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RV-3B Dave's in Colorado

2nd Try, Inner Flange

Since the first inner flange was unsatisfactory, I made another one. Here it is, still in the canopy as laminated. I?ve removed the peel ply but haven?t separated it yet. I hope it's not too thin....

f244ea9f-59f0-a049-b87c-d2582e7923df


I?ve also attached the elevator tips permanently, although they will need some filling and shaping when I get closer to the finish and am doing that sort of thing.

Dave
 
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The inner flange has been removed, marked and trimmed is ready for prep for the bond.

In the meantime, I thought that you might be interested in the maintenance manual that I?ve been preparing. When I come across something that seems like it?s worth remembering for future maintenance, I?ve been jotting it down, along with photos. At first it was all in one manual but the organization got unwieldy, so I separated it into chapters. At the time, I was using the Mac software Pages. More recently I changed to the free open-source Office-like package, Libre Office, which I like a lot. Hence the ?.odt? suffix.

Maintenance%2BManual%2BChapters.jpg


I finally got the inner flange glued to the canopy and outer flange. Here?s the stack curing. I clecoed it down to ensure that it doesn?t warp. I used 2216 for this bond because it sticks to the canopy.

Inner%2BFlange%2BBond%2BCuring%2BS.jpg


Although the fairing is in place, that?s not part of this bond. That?ll come shortly. I knew I wouldn?t have time to manage that joint, too. It's there to give me something to cleco the flanges to.

Dave
 
Before I went to bed that night I glued the inner flange on, I pulled that green electrical tape off on the inside. It’s purpose was to keep the black sticky 2216 glue off of the canopy. The glue had flowed over the tape, not unexpectedly, and there were some glue tentacles that remained as I pulled that tape off. I tried to keep it off the canopy but was unsuccessful. It was still in a state where its adhesion was greater than its cohesion; I couldn’t pull it off the canopy where it had touched. I went to bed knowing that I’d have a real problem.

When I got the canopy back upside down the next morning and had a look inside, I thought that maybe I could grind the epoxy off. Yeah, that would work, sort of, leaving a lot of polishing ahead. But the glue hadn’t completely cured. I could sand or file it, no problem, but an Xacto chisel blade was able to remove it. In most case there was no residual mark. I was so lucky. Problem solved.

On the flanges, though, it wasn’t so easy. The canopy itself had been unprepared where I removed the excess glue from it. The canopy flange was fiberglass and had a roughened surface. The 2216 didn’t come off there. For those, I’ll have to grind them off.

3M’s 2216 epoxy really does a good job of sticking to things.

In case you’re wondering how the flanges and the canopy all go together, here’s a sketch that I made. The flanges are rounded at their apexes but that’s a bit hard to do with my drawing package. You’ll have to imagine that for yourself.

Canopy%2BFlange%2BSketch.jpg


The canopy latch handle is located - hope it’s in a decent position. The aft canopy latch, at the aft most end of the canopy, is operated by this. The actuation rod is shown here with the latch handle. The bend closest to the latch is undergoing several tweaks and this is not the final version of that. The rest is, though.

Aft%2BLatch%2BInside%2BS.jpg


It continues outside the cabin but inside the canopy. The red circle closest to the cockpit marks where a guide bushing will go, and the rod itself will engage a standard eye-bolt in the fuselage that pokes through the canopy fairing at the red ellipse.

Aft%2BLatch%2BOutside%2BSA.jpg


Fortunately, I realized that I needed to set this up before the canopy is bonded on. There’s not room to access it later.

Dave
 
The forward-most guide flange was made in two passes plus trimming. I wrapped a foam block in packing tape and taped it to the fairing. Then I made a fillet of flox and laid up six layers of BID.

Guide%2BFlange%2B1%2BS.jpg


With the block removed and the flange and fairing sanded, I made a similar fillet and laid up four more layers of BID for the other side of the flange.

Guide%2BFlange%2B2%2BS.jpg


Finally, I trimmed it. I keep a set of washers of various sizes handy for use as templates for different sized curves and used one here.

Guide%2BFlange%2B3%2BS.jpg


The bushing needed to have an ID of 5/16” and that’s a size that Van’s doesn’t sell. But Grainger does, and the bushing is now in place. And yes, the flange clears the canopy.

Dave
 
Man, I spent so much time over-thinking my canopy, and I rebuilt what was left of an existing one! I started it at one house in Michigan and finished it in another house in Tennessee! My next airplane is going to be a pre-punched kit with good instructions. I want to do more and think less. The canopy turned out pretty nice, at least. Have fun! :D
 
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Man, I spent so much time over-thinking my canopy, and I rebuilt what was left of an existing one! I started it at one house in Michigan and finished it in another house in Tennessee! My next airplane is going to be a pre-punched kit with good instructions. I want to do more and think less. The canopy turned out pretty nice, at least. Have fun! :D

Amen Katie!
Outstanding work David! What fun watching your work from afar.
 
Aft Canopy Latch, Check

Katie, you’re absolutely right about the thinking that’s going into this. At this point I’m beginning to look forward to other parts of the construction. Kentlik, thanks for the comment.

Things are slowing down right now in the shop, due to outside matters. I’ll make progress as I can. This shouldn’t last too long. I did find time to make some progress at the aft end where the actual connection is. Here it is unlatched:

Aft%2BCanopy%2BLatch%2BUnlocked%2BS.jpg


And with the canopy latch engaged:

Aft%2BCanopy%2BLatch%2BLocked%2BS.jpg


The actual bar that passes through or on the various pieces is not the final one, and I don’t have the right size screws yet. There’s a bit of work ahead here. The final bar will have its end tapered, too. But this part of the canopy latch works, and I was using the cockpit handle to operate it.

Remember, what this thing does is prevent the aft end of the canopy from lifting up. Imagine the fuselage trying to sink below the fairing in the photo and it's a bit easier to grasp.

Dave
 
Canopy Fairing Has Its Hinge

Life has caught up with me again. Here and there, I worked a few moments at a time. Sometimes I was delayed for parts, but most of the time it just happened.

