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-   -   RV-3B Dave's in Colorado (https://vansairforce.net/community/showthread.php?t=85658)

ppilotmike 02-19-2019 03:56 PM

Parachute
 
Dave,

I always thought that pan was there in case you wanted to wear a "sit on" parachute for doing aerobatics. Might be worth incorporating "easy removal" into your design.

David Paule 02-19-2019 04:56 PM

I won't be wearing the old-style seat-type parachute. If I wear one at all, it'll be a back cushion type. And the seat pan change is permanent.

Frankly, I don't see what the fuss is about. Here are the RV-8 seat ribs, for example:



And closer to the RV-3B heritage, here are the RV-4 seat ribs:



The pictures are also lurking here and here.

Dave

David Paule 02-26-2019 06:55 PM

Thanks to Rick Brennan!
 
Since then, progress has been made: the tapered pin is within 1/8”, which is about the axial equivalent, roughly, to the .004" diameter needed of being ready for assembly. The final eighth inch, though, needed another #3 reamer.

Once we got back together again, we followed this process. I’m starting at the beginning of the recovery here rather than the final 1/8”.

1. Secure the assembly on the mill.

2. Drill through the joint with the smallest drill that's close to the final size for the small end of the tapered pin.

3. Step drill the hole so that the drills don't exceed the taper wall sides, but going as far as possible short of that.

4. For the final reaming with a tapered reamer, put the reamer in a Tee handle.

5. Make a mandrel such that you can use a milling machine for pressure, pushing down on the reamer.

6. Press down on the reamer with the mill while a second person rotates the reamer by hand. For here on out, the mill is turned off. Use plenty of cutting oil. There is plenty of axial force on the reamer, and plenty of necessary torque on the Tee handle. Use work gloves. Only turn it in the cutting direction, even when pulling it out for a look.

7. Check often. But it goes slowly enough that if you do that, you won't exceed the tolerance. When checking, don't neglect to deburr the exit of the tapered hole. That burr hinders the assessment of the progress you're making.

And the bottom line is that this side is done, finally, after a LONG time of being unworkable. Thank you, Rick!

Dave

David Paule 03-11-2019 06:49 PM

I bolted the engine mount on again and rigged the right gear leg and pilot-drilled it to 1/8?. This photo shows the drill guide I used - I made it. Later, Rick drilled and reamed it out to .311, and the close-tolerance straight pin is a tight fit.



After double-checking that the seat pan and baggage floor patterns that I?d made actually fit, always worth doing, I cut them out. The baggage floor is in two pieces to make them easier to remove. After some work the pieces are deburred, bent and clecoed in place. The flanges were bent before the overall curves, and those were bent before I drilled the holes.



I didn?t mean to, but the landing gear and the floors are going on at the same time. Actually they take turns, but they?re both up for attention now. At the moment, the floors are getting some work.

Thought you?d like to see one of the shop tools in use. The shop vac in the foreground is probably the most common tool that I use since I hate to track aluminum into the house. Once in a while, though, I let the Roomba robot vacuum run around and get the bits I miss. I replaced its battery and it seems to go on forever now.



If the photos should disappear, also try

this place, this other place, and this place, too.

Dave

David Paule 03-26-2019 03:52 PM

Now both the seat and the baggage floor are pilot-drilled.



After this, I removed these and drilled the substructure for the nut plate mounting screws. No photo on the holes, and the hardware is on order. I did remove the flat seat ribs and added the nutplates to these, as it was easier to do that then do them in place.

With both landing gear legs drilled to the engine mount, I located and pilot-drilled the U-403 brake mounting fitting to the axels. Then, Rick and I drilled its mounting hole. The drills used were, in order and in inches, 1/8, 3/16, 1/4, N and finally the .311 reamer. I forgot to get a photo, but there wasn?t anything especially noteworthy about the set-up. Rick made some aluminum vee-blocks, which did a fine job gripping the axle. The 1/8 bit was in the pilot hole, which was just deep enough to locate it. We eyeballed the bit for verticality, rotating the axle as needed, and then went ahead and drilled it.

The landing gear is all going back to storage as I won?t need it for a while. The reason all this took place now was merely because it was easy to align to the fuselage at this stage. I?ll all in favor of making things easy. Besides, it's so much easier to rotate the fuselage when the gear legs aren't on it.

I found several smallish parts that haven't been plated yet, like the brake flanges and rudder cable straps, and got those ready for plating. I'd better have a look in the crates to see if there's anything else, too.

The photo is hosted here, too.

Dave

David Paule 04-10-2019 04:42 PM

Here is the final seat riblet being glued in. I’m using a small heater to keep the epoxy warm and speed the curing.



Since that photo, I riveted them all to the factory seat ribs.

