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RV-3B Dave's in Colorado

Seems like it's been a long time... in fact it has been.

The things I've done in the last month are small stuff. I'm getting ready to attach the next long side skin, and while it's still off, wanted to do some of the smaller stuff. These are things like riveting those bulkhead flanges that I made to the bulkhead's webs. These are finally done, along with a few less exciting things.

Riveted_Bulkhead_Flanges_S.jpg


Since I'm waiting on a few things before gluing the side skin (it's the right one this time), I started on the belly skins under the seat. There are two of these, F-322, and they overlap both the spar bulkhead and the seat bulkhead, with two rows of rivets each. Drawing 23 shows most of the rivets, with Drawing 24, section A-A, as a supplement. Still, the rivets between the F-304 bulkhead, that short one in between the two center seat ribs, and the skin aren't mentioned anywhere that I could find. Here's a top view of the seat structure from Drawing 24, showing the bulkhead. Not being the bottom view, the rivets that are shown don't apply to the external skins.

Dwg_24_Excerpt.jpg


I've been locating and drilling holes in the fuselage frame under the seat and in the skin. The right-hand skin there is now mostly drilled and clecoed. It needs some trimming, and yes, I know not to cut out the skin in the area aft of the rear spar.

I've been going so slowly that I thought a bit of motivation might be appropriate. I know that a lot of us put up photos of similar airplanes or sketches of paint schemes that they like. Other people display model airplanes... the list is long. Since I like, never, pay much attention to self-help posters, it occurred to me that the back cover of the 2017 Van's Aircraft calendar might be just the thing. By the way, friends, that cutaway RV sketch in the background is an early view of an RV-3, just as it should be.

Back_Cover_2017.jpg


We'll see if it speeds things up.

In case these photos disappear, perhaps the alternate photo hosting might continue to work. Perhaps. Worth a try in that event. Here are duplicates of these images:

https://imgur.com/tGyq3T1
https://i.imgur.com/L4zn2Ve.jpg
https://i.imgur.com/6EoEz5U.jpg

Dave

Awesome! Watching this build is encouraging!
 
I got a PM asking a) which version of Gflex did I use and b) what about adding aluminum powder to the epoxy and c) what about aluminum shims?

I used the Gflex 655K stuff. It's the thickened variety. I bought, I think, a two quart package. With no additional additives, it doesn't sag on a vertical surface, at least in the thicknesses I've used. It's the right viscosity, right out of the can.

I've tried adding aluminum powder at about 5% to 10% by weight to the mixed epoxy weight, and that did add viscosity (which didn't help anything) but also made the epoxy noticeably more brittle, so I discontinued it. It also seemed to diminish the adhesion. My goal adding it was to make the epoxy have more stiffness in compression, which it did, but wasn't ultimately an overall improvement. Now I use the epoxy straight with no additives.

My mentor will not accept a gap thicker than about .015" without aluminum shims. I try to do the same but that's a difficult thing to control well on sheet aluminum parts. Once in a while, not often, I have a shim on top of another shim. The glue does a good job of keeping these intermediate assemblies in place. In fact, that's where I really like using it: to keep parts in place during bigger assemblies.

In other news, I botched the left-hand belly skin under the seat. There was one rivet which had too small an edge distance. There's a new part on order. That exercise used up the weekend for me.

In the meantime, I'm back to work on the right hand tailcone side skin, prepping the various parts for the bonding operation.

While it's inevitable that the tasks immediately ahead do kind of stand up and wave for my attention, one thing that I'm trying to do is to only work on a few separate things at a time, the fewer the better. One, just one, is ideal. The project feels less complex that way, since I only have a single thing to think about at a time. The shop is easier to work in, too, with less clutter and less chance of losing things.

One thing I wanted to include on the panel is a decent slip indicator, one that's physical like the ones in a turn and bank instrument. But I didn't want one of the huge ones that seem to be available from the major vendors. I ordered an S0093-2 from Rieker, Inc., and it arrived. It's very light and tiny, maybe 2" long and about as big diameter as a pencil. Here's Rieker's stock photo. Mine has a white background. Cute little gadget. The ball is highly dampened - I think it'll work very well.

S0093_WHTball_sm.jpg


This, the 8-day clock and the airspeed indicator are the analog devices that will be in the panel. I expect that with these and my old last-century non-electric eyeballs, I could probably get the plane down successfully if the electrons decide they've had enough fun and want to take the rest of the day off. But I do hope that they stay on the job.

Dave
 
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One thing that someone asked about off-line about bonding and using shims, is that yes, of course, each surface of the part-to-shim-to-part joint needs to be properly abraded and cleaned. There's no point otherwise. And don't just take a wag at the epoxy quantities; measure it with a gram scale.

Here's that photo of my slip indicator. The housing is plastic, contributing to the very low weight.

XylcYfz.jpg


The right-hand tailcone side is now on for the final checking before gluing. There's still some prep to do before I get that far though.

8Qm3sBf.jpg


The F-303F strip in the spar bulkhead center section has, for some time, had the AN426AD4 rivets installed. I understood these to attach this piece to the bulkhead pieces, with the AN426AD3 rivets for the skin splice while the skins themselves didn't have these rivets. I looked at the drawing, below, again, since those skins are next, and decided that I was mistaken: the AD4 rivets definitely appear to go through the skins as well as the F-303F strip and the bulkhead halves. I drilled those out and match drilled these holes through the skins, after replacing the left-hand skin because of insufficient rivet edge distance on the previous one.

KLHZESD.jpg


The area is also shown on detail B-B, Drawing 23. Note that the rivet spacing conflicts with Drawing 11. However, Drawing 23 is all about the skin riveting while Drawing 11 is all about the spar bulkhead. I think that a reasonable interpretation would be that 11 controls the locations of the AD4 rivets and 23 controls the AD3 rivets - but it's conservative to use the closer spacing:

bO8TLlO.jpg


In my case, it's moot - the holes are already drilled.

The seat belly skins are clecoed on now:

UcP8uRX.jpg


The belly skin for the firewall to the spar bulkhead that came with the kit is, for some reason, slightly too short for this fuselage. I'll order a larger one. The forward side skins appear to be the right size.

If these photos have disappeared, try this alternate hosting location:

Here, here, here, here, and yes, here.

Dave
 
At the time (in an previous post) when you mentioned setting those F303 strip rivets I did wonder why you did that, couldn't see that it would compromise anything anyway. I did give my #30 reamer plenty of use when I riveted the floor sheets on mine as the 4 layers that come together here did make hole alignment for easy rivet insertion a little difficult.
Your fuselage is looking very nice Dave, looking forward to seeing it flipped.
 
At the time (in an previous post) when you mentioned setting those F303 strip rivets I did wonder why you did that, couldn't see that it would compromise anything anyway.....

I did it because it kept the two spar bulkheads located correctly with respect to each other, sort of as a tooling aid. But in retrospect, that wasn't necessary.

Dave
 
Glued the RH Tailcone Side

I gathered together the same crew as last time, experience counts, and we glued on the right-hand tailcone side today. Like before, we used thickened (this version comes prethickened) G/Flex epoxy along with an exoskeleton framework that will come off when the glue sets far enough.

But that's in the near future.

Today, we spread the glue, put the skin in place, and clecoed on the exoskeleton and filleted the glue along the inside edges of the bulkheads and the longerons against the skins. In fact, that's what Dave is doing in this photo.

2J0zYKZ.jpg


After a few hours, while the glue was still tacky, I removed all the clecos and replaced them with fresh ones. The original ones had been oiled so that they wouldn't stick but the replacements weren't.

One of the benefits of adding this overall process, of gluing the skins on, to the general RV construction, is that it provides hours and hours of prep work. It's a good way to absorb excess spare time.

One of the steps before the actual bonding was double-checking that the fuselage is still straight and true in the jig. Got lucky there: it hadn't changed and was still in rig.

If the photo disappears, try looking here.

I'd ordered a new F-321 belly skin and it arrived. My original one from the factory was just a tiny bit short; not knowing whether it was the factory or my particular fuselage, I just ordered a new piece. I ordered 25" x 26" x .040" and it'll clearly fit okay.

Dave
 
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David. I have been following your thread here for some time. Really great work. And as a flying RV-3B owner I have perused your photos when working on the bird, in a sort of anatomy book fashion. It's great to see the structural detail when I am doing systems runs and the like.

Your bird is looking to be a stellar example.

Thanks for taking the effort to document things so well.

Jim
 
The exoskeleton is now off the side. Even without the clecos, it hasn't fallen off the fuselage, so I suppose the magic worked again.

I had made one mistake, though. The exoskeleton at the top longeron, which you'll remember is at the bottom of the inverted fuselage, immediately adjacent to the jig as is the longeron, has some squeeze-out that I didn't remove soon enough. With the exoskeleton off, this flashing was very apparent. Here's a bit of it. It's that tan band under the aluminum.