Well, enough whining. Here’s what’s been done.

I disassembled and then reassembled the latch mechanism, after lightening it up a bit. Flight hardware this time, etc.

Shifting back to the fairing, I applied micro to the top inside of the fairing, the places that would be at least awkward to get to, and perhaps impossible, once the canopy is on. Here’s a pic of the aft most two sections with the micro on. I might have been a skosh lavish with the stuff.

Fairing%2B-%2BMicro%2BOn%2BS.jpg


After sanding, well, after considerable sanding, I gave it a shower. Feel free to look away if you’re a sensitive person - here it is in the shower, posing. It’s not the least bit shy.

Fairing%2B-%2BMicro%2BSanded%2BS.jpg


Since it was both simultaneously too warm and not humid enough to spray the Ekopoxy primer that I’m using for the interior, I needed something else to do. What I did was drill and cleco the canopy hinge to the longeron and to the fairing. With it all clecoed together, I could do something so basic and so important it could have been a milestone all by itself: I opened the canopy fairing. And hey, guess what? There’s no way to hold it open yet. Plus it’s about as floppy as a newspaper in a spring breeze. While I know that the canopy itself will stiffen the assembly, what I need to do is build a frame. The basis for it is in place, a stiffener just above the hinge.

Here, the fairing is resting on the roll bar, not a permanent rest for it. You can just barely see the stiffener inside the fairing near the hinge.

Fairing%2BHinged%2BS.jpg


There are some considerations for the hinge worth noting.

1. There needs to be a way to remove the canopy and fairing and frame from the fuselage. Somehow, that hinge pin has to be able to be removed. What I plan to do is at the aft end, bend the pin inboard, then down, and finally aft, where it should rest in a tooling hole in the seat bulkhead. That’ll secure it when I don’t want it removed. When I do, I’ll pull it around and slide it out of the hinge aft-ward.

2. The hinge needs to be slightly outboard of the longeron or the fairing/frame will bump into the side of the fuselage. I did not allow for this when I made the fairing, but it’s sure as heck included now. It would have been easier to do it earlier, and the manual even mentions this, too.

3. There needs to be some sort of weather protection at the hinge, lest the cockpit flood. That’s TBD but shouldn’t be too hard.

Not precisely part of the hinge, but there also needs to be something to hold the canopy open, as I hinted above. Ideally, it should be incorporated into the part of the frame that I still need to build at the seat bulkhead. Some people attach it to the roll bar but I failed to provide provisions for that when I built it, and am reluctant to retrofit that now. Have ideas but haven’t settled an an approach yet. But I have ruled out a cord/cable/rope/chain/etc. in favor of something which will provide a positive stop. Right now I’m thinking of either a folding strap latch like some people have used or an air spring. Or something else, and yes, I have something in mind that might work, but probably won’t.

I should probably mention that after consulting with Van’s Support, I’m using LP4 rivets for the hinge to longeron joint roughly per the RV-4 Preview Plans. For the hinge to fairing/frame, I’m using AN426AD3 rivets and am gluing the hinge to the fairing/frame. The rivets here are per Drawing 33.

Canopy%2BRivets%2BA.jpg


These photos are hosted elsewhere. Now here they are again in VAF hosting, as an alternate.

Dave
 

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Dave,

On my RV-3B the canopy hinge had two pins that inserted from the center of the hinge outboard, each. So the bent end of each pin met in the middle. I think one of the hinge bulbs was removed where they came together. So instead of one long hinge pin accessible from the outside the two shorter ones were accessed from the inside and there was less alignment and friction problems than on long pin. And no hole or other access feature was needed on the outside to accommodate pin insertion/extraction.

This is the same concept used on many of the seat back hinges where there are two pins on the seat back hinge, each pushed from the center outboard for half the hinge line as it would be impossible to insert one pin without there being a hole in the exterior skin to compensate for the straight length of one hinge pin inserted from the side.

Also, my canopy hold open device was an over-center link that folded from the center up. When in the pilot's seat I could release it with my elbow. It did a good job of holding the canopy. It was attached to the seat back bulkhead rather than the roll bar.

u157QsI.jpg



iCWJP5l.jpg


Jim
 
Thanks, Jim, I appreciate the pics.

Having just put the pin in today, fighting it the whole length, I might go for the split pin arrangement. Have to say the whole length one was a pain. Confirms my plan not to use piano hinges for the cowl.

The hold-open arrangement you use is one of the three most likely options I'm considering. The other two are a different sort of folding strut or an air spring.

Dave
 
Don't be too quick to write off the use of piano hinge for the cowl. I had the fancy quarter turn fasteners on my Midget Mustang. They were heavy and expensive, but they worked VERY well.

My RV-3 has hinge pins for the cowl at the split, top-to-bottom, and at the firewall on both the top and bottom cowl and I've come to LOVE them. The original builder did a fantastic job of making sure everything fits and the hinge pins aren't being used to tweak anything in place or suck anything in. He also included some bent needle nose pliers that have a hole drilled in the jaws that fits nicely over the hinge pins to aid in removal and installation. Next time you're up flying, plan to come visit me at CO12 and we'll remove and reinstall the cowl. I've become quite proficient with the recent engine rebuild. I'd fly it over to Boulder, but I'm out of service right now because my prop needs to be serviced.

FWIW, the Glasair 1RG I recently purchased also uses hinges for the cowling and I'm very happy with the arrangement.
 
If done right the hinge pins on the cowl work fine. My RV-3 had a little piece of hinge to retain the bent pin handle at the front of the cowl. My RV-8 has pins that are inserted from the cockpit side so the exterior hing line is smooth and pin is hidden. That requires a longer pin with nylon tube guide to keep the pin aligned when inserting. Nice and clean but more work.

If you go with Skybolt / Camloc type fasteners you might consider leaving them loose without retainer washers. While you will have to put them in a cat food can when taking off the cowl they won't fight you like retained ones can do while you try to pry off the cowling and all the little lock pins are catching in the holes.