All the seat and baggage floor nutplates are finally riveted in. I thought that I’d need blind rivets throughout and ordered them for the job. But there’s enough access on most of the nutplates that I could squeeze regular rivets instead. Didn’t even use oops rivets. Instead I dimpled the nut plate tangs and dimpled the flanges of the ribs and bulkheads. Wasn’t a problem.

Well, not all of them. Some did need the blind rivets, those are done, and one location needs a one-lug nut plate, which I don’t have yet. But all the rest.

I formed the bottom ends of the seat back and drilled the pilot holes for the sides. That all was fun and went pretty quickly. Turns out that the formed fiberglass sear back top doesn’t fit very well. The bottom is bowed and the sides are too deep, and all that was on record in a build log about ten years ago. No change in the glasswork since. My kit is 2012, for reference, and even then it was a few years.



The seat’s positioning will need to be carefully done. In this photo, the flap weldment is simply placed in there in about the right position, and so is the seat. These will need to move around slightly, but it does give you an idea of the fitment situation.



Later, I bolted it down to ensure it's correct location, and discovered that I'd located the LH seat belt anchor in the wrong position - the flap handle interfered with it. Look carefully at Drawing 24, in the lower right corner. The two anchors are spaced differently, and I hadn't caught that. Email is in at Van's asking for advice.

One thing I was worried about turns out to be a non-issue: how to locate the holes in the fuselage bottom for the flap rods. With the flap handle in the full up position, there's absolutely no doubt where to start cutting. The fuselage is practically begging "here, cut here!" Later, though.

The seat back top is the white gel-coated fiberglass. I understand that the pink fiberglass is a newer generation, and the gray ones are the current newest. But for the RV-3 small parts, we get white. Regardless, it’s all doable.

More importantly, the as-received and as-drawn seat back seems to be 2.5” to 3.0” too high, also mentioned in a build log. Here it is from the front.



And from the rear side.



This is about where the seat back top needs to go. It should nest in the seat bulkhead like this.



To get that position, the seat back’s position will need to be carefully arranged.

The photos are also hosted on www.halie.com: this one, and this one, too, plus this and this one here, as well as one more and this last one.

Dave

BillL 04-10-2019 05:41 PM

Quote:

Originally Posted by David Paule (Post 1327794)
Since then, progress has been made: the tapered pin is within 1/8?, which is about the axial equivalent, roughly, to the .004" diameter needed of being ready for assembly. The final eighth inch, though, needed another #3 reamer.

Once we got back together again, we followed this process. I?m starting at the beginning of the recovery here rather than the final 1/8?.

1. Secure the assembly on the mill.

2. Drill through the joint with the smallest drill that's close to the final size for the small end of the tapered pin.

3. Step drill the hole so that the drills don't exceed the taper wall sides, but going as far as possible short of that.

4. For the final reaming with a tapered reamer, put the reamer in a Tee handle.

5. Make a mandrel such that you can use a milling machine for pressure, pushing down on the reamer.

6. Press down on the reamer with the mill while a second person rotates the reamer by hand. For here on out, the mill is turned off. Use plenty of cutting oil. There is plenty of axial force on the reamer, and plenty of necessary torque on the Tee handle. Use work gloves. Only turn it in the cutting direction, even when pulling it out for a look.

7. Check often. But it goes slowly enough that if you do that, you won't exceed the tolerance. When checking, don't neglect to deburr the exit of the tapered hole. That burr hinders the assessment of the progress you're making.

And the bottom line is that this side is done, finally, after a LONG time of being unworkable. Thank you, Rick!

Dave

I had to repair my 7 tailwheel stinger with a taper pin on the large end and read about sharpening. I feared it was very difficult to do or it was not needed at all. It was needed and with a little care it really helped.

I used a diamond hone plate (3" x 9") by hand to touch up the reamer cutting faces about every 3-5 revs. It really helped to get through the whole job with the same reamer. Only one was done, but likely it would do two. The larger diameter of the main gear would definitely be a challenge. Congrats on getting this done.

David Paule 04-11-2019 07:40 AM

That's a good idea, Bill. You ought to put it in Tips. I'll bet it would help out a few people.

Dave

David-aviator 04-11-2019 07:41 AM

Outstanding workmanship, David.
I am impressed with your skill and patience. Will be a fine airplane.

David Paule 04-28-2019 07:51 PM

Thanks for that comment.

Mostly I?ve been working on the flanges of the bulkheads for the top tailcone skin. The skin is F-323, for reference, and it?s .025 thick.

As Paul Dye noted during the construction of their RV-3B, the top sections of the tailcone flanges don?t really fit. At the longerons, they?re too narrow, all of them, and elsewhere they?re either too high or too low or poorly curved. First, I tried to correct the F-305 seat bulkhead and then the F-309 bulkhead, the aft most one that this skin attaches to.

Here?s the before and after photo of the seat bulkhead flanges at the longeron. The rest of that bulkhead isn?t too bad, and will be accepted as is.