CjGvFOI.jpg


If I'd trimmed it off the evening we glued it, all would have been fine, but I didn't. I removed it the next morning but it needed a Vixen file.

You can also see some glue that oozed through a rivet hole and another that got filled up. We were a bit generous with the glue, apparently. I don't put a cleco in every hole, since the idea is only to make the surface smooth and hold the skin on in the right position. After I took this photo, I spotted that and it came right off. In any case, cleaning up the rivet holes and countersinks generally is pretty easy.

This side came out better than the left side.

The alternate-hosting site has this photo, too.

Dave
 
I finally reread the manual for the areas I've been working on. Should have done that earlier, as it would have told me the correct way to assemble that spar bulkhead strip that I had to unrivet. The manual says "The rivet holes through the skins and the bottom flanges of bulkhead F-303 should not be drilled until both skins are in place."

I agree with this with one exception: if you drill through the bulkhead flanges first, then when the skins are in place, you can back-drill through the skins using a 12" bit, and there will be no difficulty locating the holes on the skins. Just watch out for edge distance when you're locating the holes on the flanges and when you set up the skins for drilling.

Also, note that some of the rivets are -4. When you're doing the drilling, if you don't go bigger than #40 at this time, you'll save yourself some time. You can drill those holes to #30 before dimpling. Just don't forget.

I glued the strip on to the flanges. That'll let me remove those clecos during the fitting of the forward belly skin.

A machinist friend made the button at the end of the manual flap handle and cut the slot. The bearing blocks for this are ready now, too. The plans don't show it but the manual correctly says to install nutplates under the bearing block mounting angle to facilitate easier maintenance. Since my seat rib flanges were running low on edge distance (the extruded angle is ample) I made a small plate to rivet the nut

Image_1.jpg


The photo also reveals that the exoskeleton angles for the seat pan skin are done. I had to use my shrinker/stretcher to get the correct curve in these.

Here's a bit of tape that I removed as part of the process when I glued the right side skin on. Clecos protruded through the holes and carried glue along with them. I pulled the tape off and the glue came along with it, nice. Since the clecos themselves would push the tape away, I poked slits through the tape in each of the cleco locations before gluing.

Image_2.jpg


The alternate photo hosting site has these photos, too. The first one and the second one.

Dave
 
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The left-hand belly skin under the seat is now glued on. Here it is with the glue curing, the exoskeleton in place, and the tape freshly off. Removing the tape is one of the first things to do after the clecos are in (the first ones are wiping off the cleco tips and filleting any joints).

Image_3.jpg


Then I made the exoskeleton for the right-hand side and did all the prep. As of today, this skin, too, is glued on. This photo shows the same status as the first photo but on the right side. Note that some tape is still on, under the exoskeleton.

Image_4.jpg


While I was close to the details, I resolved to correct a bad area on the very bottom-most longeron just aft of the firewall. I hadn't positioned these correctly on either side. Initially, I thought that shimming them would suffice, but the more I thought about it, the more I leaned towards simply replacing these. Haven't done that yet, but that's coming up on my list.

The arrow shows the gap. This is the left side; the right side is worse.

Image_5.jpg


Alternate photo hosting, in case these photo have disappeared

Here's one,

Here's another,

And if I've done it right, here's the final one.

Dave
 
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Forward Belly Skin

Working on the forward belly skin, F-321. This one is the .040 piece that goes to the firewall.

The first bit of work I had to do was to correct the bottom edge of the forward lower longerons and the F-312 (mine aren't stock) ribs so that their aft edges fair to the seat-area belly skins. I'd made them too high. Fortunately I had enough material to do these things.

I put a description of this on the RV-3 Clarifications page.

After that, I had to bevel the forward edge of the forward belly skin to fit between the firewall bottom cross-piece and the firewall lower flange - wish that were wider, but it's not.

Then I could start clecoing the skin on. I worked from the going front aft and things went well enough until I got to the spar bulkhead. That has the wing dihedral angle in it so that the bottom of the skin isn't flat. Since the forward belly skin is one-piece, that meant that there's a compound curve going over the bulkhead flange.

I made a tooling piece and suppose I should call this a Howe fitting like the ones I used on the wing. Same sort of affair, held on and pulled tight with straps. Fortunately the .040 skin is relatively robust and it pulled down without trying to buckle.

Putting the carpet on the fitting, with a much-used roll of carpet on the right,

F321_Howe_Fitting_1_S.jpg


And then I added a post in the center area, where I wanted local pressure.

F321_Howe_Fitting_2_S.jpg


The skin overlap at the center of the spar bulkhead, where the seat belly skins overlap, left a bit of a gap under the F-321 forward belly skin. I glued on some shims and they're curing now. I can strap down the Howe fitting when they're set.

The photos are also at this place and this one too. Just in case.

Dave
 
I clecoed the forward belly skin back on and used straps to tighten the Howe Fitting in place over the spar bulkhead. That is, it's "over" because the fuselage is being built upside down, but as far as the airplane is concerned, it's under the belly.

Fwd_Belly_Howe_Fitting_S.jpg


The compound curve due to the overall geometry still produced a ripply in the skin. I could not find a way to position the Howe Fitting to avoid that, even using shims. This shows the ripple.

Fwd_Belly_Ripple_S.jpg


With no other alternative, I consulted my mentor, who said that he'd cut the skin to relive the ripple. I decided to try it. A colleague in Australia had sent me a photo showing that he'd done it too; plus the RV-4 plans show something similar in the same location.

The cut was made using a Dremel cut-off disk and took a very short time. It's about .050 to .060 wide and 1.72 long. The hole at the end is for stress relief and is reamed to #30.

Fwd_Belly_Split_2_S.jpg


Here it is in place. Bottom line, it works. The ripple disappeared.

Fwd_Belly_Split_1_S.jpg


Now I wish that I hadn't thrown out the nicely drilled exoskeleton for the spar bulkhead after gluing on the seat belly skins. But it's a small workshop and alas, I did that.

The pictures might also be found here, here, here and here.

Dave
 
RV-3 building

Wow, what a great documentary on building the kit. I have picked up a kit ( SN 10006) with a lot of the work already done. But reading about your building helps me understand what all goes into one of these. I am a couple of years away from having a place to finish building the kit, (if I do) and will continue to review your building to learn more. I am also looking at possibly selling the kit but want to pass on as much information as I can. My wife(as do I) filp/flops on sit on it versus sell it. Storage may become a problem.
I will be researching the RV-3 more anyway. I would be a first time builder and need to move to an area with a good building chapter for help. Right now I am working towards the CFI rating as I enjoy sharing the sky?s and teaching/coaching people.
Thanks for sharing all your work on this with us.
 
Garwin, I tend to be slower than a lot of builders, so don't get the impression that an RV-3 is a huge amount of work, as it might not be for someone else. It's entirely doable and it's been an enjoyable process. I started this kit more for the project than for a flyable airplane and that might tend to draw the project out a bit, too.

You're right about documenting the construction of it. I hope to do that just to show how I've approached certain tasks and some of the RV-3 hidden gotchas.

Lately I've been working on the tunnel and that's been one of the more fun little jobs. I'm still figuring out how to add some Fiberfrax and titanium to the belly for insulation and as a firewall. I just need to settle on a construction sequence but there are no real stumbling blocks with it. I'll discuss that when I have some more time as the April - June period tends to be my busy season.

Regards,
Dave
 
With the tunnel shells and bulkheads drilled and fit, it was time to consider the belly insulation and fire protection. The insulation is 1/16" Fiberfrax and the fire protection is .020 Titanium. I chose that because the FAA recognizes .016 Ti as acceptable for firewalls and .020 was available from McMaster at a reasonable price.

Most people who do this use stainless steel foil. KatieB used that foil, for example.

Katie_B_Foil_FW.jpg


But I got to thinking that the protection is more than from heat; it's to guard against actual fire under the belly behind the engine hot air outlet. The belly is aluminum, .040 thick to be sure, but still aluminum. I decided that primary firewall protection should be added. Hence the .020 Titanium.

At one point, it looked as if the Fiberfrax and Titanium sandwich would both go between the tunnel shell inner flange and the belly skin, and made this test piece to see how much the Fiberfrax compresses after being riveted with LP4-3 rivets. The side view shows minimal compression.

Fiberfrax_Compression_S.jpg


When looked at in the right light at the right angle, though, some dimpling is visible in the simulated belly skin.

Fiberfrax_Dimpling_S.jpg


Later, I riveted an AN470AD4 rivet in one end and that seriously did compress the Fiberfrax.

Therefore: the Fiberfrax should not be part of the structural connection between the skin and the tunnel. I decided to stop the Fiberfrax by the inboard edge of the tunnel shell. This led to some rivets on the belly going through the Titanium and others not. It appeared easy to screw up (still does) so I made this guide.

