once you have the basic trimming done, the front inlet ramp comes off and you have to bend it along a line that starts at the point where the cowl inlet edge is tangent to the ramp surface and ends up in the corner where the front side baffle and inlet ramp connect. The bend brings the front ramp roughly into line with the inlet.


Like so. There’s still more trimming to be done, because the way this works is that a strip of baffle seal material goes around the pink bit and seals against the ramp and sides. On the right hand side of frame is the 540 front baffle. I’m not promising this is going to work, but it seems to fit OK., and if it doesn’t, I can use it as a template to cut on one of the spare 360 baffles I ordered from Van’s just in case.

Also a conical gusset goes in the corner where my fingers are, one that more or less matches the shape of the inlet. This does two things, it gives a better seal under pressure and stiffens the structure where the air comes in.

After that’s all done comes the fun part: Trimming the upper edges all around to match the contours of the top cowl.

Oil Door.

March 13, 2012 / posted in Electrical, Firewall Forward, Fuselage / No Comments

6 hours.

Yesterday and today.
Yesterday I worked on the oil door. The finish kit comes with a fiberglass version, and it’s meant to be held down with an elephant-ear Camloc fastener, but it looks like ass if you do it that way. A better alternative is the Nonstop Aviation hidden hinge kit.


It mounts the door on a sprung hinge that opens up and out of the way of the cowl. You can use the fiberglass part from the kit for the actual door, but like some others have done, I made mine out of .032 aluminum. The reason? When the fiberglass part gets heated by the engine, the pressure from the hinge trying to open will warp it. Aluminum has no such limitation.


Once the door is cut, formed and drilled, the flush-mount Camloc release latch goes on. I actually made two of these things, because I screwed up the Camloc location on the first one. No biggie. I still have half of a .032 horizontal stabilizer I’m using for stock.


When it’s all in place, it closes flush and latches properly, but getting the hole for the latch handle was kind of a bear.


When it’s open, the spring keeps it out of your way so you can check oil, remove hinge pins, etc.

Today I was doing more checks of things under the area where the top skin will go, because that’s going to have to go on soon. I spent some more time securing wires and torquing down Adel clamps. In doing so, I found that I never riveted the row on the longeron right next to where the canopy closes. They leave them open at the QB factory because the slider canopy mounts a little differently. This isn’t all that easy to deal with when the panel and other things are installed, but it’s not that bad either. All I had to do was disconnect the vent hoses so I could get hands and bucking bars up inside the channel by the longeron.

After that, I started putting the baffles back on, but didn’t get very far. I’ll do some more of that tomorrow.

Cowl Fitting 6, 7

March 4, 2012 / posted in Finishing, Firewall Forward / No Comments

13 hours.

This counts last weekend as well, and I suck for not making the update then, but I had some pressing stuff going on. Anyway, more stuff happened on the cowl, mostly fitting, shaping, and the drilling of hinges.

Before I get into all that, I’m going to post some photos from the last entry.


To rough in the landing gear cutouts, I had to use a piece of angle, where I marked the distance from the center of the airplane to the landing gear leg.


The idea was to transfer that measurement to the bottom cowl to mark the approximate place the landing gear cutouts needed to be.


Like so. Although, the fiberglass flexes so much any measurement would have been approximate at best, so I left plenty of room for error. Fiberglass isn’t like metal, if you cut too much away, you can build it back up, but it’s a pain in the ass.


Remember I said I did a lot of hinges? Here’s one almost done on the bottom cowl. This is a piece of piss. Cleco-clamp the hinge to the edge, drill 1″ holes along its length. Easy.


The side hinges weren’t too bad either.

But the fun comes with you have to drill holes in the fiberglass on hinges it covers up. This is where the new pink cowl with its honeycomb structure help a lot. What I did (and I learned this from Bob Collins, thank you Bob!) What I did was put the cowl on, and fine tune the fit with some of that PVC tape I had lying around. It’s great stuff, super strong, and doesn’t have all those fibers like duct tape. Then I stuck a light up inside the cowl, pointing at the hinges, which I’d already drilled holes in.


With the light inside, the holes in the hinges light up the fiberglass and gave me a really good drill guide to complete the task. The first one sucks. You have to somehow hang on to it and make sure the drill goes in right, otherwise it can oval out the drill hole.


The desired result is Clecoes holding the hinges all the way up and down the line.


More or less like this.


The other fun bit is figuring out what to do with the hinge pin. I have to drill a slot for it to enter and exit the hinge, and I’ll have to conceal it later.

Like an idiot, I didn’t cut out the oil door per the plans before starting the hinge fit. It didn’t seem to have any ill effect, but after the hinges were drilled, I took the cowl apart and cut out the hole for the oil door.

But I didn’t get much past this part. It was Oscar night, and we in the movie biz make a big deal out of it. It’s also cool to have 5 friends nominated this year.

This week was killer, so I got nothing done. But today was pretty solid.