The aft canopy latch goes through this one. It goes right through that gap between flange segments.

Then I did the F-309 bulkhead flanges. These needed thickening, not much, and rounding. I started with the areas adjacent to the longerons and filled the small gap with a thickened G-flex epoxy. It?s the same epoxy I?m using elsewhere with some flox and aluminum powder added for hardness. All it is, is a bit of a shim.



That worked out so well that I did the same thing to add some roundness to the too-straight flange segments. You can see that the topmost flange is essentially flat. I arranged the aluminum form so that it faired to the fuselage shape and at the top, faired to the seat bulkhead forward.



The blue vinyl is a decent release surface all by itself. To make certain, though, I put a couple coats of paste car wax on it. It came off with no problems.

The next bulkhead forward is the F-308 bulkhead. For this, I removed the flanges on that bulkhead. I?ll make totally new ones. The material thickness is .032 on this bulkhead, in case you?re ever in the same spot. The process I?m following is outlined this thread by Paul Dye and Louise Hose:

http://www.vansairforce.com/communit...ad.php?t=61927

And I bought more magnets on order to hold the new flanges in place. I use p/n ZD84PC-PNK magnets from K&J Magnetics. They grip well, are easy to find when they jump away from sight, and seem to be very robust compared to the all-metal kinds. Recommended.

The plywood work platforms that I?ll need to squirm into the tailcone are all cut out now. I realized that although the flap weldment is not yet installed, the work platform needed to clear it when it was installed, too I had to trim it. Having flat seat ribs makes supporting the platform a lot easier in that area. Remember, on this airplane the seat pan is removable, so the platform could be handy one day.



The tennis ball protects the area around the control stick when the stick moves around. This sometimes happens when I roll the fuselage around. With a 1? hole the tennis ball goes right on.

So far I?ve only got part of one of the new flange strips cut out.

I strapped the tailcone top skin in place and was mildly surprised that it?s big enough. And even better, with some straps and cheap angles, it fits without needing rebending - the first curved fuselage skin to do so.



Here?s what the cave looks like. You can easily see where the new flanges will go and why they are needed.



Unfortunately the work platforms aren?t completely finished yet. It?s unfortunate, because I believe that the top skin is currently where I?d like it and I?d like to back drill some holes, and it takes climbing in the cave to do that.

You know, I?ve been thinking that I missed an opportunity to make the platforms fit the sides. If the fuselage was rolled on its side, there would be more width but less height and it might be easier to back drill the rivet holes. On the other hand, they'd be useless once I got the wings on, wouldn't they?

The work platforms got a final coat of finish after I took the photo, but it?ll be a day before they are dry enough to work on. I?m using Minwax?s polyurethane varnish. I?ve got plenty of experience with the product, with several of Minwax?s line, actually, and am happy with it. Their products go on well, cure quickly and are durable. And the best part is that I had a can on hand from a different project.



The alternate hosting links are -

First one,

Second one,

Third,

Fourth,

Fifth,

Sixth,

Seventh,

and the eighth and final one.

Dave

David Paule 04-30-2019 05:26 PM

Deep In the Cave
 
Got to say that it?s getting narrow in here. The cave is the tailcone; I?m in it as far as the F-309 bulkhead, where my shoulders are wedged. The gray things on either side are my elbows and arms as I was holding the camera over my head. We?re looking forward.

The bright white circle is a lamp. It?s off right now but its reflector did a good job with the camera?s flash.



You can see the back side of the F-308 bulkhead, then the seat bulkhead, and out in the open, the instrument panel. It ought to be apparent why RV-3 builders need to remake the fuselage bulkhead flanges. And if you look closely, you can see that the F-308 bulkhead still needs to be joined - it?s splice plate is made and drilled but not installed.

Right now, the top tailcone skin is clecoed from the front back to the F-308 bulkhead.

Just thought that you might enjoy the view from the cave.

The photo is also here.

Dave

David Paule 04-30-2019 07:42 PM

Tonight, I crawled into the tail area of the fuselage to back drill the rivet holes from the front and back bulkheads and the longerons into the top skin. Since there are no flanges on the middle two bulkheads, F-308 and F-309, all I did was the perimeter.

From the work platforms, I could drill back to about the static ports, maybe slightly farther. For the aft-most, I figured that I could round up one of the neighbor kids. It turned out that with a longish bit in the 90 degree angle drill, and some effort, I could drill the aft-most bulkhead and the nearby longerons through that bulkhead.

Yes, somewhere deep in the cave, I made a blood offering to the gods of the sky. Did not plan that.



Some trimming will be required.

The photo is also here.

Dave

David Paule 05-08-2019 07:35 PM

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

RV3Kev 05-12-2019 02:55 AM

Rivet + Adhesive ?
 
Dear Dave

Why the adhesive plus riveting? Using adhesive adds weight so I'm assuming that there is some net benefit.