Fwd_Belly_Skin_Annotated_Commented_S.jpg


One issue is that with the Fiberfrax stopping at the inboard side of the tunnel shell, and the rudder pedals above the tunnel shells, what about insulation there? But I think that the tunnel shells themselves will give me some insulation, and if I add a bit of the Titanium to the inner wall, it'll be somewhat protected, for a short while anyway, against flame. With no Fiberfrax on the inner walls, heat on the Titanium can work through to the aluminum tunnel shell. No problem for normal flying but in a real fire situation, they could melt. Still, that'll give me some protection for a while.

The photos can also be found -
here,
here,
here
and
here.

Dave
 
After making the titanium belly overlay, I clecoed it in place. Forward is to the left. That overhanging part is to allow for a rounded entry for the air exit.

Belly_Ti_Fitting_S.jpg


Then I glued the belly piece, the aluminum one, on to the frame. We'll get to that photo shortly.

With the belly on it was time to rough-fit the forward side skin. I started on the right-hand side. I had assumed that the cut to fit the overhanging seat belly pan would be difficult and it wasn't too hard. It was just a matter of marking the edge of the belly skin, fitting, repeat. Another part that I'd thought would be hard was locating the rear spar stub, which pokes through the side skin.It wasn't so bad, either. I drilled holes at either end of the cut-out and then used my Dremel to cut the slot out.

Did you know that I've already worn out my first Dremel-like tool? Now I'm on a name-brand one, and frankly preferred the older one, a "Master Mechanic."

Here's the rough-cut of the right-hand forward side skin in place. You can see that I went slightly too far on the bottom of the rear spar slot.

RH_Fwd_Side_1_S.jpg


And here's a photo of that forward belly skin I promised you, plus the untrimmed bottom edge of the side skin. The rectangles on the belly are there for the double-flush middle rivets to the titanium overlay. These are also stand-offs to ensure that the Fiberfrax doesn't get compressed by these rivets. The rivets are double-flush so that they don't interfere with my feet in case I leave the floor uncovered.

RH_Fwd_Side_2_Fwd_Belly_S.jpg


I'd taken the opportunity of the above photo to mark the side skin for trimming. Here it is trimmed and unfinished. You can also see the titanium overlay, now dimpled, resting on the fuselage out of the way.

RH_Fwd_Side_3_S.jpg


When people say that the RV-3B isn't prepunched, this is what they mean. This side started as a rectangular piece of aluminum, cut slightly oversize to allow for trimming.

You might note that several skins haven't been riveted yet: the right-hand tailcone side skin and the belly skins forward of the rear spar. These need to be riveted before these forward side skins get glued on.

The photos are also hosted here, here, here, and here.

Dave
 
Here's the titanium belly overlay in place. Nothing unusual about this except that the .063 spacers in the middle area under it are forcing it to lay in a mild compound curve, since the perimeter lays flat on the aluminum belly. I just clecoed it on so that I could verify that indeed, this works.

Ti_Belly_Overlay_in_Place_S.jpg


Then it was time to start shimming the area at the seat bulkhead where the bottom longeron and the angle that goes by the seat area all intersect. The design is somewhat crude there and I ended up with a bit of space to shim on the angle at the seat. This is the area at the red ellipse below.

Forebody_1.jpg


If I ever build another RV-3, I'll pay a lot more attention to this area during the construction. And no, I don't have a solution that you can implement on yours. Please understand that since I'm not a great builder, that I could have simply screwed up -- but I don't think so; this is not the only one of these to need something here.

I'd bent the angles, somewhat, to allow for this, but there was still some space to fill. So I clamped an angle on the outside of this area and measured the gaps. From that I selected some shims from my scrap pile, cut them, abraded them and cleaned them, and then glued them on. Here they are with the glue still wet and the clamps still on. First the right side.

RH_Seat_Angle_Shims_S.jpg


And the left side,

LH_Seat_Shims_S.jpg


I anticipate that these will be sort of a starting point, with more shims necessary. But I won't know that until I've cleaned these up.

The photos are also here, here, here and here.

Dave
 
"The design is somewhat crude there and I ended up with a bit of space to shim on the angle at the seat."


Yes, a good description! I shimmed mine here too but not to the same extent, same idea just not quite as far.

Russell
 
The Titanium layer on the forward belly has a portion that needed to be rounded to be part of a more efficient cooling air exit than the stock design. In this view, it?s already partly bent. I just grabbed one end of the pipe with Channel Lock pliers and rolled it up. The pipe, of course, was taped to the Titanium.

Ti_Ready_to_Curve_S.jpg


Then I rolled the initial curve into it the same way as we roll the empennage surface leading edges.

Ti_Initial_Curve_S.jpg


Getting a pipe with a fatter diameter, I was able to give a more gradual aft radius.

Ti_Final_Curve_S.jpg


This is the final shape, except that I expect I?ll need to do some trimming when I put the engine mount on.

The front bottom of the belly has some nuts and bolts that attach the engine mount fittings. I?ve got these nuts torqued. The reason they?re being shown here is that the tunnel shell will eventually get riveted over them and they?ll not only be inaccessible, they?ll be hidden from sight. However, if absolutely necessary, an access hole could be put into the tunnel bulkheads, which are now pilot-dried for that.

Fwd_RH_Nuts_Torqued.jpg


Fwd_LH_Nuts_Torqued.jpg


The alternate hosting has them here, here, here, here, and here.

Dave
 
This isn't the main stuff I've been working on lately but it's part of the project.

I’d gotten one of Gil Alexander's Skyview network hub printed wiring boards and the rest of the components, all connectors, made it a kit. I don’t need it yet but I thought that I ought to build it up now anyway. A friend of mine builds electronics equipment prototypes so I asked her a couple of assembly questions. Rather than an answer, she just told me to bring it to her lab. She then soldered the connectors to the board for me. I have to admit that she did a lot better job than I’d have managed, using tools that I don’t have. Here’s Maria Toscano-Leary soldering the SV hub kit.

Maria_Soldering_SV_Hub_S.jpg


Here’s the network hub side by side with Dynon’s version. The main difference is that Gil’s includes the two autopilot connectors directly. The white connector on Gil’s is a provision for the power and ground wires to the autopilot servos. There were no assembly surprises.

SV_Hub_Comparison.jpg


I'm still working on the electrical layout and haven't actually decided which I'll use yet. With the panel being both small and intended for day VFR cross-country, I might just go for the lighter one, after I make some sort of enclosure for the sides and bottom of the kit hub. Right now I'm thinking of a wrap of electrical tape....

The photos are also here and here.

Dave
 
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Belly Rivets

Riveted the seat belly skins and the belly skin that’s immediately aft of the firewall. The Titanium overlay did not get riveted on at this stage. Since the fuselage is still upside down in the jig, I bucked the rivets from underneath, while my helper, Glenn Potter, drove them from above. It was a hot day and it got hotter inside the fuselage. But the worst part was that my close-work reading glasses would fog up, and that, combined with the relatively poor lighting, made my share difficult.

We lost some time on the first afternoon when I learned that Glenn, instead of merely being late at the shop at my home, had showed up early out at the hangar. He ignored the fact that every bit of work he’d done so far on the RV-3B was at my shop here at the house, 15 miles away, and was waiting patiently for me to appear at the hangar. Good thing cell phones have been invented or he’d have had a long wait; I wasn’t planning to stop by the hangar until the next day.

The riveting took three afternoons. It cooled off and I set up a fan; things improved.

Belly_Glenn_S.jpg


The red tape marks rivet holes for the Titanium, which get riveted at a later stage.

Here’s the proof - no clecos on the belly!

This job took some figuring out since I seemed to need one or two more bucking bars than we had on hand. Plus, my drop light died and I had to use a flashlight. Primitive, eh? Always one thing or another. But now, done.

This and the previous post above kind of brings home to me how much my friends are helping me build this one-seat airplane. Couldn't do it without them.

No_Belly_Clecos_S.jpg


The photos are also lurking here and here.

Dave
 
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Before I can glue the forward side skins on, the tunnels have to go on, at least where they fit in between the side skin and the lower longeron. Since I did a poor job on the left one, it’s on order and I’m working on the right one.

Both the forward tunnel bulkheads are riveted to the belly skin.

I’d planned to install the Fiberfrax and titanium underlay (overlay?) at a later stage in the assembly, but a trial fit proved that the titanium would not go under the tunnel inboard flanges then. I need to install the titanium before the tunnels go in. This meant that today’s job was fitting the Fiberfrax and locating it.

I trimmed it to size, adjust a little to suit, and then pressed it into the spacers along the belly skin. Here the Fiberfrax is cut out for the first one. The Fiberfrax is so soft that it’s easy to do this just by feel.

Fiberfrax_Fitting_1_S.jpg


As shown, I used an Xacto knife with a #2 blade. Proceeding right along, shortly the Fiberfrax fit fine.

Fiberfrax_Fitting_2_S.jpg


My original plan was to lay some 3M Fire Barrier 2000+ down on the belly to hold the Fiberfrax in place, but I soon realized that this batch of Fiberfrax was the sedentary kind; it didn’t want to get up and wander around. Those spacers hold it just fine. Just as well, the local stores are out of the Fire Barrier and my previous tube is clogged with cured stuff.

