Preliminary fitting of the prop was a necessary step to fitting the spinner. Here are pictorial highlights of getting the spinner fitted to both the prop blades and backplate.
With the plexiglass canopy parts mostly under control, I’ve moved back to finishing the canopy frame and skins.
First off, I finished match-drilling the rear canopy frame. Nothing too difficult here.
I pulled the frame off the fuselage then deburred, countersunk, primed and riveted everything together. Then, I started on the canopy lift strut attach brackets.
The forward attach points require a lot of tweaking and fitting to fit inside the forward canopy frame. Once match-drilled, they’re tapped to accommodate #10 screws that keep them in place on the frame, and also for the large “knob” that provides an attachment point for the lift struts.
This quality Vermont American tap failed on its second use. I did a little research on where VA’s tools are made, and it seems like their name should really be Vermont Chinese, or Guangdong German, or something that more accurately depicts where the company really resides.
Not that I mind buying cheap Chinese shit tools…I go straight to Harbor Freight when I need a tool that I’m gonna intentionally tear up or modify, only has to last for a few uses, or most importantly, is something that my life won’t depend on.
I’ve been waiting a long time to use these custom-machined canopy strut mounts from Rich Mileika at Machine, Inc. Not only did they save a lot of fabricating time, they look really cool too.
Locating the right position for these mounts was the easy part; getting them screwed into place was harder. Once the mounts were match-drilled to the canopy rails for #10 screws, I had to get up, under and behind the canopy rails to get the locknuts in place.
I didn’t have any wrenches that would get into this spot, so I improvised…I took a cheap 11/32″ socket, hammered it onto a piece of 1/4″ aluminum fuel tubing, and bent the tube such that I could get the socket around the canopy rail. As ugly as it is, it worked like a champ. After I used it to get the mounts installed, I pulled the socket off and reattached it with JB Weld – probably won’t be the last time I’ll need to use this device.
Here’s the canopy frame with the lift struts attached. Cool.
I put the canopy back on the frame…it’s time to start fitting the side skirts.
The challenge here is getting the skirts clamped in place. Some builders have made some really spiffy clamps out of aluminum C-channel to slip under the skins and hold them in place, but I didn’t have the patience to do that.
Instead, I just used some 3M two-sided tape to hold the skirts in the correct position until I could raise the canopy and clamp them with regular Pony clamps. In the pic above you can see that I’ve already laid out and pre-drilled the side skirt rivet holes.
Lookin’ good prior to drilling…
And after several minutes sitting inside the closed canopy (cool!) with an air drill, the side skirts were match-drilled to the frame. Not much left at this point except to countersink the frame holes and debur/dimple the skirts.
One of the things I wasn’t too happy about was the fit of the forward canopy skin to the forward fuselage skin – they just didn’t quite line up.
As I tend to do, I threw money at the problem. I made a trip to Harbor Freight and bought a metal shrinking/stretching tool set. After practicing on some scrap sheet metal, I used the metal shrinker on the leading edge of the canopy skin.
The results were better than I expected…the metal shrinker really closed up some of the gaps between the canopy skin and forward fuse. Unfortunately, I didn’t get a picture of the fit with the canopy installed, so you’ll just have to trust me.
One slight downside to the metal shrinker is that it leaves small toothmarks on the metal when it’s used – but a scotchbrite pad on the die grinder made quick work of them.
Like most tip-up builders, I chose to install the optional canopy reinforcement kit. Otherwise the canopy frame is pretty floppy even when the canopy bubble is installed. There are a lot of holes and slots that need deburring, fortunately there really isn’t much more of this to do on the project.
The plans call for the three large lightening holes to be “flanged”, or have the edges of the holes bent slightly to make the metal stiffer. There are lots of way to do this, and I chose the old-fashioned way – a piece of delrin with a slot cut into it, which is used to bend the edge as it’s slid around the inside of the hole.
It’s a pain, because several passes are required to get a good bend – but in the end, the flanges came out great.
Here are the stiffeners drilled to the canopy frame.
There are small tabs to be fitted and drilled to the stiffeners…not hard to do.
…and they’re done.
At long last, it’s time to prime the canopy skins and stiffeners, and rivet them to the frame.
Blecch…priming. I’m glad there isn’t much more to do.
Priming the canopy frame was a pain, but hanging it from the engine stand made things easier.
The canopy skin doesn’t fit particularly well on the frame, so I used an epoxy and flox mixture to fill gaps between the skin and frame. Once it cured, Bob DiMeo and I riveted the skins on. The epoxy/flox mixture worked pretty well – there aren’t the dimples in the canopy skin that I’ve seen on other projects.