Kevin

David Paule 05-12-2019 07:09 AM

Kevin, It does a couple of things besides absorbing time and money and supplying weight.

The big thing is that it fills small gaps that might otherwise exist in the airframe. The RV-3B has many of those, or at least mine does; maybe not so much for a better builder. The glue acts as a sort of liquid shim.

The second thing is that once things are glued, they can be riveted at leisure and there aren't any clecos to mess with. It's a great holding fixture. Just don't forget the rivets.

Here and there, mostly for small things, I'm skipping the glue. The ADAHRS bracket, for example, isn't glued. But most of the fuselage and certainly all the fuselage skins are glued.

I regret not gluing the wings and tail. On the other hand, they're done and they might not be if I were gluing 'em. It sure adds to the time involved.

Dave

ColoCardinal 05-12-2019 07:13 AM

Looking great David. It is tough work avoiding
"painting ones self into a corner" on a project such as this. Thanks for sharing, once again.

David Paule 05-14-2019 07:37 PM

The ADAHRS mount is complete and aligned. This photo was taken after riveting.



You might have been wondering how I?d hold in in place, and assumed I?d put screws through the holes on the flanges. That probably would have worked but it wasn?t my plan. I felt that it would be too hard to install a screw and a nut, probably nylon or brass, with one hand working through that bulkhead hole. If you look into the hole on this photo, you?ll see that it?s terribly misaligned.



The misalignment was intentional. The idea is to thread a ty-wrap through it, around the front of the unit, and snug it up from the back. This can be done, I tried it, but it isn?t all that easy. But it works. The ty-wrap pulls the ADAHRS forward against that front stop, which serves both to locate it in yaw and position it longitudinally. There?s a ty-wrap on both sides for a little extra security. This is shown with loose ty-wraps in the next photo.



Moving on to the baggage compartment close-out, which needs to be removable, the manual lists three drawings that supposedly describe it. In fact, none of them refer to it at all. But the RV-4 and RV-8 preview plans say it uses #8 screws. They don?t say how many. Since it?s not structural, I arbitrarily chose to use four of them.

Here it?s shown fitted in place. Amazingly, it fits. It?s not pretty but it fits. I was astonished. Since it does fit, I can almost forgive the poor formed shape that it has. I?d like to see the tooling that produced that. Take a look around the top contours to see what I?m referring to. Isn?t that something?

Well, no complaints here. I signed up for this with a good idea of what I was getting into. I did have to trim the bottom edge to clear the floor.



There?s zero chance of merely dropping a screw from the close-out into the surrounding bulkhead because although it fits, there?s little in-plane overlap. Brackets are required, so I made four and glued and riveted them on. Here, the glue might help with the overhang. The brackets attach to the front surface of the close-out and extend past the peripheral rim to the bulkhead. The bottom nutplates were installed but at the top, the plywood bulkhead stiffener prevents that for now.

I made the transponder antenna doubler and riveted that in. Thanks to Rick Brennan for bucking help. It?s the gray rectangle above the elevator pushrod.



I?m using Delta Pop?s ?Ultra Low Drag? antenna, and a pretty thing it is, too. But I?m not mounting it yet.

Incidentally, I checked with the manufacturer of the antenna about priming the skin or the doubler. He said that with hole-filling rivets (that is, the rivets we use) people report good results. Also the antenna base is plastic, not metal.

The left-hand seat belt anchor was mislocated originally. I moved it inboard to a new location, after getting some advice from Support. Thanks Van?s - seven years after buying the kit, they?re still supporting a discontinued model.

And finally, I figured out where to put the outside air temperature sensor. I understand that there are as many opinions about this as there are RVs, so I took my mentor?s advice, and placed it on the F-310 bulkhead, at the forward end of the aft shelf. It?ll be under the tail fairing and easy access to the nearby ADAHRS.

The secondary photo hosting is at here, here, here, this place, and yeah, here, too.

Dave

David Paule 05-29-2019 12:22 PM

With the seat belt anchor relocated, it was time to adjust the seat back so that it clears. A slight bit of carving on that 45 degree flat area and that was done. When I went to fit the piano hinges, I found that the good extruded kind had mysteriously lost its pin. A replacement pin is on order.

The upper end of the seat back side rails needs trimming and the inside of the seat bulkhead, too, to allow the seat back?s fiberglass top to fit into the upper part of the seat bulkhead. For a relatively simple part, the seat back sure wants a lot of miscellaneous fitting. Worth mentioning is that the top of the F-328A seat back is approximately 2 1/2? too high and also needed trimming.

Here?s the bottom. Only the left side needed trimming, the right was fine.



This shows the flanges of the seat back rail and the bulkhead. Both need further trimming.



After placing the fiberglass F-328C seat back top in position, I was able to draw the area of the bulkhead top in which the shoulder harness slot gets cut. You might remember that I?d left that till now just in case, following one of the RV-3B Build Commandments: Do not do anything until you must. The other one is: Do what you can early because you might not get access later. Yes, these conflict with each other, part of the fun. In this case, waiting was worth it.