As far as canopy hold-open devices go, I like one that doesn't impose a bending load in the canopy when closing it like an air strut can. With the mechanical folding link there is zero resistance when lowering and no twisting load on the frame in either direction. Not saying an gas spring would be a no-go, especially if a lower design pressure than normally used in automotive and commercial applications.
 
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Although the canopy still isn’t on yet, it was time to get an idea of what sort of geometry was available for the canopy frame cross-stiffeners (the ones front and back that go side to side). These are going to be foam core, fiberglass and carbon. Here’s me with a 1.5” cushion under me and a 1” cushion plus a 2” foam spacer for the seat back. With my age and the pandemic, I let few visitors in to the house but with the garage door open and makes all around, they can come into the garage. One took this photo.

vD0LdBB.jpg


The c-clamp was holding a dummy cross-stiffener in place at the panel, something to give me an idea. But the main thing was all the space I have between me and the seat bulkhead. Some of that can go to the cross-stiffener and some to the hold-open device. And that design is being narrowed down. A possible idea that I hinted about earlier won’t work but another might.

The latch assembly has the usual forward and aft latching bars. I’ve added an aft-canopy latch point, remember, so I have two of them. In an effort to minimize the build-up of friction, these bars attach to rod-end bearings at the latch itself, and those will be secured with jam nuts. There are other ways to do that, such as small holes in the bars and safety wire around the rod-end bearing pins, but I’m comfortable with this.

The next issue was how to hold the rods while gently tightening the jam nuts. The approach I chose was to get some aluminum hex bar and drill it out and glue them on. VAF member Rick Brennan kindly did the drilling on his mill. Thanks Rick! Here are the rods and the bit of hex, which is only to hold the rods while snugging the jam nuts.

U7iDBze.jpg


Here’s a quick look into the canopy-less cockpit as I had it at one point. Before too long, I removed the 2” foam spacer under the seat cushion but who knows - once the canopy is on I can play with that. Also the cushions are not RV-3 cushions. They were made for a different application all together, and I’m merely re-purposing them, to use a semi-dumb word. After this photo, I added another, final, coat of the dark gray interior paint.

SCYAJpC.jpg


Some cockpit work needed before flight.

Dave
 
One thing that I needed to do was finalize the conceptual design for the hold-open link. Right now that’s planned to be a bar, pivoted on the aft fairing frame cross-member 5” radius from the canopy hinge pin. In the picture below, those are the white lines. The link is the blue lines, and close to where they cross will be the sliding connection to the aft seat bulkhead. Virtually all other geometries caused the link to interfere with either the harness or the seat back.

The tentative idea is to have the top end of the link have a notch that drops over part of the sliding connection fitting. A spring will add assurance that it will stay there, and it ought to open and come to a stop and stay there. To close the canopy, lift the link past its catch and then close the canopy.

Yes, this will protrude above the turtledeck and be visible, regrettably. But it’ll be under the canopy rather than in the outside air.

Possible link shapes: either a flat aluminum bar or a tube similar to the canopy latch but with different end terminations.

YIAiGo1.jpg


The wooden blocks are to provide spacing for this. They gradually go to 1/8” from the current 3/4”, so that the aft canopy cross-member will be near the seat bulkhead for the aft latch bar. My head and shoulders clear that nicely.

The hold-open link attaches to the seat bulkhead and to the aft canopy cross-member, which I hadn’t built yet. The forward cross member will go under the shade that’s integral to the canopy fairing and can be 3/4” deep. The aft one goes between the pilot and the seat back frame so it has to be thinner. I made a foam blank from 1/2” PVC foam. Since it appeared hard to fiberglass, I also made several practice pieces.

zU1p7FL.jpg


The top two pieces used the foam I was planning on using for the front cross member, 2 pcf construction foam. The bottom piece is a sample of the 5 pcf PVC foam aft cross-member foam that I’d tried to heat-form and got too hot, while the piece above it was a trial piece of the same foam that I’d wrapped with 45 degree BID, with the glass wrapped along the bottom and along the top. The top two pieces and the middle piece were spiral-wrapped with 90 degree BID. Unfortunately the wrap wasn’t at the 45 degree angle and I couldn’t make it so.

The middle piece wasn’t intended to be practice. It was supposed to be the beginning of the aft cross member. But the lay up was also sufficiently uneven and in places not attached to the foam core so I scrapped it.

This attempt did use heat-formed PVC foam. I formed it to be parallel to the seat back on the right but 3/4” away for that hold-down bracket, and within 1/8” on the left for the latch bar.

The one I was working on today merely goes from one side to the other with those spacings, no bend needed.

Once I got it covered with 45 degree BID, I applied some carbon. Here’s the first pass on that going on. So far, this will fly. I’ll let this cure and then do the edge that’s on the bottom in the photo, to build up bending stiffness.

HvrG9qQ.jpg


Dave
 
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Got the aft cross-brace glued in but not yet tabbed with glass to the fairing. As-is, it significantly stiffens the entire fairing/frame assembly.

oY60FPd.jpg


The front cross-brace has the carbon on the outer surface only so far, and that surface’s +/- 45 degree plies. It’s lagging the aft one but coming along.

This period I’ve been taking some time off work because I’ve been going down to the airport and flying. I have a Cessna and finally the wind is less and the forest fire smoke has gone, at least locally, and it’s pretty nice. It’s a curious position - whichever plane I’m spending the day with, the other is getting shorted.

Dave
 
The forward cross-bar has all its carbon now and is done. What's interesting to me is that the two cross-bars have carbon caps top and bottom and that's the only carbon I've needed for stiffness so far. I bought a lot more than I ultimately needed.

This has been slow going. I'd add some glass or carbon, let it cure, and it takes the better part of a day before I can work on it some more. And there's been a lot of thinking in between actually doing things.

One thing I've learned is that you you want a project, then the approach I've been taking is excellent. If you want a flying airplane, either buy one or build a mature kit exactly per the manual. Make no changes. Many years ago, a friend told me something important. He'd built a Volmer amphibian so he knew what he was talking about. He said about his recently-purchased Cessna 170, "I didn't have to built anything. All I did was sign my name a few times." The lesson stuck and after a few years I've had a flying airplane at hand ever since. A good thing too, since I flew my Cessna 180 earlier this week and this RV-3B won't fly for a while longer.