But there were two places where I wanted to add some anyway, so I cut the tube spout open and was able to put some into a syringe left over from the tank sealant days. I used this to caulk the seam at the firewall flange. The only reason was to help preclude exhaust leaks there, and yes, the titanium goes over that too. And I had one rivet hole the I drilled for the titanium which was in a poor location and which I intend to leave unfilled. I caulked that with the Fire Barrier, too.

I’ll have to get a tube later in the game, though.

Worth noting is that Fiberfrax is an aggressive collector of dirt and dust. I've never seen anything like it. When I wasn't working on it I laid a sheet of .010 polycarbonate over it to cover it. Nothing special about the plastic, it was handy and cut easily with scissors.

After the usual prep work, I was able to glue the titanium underlay to the forward belly skin. The prep work took less time than normal since the titanium with the .040 belly skin is stiff enough not to need an exoskeleton. Plus skin-to-skin joints generally don’t need one.

I’ll leave most of the clecos in until the rivets go in, since I’m not sure how well the titanium adheres.

Question for English majors - is Titanium or titanium the preferred spelling? Seems to me that since aluminum and steel aren’t capitalized, that there’s no reason for titanium to be, either. The names all describe elements, even though we use alloys of them rather than the pure forms. I haven’t been consistent before with capitalizing them. What do you think?

The next step was to glue the right hand tunnel on, since it’s inboard flange goes over (under?) the titanium. The glue is now curing. This inboard row of rivets can’t be bucked. I nearly wrote “nearly can’t” but with the forward bulkhead riveted in place like it is, it’s impossible. Fortunately, it uses blind rivets. When the glue’s thoroughly cured I’ll drill those holes to final size and install them.

RH_Tunnel_Glued_S.jpg


Back to the RH side skin. The frame prep work is nearly done. You’ll see that there are no rivet holes yet through the firewall; the strips that attach to the inboard side of the firewall flanges haven’t arrived yet. Ideally, I’d dimple the side skins and firewall flanges, and maybe I’ll get to do that.

RH_Frame_Prep_S.jpg


The RH side skin itself is nearly ready, but whoa! The zinc chromate primer is way to rough to the touch. It’s unacceptable. Then I remembered that I had planned to paint over that with a color coat anyway, and decided to remove the zinc chromate. That was a messy job. I’d pour lacquer thinner on, let it rest for a few minutes and scrape it off, using a plastic scraper so that I wouldn’t scratch the skin. I’ll have to do more on another day, there’s more to go.

Fwd_RH_Side_Skin_Deprimed_S.jpg


That’s it for this episode.

The photos also reside here, here, here, here, and here.

Dave
 
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Well, with a bit of help from Sam Ritchie, local RV-10 builder, we glued the RH forward side skin on today. This is the cockpit side. This was the culmination of considerably more effort than had been apparent. Among the things that delayed this were:

The skin had been primed. The paint job turned out to be extremely rough, so I removed it completely, as I've mentioned.

With all the various overlaps of the construction, I had to add a lot of shims in a number of places. You may have noticed that.

I had to decide what I was going to do about the forward turtledeck later one. This is the one that goes between the firewall and the panel on top. According to the plans this overlaps the side skins and is attached with #8 screws and I believe the RV-4 is similar. If I were going to accept the overlap there, I’d have to fit those #8 holes in between the -4 rivets at the forward end and those rivets are spaced about 3/4” apart while the screws are roughly 2.5” apart. Worse, I’d have to drill, countersink the longeron and dimple the skin. That would only add a day’s delay. Still, the panel attachment meant that the position of the screws at the aft end would need to be a SWAG and the integration of the cowl cheek flanges would not happen for a considerable time down the road.

Or I could glue the skin on and countersink right through the skin, a less-desirable alternative but marginally acceptable.

Or I could install an angle on top of the longeron and screw the turtledeck skin to that. This offered a few advantages at the cost of a little weight and slightly reduced access to the forward equipment bay. And this is the option I’m choosing.

With all the various options and issues, actual thinking was required. Whatever else you can say about building an RV-3B, one tool is absolutely essential: an operable brain. I called my mentor; he has one of those. He outlined several of the conflicts inherent in this area, a good briefing.

Yes, I checked that I indeed have a #8 dimple die set on hand for when I need it. It seems that I needed that already for the tanks and there it was, right where it should have been.

Sam_Glue_S.jpg


Here’s the skin still clecoed with the exoskeleton in place, while the glue was curing.

RH_Side_Exo_S.jpg


You can see the the exoskeleton for the top longeron is bent. I used the stretcher to do this. I'm finding it to be a handy tool that I should have gotten earlier. It's too late in the construction to get much use now, but it still has its moments.

Also that the forward edge at the firewall flange is clamped but not clecoed. I’ll drill those rivet holes later, probably when I install the cowl cheek bulkhead and the back-up strip for the quarter-turn fasteners.

Then on to the left side. I’d had to replace the original tunnel side so I started hacking at the new one. I needed to shorten it and recess the turned-in flange and that’s as far as I got today.

The pics are also hosted here and here.

Dave
 
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Here?s a photo of the RH Side, glued but with the clecos removed.

RH_Side_S.jpg


Once the tunnel side was useable, I removed it and started drilling and checking the LH cockpit side skin. But first I took a few moments (that is, something over an hour - this is an RV-3B, after all) to go back to kindergarten to make some simulators for the systems boxes I don?t have yet. These boxes will all go somewhere but I?ll have to figure out where later and that?s what these are for. I?ve got most of the others on hand and can use actual components once I have good access to the interior.

Step one was to mark and cut out the cardboard.

Arts_Crafts_1_S.jpg


Step two was to tape the boxes to shape. These represent only the outermost envelope of their volume and make no attempt to conform to their real shape.

Arts_Crafts_2_S.jpg


Worth noting is that except for the empennage, virtually all the exterior skins that came formed, came mis-formed. They all, without exception, required some tweaking. Some took more than others but I had to rebend every one of them. This is apparently an RV-3B thing, but if you?re thinking of building one of these airplanes, consider this, too.

Here?s an alternate host for the photos:here, here, and here.

Dave
 
Worth noting is that except for the empennage, virtually all the exterior skins that came formed, came mis-formed. They all, without exception, required some tweaking. Some took more than others but I had to rebend every one of them. This is apparently an RV-3B thing, but if you?re thinking of building one of these airplanes, consider this, too.

Dave

You made me laugh out loud with this statement!

Thanks for reinforcing my decision to sell my RV3 kit!

I?ll be in Boulder sometime over the next 10 days or so helping my niece settle into her rented condo at Gold Run. I?ll give you a call and try to stop by. Always enjoy reading your updates.
 
Missing Photos?

I discovered that some of the images, hosted by www.Postimage.org, have apparently gone missing or at any rate fail to download on my computer. I'm replacing them as I find them and have time.

So far, the second hosting by Imgur seems to be fine. Hosting by imagebam, though might not.

If you know of any, please PM or email me (via my username at the upper left) and I'll add that post to my list.

Thanks,
Dave
 
Dallice Tylee came over to help me drill and cleco the LH cockpit side skin. At the aft end there?s a mild compound curvature that presses into position nicely but which I can?t quite manage by myself. This isn?t a kit flaw but a natural part of the design. She pressed a block of wood to the skin while I drilled from the inside, after which she put clecos in. Fortunately she?s both self-employed and a neighbor as well as a pilot, and was able to come over without a scheduling hassle.

The photo shows me yanking out some clecos to fit the LH tunnel side under the skin.

tCQQlzH.jpg


I also made a cardboard simulator for the compact EarthX battery for comparison. The previous one is common to the other sizes. Comparing these to the cowl cheek bulkhead and after locating the aft end of the cheek cone on a table, I soon found that neither battery would fit in the cheek in any orientation. The aft corners of the battery will protrude from the cheek, and no, I?m not going to have small streamlined bumps for them on the cheeks.

In fact, I?m a little surprised I even considered that.

That LH tunnel that's shown in my hand is now glued on and the side skin is removed for dimpling.

With both tunnels glued on, I decided that access to them is better with the LH cockpit side skin uninstalled, and took the opportunity to put in the LP4-3 blind rivets that go through the cockpit floor. Incidentally, don't believe the 2 1/2" dimensions shown in the plans. With the actual parts, decide for yourself what the spacing needs to be.

fJwt6p0.jpg


Additionally, I riveted the tunnel bulkheads to the shells. The rivets at the back end and the ones through the side skins remain to do.

The photos are now mostly hosted at Imgur.com. But they are also hosted at Haile.com

here and here for backup.