The shoulder harness slots are detailed on drawing 21. The local reinforcements looked annoying to make. The RV-4 plans show that part in more detail as F-407D, which is a DIY part. If you want to make the part, follow that drawing. It?s not on The List of parts that Van?s sells, being a DIY part on the RV-4, too. ?The List? is their nomenclature, not mine, if you?re not familiar with their parts ordering system. Fortunately I?ve got the RV-8 plans as well as the RV-4 plans, thanks to their handy flash drives. The equivalent RV-8 part is F-807D-1, for $2.40. Hoping it?s the same part, same fit, I ordered a pair. We?ll see.

This shows the F-407D detail.



I placed the slots horizontally rather than aligned with the curve of the bulkhead, thinking that my shoulders, sag though they will, are closer to that than to the bulkhead curve.



Remember those flanges I needed to make for the F-306 and F-308 bulkhead tops? After a number of trips into and out of the cave-like tailcone, they are all finally fit, drilled and clecoed in place. Not ?are,? ?were.? For I glued them to the bulkheads and then riveted them. Not especially pretty but, I hope functional.



A while ago, I?d made a cardboard mock-up of the EarthX battery. More recently I found that they sell an empty battery case, so I bought one. Good service - it came the next day; they are somewhat local. Tried to find a place to fit it and hold it down, a place where it and the contactors are reasonably close and not immediately adjacent to fuel lines. Have a partial plan but it?s not this one. This was one of the options I did not choose. It placed the parts within a few inches of the fuel lines.



That?s the firewall and its recess to the left, with the spar bulkhead on the right. The battery case is resting on the forward floor. One rudder pedal is just visible at the bottom. The contactors are shown upside down, as I learned after I'd taken the photo. They are rather close together only because the bit of scrap they're clamped to here, was that long. This was just to assess the location and mounting.


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

Dave

David Paule 06-10-2019 07:56 PM

Here are a few photos showing the seat back as it fits inside the cockpit.

This shows the clearance at the lower left, where I had to relocate the seat belt attachment.



The bottom back of the seat back clears the flap bar. But after adding the .040 shims per the manual and the piano hinges, there’s that much more clearance than shown.



The sear back folds forward to allow some limited access to the baggage compartment. Here it is folded forward.



Here is the seat back from the front. Points of interest are the bottom corners at the seat belt attachments and the clearance to the seat bottom.



As of right now, the aluminum frame of the seat back is all riveted. The fiberglass part is not yet permanently attached. I started by blind riveting and after replacing a few rivets, ended up doing it with the gun in one hand and bucking bar in the other. Surprisingly, that worked better for me.

I had one of Flyboys pneumatic tailwheels on order, and it arrived. Here it is disassembled. They recommend 50 psi and based upon my experience with my certified airplane, I feel that’s a very good pressure to start with. Note the sealed bearings.



As is my habit, the photos also lurk in this place, and that place, and another place, and this place, too, and finally this last place.

Dave

Snap 06-13-2019 03:46 AM

Quote:

Originally Posted by David Paule (Post 1330924)
I bolted the engine mount on again and rigged the right gear leg and pilot-drilled it to 1/8?. This photo shows the drill guide I used - I made it. Later, Rick drilled and reamed it out to .311, and the close-tolerance straight pin is a tight fit.



After double-checking that the seat pan and baggage floor patterns that I?d made actually fit, always worth doing, I cut them out. The baggage floor is in two pieces to make them easier to remove. After some work the pieces are deburred, bent and clecoed in place. The flanges were bent before the overall curves, and those were bent before I drilled the holes.



I didn?t mean to, but the landing gear and the floors are going on at the same time. Actually they take turns, but they?re both up for attention now. At the moment, the floors are getting some work.

Thought you?d like to see one of the shop tools in use. The shop vac in the foreground is probably the most common tool that I use since I hate to track aluminum into the house. Once in a while, though, I let the Roomba robot vacuum run around and get the bits I miss. I replaced its battery and it seems to go on forever now.



If the photos should disappear, also try

this place, this other place, and this place, too.

Dave

Great read, Dave!

To which angle / track / toe-in or out did you set it up? 0 on everything without any load?

David Paule 06-13-2019 08:20 AM

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

lr172 06-13-2019 09:48 AM

Quote:

Originally Posted by David Paule (Post 1345248)
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

HFS 06-13-2019 12:39 PM

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

David Paule 06-24-2019 04:52 PM

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

sf3543 06-24-2019 05:45 PM

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.

David Paule 06-24-2019 06:36 PM

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

David Paule 07-11-2019 12:48 PM

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

sf3543 07-11-2019 03:09 PM

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.