More riveting fun, this time after several pop rivets have been pulled. The pop riveter takes some manual effort to use, and my forearms are aching.
Unfortunately I neglected to take any pictures while I painted the canopy frame interior with JetFlex WR. This took a long time…I did a lot of repainting to get a good finish, and it was a real pain.
After the JetFlex dried, I masked off the glareshield for surface prep, priming and painting.
I used a good flat black automotive enamel to paint the glareshied, and it came out very nicely.
I installed the canopy strut pivots…kinda satisfying to do something so simple.
Here’s a bit of visual progress…the painted canopy frame with the canopy installed. Very cool!
Another picture? Sure, why not…
The last bit of work was installing the aft canopy latches.
I don’t have much to add to the instructions, except that I had to do some improvising to keep the latch fingers clamped in place while I match-drilled them. A piece of spruce filled the bill.
I also clamped and drilled the upper canopy safety latch block to the canopy frame. Unfortunately, I forgot to take any pictures so you’ll have to use your imagination. I deviated from the plans a little and installed a spring beneath the washer and cotter pin that hold the handle in place. Once the block wears a bit and the handle turns more freely, the spring will pull the handle tight against the frame and keep it from inadvertently rotating to the close position, with the unfortunate effect of locking the canopy from the inside. It’s happened to other builders, and I’d like to avoid all the gyrations they had to endure to get the handle unlatched.
Most tip-up builders don’t go to the trouble of installing the canopy emergency release because (a) no one has ever bailed out of an RV-7, and (b) the release handle takes up valuable real estate on the instrument panel.
I’ve been debating the merits of installing the release for a few years, and finally came to the conclusion that I’d rather have it and not need it rather than the other way around. I also want to keep the instrument panel relatively simple, and keeping space for the release handle forced me to do that.
The first step was to drill the release pivot block to the hat section on the subpanel.
With the holes drilled, I installed nutplates to accommodate the attach bolts.
In this picture the pivot block and actuator arm are in place and attached to the canopy hinge pins with steel rods. Actually, the left rod isn’t connected to the actuator because the rod was slightly short even though it was fabricated according to the plans. So…I got to fabricate another one that was 1/16″ shorter.
There’s not much to add about fabricating the steel parts, except that the slots in each steel rod that accommodate the actuator and pins are most easily cut with a Dremel tool with a cutoff wheel. Some work with files will still be required, but the Dremel will get 95 percent of the cutting done.
The release mechanism is on the shelf now, and will be reinstalled right before I’m ready to rivet the front fuselage skin in place.
It’s December 29 and I’m finally getting a chance to complete this post on finishing the rear window. So for all you Mighty RV fans out there (I think we’re now up to three), here’s a narrative on trimming, fitting, marking and drilling the final part of the canopy.
Vans’ instructions call for rough-marking the rear canopy trim line before cutting the canopy into forward and rear sections. For some reason I didn’t do that, so with the forward canopy separated and placed in approximately the right position, I laid the rear canopy over the fuse and marked a “do not cut” line around the fuselage skin edge. Yeah, I went over the top with reminders about where not to cut…
I then did a rough estimate of a “cut here” line based on the no-cut line. I don’t recall the distance, but it was generous – I took off just enough so that the canopy would fit under the skin.
Here’s the first cut line marked with masking tape. I like that Scotch yellow-green masking tape…it just looks more “aerospace-y.”
I got the first trim cut just about right; the rear canopy seats nicely around the skin edge, and there’s enough overlap of the roll-bar to make it easy to final-trim the forward cut line that abuts the front canopy.
The only thing you can’t see in the above picture are the bits I had to cut out of the forward lower corners of the rear canopy so they’d fit around the roll-bar attach fittings.
One final task before drilling to the skin and rollbar – marking hole locations for the screws that attach the fuse skins to the canopy. I borrowed a trick from Mike Bullock and used a piece of masking tape to lay out hole spacing. I laid a piece tape parallel to the skin edge at the correct edge distance and marked the location of the first and last screw holes.
Read the plans carefully here, because Vans doesn’t explicitly call out the edge distance – it’s inferred from one of the cross-sections depicted in the plans.
With the first and last hole marked, I pulled the tape off, measured the distance between the first and last holes, and did a little airplane builder math to mark the rest of the screw hole locations. After that it was an easy matter to put the tape back on the fuse and mark the holes for drilling.
One side note – regular masking tape is kinda stretchy for laying out hole spacing, so I used some 3M plastic fine-line auto painters tape I had laying around from a previous project. This stuff worked great – it was easy to get the holes spaced perfectly because the plastic tape didn’t stretch much at all.