Dave
 
Here?s a photo of the rivet holes in the side skin that are hidden by the wing. The row at the top of the photo doesn?t need to be flush. The plans are a bit vague about this area - I?m sure that other people have built their planes a little differently here. But for me the ease of riveting is more important than the extra work dimpling them. I could have gotten the AN442 flat protruding head rivets for this but I didn?t. Those are as easy to set as flush ones and are otherwise like universal-head rivets, but with a flat top. While we?re thinking of easy-to-set rivets, if you go back to reread that riveting spec MIL-R-47196 that?s on Van?s site, I?m pretty sure it says that flush rivet sets can be used on universal-head rivets. That?s also easy. But there?s a small dimensional window between a proper shop head and going too far squishing the factory head, so I haven?t been doing that.

The area outlined by the red dashed line will not be glued.

JDsvPqc.jpg


I rechecked the twist of the fuselage. Once the cockpit side skin goes on, no other tweaks can happen. This is it.

Here?s the longerons at the spar bulkhead:

vggNd10.jpg


And the longerons at the seat bulkhead:

3BieUzY.jpg


I also checked the firewall and it?s aligned, too.

I was unable to check the aft end of the tailcone due mostly to not being able to see the level.

Rod Woodard dropped by the Boulder airport for a visit. It was great to see him again and to examine his new RV-3. It?s a very pretty airplane and I got to look at a number of things that I?d wondered - throttle quadrant location, seating height, fuel selector position, fuel vent position and configuration,, antenna locations, etc. Details.

Here, here, and here are the backup photos.

Dave
 
Sunday before Labor Day was kind of a big deal. With the help of Charlie Stein and with Rod Woodard observing, we glued the LH side cockpit skin to the frame.

This marks the final skin while on the jig.

This skin, like the entire RH side, tailcone and cockpit sides, are as yet unriveted.

Rod Woodard took the first four photos.

The day was interesting and fortunately, uneventful. It went pretty much according to plan. It took 77 grams of mixed epoxy and there was a little left over. In the photo, the lids were ajar because I wasn’t sure if I’d need to mix another batch or not. As you can see from the cans, I’ve been using them.

cWvNqoH.jpg


I’d already put the tape on the inside of the skin.

Avu7OyS.jpg


Charlie Stein and me,

gzkHgw0.jpg


Once the exoskeleton and clecos were off, I stood back for a few minutes to look at it.

Incidentally, for this skin I countersunk the longerons .012 deep, using a rivet as a gauge. This gave me a noticeably smoother surface than the dimension of .007 that the factory recommends for non-glued joints. On the bulkheads I've been using the tank dimple dies and they work very nicely for glued joints.

L36kiA6.jpg


Then I removed the front part of the jig that had supported the firewall. The plan was to install the engine mount and then the main gear legs, but the bottom front cross member of the jig isn’t removable and was in the way. Here’s the firewall without the jig obscuring it. Yes, I did remove that bump in the center of the cross member.

9h3wLfK.jpg


I also learned that, as I had rather thought, that the belly round-over will need trimming. Might even need removal but it’s too early to be sure.

The photos are also here, here, here, here, here, and yes, here too.

Dave
 
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It's a Canoe

I bought a couple sawhorses and unfastened the fuselage from the steady, reliable Fry jig. Man, that’s a good tool. I lifted the fuselage on to the sawhorses, one by one. The RV-3B fuselage, in this state, is light in the tail and not so much heavy up at the firewall as it is awkward. It was not hard to do it myself,

Folks, I present the canoe.

c8w3JmB.jpg


While I really would have liked to put the main gear on and get it aligned and rigged, there just wasn’t enough room before hitting the jig. If I’d have known, I would have raised the fuselage up from the jig 2.00” at the start of assembly. That would have made some things considerably easier as well as permitting the gear to go on.

If I’d done it, put the gear on, I’d have removed it shortly, too, to facilitate other things. Other things like moving it around on the sawhorses and working around it, since my shop is small. I still think that’s the best time to do rig the main gear.

No, I’m not going to try to add 2” shims and reinstall the fuselage on the jig now. Thought about it and decided against it. You might say that canoe has paddled off.

Heck, yes, there's a backup photo right here.

And yes, the Fry jig is for sale. See the ad in the Classified section. It also fits an RV-4. In fact, it was intended for an RV-4.

Dave
 
The Fry jig is sold and gone. It will be used by a repeat RV-4 builder in the area.

The concept of installing the main landing gear legs is still on the table, since I could do it with the canoe upside down on the sawhorses. I asked some of the local builders and Eric Lanning volunteered to spray them with Azko Nobel primer for me. I included the tail spring too. Azko Nobel is one of the better primers and frankly, I?d have been better off to have used it myself throughout. It?s very tough, resistant to aircraft chemicals, and epoxy sticks to it. It was ideal for the landing gear legs.

Here?s Eric spraying the legs in his priming booth.

4xSv1q9.jpg



And here they are during the first hour, while they are still soft to the touch.


2zjIcbU.jpg


After that I was able to put them carefully into my car and drive them the 90 miles home.

At this time, the entire right-hand side is unriveted, as is the left side forward of the seat back. The glue is keeping things together, and a few clecos ensure than no edges lift and start unzipping. I was reluctant to do much interior installation or install the main gear until that riveting is done. It?s scheduled for next week. One of the things I could do now was hang the engine mount, which requires trimming the hot air exit fairing at the bottom of the firewall. That?s the titanium belly overlay I added on earlier. The titanium is one of the things needing riveting, though, so I had to be careful not to accidentally rip it loose.

Trimming the exit fairing was relatively simple: fit the engine mount, trim any of the fairing that interfered, repeating both steps as necessary. Took a few hours. Here?s the trimmed fairing.

Pz2Z9py.jpg


However, the engine mount has a teensy problem. When it was built, the bottom cross-member was welded on somewhat lower than the engine mount bolt holes to the firewall. The plans show it, drawing 29, as being in line with those holes.

tiN78y4.jpg


Compare to the actual engine mount. I?ve drawn a thin centerline between the mounting bolt holes.

XkPB569.jpg


And observe that the bottom cross tube is a bit forward of the firewall, too. The fairing, you?ll recollect, curves upward there. As a result, there?s interference along the entire bottom cross member as it rests on the fairing.

FoKZznv.jpg


If I press the engine mount down to the correct position, the fairing bends down around 1/4 inch or so. And that doesn?t include the clearance that I?d need to prevent the mount from chafing on the fairing, due to the three dissimilar metals which would be in contact.

Turns out that this isn?t a new error. Here?s that tube on an RV-3 built 15 to 20 years ago.

QKMi39I.jpg


Elsewhere on the fuselage, looking towards the top tailcone skin, I found that the aft four bulkheads, F-305, F-306, F-308 and F-309, do not line up well at all. The two middle ones are high and all four are slightly narrow. This isn?t too much of a surprise as they were fitted for fairness along the sides and bottom (the accessible areas whilst in the jig), getting the top be as it would. Still, it was slightly encouraging that the bottom 3? or so is the only areas too narrow.

Stay tuned for the next episode, folks.

Alternate hosting: here, here, here, here, here, and here.

Dave
 
The canoe was only glued together when I took it off the jig, not yet riveted. Still to be riveted were the entire right-hand side skins, firewall to tail, the left-hand cockpit side skin, and the titanium belly overlay.

With the help of Glenn Potter, I got these done this week. Having the canoe off the jig and on sawhorses really helped as it was possible to rotate it to a convenient position.

The riveting came out decently enough. I'd been worried that I'd screw something up but it looks like we did okay.

Dave
 
Glue Technique Tip -
As the total thickness builds up, you may need longer rivets. Buy them early and you will have them when you need them.


When that riveting work was done, I really truly had a canoe.


Back when I ordered the finish kit, I ordered a clear Todd?s canopy. More recently, I decided that a light tint would be better. Lance Logan now has canopies available. He took over Todd?s equipment. Lance Logan is the supplier to Spruce, so I had the option of ordering direct or through Spruce. I discussed it with Lance and decided to get it directly from him. The quality of the pre-purchase assistance was terrific.

I chose the 2515 Light Smoke, which blocks 88% of UVa and 99% of UVb. The other easy option was 2094 Gray. Lance sent a sample of both and the decision was pretty easy. The 2094 is pretty dark.

I sent a check and very shortly afterwards, a canopy arrived. And I do mean shortly.

First, here?s the earlier canopy that Todd?s sent, the clear one.

kiAOWLe.jpg


Next, here?s the new one that AeroCanopy sent.

NW0HB0I.jpg


There were some differences in how they were packaged and in a few other things, but all in all, I?m very satisfied with the new one.


Way back when I was assembling the firewall, what I should have done was take the engine mount and the firewall to a machinist friend and have him match the firewall holes to the engine mount. Then I could have used bushings to hold them to the 1/4? hardware on the jig.

But I didn?t. None of the firewall holes were drilled, of course, since this is an RV-3B, but they were center-punched to mark their location. That was nice of them. I determined that the middle two hole locations were somewhat close and that I could use them as a starting place to align and drill the outer four holes, which were, if not located properly, at least on the same firewall.