David Paule 07-17-2019 06:05 PM

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

David Paule 07-31-2019 12:33 PM

After thinking about it some more, I decided to make a free-standing roll bar rather than tying it to the seat bulkhead like the RV-3B plans show. The new approach will emulate an RV-4 roll bar except adjusted to fit my RV-3B, and without the horizontal shoulder-harness attachment piece. Here?s what the RV-4 roll bar looks like.



Cutting out the roll bar fittings gave me a chance to use different tools than I?d used back in the later ?60s. Then, all I had was a hacksaw or in some places, a cold chisel. The cold chisel works good if you have a deep smooth-jawed vice and don?t mind ruining the cut-off part. With those, it?s fast and easy to get a good cut. The hacksaw is a bit tedious but works okay with the right blade and where there?s not too much depth to cut.

With this job, I used my die grinder with a cut-off disk. Also fast and easy and the off-cut side is as good as the part you?re making. I like it. My coarse mill file does ok for the final shaping, if necessary, and the 12? disk sander, of course, is a lot like a grinder.

The only thing is, compared to aluminum, steel is a very dirty product.

After it was cut and fit, I took the steel parts and the jig I?d made down to Sterling North, who welded it for me. This made obvious some parts of the basic design which really should be improved. Quick summary - the bottom fittings on the big tubes, that whole joint should be different.; the top of the vee should be different, and the bottom aft fittings of the aft braces should change. An experienced welder could offer tips if you need them.

I took the roll bar home and drilled the mounting holes though it and the top longerons.



Here?s a view from aft, showing the offset to the right.



It?s really obvious from this perspective, isn?t it?

Next, I took another look at the seat ribs in the fuselage. I?d been wanting to run some cables across the cockpit there but there wasn?t room to drill holes through the seat ribs. Another thing I should have thought of before riveting them in place. Still, there were some lightening holes in the seat ribs, and Granger sold me some plastic bushings that fit. Unfortunately the forward elevator pushrod does a fine job of blocking the path between the middle one and the right-most one.

This caused me a week or two of angst while I thought about it. Then I realized that if I had some sort of something that would re-route the cables around the pushrod, that would do the trick. The second iteration of that concept is in place now.



You can see the cables bundled up at the top of the picture. Right now they pass though the top-most bushing, the center bushing, up through the small bushing in that little fitting, which suspends the cable clear of the pushrod, and back down through the bottom bushing, all to the right of the rear spar carry-through and flap tube. In the photo, forward is to the right and left is up. The cables include the ADAHRS and the pitch servo.

This does a good job of clearing the pushrod. Yes, I tried it at all extremes of motion.

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

Dave

David Paule 08-05-2019 07:18 AM

Tinypic Going Away
 
A large number of earlier photos are posted on Tinypic.com. Apparently that's going away. If they don't have backup photos listed at the bottom, like I'm doing now, and you'd like to see a particular photo, please let me know.

Tell me which post number and I'll refresh it.

Dave

David Paule 08-07-2019 11:46 AM

Tinypic and Alternate Photo Hosting Here
 
The www.tinypic.com site had a note saying that the service will be discontinued in 2019. It's already August 2019, so the clock is ticking. They said,

"While you may continue to host images from our site until further notice, we encourage you to consider selecting one of the premium plans offered by our sister site, Photobucket."

I reviewed this blog of mine and here are the posts using Tinypic.com:

Posts 1 through 323 (and yeah, that's a bunch!).

I started using a different picture-hosting site in post #329.

Unfortunately I hadn't started including a back-up set of photos until post #221, and then my use of back-ups was intermittent for quite a while.

I also have PDFs of all the pages, but my page length is 40 posts rather than the default 10, so the PDFs are pretty big - too big to email and I no longer have a file-hosting site. I might have some time later this year where I will be able to devote more time to blog maintenance than now, and if so, I'll try to update the photos with alternate hosting and backup hosting links. Are there particular posts I should start with?

I also have a table of contents file that I can email. It's more or less up to date, so please advise if you'd like a copy. There won't be a subscription update service so you should consider that a one-time good deal, and add future updates yourself. It's a text file so it's easy to use.

The sites I use now are:

www.imgur. com.
This is a free site, but an account is needed, I think. It's easy to use.

www.postimage.com
Another free site, no account needed. Also easy to use.

www.halie.com
Another free site, owned by a VAF member (thanks, Bill!), and easy to use except for the fact that if it does allow batch loading, it's sure not obvious. See this post for its introduction. I have not yet gotten any emails from them.

Worth noting is that even if a hosting site offers photo-size adjustment, I've been using a program on my Mac for that. I use Preview, a Mac feature, and set the photo width to 800 pixels.

Ok. Regular programing will resume, with of course, special announcements as appropriate.

Dave
P.S. Later in the day, I spent some time updating the photos in post #1, just to get a feel for the job. It's slow but manageable. Don't count on a rapid change. It's likely that when I have that time later this year, though, I might be able to hit it then. Again, if you have a particular post you want updated, do let me know.