Laying out screw holes on the roll bar was easy – all I had to do was match the locations of the holes I’d already drilled for the front canopy.
I bribed Ellen with the promise of a nice dinner at our favorite Mexican restaurant if she’d come up to the hangar and help drill the rear canopy, which she graciously agreed to do.
This was a piece of cake compared to the front canopy but there are a couple of tips that help improve the drilling process. First, it’s a good idea to pre-drill the fuselage skin holes with a small drill bit without the rear canopy in place; the small holes help center the tip of the 1/8″ plexiglass drill bit when match-drilling through the canopy.
And second, be careful to not drill through the rollbar with the plexi bit – this would enlarge the holes past the size necessary for a #6 tap. Use the pre-drilled holes on the rollbar to locate the holes, then drill them with the plexi bit just deep enough to break through the opposite side of the canopy, then enlarge later to full size when the canopy is off the frame.
And here’s the final product after match-drilling. I still have to trim the forward edge to match the “big cut” line, polish the canopy edges, countersink the screw holes and drill them to final size, but everything looks good for now.
I won’t trim the forward edge until I get the front canopy back on the frame with the lift struts installed S.me builders say that the struts push the whole frame aft, so I don’t want to do any edge trimming until the canopy is sitting in it’s worst-case position with respect to the gap between halves.
P.S. – If I haven’t mentioned it recently, I think I’m one of the luckiest builders – and really, one of the luckiest men – I know to have a wife and partner like Ellen. She’s learned to be an ace riveter, encouraged me to keep going when I’ve wanted to quit, and helped me keep perspective on the truly important stuff – and I don’t mean the airplane.
I’ve been busy over the last couple of weeks on consulting projects so I haven’t had the time to work on the airplane until this weekend. On Friday I finished adjusting the forward canopy skin to accommodate the canopy itself.
Look at the little piece of green duct tape in the lower left corner of the picture above…that arrow-shaped opening is the final result of trimming the “fingers” in the skin so that the canopy sides transition smoothly to the side rails.
I spent the better part of the day laying out and pre-drilling holes that will eventually accommodate #6 screws that attach the canopy to the frame. After that Ellen and I put the canopy back on the frame, then taped and clamped it in place for drilling.
Here’s a pic for the Friendly Aviation Administration to show once again that yes, I’m actually building this thing…
Starting at the top of the canopy bow, we drilled #30 holes through the plexiglass into the frame using an Avery plexiglass bit. We anchored the canopy down on one side and then the other by drilling and clecoing holes 6″-8″ apart, then went back and drilled the rest of the holes.
This is a Big Deal…there are only a few minor adjustments left on the side skins, and I still need to trim the rear of the canopy to it’s final cut line, but those are small tasks that I can finish in a day.
Cutting the canopy isn’t something to rush. I read and re-read Vans’ instructions, and researched other builders’ websites, to get a good idea of how to trim the canopy without damaging it. A replacement canopy is more than $1000, so cracks are something to be avoided.
I started this part of the project a few weeks later than I wanted to…my hope was to get the canopy cut and installed in August while the temperatures are still warm enough to not keep the hangar heat turned up. Fortunately, September has been fairly warm so not too much hangar heating has been required.
I set up everything needed to start trimming. Per the instructions, I first cut off the portions the canopy where it was clamped in place for molding. The back of the canopy was the first to go…
…and trimming turned out to be a little easier than I thought, but some care is required to get close to the cut line marked by the tape.
The cutoff wheel creates a lot of plexiglass “snow” particles as it works, except that this snow can be uncomfortably hot when it hits your skin. I didn’t want any of that crap in my eyes or up my nose, so I wore safety glasses and a respirator…
With the clamp marks trimmed off, I marked a centerline on the canopy per Vans’ instructions. This is a little tough to do as it’s hard to accurately place a tape measure around the canopy. I wound up using a piece of string pulled tight from side to side…mark the string where it lies on the edges, then double it back on itself and you have the centerline – sort of. I don’t think it was very precise, but it also seems to be close enough.
There are a couple of tabs on the front canopy frame that overlap the side rails. The instructions require that the tabs and side rails be adjusted to match the curve of the canopy’s front edge, then drilled and riveted. There’s not a lot of guidance here, and it’s hard to see through the protective plastic sheeting on the canopy to tell how the curve should lie. So…I took my best shot.
…and everything looks good for now.
I’m reasonably happy with the canopy fit, so I started marking the line across the rollbar where the canopy will be cut into forward and rear sections. This process is not-really-affectionately known to builders as making The Big Cut.