Okay, philosophy lesson over, let's get back to it.

I've been working, even more slowly than normally, on the hold-open latch. The basic concept is simple enough. In this photo, the retainer plate on the front of the stop is missing but you can see the two white bushings and their screws that it attaches to.

m00FIRG.jpg


To unlock it, merely lift the bar and close the canopy. That part works just fine.

There's a bit of some eccentricity at the outer connection to the bar since it not only pivots around it's attachment screw, it has a small rotation about a yaw axis as well. That is accommodated by a slightly oversize hole in the end of the bar. That part also works just fine.

So what doesn't work so well? The bar itself rotates to a more vertical position as the canopy closes and the bar's inboard tip moves aft. It contacts the roll bar. I've been tweaking things to prevent that and perhaps the next posting will show more. At the moment, having dropped and lost one of the only two white bushings that I have, it's disassembled.

Dave
 
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gas strut

Dave, did you perhaps consider a small gas strut to hold open the canopy? It looks like some hours have already gone into creating the latch. Just a thought, when I saw it. And I guess whatever the solution it will need to allow the canopy to zip off per Vans design if it ever accidentally opens in flight.
 
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Paul, that was one of my first ideas. The other was a tape-measure tape used as a folding strut.

I decided against the gas strut partly because at that time I couldn't figure out how to connect it to the fuselage and partly because I was concerned that it wouldn't break free if it needed to. Now that the canopy frame is further along, I can see ways to attach it; the breaking free issue is probably minor but remains.

I bought a tape measure and tested the tape. It would not support the load intended for it. Also, repeated folding of the tape let it take a permanent set, making it even more buckle-prone. A further problem was that the mounting points would have needed to be carefully oriented so that the folded tape didn't interfere with either the canopy frame or me. While the idea has merit, the execution would have taken more time than I was willing to spend with it.

The current concept has a couple of break-away possibilities. The first is the guide bushings and screws at the top of that small bracket. They are #8 and cantilevered from the bracket. The second is the bracket itself at its attachments to the bulkhead.

Dave
 
Good one, thanks.

4eTnNal.jpg


Who knows, maybe if I need an alternate..... These come in a variety of sizes from numerous vendors. But I don't know if they'd carry the anticipated load of up to 100 pounds in the open position, in tension. Also, I expect that when they straighten out they'd snap straight and that could be a problem. In many ways, this is a heavier version of the tape measure tape I was considering. While this has better ends, for my purpose anyway, otherwise it's just bulkier and heavier. But off the shelf, an important consideration.

So far I'm content to work with the concept I've pictured in my photo above. This is probably a good time to present the "Five Rules of Good Engineering." I didn't write these but I learned from them.

1. Part of the art of being a good engineer is knowing where
to steal good ideas.

2. Get it good enough and get on with it.

3. The best way to solve an engineering problem is to guess the
right answer.

4. Any **** fool can figure out another way to do it; i.e., the
first solution to a problem is often entirely adequate.

5. If you can't fix it, feature it. There's always a way to market
the problem as a benefit.

Dave
 
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Here's the final version of the hold-open latch. I still need to trim one leg of the bracket where it touches on the shoulder harness slot. I clecoed the canopy on just to get a feel for it with that, plus notice that bit of blue tape? To see if that touched the canopy. It didn't. In the open position:

FqlQSfd.jpg


And in the closed position, this time with the canopy removed.

3aM7kDC.jpg


Here, the latch arm doesn't interfere with the canopy. It did with the prior version. As it is right now, it works quite nicely, latching by itself when the canopy is opened, and by lifting the latch arm, the canopy is free to close.

The biggest changes as this evolved were the brackets that go on the seat bulkhead. Here is the evolution, from #1 through #3. Number 4 is the current version. Each tweak got me closer, although with #3, the poor canopy would touch the latch arm, so I had to tweak it one more time.

zRmUPJ6.jpg


Dave
 
Final latch

Dave, Mk III of the canopy latch looks good, I like how you managed to have the arm out of the way when the canopy is closed.
Perseverance paid off.
We of the older kits are BUILDER men! ;)
 
The main latch bars are now drilled through the frame to the fuselage. Since these photos were taken, I bonded brass bushings in to the frame, but that’s still in progress.

Here’s the latch shown open (the cam is not installed at this time):

k4iN8Fa.jpg


Here the latch handle is half-way:

4TzytlI.jpg


And here it is in the closed and latched positioned. These photos show that the latch bars do not slide axially, but because of the latch handle rotation, have a small rotation coupled to the axial motion. It's not much.

7oU9orZ.jpg


If you don’t remember the avionics shelf, go back to post #473 for a quick review. I removed the forward coaming, the cover forward of the panel, and trial-fit the avionics shelf to the fuselage. Here it is roughly in place.

vuDanik.jpg


Its aft face will become the switch panel. Here’s a view from the cockpit showing that face.

zgq4lMJ.jpg


The shelf had been resting in a pile of parts. Being fiberglass, and this being a fiberglass phase of the project, it seemed appropriate to do a bit of work on it.

Dave
 
Here’s the avionics shelf with the goodies resting on it. I think there’s room to run the wiring around but that’ll have to await actual placement.

XgQzPus.jpg


At this point, all three canopy latches all work as they should. That took more time than I’d expected. But they work now.

Since then I’ve been filling and sanding the canopy frame/fairing assembly. You know (or will know) the routine:
Fill, sand, paint, repeat. Over and over again.

In this sequence, there was a lot of time where I’d be waiting for something to dry. One thing that needed doing eventually is the manual flap handle latch system. Most of its interior parts are complete but unassembled; the latch or quadrant attachment has not been started. Here’s an overview of the system from drawing 30.

JK25ydf.jpg


Note 2: See these AN3 bolts? That’s because the latch hangs off of the seat rail, and the downward force is carried in what stress analysts call “heel and toe action,” with the bolt in tension. The quadrant must rest solidly on the seat pan - this was verified. It’s not a robust design and in any event, it interferes with my flat seat, which has #8 screws all along that angle.