I didn’t get a super-early start today, because I took simba down to Marina Del Rey for his walk.

Today, I riveted the hinges to the cowl.


The blue light from outside on the pink cowl makes everything look like it was shot in a Miami disco in 1983.


Riveting these was tedious and repetitive. Like these photos.

But eventually all the rivets got done, so I started working on the inner flanges, which get platenuts riveted to them and the two halves screw together through them.


The smaller hole was the temporary one I used to hold the two haves together during fitting. it will get filled in when I go into fiberglass mode.

And that’s it. tomorrow, I’ll probably work on cleaning up wiring so I can rivet on the forward deck skin.

Cowl Fitting 5

February 13, 2012 / posted in Firewall Forward / No Comments

4 hours.

Yesterday was a lot of not-so-fun stuff positioning the bottom cowl to get it into position to mark and cut the bottom and sides. I have to concur with the general opinion that the instructions at this part of the build suck a thousand sucks. They’re opaque, terse, and confusing. Fortunately, the drawing is good.

Once I cut and shaped the front part to get a decent fit, I marked the bottom, took it off, then trimmed off the excess so the cowl could slide up into position. Then I had to do the fitting dance again, after which I marked the trim lines for the top sides and back. I took it off again and made the cuts. The fit isn’t utterly godawful, but it’s not my favorite work, either, so I set to work on the hinges. I got the bottom hinges drilled, then knocked off to go to a friend’s birthday party.

Today, I drilled the hinges for both the cowl halves and the side firewall hinges. Lots of deburring and countersinking. I have one side hinge left to deburr and csink, and those can probably be riveted on.

Cowl Fitting 4

February 6, 2012 / posted in Firewall Forward / No Comments

3 hours.

The fitting of the bottom cowl continues. There are lots of ways to fit this thing, apparently. Trim the bottom to the top, trim the top to the bottom, and the science-y way, which is to draw a line bisecting a 13 1/4″ circle, then extend that line all the way out and down the cowl. Well, that ain’t gonna work. For one thing, I don’t have the kind of equipment necessary to make a perfect 13 1/4″ disc to use for reference, so that’s out. The flange up front fits OK on the left side, but it’s total crap on the right. It’s not even the same shape, really. I tried hacking off the flange at the corner where the fit sucks the most, but I need to cut it down some more.

However, I was able to get the areas on the inlet marked for trimming, which will enable a better fit along the side. When I cut the top cowl, I may have goofed. The right side wraps around so it extends 4 1/8″ down past the line of the top skin. On the left side, it extends down 4 3/4″ which is a considerable difference. However, I don’t think it’s going to cause too many problems.

Everybody says you can’t really trust the edges of the fiberglass cowl pieces, and I don’t. But hopefully I can get a decent fit on the bottom cowl this week.

Cowl Fitting 3

January 30, 2012 / posted in Firewall Forward / No Comments

6 hours.

Another day, another run at the cowl. First thing was to get the cowl-side top hinges on so I could drill the top cowl to them. This is one of those times where fit is critical, because an error here multiplies itself all over the place.


This is the arrangement I came up with to lock the hinges in place as best I could. On the relatively flat part, I used the 1/8″ aluminum pin that came with the hinges to minimize the slop, driving it in until it couldn’t get past the curved parts on the outboard end. With this set up, I measured 1″ back from the center of the hole on the firewall flange which put the hole right in the middle of the hinge meat. These things are going to take a crapload of vibration, so it’s important that the fastener loads are spread as well as possible.


With the top cowl in place, I drilled where I’d marked. I was doing three on each side until I got down to the tight-radius bend, where at that point, it really didn’t matter, because nothing was going anywhere with most of the clecos in place.


Like so.

With all these guys drilled, I made the hinge pins from the .090 stainless steel provided in the kit, with 90 degree bends at the center ends, and some loops to zip-tie together. The plans say FA about securing these, so I consulted VAF again, and was given several options, one of which was the above solution. Simple, elegant, safe. I like it. I also had to taper the outboard ends of the pins so they could find their way into the eyes of the hinges. Getting them to go all the way down the length of the hinge is kind of a chore, but after a few tries, I got the knack of it, and now they insert and remove pretty easily, and the cowl doesn’t move around at all.

After that, I figured what the hell, I’ll try to fit the lower cowling. This didn’t work out so well, because it’s really big, really awkward, and I need to make cutouts for the landing gear. The idea is you’re supposed to suspend the thing below the top cowl, make everything fit, then drill the hinges. The prop is a bit of an obstacle, but it’s not too bad, what’s vexing me right now is the cutouts for the landing gear. I don’t want to eyeball it and take off too much fiberglass, because I don’t want to have to build it back up later. As usual, it’s always easier to remove material than to put it back. I might need some help on that one, but once that’s done, fitting and trimming the lower cowl shouldn’t be too hard. I also have to do the oil door, which I might get into this week. with the lower cowl on, the oil door is the only access to the area inside the cowl.

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