Drilling them from 1/4? to 3/8? was easy. For the two middle mount holes, I used a Harbor Freight Unibit clone and that left holes just slightly under 3/8?. I finished them with a reamer and those fit the engine mount. Since I lost the AN6-53 bolts that it?ll take to bolt them to the firewall, I bought some hardware store bolts for the job. No worries, they?ll be replaced. This won?t be permanent for a while yet anyway.

The outer four holes were visible through the engine mount?s attachment holes but that?s about all I could say for them. What to do?

I discussed it with the aforementioned machinist friend and decided to get some bushings.

First, I bushed the holes down to 1/4? and used a slightly undersized twist drill to walk the firewall holes closer to center, followed by the 1/4? reamer.

Second, I removed that bushing and the remaining bushing had a 5/16? bore. I did the same thing, using undersized twist drills to get close, and then the 5/16? reamer.

Last, I repeated the process with no bushings, ending up with 3/8? coaxial holes in the firewall and engine mount that the bolts would go into.

How was it? The first bolt with the bushings was very slow but not especially difficult. Learning curve, you know. The remaining bolts went quickly. At the conclusion, the engine mount was temporarily bolted to the fuselage.

Goody - a convenient place to grab when moving the fuselage around.

Bt9Aw6W.jpg


I rotated the fuselage upside down - geez, that looks familiar - and discovered that with a sawhorse under the upper longerons forward of the panel, I could level it by shifting one sawhorse end fore or aft. When level, I marked the location.

Upon trial fitting the main gear legs, guess what? they don?t go in their sockets. I had to decide whether to reduce the legs or open the sockets. Turns out that the gear legs are 1.375? diameter but the ends of the engine mount sockets are about 1.365?, or .010 smaller for the diameter. I thought that this was due to some excess cadmium plating that migrated into the sockets. The plating company assured me that they?d mask those holes. Looks like they gave me a headache instead. Later I discovered that the plating made a minuscule difference, and that the fit is what the factory sent. No worries, it's an RV-3B, and I signed up for this.

I bought a brake cylinder hone tool. I had never used one of these but heck, it?s a tool right? And I?m a proud member of a toll-using species, right? Plus I have an aptitude for mechanical things. How hard can this be?

Turns out that it wasn?t hard, just tedious. First, the tool.

HRlr1M9.jpg


I dipped the stones in alcohol and ran it on partial speed at about 40 psi, for about 30 seconds at a time. I didn?t want to burn out the stones but I really didn?t want to have the sockets get too loose. Here?s a photo of my doing the honing thing on the top of the right-hand socket. One thing to be careful about is to stay on the internal boss and neither get past it nor remove the tool while the stones are spinning.

GGdJLAA.jpg


It took about fifteen passes to get the top end of the right-hand landing gear strut past the bottom part of the socket. I was still about 1/4? shy from being able to insert the strut all the way. One more thing that I wanted to avoid was getting the strut stuck in the socket so that I couldn?t remove it or adjust it. I made a couple more passes with the hone and then put it all away. I ordered a replacement set of stones and they?re about a week out.

But no worries, there are plenty of things to work on. I started one of those.

Also at Todd's canopy, AeroCanopy canopy, Engine mount attached, hone tool, and actual honing.

Dave
 
I?ve been sort of roaming around the fuselage, doing things that looked interesting.

I put together the pitch servo mount, following the Dynon RV-4 mount arrangement. It also holds the elevator bell crank. Here it is from the front, looking aft. I need to touch up the primer slightly and then the baggage floor skin fits under the forward end. I used nutplates under the mounting bolts.

OXbcrDi.jpg


It?s looking like Van is a lot bigger man than I am in several ways, and one of those ways is simple body length. The RV-3 has depressions built into the seat ribs for butt room. Neither of the two RV-3s that I?ve sat in demonstrated a need for that recess, so one of the alternatives I?m thinking about is revising the ribs to make them flat on top. I checked with Van?s Support and they say that?s acceptable but wouldn?t specify rivet spacing or type (I'll probably use blind rivets). The major load is the downward crash case, if you?re interested.

The red lines show where the new flange will be.

yHczTj9.jpg


Another easy fit-up was the aft deck. The orange dots are magnets with mating ones underneath. That does a fine job holding the deck in place. I needed to locate and cut the openings for the stabilizer mounting bars and trim one side to fit, but the stock piece that came with the kit, fit pretty well.

fOGKEd1.jpg


Since the RV-3B isn?t a prepunched kit, there are no holes in the deck yet. Before locating the access holes that are in the plans, or the fastener holes, it seemed prudent to see if the stabilizer actually fits. Remember that the fuselage was built to fit the bulkheads and skins and more or less follow the plans. When people say that all RV-3s are different, that?s not an exaggeration. Let?s just say that there was some question - would the stabilizer fit at all?

vufau1g.jpg


The answer, I?m happy to report, is ?yes!?

The stabilizer came down from the rafters, sat in place for ten minutes, posed for some photos, and then went back up where it?s been safe for the last several years.

I marked the front spar and the front spar mounting angle positions and realized that the access holes in the deck will need adjustment. The rear-most hole in the deck allows for the elevator horn to extend down into the fuselage, so I marked the elevator hinge centerline position on the deck. I was going to mark where the aft hole needed to be when I realized that the horn is an RV-4 part. Okay, no problem, I?ll deal with that some other day. I?ll need to bring the stabilizer and both elevators down and assemble them and measure stuff.

With a small bit of epoxy curing somewhere else, it seemed like a great time to leave the project for the night.

Same photos located elsewhere here, here, here and here.

Dave
 
Once the honing operation on the landing gear sockets was complete, I started to get the gear located. The honing gave me a mild press fit on both legs. I had to use lubricant to get the legs into the sockets. After they were in, I got a tip that on a few engine mounts, the internal sleeves were dislocated top to bottom so I removed them again to check that. Mine seem to be okay, although the internal inserts that were supposed to be 3? long were only an inch long. I?ll try that. And the legs went back in.

It seemed to me that the main thing to check was to get the legs so that the plane is sort of level in roll while on the ground. The toe in/out appears important, too. Camber isn?t under my control. The overall yaw position of the axels isn?t either; nor is the side to side position.

I leveled the plane in roll and marked the side of the fuselage for the sawhorse position. The top longeron, forward of the spar bulkhead, slopes downward. This lets me adjust the roll position simply by moving the sawhorse.

I clamped a 6? angle to the longerons and laid a level on it.

fMsJz9L.jpg


And marked the fuselage so I could repeat it.

AUCTxY3.jpg


Here?s proof that the gear legs fit in the sockets. They aren?t aligned yet.

yw94OeJ.jpg


The top ends can be adjusted +/- 3/16? in or out of the sockets to level the gear, according to the plans. Mine needed more than that.

For the toe in/out business, the manual says make them straight. My mentor says 1/2 degree toe-in. For mine, that appears to be about a .040 shim at the aft outboard end of the axel, which I added.

The photo shows that they are level - a bit later, without having touched anything, they were 1/10 degree off. So there?s some work to do yet.

apCnvUj.jpg


I was uncomfortable with the edge distance internally with the gear legs in this position, and contacted the factory. After a few emails I talked to Sterling, who was very helpful. I finally decided to accept a small error in the roll alignment in exchange for better edge distance. Sterling sent me a photo of another RV that had much more error than what I should have and commented that it flew fine and that it was unnoticeable to the pilot.

The next step was to drill those holes. I don?t know about you, but drilling long holes in expensive, important bits of heat-treated steel isn?t something I think is trivial. My mentor sent me a very nice drill guide he?d made which apparently works fine for some of the other RVs and perhaps a Rocket. It didn?t fit my RV-3B because some of the engine mount tubes got in the way. I looked around the shop for scrap and after some thinking made this.

kqIMPWa.jpg


I?ll have to make another one of the thicker body parts of it for the RH side. The black line is the Allen wrench for the two set screws which secure the bushing. It fits into a hole I?d drilled to make a holder for it so I didn?t lose it. I would have put the bushing in with the bigger end towards the hole but then I?d have needed to unfasten and realign it with every drill in the sequence; each size drill has a separate bushing.

The two set screws are threaded into the 1/2? plate aluminum.

8-33 x 5/16 long Set screw size
5/64 Allen wrench size
#44 Retention hole for the Allen wrench

So there I was with a drill guide in place and some new drill bits to match the bushings on hand. All I had to do was get up the gumption to start.

Surprisingly, the drilling went well. I?ve only drilled one leg so far. I stopped at the letter N drill and with that one, only went part-way through, so that the B&S #2 reamer would have some material to seat on at the narrow end of the hole. Initially, reaming the hole went fine, but before too long the reamer wouldn?t cut. Apparently this is a known issue, early wear, for the ones from Spruce. It was worn out. I ordered a new one from ATS.

The plan is to follow that with a B&S #3 reamer to final size.

The photos might also be found here, here, here, here and here.