Here’s what it looks like looking aft, also from drawing 30.

ECL7gMr.jpg


Note 1: With a downward force on the quadrant, those poor bolts need to transfer all the bending into the angle. The drawing shows the quadrant resting on the seat pan. Remember that my seat pan rests flat on that angle. I was pretty sure that I couldn’t get #10 nutplates in there if I wanted to. So I installed one more #8 nut plane and looked for ways to eliminate the bending around the rail.

After rejecting things like struts underneath, I settled on a beam to the seat rib next inboard. But since I’d need to cut away the seat pan to clear the mounting angle for the quadrant, that 2 x 1 1/2 x 1/8 angle, I needed to support the free edges of the seat around the hole. This shows the beam in place.

nlYtTJF.jpg


Getting back to the canopy fairing, it looked like today was a good day to spray it because the humidity was up. Stewart Systems EcoPoxy, water-based, needs a somewhat humid environment. Since my usual table outside had four inches of fresh snow on it, I painted it in the shop. EcoPoxy dries to the touch quickly enough that I could get a photo before I lost daylight.

SbLOn00.jpg


The timing was a bit of a jiggle because I was rising, proofing and baking a loaf of sourdough bacon bread simultaneously.

cteFlyX.jpg


Compared to an airplane, bread is instant gratification.

Dave
 
David - is that tall battery really going to fit all the way over there on the edge? Just checking.....

Your task on the avionics shelf layout is very familiar - I had to do the same thing on the Subsonex, as there was no guidance on where things should go, and the tapering glareshield (not applicable in the -3, of course) made for an interesting set of compromises.
 
Paul, good eye. A quick double check shows that it will probably need to be moved. My initial check had indicated that it would fit. Tonight's check was fairly cursory but it suggested the opposite. If necessary, I'll rearrange things, of course, and probably shuffle the contactors and ANL holders with the battery.

What I'm concerned with are the wire runs. Ideally, I'd like to arrange them so that they wouldn't impede removal of a device. That'll be a fun exercise when I get that far.

Dave
 
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Thanks for your blog Dave, interesting, well written with a good choice of pictures :cool:

Interesting to read how you encountered the same problems (ex. bulkhead flanges, etc, etc), plan inaccuracies, and more. Same as hundreds of -4 and -6 builders resolved with some head scratching before social medias or the internet. Brings back some sweet memories...
Built 3 VS on my -4, ordering from North Plains by fax, overseas money transfer and astronomical shipping charges, all fun in good ol’ times.

Some of your problem solving is, well, let’s say interesting, but on the whole a very good quality build, well done, looking forward to more.
 
Paul, good eye. A quick double check shows that it will probably need to be moved. My initial check had indicated that it would fit. Tonight's check was fairly cursory but it suggested the opposite. If necessary, I'll rearrange things, of course, and probably shuffle the contactors and ANL holders with the battery.

What I'm concerned with are the wire runs. Ideally, I'd like to arrange them so that they wouldn't impede removal of a device. That'll be a fun exercise when I get that far.

Dave

I am sure I shuffled stuff around on the Subsonex tray a couple of dozen times, each time thinking I had the “final, best” layout until I thought of some other reason it wouldn’t work (wiring runs being once of them). Also, I am sure you’re going to do this - Nutplates for all mounting screws so that out is easy to R&R components when required!

Paul
 
Paul, yes for sure, nutplates are on the list. I might use Click-Bond or the homemade version David taught me.

Tony, unfortunately not. But I come from long-lived people and there's hope that I'll get it done one of these days.

Incidentally, looking over the canopy fairing interior after spraying it, it definitely needed another pass of filling and sanding. In progress today.

Dave
 
The interior of the fairing is painted now. It took thee coats and if I had the time and paint I could have kept going, filling, sanding and painting. The paint added two ounces. The overall fairing/frame weighs 5 pounds 8 ounces without the latch hardware.

In these photos the fairing is upside down.

Here the latch is shown latched.

kQwP5PS.jpg


And unlatched.

7nS6VR7.jpg


The hex pieces on the bars will let me hold the bars when I tighten the jam nuts.

Later I painted the latch bars and make the external canopy latch handle. The latch bars were a little awkward to paint. They are tubes and needed paint all around. I set LP-4 -3 rivets in a piece of scrap angle and left the stems on the rivets. With the angle clamped to the table, I slipped the bars over the stems and sprayed them. Worked well, but a little wobbly. Before putting the angle back in my scrap bin, I removed the stems so that I wouldn’t get stabbed later.

Incidentally, I was using a $14 Harbor Freight touch-up gun for this. Good enough.

Dave
 
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Before gluing the canopy to the fairing/frame assembly, I needed to prepare the outer latch handle. Otherwise I wouldn’t be able to latch it from the outside. I chose to do it like the RV-8 plans show, even though their handle is a little different than the RV-3B version.

Mine is the C-406 handle. The RV-8 version is the C-656 one.

xxFHiQi.jpg


Note that this uses an 8-32 screw. The RV-3 and RV-3 type uses a 10-32 screw, as shown here in the RV-4 drawing:

00WxdA0.jpg


To my eye, using a #10 screw here appeared to cut away too much of the tube. We’ll see - I haven’t done the analysis but it wouldn’t be difficult to drill out to #10 if need be.

I drilled a pilot hole into the handle on the drill press, using a Vee-block to ensure squareness.

To line it up with the long axis of the plane, I removed the canopy fairing/frame and measured down the fuselage side from the left top longeron a couple inches and drew a line parallel to the longeron on the blue vinyl. After reinstalling the canopy fairing/frame with the latch in place, I pressed the handle on to the shaft. Then, with the latch in the locked (i.e., flight) position, it was an easy thing to rotate the handle until it was parallel to my line.

I had to use a 12” drill bit to drill through the shaft because the handle’s hole was so close to the side and the long bit was flexible enough to allow that. That’s why I used a pilot hole.