Also, while the Tinypic photos still work, consider saving the pages as PDFs. On my Mac and maybe on a Windows machine, it's an option in the print option box, and fairly easy to do.

David Paule 08-23-2019 10:17 AM

With the roll bar in place, I trimmed the turtledeck so they fit together. Haven?t made the fill-in pieces at the front of the roll bar yet, though.

The clearance recesses weren?t all that hard to make, but they were tedious.



One of the things I?ve wanted to try are the Eastwood two-part rattle-can paints. I bought the epoxy primer and a top coat. In the photo, my reading glasses keep them from rolling away.



I used some this paint for the roll bar. The gray epoxy primer is a very light gray. To me, it?s attractive. I top-coated it with their under-hood black, another two-part paint. I don?t know it?s nature but possibly it?s a urethane. Don?t think it?s an epoxy. The paint is very easy to work with. Once mixed, the cans are good for 48 hours, and that?s all, so I needed to be ready to go then. The cans cover 10 square feet and cost about $25 a can. I?m only using it on the roll bar except that I used up the excess epoxy primer on some other parts, without top-coating them.

Once the paint dried, I bolted the roll bar in place.

Remember the work platforms from post #410? There are a few things that need clearance to go from below them to above them, like the pitot-static tunes, ADAHRS cable, transponder cable and antenna lead, and so on. I need to carve them a bit to accommodate those things. If you decide to make work platforms for your plane, which I recommend, you will too. FYI.

Alternate photo hosting today is at www.postimage.org. Here's the turtledeck cut-out, and here's the Eastwood paint.

Dave

David Paule 09-07-2019 09:55 AM

Been working on small stuff for now. I added a couple Adel clamp tabs to some stringers, things like that. Here’s one of the things, the shoulder harness attachments. I’d seen one RV-3B that had the turtledeck locally flattened at these attachment fittings due to the rivets forcing the skin to conform to the thicker bars. I glued these fittings in place before riveting and the external contour is fine. The photo shows it glued but not yet riveted.



Here’s the photo of it riveted. I back-riveted these. You can see that the curvature of the skin is preserved, which was my primary goal.



I’ve been tooling up to attempt to paint the inside of the tailcone. A rattle can paint would do quite well here, the goal is merely to make it white for a little more light when I need to work back there. I chose to attempt a finish paint job using exterior paint and equipment, less a paint booth, which I haven’t put together. So far I got

Devilbiss filter, drier and regulator,
Devilbiss FLG-4 HLVP paint gun,
PPS cups and adapter,
3/8” air hose with high-flow fittings,
Stewart Systems EkoCleaner, EkoEtch, EkoPoxy and Ekocrylic,
Hobby Air system with the full hood, shared with another builder.

I got started and put the EkoPoxy primer on the skin. It took two coats to cover and dried quite rough. But in a few hours the roughness had disappeared and the surface is smooth with an even satin finish. I like it.

Mixing the EkoPoxy took a call to Stewart tech support. When I opened the can, it looked like mud. Thick chunky mud, with some liquid under it. Turns out that’s normal. It took a drill mixer to mix it. I first tried a MixerMate and broke one of the mixing ears off in it. A bit of a mess. Here it is just opened; you can see the liquid at the far left.



The MixerMate does do a good job sealing the can and its built-in spout is a nice thing.

I shot a coat of clear gloss Ekocrylic over the Ekopoxy for a learning and evaluation exercise. Well, I learned that clear over white, in indirect lighting, isn’t easy for a first-time painter. The finish came out clear, glossy, but either a bit thin or some orange peel. It’s good enough for the tailcone interior, which is where I used it, but I’d like to practice more if I were doing the exterior.

If you’re planning on painting the tailcone white for easier maintenance, which I do think is a good idea, after comparing both the satin primer to the gloss topcoat, I prefer the satin or flat paint texture. It helps give more even lighting there. FYI.

Yes, this took more time and money than merely using rattle-can paint would have, but I've been concerned about eventually needing to paint the plane, and wanted to see if I could get sort of an advance idea of what I was getting into.

The alternate photos are this one, and this one, and this last one.

Dave

David Paule 09-16-2019 06:36 PM

Here?s a photo of the EkoCrylic-painted tailcone interior.



One of the smaller things I did was to install the Adel clamps at the aft end of the rudder cables, to hold the plastic tube in position. The Adel clamp?s best position was with the tangs attached to the skin. I hate to have hardware poking through the skin so I needed to use flush screws for that. That brought its own issue, of how to dimple the skin for the screw head. The location was considerably beyond what any of my tools could manage.

Had to think.

What I came up with was this arrangement, which worked quite well, somewhat to my surprise.



The leading alternative would have been to glue a thick piece of aluminum inside the skin, and countersink through the skin for the screw head. But the dimple is better.