Dave
 
Tool Woes

While I was waiting for the new reamer, I decided to work on the drill guide for the other side. Partway through cutting the 1/2" thick aluminum plate, the bandsaw broke. The thing was at least 30 years old and had always been cantankerous, so I gave it to a younger neighbor.

After some searching, I bought a Rikon 10-326 bandsaw. I expect it'll be an upgrade but we'll see. I'm assembling it this weekend, so it's too soon for a tool review.

Dave
 
Engine mount/landing gear to the machinist -
Since I just couldn?t cut a tapered hole in the landing gear mount, I took it to my machinist friend. But I?d gotten far enough so that I could use the tapered pin as a positioning tool. He?ll get to it one of these days. For him, it?s a hobby. He?s a physicist and his company is very busy these days.

ADAHRS bracket -
With the engine mount off, I flipped the canoe and looked around for the next thing to work on. Seems as if that might be the ADAHRS mount. I made a sketch showing where one could go on an RV-3B and found that the place I preferred was just under the top of the F-308 bulkhead.

These brackets let the ADAHRS slide in. I?ll put stops in the slides at the aft end and use nylon screws or tie-wraps or something to secure the front end. They can?t actually get riveted to the bulkhead until the bulkhead is a least clecoed to the turtledeck to skin, and all I?ve done in that direction is screw a wooden frame to the back of the F-308 bulkhead.

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Panel -
I laid out the panel and cut it out. The panel, so far a virgin one, fits the fuselage. My fuselage is slightly wider than the plans dimensions, so I had to adjust the width of all the points by a bit over 1%. Not much but it added up. You might think that this is something that I should have laid out in CAD and had water-jet cut, and that would have worked. But this was quicker. From a piece of bent aluminum to drawn in Sharpie to cut out, edges finished and hanging on the longerons only took three hours. I must say that new bandsaw sure is a nice tool.

I made it 1/2? deeper, top to bottom, than the plans call for. The excess height is below the longeron, with the curve above the longeron per the plans. It eases the panel layouts a bit. As I?ve hinted, I?m planning on a Dynon Skyview system with one screen and a few peripheral analog devices. I?ve played with cut-out photos of the various odds and ends that will go on. But I won?t freeze the layout and cut the holes until I get closer. Things change. The panel currently has no holes for the gadgets.

The current plan for the panel includes:

Dynon Skyview, probably the 7?,
11? iPad Pro, unless I use the 10? Skyview,
Trig com,
2 1/4? asi,
2 1/4? 8-day clock,
Slip indicator,
2 ignition switches,
Alternator/master switch,
Fuel pump switch,
Running light/landing light switch,
Nav/strobe light switch,
Perhaps the autopilot disconnect switch.

That?s a lot of stuff to jam into an RV-3B panel, so don?t expect beauty.

Since the stock top of the stick doesn?t poke up very high, there?s gobs of clearance. I measured 3.7? from the top of the stick to the bottom of this panel. My stick might be a slight bit high, and the bottom of the panel is 1/2" low.

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The RV-3B panel has a flange around the back side. After some consideration I decided that I could use the F-803CPP strip that Randy Lervold recommended. This is an RV-8 part for the purpose. I?m using a bucking bar to force the strip in place on the panel, and checking into the table to hold it securely. Here?s SK-40 showing how. Got to be careful doing this since some bucking bars have rounded edges that the panel would nest into; a sharp edge is needed for a bucking bar to work.

isKmBou.jpg


The center piece of the strip is wider than than the other tabs. I had to shrink that to get it to bend slightly to confirm.

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The main issue with the F-803CPP is that the notches are cut so far into the smooth flange that there?s precious little left for the attachment screws. On the RV-8, it uses rivets. The RV-3B uses #8 screws, which need more edge distance. I decided that if I was careful, I could place them away from the notches, at the tabs. It?ll mean 2? spacing instead of 2.5?, no problem there, I think.

The alternate hosted photos are:

ADAHRS Bracket

Panel on Fuselage

SK-40

Panel flange 1

Panel flange 2

Dave
 
Engine mount/landing gear to the machinist -
Since I just couldn?t cut a tapered hole in the landing gear mount, I took it to my machinist friend.

I made it 1/2? deeper, top to bottom, than the plans call for. The excess height is below the longeron, with the curve above the longeron per the plans. It eases the panel layouts a bit. As I?ve hinted, I?m planning on a Dynon Skyview system with one screen and a few peripheral analog devices. I?ve played with cut-out photos of the various odds and ends that will go on. But I won?t freeze the layout and cut the holes until I get closer. Things change. The panel currently has no holes for the gadgets.

The main issue with the F-803CPP is that the notches are cut so far into the smooth flange that there?s precious little left for the attachment screws. On the RV-8, it uses rivets. The RV-3B uses #8 screws, which need more edge distance. I decided that if I was careful, I could place them away from the notches, at the tabs. It?ll mean 2? spacing instead of 2.5?, no problem there, I think.

Dave

That's why it is best to build these kind of parts from scratch. I don't have my plans in front of me, but I don't think this part meets the spec's on the RV3 plans.
 
Thanks for the comment. As it turns out, the RV-8 part that I used matches the part shown on Drawing 17, except that the rivets are on 1? spacing rather than 1 1/4? spacing per the drawing. And that increased rivet spacing is not detrimental. This part has 5/8? flanges just like the RV-8 part.

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But here?s the left side of SK-40 showing the same part with a different description. This one shows 3/4? flanges.

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This is typical of the RV-3B plans. There are a number of areas where the parts or assemblies are shown with different dimensions. I?ve found it handy to look at the RV-4 plans or the RV-8 plans for an idea of the design trend of Van?s, or just for some clarity. In this case, I?m using an RV-8 part. Looking at the RV-4 Drawing 23 indicates that a 3/4? angle is to be used on that plane.

Determining intent of the RV-3B plans is something like determining intent within the U.S. Constitution, but without the assistance of nine highly qualified justices, each approved by the Senate.

I?d have preferred a 3/4? flange for better edge distance,, if that were all there is to it, but that?s not the whole story.

If you look at RV-3B Drawing 25, there?s a panel edge detail that?s similar to the one on the RV-4. The RV-3 version is a strip of .032 x 1? that fits over this formed flange and over the edge of the panel itself. Although the actual detail of attaching it is not clear, there it is. It should provide more than sufficient edge distance for the screws.

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The unresolved question is whether this strip gets riveted to the skin or the flange. I?ve heard it done both ways, with the general experience favoring riveting it to the flange, not the skin. That?s what I?ll do, glue and rivet it to the flange using the nut plate rivets.

I brought the forward turtledeck home since that?s the next skin to be fitted. It?s just resting here to give me an idea of the amount of material I have to work with. Unlike some of the other skins, Van?s was generous with this one. Plus its curve is close to about right.

DDJUQxP.jpg


And since I needed to locate the cheek bulkheads in order to figure out where to put the Mil-Spec cowling fastener mounting strips, I also brought home a Cheek Bulkhead Locating Fixture, which is more properly known as the top cowl. It?s way premature to be thinking cowling, isn?t it? But we had to place it in rough location to clamp the cheek bulkheads on. They seem to fit lower than I?d have expected. Here?s Mark Mantei holding the top cowl in place. With a bit of shifting left and right and a lot of pressing down on it, it sort of fits not too badly. Nothing that brute force and epoxy can?t ameliorate.

z0ouva3.jpg



The photos are also hiding out here, here, here, here, and yes, here, too.

Dave
 
With the engine mount still at my machinist friend?s house, I made the bulkheads straight and flat. For the firewall, I used a steel carpenter?s square (later changed to a larger one).

cdlEcvb.jpg


The square was attached to the firewall with magnets. The magnetic field goes right through the stainless steel firewall and grabs the steel square. The magnets are those small objects spaced irregularly.

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The seat bulkhead and most of the remaining ones use cut-up scrap plywood. Fortunately, the project before this RV-3B was making new cabinets for my kitchen, so I had some plywood on hand. Here?s the seat bulkhead.

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And here are the others. For the aft-most bulkhead, I merely clamped a couple strips of plywood to the bulkhead. This bulkhead is relatively small and this is sufficient.

TMc0zJ0.jpg


I made a dirt-simple brace to support the instrument panel in the right position to line up the top front skin, shown here clecoed to the panel. I rotated the fuselage on its side to make access to the back of the panel easier. Even at that, I worked bent 90 degrees at the waist and twisted about 120 degrees. 19 years of yoga earned its way on that one.

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Later I added the panel edge strip. This was distinctly out of sequence and ideally should have been done before I drilled the skin rather than afterwards.

vXIRdJu.jpg


This is the strip discussed in the posts above. On my plane, this will be riveted to the panel and used as a sealing strip back-up for the canopy fairing. The concept is easiest to see on this other RV-3B. I?ve labeled the pieces to make it easier to see how it works.

5l338FF.jpg


Perhaps the photos are also
here,
here,
here,
here,
here,
here,
and here, too.

Worth a try anyway, if the other photos have gone belly up.