Removing the latch assembly and reinstalling it in the handle, with the handle back in its Vee-block, it was easy enough to drill it for the 8-32 tap.

However, when I went to tap the hole, the tap handle interfered with the latch mechanism itself as shown here.

G8AvS1B.jpg


Yes, I know I could have done this in my drill press or something, without using the tap handle at all. But I removed the assembly (two screws) and completed the job. Then I countersunk the end of the handle for the screw head, and carved the handle into shape.

I’d hoped to report that the canopy was glued to the fairing/frame assembly by now, but it’s not. I decided to finish the interior flange of the canopy attachment flange before that, since it would be difficult to finish it later. I had planned to simply brush on some of the gray paint. I'll use that HF touch-up gun for this. There’s some more filling and sanding ahead again.

Dave
 
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One of the small things I did recently was putting the flap handle together. I’d previously made the rod assembly inside the flap handle and someone made me a nice Delrin button, which I promptly lost. Hate that. One day it showed up again, having carelessly wandered into the wrong drawer. I assembled the system and found that my spring was way stiffer than desired.

I have a trick for assessing spring forces. If it’s for something that I operate with my fingers, I compare it to a common wooden clothespin, which generally has a decent feel. That led to trimming the length of the spring by about 1/2 inch, and now the button force is not bad.

The unprimed thing in the flap handle’s slot is nothing more than a tool, a retainer for the interior hardware. Whacked it out of .120 scrap. It does have one flap notch just to prevent it from falling out.

iQ2jH1g.jpg


Here’s a photo of the canopy fairing/frame while the canopy itself is still off, taken to show it’s overall size. Or show mine, depending upon your point of view. I'm the one wearing the mask.

zeZlYFw.jpg


More small things -

Made the covers for the roll bar cut-outs in the top tailcone skin.

Removed the gray SEM primer from the to-be-visible parts of the cockpit so that I can spray them with that gray epoxy primer I’m using on the interior.

Filled and sanded the interior portion of the canopy flange, and sprayed it gray.

After removing the tape on the inside of the canopy, I found that I had inadvertently made several smallish scratches near the perimeter flange. Some of them were a millimeter deep but short. I’m repairing those. Here’s how.

I put a Novus starter kit on order. For now, I used 400 grit to remove the actual initial damage, and then 600 grit to smooth that somewhat. The next sandpaper I had was 1,500 grit so I used that to get those small sanding marks out. Finally, I used 2,000 grit, the highest I had, to take it one step further. Besides this one, there are four other locations. This is by far the largest.

C1j2Ctp.jpg


I found that small strips of sandpaper, about 1/4” x 2” seemed to work best, and used them wet. This size seemed to minimize inadvertent over-sanding. I went through lots of small pieces of paper towel, cleaning the canopy, every few minutes.

There are also a couple of places on the flange that will need a final coat of the gray paint when this is all done.

Dave
 
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The canopy hinge pin retainer was pretty easy and works nicely. It's just a bent end that snaps into a tooling hole in the seat bulkhead.

zinYcrK.jpg


Here’s the right hand roll bar cutout cover. The left hand one is similar. Hint - the cover is cut on the inboard side to allow for installation. Drilling those rivet holes was difficult. It would have been easier to make the cut at the aft end. I chose to put it where I did so that the roll bar itself would tend to hide the cut.

hzjDwmQ.jpg


Touch-up paint for the roll bar is on order. It uses Eastwood’s 2-part rattle can paint. It sprays well and is durable, but once the paint is mixed, the can is only good for 48 hours. Still, for some jobs, it’s the way to go.

Since the Novus kit for polishing the canopy hasn’t arrived, I decided that I’d determine how thick a seat cushion I needed with what I had. I clecoed the canopy to the fairing/frame and attached the hold-open latch. The other latches are operational.

kuMcva7.jpg


The round thing on the seat is a block that’s 1 7/8” thick. The “seat” is merely a slab of 2” insulation left over from the fairing mold. Turns out that with this thickness, the block just fits between my head and the canopy. This clearance is about what my mentor advised, so I guess it’s good.

You’ll remember, perhaps, that the RV-3B has a concave seat, to allow for a tall pilot.

B3e4abv.jpg


I had made mine flat since most people seem to carry some foam filler down there.

Now that I know my sitting position, there are any number of things to work on. An incomplete list:

Throttle,
Manual trim lever,
Avionics shelf,
Side panel design,
Rudder pedal and brake cylinder mounting (they are merely clecoed in for now),
Fuel valve,
Com antenna doubler,
Baggage rib beef-up.

The last is because I lightened them before I installed them, and went considerably too far. These are the parts with the blue vinyl.

FQBtamg.jpg


Now they are glued and riveted in and are clearly not strong enough. The really annoying thing here is that my career was as a stress analyst and I did not address these. Time to fix them. I’m installing some light angles vertically where the webs are in between the holes. I’m not putting them at each location but about every other location. I’ll still save some weight, but not as much.

I’m using some of the extra 1/2” x 1/2” x .025” angle stock that the baggage floor stiffeners are made of. Fortunately, I’d bought extra. Any two of these can carry the rated baggage load.

Dave
 
I sure hope so. Your RV-3B is one of the really good ones. Rob gave me a tour when he brought it out here.

The baggage rail stiffeners are now installed. They were glued in place and then riveted. The work platform is askew because the fuselage was on its side; I rotated the photo so it appears right side up.

QW0zVbr.jpg


The Novus kit arrived and I was able to polish out the remaining marks on the inside of the canopy. That stuff really works! After that I sprayed the last few places on the canopy flanges that had been marred during that work. It wasn’t the work itself that marred the canopy flange paint, though, it was the tape I’d put on the fresh paint to identify the locations to be worked on, and which lifted the paint in small spots. Anyway, that got fixed too.

After a little more prep work, Dallice came by to help me glue the canopy on. It took us just about an hour. There was considerable squeeze-out, as hoped for, and in the photo Dallice is filleting the edges. After it had oozed for a while, I opened the canopy and did the same in a few places inside.

791SO1J.jpg


That milk carton on top is filled with scrap metal. It makes a good weight.

