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  #421  
Old 06-13-2019, 08:20 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,866
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A slight toe-in, .040 at the end of the threads on the axle. I think that's less than 1/2 degree but don't remember.

I based it on both the plans, which said to have it straight, and one of the Bakersfield RV/Rocket builders, who I think, not sure right now, said that their experience was that 1/2 degree worked well.

Dave
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  #422  
Old 06-13-2019, 09:48 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by David Paule View Post
With the help of my mentor, I made a list of things that need to be done before I glue the turtledeck on.

1. Cut the slots for the shoulder harness. They need to clear the as-yet undesigned canopy frame.
2. Install or at least prep for the transponder antenna. Install the transponder mount if access will be restricted later.
3. Make and fit the baggage compartment aft bulkhead.
4. Install the ADAHRS mount and maybe the ADAHRS, too, depending upon access.

You might recollect the ADAHRS brackets I’d made earlier.



It was intended to rivet these brackets to the aft face of the F-308 bulkhead, fairly high, so that it would be out of the way for cave access and away from magnetic interference. Turns out that while it would function fine there, mounting it to the 1 degree alignment accuracy would be a very iffy proposition, perhaps more frustrating than fun. I’m only building this plane for the fun of the project, so I need to design something easier to align. As the project progresses, my frustration tolerance has not increased. I’m just more used to it. It looks as if I can get the ADAHRS close enough to the tail for access through the F-309 bulkhead, the one at the top front of the aft shelf, if the elevator pushrod isn’t in the way, which I think it might not be. It appears to go through the next hole down. The ADAHRS would be accessible through the bulkheads’s top lightening hole.

After considerable hand-waving and playing around with pieces of angle, I came up with an ADAHRS mount that has the reliable alignment I wanted and continues the slide-in removal feature of the first version.



It is easily removable through that top lightening hole, as hoped.

The photos are also here, and here, too.

Dave
Might want to check with Dynon, but I suspect having that AOA port blocked could create problems for you at higher altitudes. I know that during static testing, the ports all need a limited amount of differential pressure between them to keep things from popping inside the unit. A tight fitting plug locks in a high pressure that can't be relieved as you climb.

Larry
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  #423  
Old 06-13-2019, 12:39 PM
HFS HFS is offline
 
Join Date: Aug 2009
Location: Lemoore, CA
Posts: 242
Default AOA Port on ADAHARS

Dynon's Installation Manual - If AOA is not being installed, it is OK to leave the red plug that comes with the unit installed. It has a small hole in the head which allows for pressure equalization during normal operation. Section 5-8

HFS
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  #424  
Old 06-24-2019, 04:52 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,866
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The seat back is done, except for priming, painting and the addition of some oxygen bottle clips. And those I haven’t designed yet.

After drilling a few more holes in the bulkheads, I ran some things through the tailcone, stuff that won’t interfere with riveting:

Pitot-static lines,
Rudder cables,
Trim cable,
Transponder cable.

Most of these are now coiled up in the floor of the cockpit area, more or less out of the way for now.

The pitot and static lines are 1/8”. It’s not quite as easy to find 1/8” fittings as it is for the 1/4” line that most of us use, but the 1/8” is more flexible. I sourced the ones for these from McMaster. The blue tube is the static line, the red is the pitot. Some of the parts from the Van’s static port kit proved handy: the small 1/8” tee, the 1/8” ID plastic tube, and of course the static ports themselves. The rest of that kit was not used. A local RV builder claimed it.

I had to add some cable support fittings along the way, in between the bulkheads. Unfortunately, now I need some connectors, pins and wiring, all on order, so this is incomplete.



That's right, no conduit.

The aft turtledeck is cut and trimmed.

Looking at the vague plans for the rudder pedal to rudder cable, the plans show a couple of steel straps.



The drawings show the cable attached to the joint between the pedal and the brake. Of the photos I have of other RV-3s, five put it directly on the rudder pedal support arm below that joint with the straps, one uses no straps or return springs and puts it on an eye bolt that is the joint’s pivot, and one puts the rudder cable end directly between the rudder pedal arm and the brake arm on that bolt, without the straps or return spring. Nobody did it at the joint using straps, per the drawing.

Speaking of the return spring, you’ve got to admire the detail on the drawing for its firewall anchor, shown on the left. This is drawing 31, by the way. Even by RV-3 standards, this is exceptional.

Here's the first alternately-hosted pic,

and here's the second.

Dave
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  #425  
Old 06-24-2019, 05:45 PM
sf3543 sf3543 is offline
 
Join Date: Jan 2005
Location: San Antonio, TX
Posts: 958
Default The plans are good!

I did mine as shown in the plans and it works out just right and
It keeps the rudder cables in a straight line.
I did have to use a couple washers as spacers for clearance. Put the longer of the two straps, that holds the spring, on the outboard side.
Of course, you need to have the rudder and pedals installed in order to get the strap length correct.
As for the return spring, I just drilled a #40 hole in the flange of the lower steel gusset in line with the cable. Used a set of springs I got at the H Depot.
The added plus to the springs is you can put a tighter spring on the right pedal to act as a rudder trim rather than put one on the rudder. At least that works for mine. Took a couple tries to get it right.
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  #426  
Old 06-24-2019, 06:36 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
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Steve, thanks for the tip about the stronger spring on the right.

