VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   My RV Build Project (https://vansairforce.net/community/forumdisplay.php?f=108)
-   -   RV-3B Dave's in Colorado (https://vansairforce.net/community/showthread.php?t=85658)

David Paule 10-16-2021 07:31 PM

The lightweight oxygen cylinder arrived. I had previously gotten a dead D size cylinder for fitting but decided that it was simply too heavy. The aluminum cylinder weighs 6.33 pounds.

The Kevlar KF-11 cylinder weighs something like under 2.6 pounds.



I wanted to drill the elevator pushrod hole in the elevator horns. Normally, the elevators would be installed, leveled and then the hole drilled. I’d already assembled it and drilled the horn’s pivot hole. What I did was bolt the elevator horns together at the pivot hole, and then shim the elevators to have the same pitch angle. They weren’t actually level here. I zeroed the digital level to the near elevator and shimmed the far one to match. Then I drilled the pushrod hole.



With the horizontal stabilizer on the fuselage, I positioned the vertical stabilizer in place and took this photo showing the gap between the two stabilizer’s forward spars. It was a rather bright day. The gap is about 3/8” and that will need to be shimmed. Paul Dye documented this back in 2011 and my kit, from 2012, was the same. It would have been nice if Van’s had addressed the situation and perhaps fabricated an interface part or even included material for a shim, but no. Just another RV-3 construction issue. I did put a piece of 3/8” bar stock on order for a shim.



After some more work, I built the bigger elevator pushrod and mounted it. Although the stick is not installed, I grabbed the mixer and moved the elevators. Worked fine. The up stop is not installed in this photo, but it’s mostly made. I still need to thread its mounting holes, but I have clamped it in position and verified the up and down limits.



and



Started to hang the vertical stabilizer and as expected, it needed a shim between the aft bulkhead, F-312, and the stabilizer spar. I made one but it needs more work before I can proceed.

Dave

David Paule 10-31-2021 12:09 PM

Here’s the front of the elevator’s up stop. This is the working side.



And here it is in use, with the elevator horns in contact. We’re looking down and aft at it, so it’s a bit odd of a viewpoint.

The center HSTAB elevator hinge lower bolts makes a good down stop. Both horns are in contact and the elevators are at their low travel limit. Just worked out that way.



The up stop is attached to the aft bulkhead with a couple of NAS514P632-6P screws. These are 6-32 that are 3/8” long, threaded into the stop and locked with Loctite.

The fuselage grew a vertical tail, and about time, too. It had been stored in the shop rafters for several years. Turns out that the aft most bulkhead, that the main spar of the tail attaches to, wasn’t aligned properly. The spar needed some shims. Those are in now.



Only the vertical stabilizer’s aft spar is connected to the fuselage. The rest is just hanging there.

With the rudder on, the next step was to trim the aft edge of the fuselage sides. I’d left these long so that I could trim them. The bottom of the rudder is slightly wider than the back of the fuselage, which made the trimming more interesting. The rudder cables fit and the rudder can freely travel up to 35 degrees each direction. The photo shows the trimmed edge and the left rudder cable.



Without rotating the fuselage on its side, an option, I couldn’t use the level to set the rudder travel. I came up with this simple tool. It sets on top of the vertical stabilizer which as yet, does not have its fiberglass tip. I used a weight to keep it in place. The cut-out is 30 degrees, the minimum travel, and the line marks 35 degrees, the maximum travel.



So far, the rudder stops aren’t in yet.

Dave

David Paule 11-10-2021 08:16 PM

Continuing with the rudder deflection and the rudder stops, I played around with the notion of bolting a stop to the bottom of the rudder horn and having it contact the small area below the bottom hinge bracket. I decided that it could probably be made to work but that I didnít want to design it, and set about making something akin to what other RV-3s have. Hereís the rudder horn deflected while I was kicking this about.



Since it looked decidedly difficult to rivet the stops in place, I screwed them in. I used AN525 screws, 8-32. That was overkill. 6-32 would have been plenty. Iím sure glad that I made generously oversized access ports here.

Here is a the left one finished.



I removed the existing rivet where the aft screw is and drilled a new hole for the forward one. I never did notice a rudder stop in the plans, although the manual says it's shown on drawing 26. Well, if so, I sure didn't notice it there.

Dave

David Paule 11-15-2021 02:54 PM

Put the whole tail on, at least the parts I have now. The horizontal and vertical surfaces lack finished tips, for example, and the empennage fairing must be made for a different airplane. But itís an RV-3B part number. I filed a few more photos of it for when I get to those parts. Itís really a bit premature to be doing that now, but with everything assembled I couldnít resist checking them. This photo doesnít show the tips.



Thereís a 3/8Ē gap between the stabilizer front spars and Iím working on a 3/8Ē shim for it now. This is a not-unusual RV-3B requirement.

The tips are mostly trimmed now, but not yet drilled. Note that the aft one doesnít extend to the trailing edge.