I worked on the front edges a bit to get them to lay down a little more accurately on the front canopy skin, but from what I’ve seen on other builders’ websites, you can do all the work on this area you want but once the canopy is drilled in place, some gaps will open up. So I’m going to get it close and not worry about it.
I hoisted the canopy onto the sawhorses and plywood, and used some long 2x4s to move it off the work surface They also gave me something to clamp some smaller pieces of 2x4s as side supports that keep the canopy from spreading as I cut it.
As other builders have also done, I laid several pieces of masking tape along each side of the cut line to help guide the cutoff wheel. I was skeptical that this would work, but it did and very well too.
I took a few deep breaths, and started cutting…
…and the process went very well. I used tongue depressors to keep the canopy separated as I worked my way along the cut line.
And here’s the completed cut…what a relief to have this done.
It’s a lot easier to move the canopy on and off the fuselage. I’ll be doing a lot of that as I finish fitting it to the frame and then drilling the attach holes.
Got just enough time in the hangar tonight to rivet the canopy frame together and put it back on the fuselage. I left the primer to dry for a couple of days, and the Nason etching primer I used was tough as nails!
There’s an small and easily fixable mistake in this pic. Can you spot it?
And now it’s time to start trimming the canopy…yikes!
More fun with the canopy this week as I spent several hours adjusting the fit of these parts that form the rear canopy frame.
The distortion caused by both the flanges and L-shaped bend in each frame half takes some work to make them fit adequately. The instructions tell builders to flute these parts to remove the distortion, but at least one of mine was just about right out of the box and really didn’t need fluting. The other one doesn’t fit quite as well, but I’m resisting the urge to flute it because (a) the fit isn’t that bad and (b) I tried fluting a spare frame part I had and it was a PITA.
In this picture the frame halves are not perfect, but they’re getting close to being good enough.
The side rails were an easier fit, because Van’s had already done all the bending and metal shrinking needed to make the side rail curve fit the longeron bends I worked so hard to perfect several years ago.
The side rail flanges don’t quite conform to the aft frame parts, but I think they’ll pull into shape pretty well when they’re drilled and clecoed.
Laying out the side rail and rear canopy bow splice plates. Note that the side rail doublers at the bottom have one hole that isn’t marked to be drilled – that’s because Van’s conveniently forgot to mention in their plans that there’s already a hole through the canopy frame in this area, and if you drill the hole in the splice plate it won’t line up with the frame hole.
Ok, so I said I wasn’t going to flute the rear frame – but I did, and it actually came out pretty well. Here’s the side rails and rear frame clamped into position.
The little cheapo Harbor Freight clamps are holding on some strips of 0.032″ scrap that simulate the canopy side skins. The side rail is correctly placed when the bits of scrap lie flush with the side of the fuselage.
Sharp-eyed RV builders will see that I’ve inserted a shim between the side rail welded angle and the F-631 rear frame half. The fit wasn’t quite what I wanted, so when in doubt – shim it out. After that I couldn’t think of a good reason not to drill everything, so I did.
These plates splice the side rails to the forward canopy frame, and drilling them was a bit of a pain. It’s vital to uncleco and peel back the forward canopy skin, as nine of the ten holes in this part don’t go through that skin and drilling through it would be uncool. You’ll see one hole (bottom row, second from the right) that doesn’t quite line up. That hole *does* go through the skin and frame, and once the other holes were done I back-drilled this one using the forward frame as a guide.
And here’s everything drilled and clamped to make an almost-complete canopy frame. As my friend Jim would say, this is one of those moments of Big Visual Progress. They kinda sneak up on you after a lot of tedious fitting and drilling, then suddenly everything comes together…et voilà, it looks like a real airplane part.
I hated to take everything apart, but there are a couple of small parts left to fabricate and fit to the frame.
Look carefully in the pic above, just under the two leftmost copper clecoes, and you’ll see a thin aluminum wedge filling the gap between the side rail splice plate and forward canopy frame flange. Scroll back a couple of pictures and you’ll see the unfilled gap.
I had to make two of those – one on each side of the canopy – and each one took about an hour of cutting, sanding, filing and fitting. What fun…but now I can take the frame apart and debur, countersink and prime everything before riveting. And that, in turn, means it’ll soon be time to work on the plexiglass canopy itself.
After drilling the canopy hinges, I had to do some filing on the seal support angles so that the canopy would open without rubbing on them. Not really much to see, because the seal support angles are hidden in this pic. But the canopy frame now pivots the way it should, and that’s worthy of a picture.