The exterior of the fiberglass is more than a bit rough, and that goes to more than just surface texture. I’ve got some shaping/sanding/filling etc. in my future. But most of that will wait till I’m back on fiberglass with the cowl. For now, the canopy/fairing/frame/latch assembly is complete but for finishing.

Dave
 
Dave,
This is such a great project to follow! Seeing how much work and detail goes into the construction of the early kits is amazing.

Looks great!
 
Moved the canopy out to the hangar to get it out of the shop. Here it in in my car.

JkW6QTH.jpg


The crate and support frame I had been using as a stand for it are in my truck for the next trip.

Kent, this whole canopy assembly is non-standard. I'd have saved a lot of work if I'd generally followed the plans here. However, I enjoy composites and wanted to make something from scratch of that material for this airplane. This is it.

Dave
 
The steps are made but so far are unprimed. Since the spar bulkhead’s flange is truncated compared to what drawing 24 shows, I added a J stiffener to that area of the step. And since the joint to the seat pan also felt less than stiff enough, I put one there, too.

s1vDfy1.jpg


0xilCbw.jpg


If you look closely you can see that initially I drilled the steps for a nutplate that belongs on a mating flange. I’m in the middle of adding the new nutplates needed, and have some screws on order.

Incidentally, Russell made his steps .063. Mine are .025. I dropped something on the left one and it put a small ding in the step. There’s probably a happy middle thickness, but it might include not dropping stuff on it, too.

After the steps, it was time to start mounting the avionics shelf. But before that, I tried to mount the rudder and brake pedals. After moving them to a position that felt about right, I discovered that I needed more hardware. Oh, boy, two jobs in a row needing more hardware.

Moving right along to the avionics shelf, it seemed like a great time to attempt to mount it. So far I haven’t needed more hardware, don’t know how this one slipped by. The fore-aft position is still a little bit TBD but since there’s only about 3/8” available to adjust it with, it’s practically there. The next thing I found was that it wasn’t quite as stiff as I’d like. First I added a layer of carbon to it, with a layer of glass on that, and that helped.

A larger improvement came with a small change to the mounting arrangement. This also pointed me to a convenient place to bring the belly wiring up to the shelf, another good thing to figure out. Those wires will come out the top of the spar bulkhead pair on the right side.

Two little brackets as yet unfinished will hold the aft end of the shelf. The forward end is semi-TBD; I've got some ideas but nothing final.

I started reassessing the position of the components yet again. Here’s one version with the EarthX 900VNT battery on the shelf.

f6WfTEh.jpg


The 900VNT is overkill for my O-320 with its 40 amp alternator but it’s the only 12 V battery they make that’s vented, and I won't put an unvemted on in the cockpit.

This post told me that the 680C fits in the cowl cheek and I verified that. John put it in the cowl cheek on his RV-4 but it also fits in the cowl cheek extension aft of the firewall on an RV-3B, and I might put it there. It would be very convenient except for needing a hatch. Here’s the shelf layout for that case.

TZBtE6r.jpg


In either case, the EMS will go on to the aft face of the firewall recess, which is convenient and there’s plenty of room for the cables.

You might notice that the last layout has the main power components on the right side instead of the left. That shortens the cables, with the battery in the right hand cheek extension.

I’ve been amusing myself trying to decide what goes on the switch panel. The switch panel is integral to the shelf but isn't really visible in these photos. The only thing I’m certain about is that this is a small airplane.

Dave
 
Steps

Good move on making the steps with 025, I have found that when entering and exiting the cockpit I am stepping onto the seat and not the "steps". Mine (as I built them) are quite heavy and I subsequently drilled lots of lightening holes in the angle pieces.
It's looking good Dave, very neat.
 
This is a mock-up of the switch panel that’s under the instrument panel. The real one is integral with the avionics shelf and I didn’t want to drill holes in it until I was sure of the positions. This is the first pass at this, revision 0, and I'm sure glad I did this rather than committing to the real thing.

LnbJ0V0.jpg


The two dowel pieces are the prop and mixture controls, both verniers.

From left tonight, the items are:

Prop vernier
Start
Mixture vernier
Master Battery/Alternator
LH ignition
RH ignition
Fuel pump
Nav/Strobe lights
Landing lights
Autopilot disconnect pushbutton
Autopilot servo power
LH Pmag breaker
RH Pmag breaker

The few warning lights will be on the instrument panel.

Still to be figured out -

Cabin heat
Carb heat
Carb ice detector switch
Carb ice detector adjustment knob
Alternator breaker

Ok, now to the question - since it’s in place, no doubt I’ve had a chance to sit in the cockpit and give it a try. How did it work out?

Well, not so great. The verniers are in the way of getting into the plane or egressing. They need to move either to a quadrant or to the left spar bulkhead side.

The start switch, and it’s a very nice start switch indeed, Stein sells these, is not bad but moving it to the left would be an improvement.

The four core switches in the middle are well-located one to another. But I’d rather that they moved to the left, too.

The autopilot disconnect pushbutton, that red thing near the right, is right in front of my right knee. I don’t think I’d bump it accidentally but it would be better situated either in the middle or on the right side.

The remaining switches are fine and their position isn't that critical, at least in this version of the design. Well, there is this one thing…. Right now there are no labels and I had thought that I’d be able to easily tell from the switch position whether it was on or off. Several of the switches have a middle position and frankly, it’s not easy for me to look at these and tell what switch position I’ve selected. This was an unexpected and unwelcome surprise; I'm beginning to understand why people install fuel pump on lights. The labels will help, I expect, as will more experience with these. We'll see.

The fore-aft and vertical positions of the panel are entirely satisfactory.

Quite clearly I have a redesign and some rethinking ahead of me.

Dave
 
Finn, there’s plenty of stick clearance, and although I checked that before committing to this avionics shelf/switch panel system, it was definitely worth double-checking now. I didn’t measure it but it appeared as if there’s at least 1.5”, and the actual flight avionics shelf is shown in place. The stick is balancing in the closest postion to the switch panel.

moOryyo.jpg


The tennis ball is my idea of a decent stick grip. You can hold it and get a good grip on it in any direction. It never feels cold to the touch and it doesn’t weigh much. Best of all, it has zero switches. A solid plus all around.