I'm going to use the straps and attach them to the hole directly below the plans point. The return spring will go on the inboard side of the pedal and anchor on the F-312 center ribs that I've modified. That gives better geometry on my airplane.

The anchor is as yet undesigned, like so much of what I have yet to do, and I can't set up the pedal exactly until I have the canopy in place and can sit in the plane. For now I'm using 3/16" clecos to hold the assemblies together.

I've been trying to report what I actually do rather than what I think I might do, since that often seems to change. Photos from other RV-3s, especially the B model, help a lot. They give me an idea of what people are making and using. Often that matches the plans, and that's always encouraging.

Dave
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  #427  
Old 07-11-2019, 12:48 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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It finally sank in that this is the time to install the roll bar. Well, build and install the roll bar. But until the canopy is on, I didn’t know just how high to make it. And the canopy can’t go on until the tailcone top is on. A chicken and egg problem.

Then I realized that one excellent option was to make it per the SK-54A drawing, and take whatever I get for installed height. Okay, plan A. Obviously I needed a Plan B or else Plan A is just a Plan. I brought the canopy home and laid it on the fuselage and started measuring things.



As SK-59A suggests, the canopy nose should be 7 1/2” forward of my instrument panel. On my plane the panel is vertical, as previously discussed. Unfortunately I missed this dimension when I had the canopy on the plane and located the canopy front at 0”, 2 1/2”, 5” and 10” forward of the panel. So at least I bracketed the plans dimension.

I’d noticed that RV-3 pilots usually sit a bit forward of the seat bulkhead. Here’s an example.



Notice how the peak of the canopy is just ahead of the pilot? My mentor pointed that out. I’ll shift mine aft slightly to try to get that over my head. In the photos below, remember that the canopy flange is still on; it’ll be cut off. That’s about 1/2” of height, so the canopy appears to be too high, but a bit of that will change. Also, in the photos, the fuselage is slightly nose-high.

Here’s the canopy at 10” forward of the panel.



Here’s the canopy at 5” forward:



And again at 2 1/2”:



Finally here’s the canopy nose roughly flush with the panel:



Looking at the photos, I think that the position 2 1/2” forward of the panel is about where I want it. It’ll offer the best head room and plenty of room for a roll bar. This position puts the canopy inside at the top about 39 1/2” above the seat. For my diminutive size, that’s probably close to five or six inches of some combination of seat foam and inert spacer. Sure glad that I filled in the curved part of the seat pan!

There are a couple other things to keep in mind. With the tail off and the engine and spinner uninstalled, the fuselage necessarily appears much shorter than it will when it’s done. And a canopy fairing will fill in the gaps around the canopy bottom. Also, the canopy sides are supposed to be squeezed together slightly in the frame. If I do that, and I don’t know that yet, that will raise the canopy centerline slightly. Finally, remember that the panel on this airplane is vertical, rather than sloped slightly forward.

Using the dimensions I picked off the canopy in it’s 2 1/2” position, I cross-plotted the canopy and its opening arc against the stock tubular roll bar. Amazingly, it’ll fit. It appears to clear the canopy frame, while opening, by about 0.70 inches. But if I locate the roll bar centerline 1.00 inches to the right, closer to the hinge, I can increase its height 1/4 inch and the clearance still improves to 1.30 inches. The clearances are “more or less,” though, since I can’t totally count on the canopy dimensions, as they’ll change during trimming. Took a SWAG at it and am applying some windage as well.

Unrelated to the canopy, a couple of Dynon network cables are presently installed. Both are factory cables. These are the roll autopilot servo and the transponder cable. The transponder cable has no twisted pairs of wires and the servo doesn’t have the power lines twisted. I called Dynon Support and was told that for these, this is okay. That was a relief. I don’t need to uninstall them, remove the lacing and twist and replace and reinstall. Good.

The back-up copies of these photos are posted:

http://halie.com/of2.jpg

http://halie.com/ofB.jpg

http://halie.com/ofS.jpg

http://halie.com/ofV.jpg

http://halie.com/ofg.jpg

http://halie.com/ofh.jpg

Dave
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  #428  
Old 07-11-2019, 03:09 PM
sf3543 sf3543 is offline
 
Join Date: Jan 2005
Location: San Antonio, TX
Posts: 958
Default Assuming you are building a tip over canopy....

I had the same dilemma.
What I did was install the canopy frame to the fuselage first. You can do this without riveting on the turtle deck. (I had to do a bunch of mods to the frame to get a good fit so good luck with that. But it was easier than making one from scratch.)
The frame determines where the canopy will sit on the airplane.
Everything turned out pretty much according to VANs plans.
Then I just built my roll bar to the height in the sketch and it worked out just right.
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RV6 (sold)
RV8 (2)(sold)
RV12 (flying)
RV3B (flying)
Legend Cub
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  #429  
Old 07-17-2019, 06:05 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,866
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On this airplane, I'll be making a composite canopy frame rather than using the factory frame. That was a compromise I made with myself to build an aluminum airplane, since I do enjoy working with composites. This permits the canopy to go almost anywhere, but that's a side benefit.

And yeah, it'll be a tip-over canopy.

Dave
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