Dave
 
The front top skin is drilled to the panel. Only the aft edge is clecoed so far. The firewall edge is held with cleco side clamps.

Front-Top-Skin-Clecoed-S.jpg


As you might have noticed, I placed my instrument panel vertically. Doesn?t match the plans and probably not my brightest move, but with the top skin roughly trimmed and drilled to the panel, there it is. I confess that the verticalness is an error. Like every single change that can possibly be made to a kit airplane, this one had a ramification. The F-320A strip that goes between the F-320 forward top skin and the panel is shown in the plans to be straight. Since my panel is vertical and that skin slopes forward, my F-320A strip can?t be vertical. I determined this the hard way.

Here is an excerpt from drawing 25 for this, showing both the slope of the panel and the straightness of the strip.

F-320A.jpg


Here are both strips that I made. The later inner one is the one shaped to fit. It?s a somewhat conical shape but of course that varies over its length. The shape was determined from the F-320 top skin, which is trimmed to fit the panel (and drilled to it, which is why I haven?t adjusted the slope of the panel).

F-320-A-Twice.jpg


The top skin, incidentally, has excess length. Wish the bottom tailcone skin did, see post #318. There was plenty of material to make both the ?incorrect? first and the made-to-fit second strip.

Incidentally, the plans say that the strip is riveted to the top skin. Mine will be riveted to the panel?s edge angle and flush with the face of the panel. I know of at least one other RV-3B with the strip attached to the panel.

The top skin?s curve isn?t bad at all. But typical of the external skins on the fuselage, the curve needs to be adjusted somewhat, in this case over the longerons. I?ve heard of at least one RV-3B where this skin is made flush to the side skin by using a curved angle doubler, with one leg on the top skin and the other riveted to the upper longeron. I?m choosing to overlap the top skin on the side skins per the plans for this one. It?s a thicker skin than the aft belly skins and so far, let?s just say that I?m working on it.

After several attempts at bending the top forward skin so that it fits better to the longerons, I brought it into the kitchen. The counter there has a 1/4? radius, which seemed perfect, knowing that there would be spring back. I clamped it to the counter and used that length of 2x4 to press against it. It took most of my weight, augmented by a foot under the bar rail and another against the pantry, not shown, to do the job but now it fits well. You can see the result at the bottom of the photo where teh opposite side to the clamped one is already bent.

Top-Fwd-Skin-Bending-S.jpg


The photos are hosted in an alternate location if the primary location goes down:

Here's one,

and the next,

another,

and the last one.

Dave
 
Russell sent me a photo of Larry DeCamp's plane, showing how he’s attaching the forward top skin to the sides. He’s installed an angle, riveted to the top longeron, for the top skin to attach to. I understand this is how the Rocket does it. He could have done much the same thing by insetting a strip partly in between the skin and the top longeron. As I mentioned, I’m overlapping the sides per the plans, and am not using an attachment strip or angle. Here’s Larry’s method.

w5vYMIR.jpg


That strip that goes around the panel got glued to the panel’s flange, as much so that I don’t have to keep checking and unclecoing it every time the skin is on or off. Here it is with the glue curing and the tape off.

n5koSyg.jpg


I used my Whitney Roper punch to put cleco holes in the top firewall flange for the top skin’s screws, and drilled the top longerons and side skin for the top skin holes. I rotated the fuselage to make it easier to back drill those holes and when the skin was strapped into position, did that and the firewall flange. All the screw holes are pilot-drilled into the top skin now.

With most of the various holes drilled, I riveted on the nutplates and dimpled the holes in the skin. So far, with the firewall still undimpled and no nutplates, the skin seems to fit.

x6IAdda.jpg


Then since I’d located where I thought the rudder cables should exit the fuselage, it seemed like a grand time to make that slot and work on something else for a bit. A while ago, I found the location using a tight string and measured ends, and I drilled the bushing holes in all the bulkheads. At this point, the left rudder pedal is clecoed in place, with the length definitely TBD, so I clamped a string to that, ran it though the holes and then….

And then I got the vertical stabilizer down from the rafters, made a few measurements and markings, did the same for the rudder, and then but those back up there. I compared my marks and bushing holes to the plans dimensions on drawing 26 and added those marks too. Reassuringly, they were close. I checked the winds aloft, the latest political polls and pilot-drilled the end holes for the slot.

Funny how the plans offers zero guidance for the width of the slot. But an RV-4 builder suggested 3/8” and since that’s the diameter of the plastic sleeve over the cables, that seemed just fine. Remember, the cable exit cover will hide the slot. Here are the end holes on one side.

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Using a Dremel cut-off disk, I made these into slots.

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I was thinking about making the short steel links that connect the rudder cables to the rudder pedals, but soon decided to postpone that until things are further along and maybe I can sit in it. That’ll help set the length of the parts.

A while ago, I’d installed the static ports. I’m using Van’s blind rivets per the plans. I’ve observed that people who use other brands static ports often have relatively poor static pressure performance, and that makes sense. They are shaped slightly differently. Van’s flight tests their own product and recommends a placement based on that. This being important, I’m using Van’s.

VB6ktgq.jpg


As is my practice, the photos are also hosted elsewhere.

here's the first, and the second, the third, fourth, fifth, and final one.

Dave
 
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Pattern Time

The strip for the Mil-Spec quarter-turn fasteners for the top of the cowling now has a pattern, not shown. I had a bit of aluminum for that, but it?s one inch too narrow, since I need to allow for the semi-conical shape of the thing. New piece on order.

Next, I figured that this was a good time to make a pattern for the baggage floor. The piece of aluminum supplied with the kit has a curious shape, and the cut-outs for the flap torque tube arms looked large to me. That plus Ironflight?s comment about needing to make a pattern for his, all combined to say make a pattern. Don?t just start cutting.

And a good thing I listened, too. I found some white poster board at the hardware store and dove in. Immediately, it was apparent that there was no way it would fit into the baggage compartment as a single piece of card stock. I cut it in half. It was then difficult to put each piece in by itself, but eventually, I got both sides trimmed. And more card stock taped on, and trimmed again. Kind of fun, working that way, but then elementary school subjects sometimes are.

When I finally got both pieces in together, and taped back together, the difficulty of putting the pattern in or removing it returned. And what about the final skin?

I temporarily installed the flap torque arm assembly and marked, generously, lines around the arms. After removing that frame and the pattern, I then laid out the cut-out from the plans. You know, it?s a better fit than I?d thought. But a tweak here and another there, and I was able to refine the cut-out somewhat. And, remember this, it was now easy to get the pattern in and out. While it might be wishful thinking, maybe the baggage floor will go in readily, too.

Here?s a pic of the pattern in place, but not the flap actuator tube. At the bottom cut-out, you can just see the plans version of the cut-out at the aft end of the hole. Yes, there's plenty of room for working at the pushrod.

18Kuu1Y.jpg


I?ll probably do some additional minor trimming before I cut metal.

On the far right, you can see that the halves of the bulkhead top are unconnected. The splice plate is under that bit of blue tape. That'll be part of the aft tailcone skin project, by and by.

And here's the back-up photo link.

Dave
 
The RV-3B has a depression in the seat pan to accommodate a large pilot, which I?m not. Typically, the builder adds foam to fill the shape. I?ve heard that some of the seat cushions get pretty heavy.

So I?m making a wee change in the seat structure. This picture shows both the existing ribs and one of the added webs. The fuselage is on it?s side here, in case you?re wondering why the photo is odd.

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I made some flanges and epoxied them to the webs. Here they are curing on the table. Later, I riveted the flanges and the webs together, using -4 rivets.

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With the parts clecoed in place,

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RV-6 owner Rick Brennan was willing to try repairing my landing gear screw-up. Two commercial machinists were not and another one was willing, but didn?t give me a sense that I?d have flyable parts afterwards. Rick not only had a sensible plan for the tapered pin, he set it up so that we'd have a Plan B if we had trouble with the primary scheme.

Here?s the engine mount and gear leg clamped in the custom fixtures ready for attack. Since then, progress has been made: the tapered hole is within .004" diameter of being ready for assembly. The final bit will need another reamer, now on hand. And with the first plan so close, we developed a follow-on Plan C if we still couldn't do it.

qkp5AsP.jpg


I have had nothing but trouble drilling holes for tapered pins on this RV-3B.

If these photos should ever disappear, try this alternate place:

Here, here, here, and finally, here.

Dave
 
Styrofoam

2" thick white styrofoam is not heavy.

For my RV-3 I got a 4x8' sheet from Home Depot and cut it with a hot wire.
Also did that to fill in the back seat.

If you're ever going to sell it to a tall pilot...

Finn
 
I suppose the future will have to figure that one out for itself, Finn, it's not on my list of things to worry about.

The rudder pedals are ground-adjustable and the cushions will be too. If I haven't sold it separately beforehand, a Todd's tall man's canopy can be included. Other than that, a tall person will have to see it and decide. Someday.

Dave
 
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