I put the tail spring in. It had been drilled a long time ago and was just awaiting its day. I couldnít completely assemble the pneumatic tailwheel assembly on because I was missing the horn. I have a good idea what happened to it and if Iím correct, itís like gone, baby, gone, gone, gone. A replacement is on order. Iím using some washers to hold it together for now.

I measured the length and that tailwheel assembly adds nearly two feet to the length, so itíll come out for the engine installation. Small shop. But while itís on, I checked, and my small Ikea cart supports it nicely and raises it a bit, if I want. Also, I checked, and the tailwheel sticks out past the rudder. A bumper!



The tailwheel is one of flyboyaccessories.comís 8Ē Condor pneumatic tailwheels. I learned about larger tailwheel tires on my C180, which admittedly has a much higher tailwheel load. The recommended pressure for this one is 50 psi.

In an effort to start attaching the control stick grip, which youíll remember is a tennis ball, I put a gob of epoxy and microballoons in the ball and pressed in a piece of dowel the right size to act as a mold. The dowel was waxed with mold release wax, five coats, followed by three coats of PVA mold release. You know, epoxy really, really works! That dowel is permanently attached to the tennis ball, which has changed identify from being the control stick grip to being the attachment test article #1. Fortunately, tennis balls are not all that expensive, compared to airplane parts. What did I do wrong? I didnít seal the dowel. I used bare wood. We learn. I did confirm that the inside of a tennis ball adheres to epoxy, once itís cleaned, and that will probably be useful.

Dave

yarddart 11-15-2021 04:29 PM

Tailwheel
 
Tailwheel your gonna love your tailwheel combination although I prefer the rocket link

David Paule 11-15-2021 04:59 PM

Thanks! Good to get your take on it. I have some TailLynx for it - we'll see how that works out.

Dave

David Paule 11-27-2021 03:44 PM

Hereís a poor photo showing the front spar joints on the horizontal stabilizer. They are currently completely bolted.



I started to do a trial fit of the rudder bottom cap and rapidly realized that it didnít fit. It wasnít even close. I had to split it to get it on.



I send a picture to my mentor who promptly sent back a photo of his, split just the same. I concluded that while Vanís has come a long, long way since the RV-3B concept, as you can see if youíre familiar with their double-digit kits, itís a shame that this progress hasnít flowed down to the RV-3B. StillÖ. If you want a project, if you enjoy the challenges and thinking and craftsmanship involved in building airplanes, the RV-3B has that. It has massive amounts of that. I currently have something more than 5,500 hours in this plane. Admittedly I was thinking more of it as a project than an airplane, until recently. Plus Iím slow.

Back to the rudder cap, I decided to get it to fit but avoid much more until I dive back into the fiberglass later on, and hereís the way it is now.



There is about 5/16Ē gap to the tailspring, which is adequate. You can see that Iíve marked a section at the top front of the cap; I later trimmed that off. The opening is needed to get the nut on the pivot bolt.

After this, I took a holiday break. Sure could get used to a longer holiday break as you might be able to detect from my digressionÖ. But now itís time to get back to work.

Dave

PaulvS 11-27-2021 05:13 PM

Some questions about the details
 
Hi Dave,
It looks like you are making steady solid progress these days.
A couple of questions about some tailcone details:

- How is the access cover for the elevator bellcrank attached to the longeron? And are you planning to fit a fairing to the underside of the horizontal stabilizer? (the plans for the -6 show this fairing as a strip of aluminum countoured to the HS and fixed with screws tapped 6-32 into the longeron between the rivets.)

- It appears that the angle that attaches the HS to the fuselage has been specially shaped around the bolt heads, is that a weight saving measure?

Thanks
Paul.

David Paule 11-27-2021 07:24 PM

Quote:

Originally Posted by PaulvS (Post 1571427)
- How is the access cover for the elevator bellcrank attached to the longeron?

Good question. I seem to have forgotten that little detail. Looking at it a moment ago, I think Iíll need to install a couple plate nuts for screws on either side. Thanks for pointing this out!

Quote:

Originally Posted by PaulvS (Post 1571427)
And are you planning to fit a fairing to the underside of the horizontal stabilizer?

Yes. A couple of fiberglass ones came with the kit. Iíll either use those or make new ones.

Quote:

Originally Posted by PaulvS (Post 1571427)
- It appears that the angle that attaches the HS to the fuselage has been specially shaped around the bolt heads, is that a weight saving measure?

The plans call for making that of 3/4x3/4 angle. I made it of 1x1 angle for more edge distance and more hole location option. After the holes were drilled, I carved it back to 3/4 where I could for weight.

Excellent questions - thank you!

Dave

David Paule 11-28-2021 09:21 AM

Well, I remembered why I left those longeron fasteners out.... I figured that it would be best to do that when I add the bottom stabilizer fairing.

Dave


All times are GMT -6. The time now is 07:35 AM.