My dog Sawyer, who’s no longer with us, spent years teaching me the advantages of a tennis ball. Here he is in mid-lesson.

GY6sStg.jpg


He took his tennis balls seriously. After he passed I counted about three dozen scattered around the house. The one on the stick is a brand new one, though.

This position of the prop and mixture verniers, over on the left, looks like it’ll work out pretty well. But not.

After I took the photo, I sat in the cockpit and found that I needed to move the verniers closer to the inboard edge there, and considerably further down. Hand clearance drove them inboard and throttle clearance drove them down.

One thing I'm wondering about is the relative position of the prop and mixture control. As shown, the prop is above the mixture. Here in Colorado I'm more likely to set the prop and then leave it alone, I think, while the mixture will need adjusting more often. Any thoughts?

I haven’t reinstalled the flap control handle but obviously that’s coming up soon.

Dave
 
thoughts

Dave,
I like the idea of the tennis ball, if it was luminous then that could also help with night time ops.

Here are some other ideas to consider, depending on how far the re-thinking is going to go:

The clock in the middle is taking up prime space and could be re-located to a wrist, or eliminated since the Dynon has built-in clocks and timers. An efis timer can be used to prompt switching fuel tanks. The efis and ipad could then be moved more to the centre and up, freeing up space along the bottom of the panel for engine controls. This may solve the positioning and convenience of the throttle and prop verniers.

I'm curious about the need for an analog airspeed, but not an altimeter? Is it intended for backup, or just personal preference for round gauges? I like round gauges too.

And assuming you must want to fly right-handed, rather than relocate the engine controls opposite to the side where you get in?
 
The airspeed indicator is simply because I am trying to preserve the operational similarity to my C180, which not only has one but has the same maximum flap speed. Also it's a back up if the wee little electrons get lost.

I believe I have enough experience to be able to estimate my altitude well enough to stay safe for the day VFR flying I do. Good enough to fly a pattern, anyway. I don't think I need a round altimeter.

The clock is to easily tell me which tank I need to be on - whichever side the minute hand is on, that's the tank I need to be on. And if I forget whether I've switched a tank, it doesn't matter, just follow the minute hand. Since I fly the C180 set on both tanks, tank switching will be a new thing for me. I wanted an assist. That led to it being both clear and obvious.

The com radio cut-out fell off of the panel. It goes in that bottom gap in the middle.

Yes, I fly right hand on a stick when I fly a stick plane. Left hand on the stick feels unnatural.

I'm old enough that I want the plane to fit my own idiosyncrasies as much as I can.

Dave
 
Here’s the next revision of the switch panel This one works fine - it’s what I’ll do for the real one. Left to right,

Start
Master Battery/Alternator LH ignition
RH ignition
Fuel pump
Nav/Strobe lights
Landing lights
Autopilot disconnect pushbutton Autopilot servo power
Cabin heat
Carburetor ice detector sensitivity
Carburetor ice detector off/on
LH Pmag breaker
RH Pmag breaker

3I0ZRzu.jpg


The carburetor ice detector warning light will go up on the panel somewhere. I thought of putting it in that space to the left of the two breakers, which would be similar to the position it’s in for my C180, but honestly, that wasn’t something I wanted to duplicate.

I’ll decide where the carb heat control will go after I figure out the side panels or at least get a hack at them.

The two verniers seem to be home right now. In case you’re wondering how I put them on, I put a flush screw in the back of the dowel pieces (the forward end) and then put magnets in the bulkhead. This let me move them around and play with them.

Flashing back a little to the mold for the canopy fairing… I learned that instead of covering it with plastic and tape, I would have been better off covering it with heat-shrink plastic film, like the kind used on windows for extra insulation. It would have given me a smoother, tighter surface. Oh, well. I learned that from Jim Marske’s excellent “Composite Design Manual.”

Back to the avionics shelf with its switch panel now.

The forward end of the shelf is hung from the upper longerons with a couple of fittings. The first step in this was to glue the fittings to the shelf’s forward face. The photo shows the shelf upside down on my work bench.

0mzIc2G.jpg


Then I laminated some glass to the fitting and the face. The shelf is still upside down in the photo.

Qaugmn0.jpg


The glass will get one screw to each aluminum angle at the outboard end of the glass to aluminum joint to ensure that the glass doesn’t separate at the bond where it’s most highly loaded.

While that was curing, I made a throttle lever. The holes can potentially give several options for getting the gearing correct. The second hole down matches the lever throw with the carburetor throttle lever travel.

hsZkhDh.jpg


The green handle is, if I remember correctly, from an antihistamine container. It’s light and stiff and the feel isn’t bad. I
Drilled it for the push-to-talk switch and tried it out - seems to be satisfactory. I also soldered the leads to the PTT switch. That one is from Steinair like the excellent start switch, but doesn’t have nearly as good feel. Like the AP disconnect button, there’s little feel to it. I've got an Otto P7-5 on order for a replacement, per Mike W's recommendation from a thread in the Electrical section.

The handle will be held on with a couple of blind rivets, unless I change handles. I don’t care for the gun handles and whatever turns up would have to beat this one. And if you're thinking, "hmmm, tennis ball stick grip, medicine bottle cap for the throttle, is he going to use a beer bottle cap for the carb heat or cabin heat?"

I doubt it.

Dave
 
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How tall are you? Small cockpit with extended panel = for short folks only.

Looking at where the longerons pass through the panel as a reference, it isn’t much of a panel extension. My RV3 panel has a bit of an extension near the middle and I’m betting I could take at least a 3 inch extension across the entire width without inhibiting ingress/egress. I’m 5’10” and of normal proportions these days.

I definitely agree that it’s something to be mindful of. My Glasair has an extended panel and it’s barely acceptable to me and my 6’ tall brother really struggles. I’m going to be cutting 1-1/2” off the bottom for my new panel.
 
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