Here?s the dimpled hole from the outside, with a screw in place.



Here?s the same thing inside.



The steps on an RV-3B are the short extensions of the seat pan that end up at the spar bulkhead at the forward end. Here?s the seat pan and the steps in Dwg 24.



When I made the seat pan, I didn?t realize that the steps were integral. So I needed to make them to fit. More thinking, since the seat pan is removable on this RV-3B. Either the steps remain connected or not, but either way, they needed to be removable. The pitot connectors and electrical harnesses go under them. The steps are in progress.

With the help of Dave Dooley, we glued the tailcone top skin to the fuselage today. This is the last large glueing job on the airframe. The exoskeleton is obvious here. The bulkhead portions are 1? x .063 2024 from Van?s, and the longerons are 1? x 1? x 1/16? aluminum from a big box store, procured locally.



I had to help the bulkheads line up with the cleco/rivet holes from inside the fuselage. It was apparent how useful the white paint was helping to spread light around. Highly recommended.

The next day, when the glue had set, I removed the exoskeleton, but left some clecos just in case, just to avoid that annoying ?crack - sproing!? sound.

The back-up photos are here, here, here, here, here, and here, too. Sorry, this time they're not in order.

Dave

RussellT 09-17-2019 12:17 AM

Nice work Dave it is looking good. I think the foot steps are designed to be removable and not part of the seat pan, Illustration A-A (dwg #24) I think shows them fixed with screws. Anyway I did mine with screws separate to the seat pan which I also made removable via 6-32 CS screws instead of the called out pulled rivets.
Regards,
Russell

David Paule 09-17-2019 11:45 AM

Yeah, thanks for the comment. That's a good place for screws. The rest of the seat pan is screwed down into nutplates. I'll need to decide if the steps get screwed or riveted to the seat pan, though I'm leaning towards screwed, to give me the option of just pulling those off.

Dave

David Paule 10-16-2019 05:25 PM

David Howe, my mentor, sent me some test coupons to glue and rivet to see if my glue process works on top of the white Stewart Ekopoxy primer. Note that I’m not bonding to the primer at this time and haven’t bonded to primer on anything on the plane. This was just for interest, that and to compare to both rattle can SEM and Azko Nobel. Azko Nobel will carry a bonded joint, but SEM won’t.

One test sample broke at 1,510 pounds, and the other two broke at about 1,400 pounds. Those two failed at a point away from the bonded/riveted joint. The three rivets alone are only good for 651 pounds per MIL-HDBK-5H, so this process adds substantial strength to the joint.

In this photo, the test coupon itself, not the joint, failed at over twice the load that the rivets alone, sans glue, is rated for. Looking at the rivet heads, it appears as if the rivets are virtually unaffected. The side clamp is there just as a support to hold the assembly in position for the photo.



The test samples were designed to resemble typical RV-3 riveted joints with the inclusion of glue, and this time, the white Ekopoxy primer. Before shooting the primer, the samples were abraded in the bond area, and then etched using Stewart EkoEtch before priming. After the primer was completely dry, it was glued using West System’s thickened G/flex.

This testing was done to assess whether this primer could be used overall, with post-priming glueing. While it could, it would require pre-abrading the parts before the etching and priming.

A later series of tests essentially compared 3M's 2216 to G/flex. The 2216 is a stronger epoxy but that's all I can say at this time.

After that, the remaining parts needing an epoxy primer were primed. Some already had the primer on one side. These parts got primed: seat back, baggage bulkhead cover and both baggage floor pieces.

Moving on to riveting, the first day Dave Dooley and I riveted the left side of the turtledeck cover at the longeron. After some QC and drilling out, I riveted some of the aft-most left longeron rivets through the back bulkhead myself.

I got a hub base prototype for the Dynon SKyview network hub kit that Az_Gila designed. You can read about it here:

It needed some sort of a base that protected the open traces from contamination and stood the hub off from its mounting surface. Steve Melton designed it and Amanda Melton 3D printed it. Here’s a prototype. It works just fine.



All fitted up with the hub kit, although not with flight screws,



I haven’t been working much on the plane recently, but we are trying to get the tailcone top riveted on. I’ve been getting things ready around the house for a period where I’ll be recuperating after some major but otherwise routine surgery scheduled for next week. I expect to be unable to work on the plane at all for perhaps a month, and then only light duty for another month. Those are relatively crude estimates of course. During that period, I hope to transfer as much of the now-dead photos that I used in this blog from TinyPic to another hosting site. We’ll see how that goes - don’t expect a lot.

In the meantime, stay tuned. I’ll be back.

Back Up photos: here, here, and here, too.

Dave

David Paule 11-03-2019 10:36 AM

I survived and am home now.

Dave

Michael White 11-03-2019 02:53 PM

Good news, Dave! Hope the recovery period is short and goes well.


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