Archive for category Bulkheads
F-705 Bulkhead Continued (1/1/12)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on January 1, 2012
4.0 Hours -
Today, I spent four hours working on the plane, but I don’t feel like I have much to show for my work. There are a lot of parts that have to be fabricated for the F-705 bulkhead, and that’s just about all I did today.
The first thing I did was finish making the F-705G angles. It was a good thing that I studied the plans some more because, when I started the parts yesterday, I didn’t realize that one side of the angle had to be shortened. I studied the plans a bit more to make sure I was doing everything that needed to be done, and then it didn’t take me very long to finish these parts.
Next, I started fabricating several parts for the upper part of the F-705 bulkhead. The plans are starting to get a bit vague, basically saying to make and attach several parts. I finding that I now have to pay much closer attention to the drawings than I did with the empennage or wings. After studying the drawings for a while, I started making the F-705J angles, the F-705L shims, and the F-705K plates.
The F-705J angles were relatively easy. I only had to cut some angle stock to the correct length, then mark out a rivet line and drill the holes for the rivets.
The F-705L shims were the easiest parts to make today, and it took me longer to find the stock material than it did to make the shims. Once I located the correct aluminum stock, I just had to cut it to length.
The F-705K plates were a bit more challenging. These had to be cut to length and then they had to be bent down the middle. If I had a bending brake, this would have been easy, but I don’t! First, I tried clamping the part between my work bench and another piece of wood, but, when I tried bending it, the part moved out from the two pieces of wood. Next, I put my back-rivet plate on the bottom of the F-705K, then clamped a board over the top of the part. I then used my hand seamer to bend the part. This worked fairly well, but only because the bend was slight. Yep, the bend only needed to be four degrees!
To bend the F-705K, I sandwiched it between my back rivet plate and a board...then I bent it with my hand seamer.
The bent F-705Ks...4 degrees isn't much!
All of the parts I fabricated today for the F-705 upper assembly.
Once all the parts were made, I had to figure out how to get them all match-drilled to the F-705 channel. At this point, I had to take a break and do some internet research to see how other builders were getting this done. Luckily, it turned out to be fairly easy, but time-consuming nonetheless.
The sequence I ended up using was to first drill the F-705L shims to the F-705F channel. Then, I used the shims to match drill the F-705K plates. With both the shims and the plates match-drilled, I clecoed those to the channel and then clamped the F-705J angle in place and used it to match-drill the channel. A bit confusing, but it worked out well.
First, I drilled the F-705L shim to the F-705F.
Once the shim was drilled, I added the F-705K and back-drilled it.
The F-705F channel with the F-705J shim and F-705K plate.
Finally, I clamped the F-705J angle in place and used its holes to drill the F-705F. It's kind of an odd assembly.
Finally, I countersunk the top of the F-705K plates since those will be riveted to the F-705F channel with flush rivets. Before calling it a day, I also deburred the edges and holes of many of the F-705 bulkhead parts, and I also enlarged several holes for snap bushings.
The last step was to countersink the top of the F-705K plate for flush rivets.
Seat Belt Anchors Installed (12/31/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on December 31, 2011
2.6 Hours -
Installing the seat belt anchors seems like a simple task. You simply drill a hole in the anchor and put a bolt through it. Well, it’s not quite this simple, and I spent the better part of two hours installing 8 anchors.
The seat belt anchors need to have a hole a bolt hole drilled in them, and some will need to be trimmed if they interfere with any rivets.
The left sides of the anchors were the easy ones. The hole in this side of the anchor is located using dimensions given in the plans and then drilled. Once the hole is drilled, the anchors can be bolted to the F-705 bulkhead. However, the plans also tell you that some of the anchors have to be trimmed so they don’t interfere with any rivets. I found this to be the case on the outer anchors, but not the middle ones.
To trim the anchors, I marked a line (making sure to keep proper edge distance from the bolt hole), and decided to try my Dremel for cutting. The anchors are powder coated steel, so I wasn’t sure if the cutting disc in the Dremel was up to the task. However, the Dremel made quick work of the parts, shooting sparks everywhere in the process.
Surprisingly, my Dremel made quick work of trimming these steel parts.
The left side of all the seat belt anchors are bolted in place.
The right sides of the anchors were a bit more complicated. For these, the anchor is clamped into position on the F-705 assembly with a 3/16″ shim between the right and left anchors. The shim simulates the hardware on the actual seatbelts (I’m planning on using Crow harnesses, if another brand is used, the shim width may need to be modified), but the hard part was finding something exactly 3/16″. After searching the garage for something appropriately sized, I finally found a short length of scrap aluminum bar that was the correct thickness. Once shimmed and clamped, the right anchor can be drilled using the hole in the F-705 assembly as a guide. Easy enough, but it took a long time to set up each anchor. As with the left anchors, the right middle anchors had to be trimmed, while the outer ones did not.
To drill the right side of the seat belt anchors, they need to be clamped in placed with a 3/16" shim.
Two sets of completed seat belt anchors.
With the seat belt anchors installed, I could move on to another area of the F-705 bulkhead. There’s a bunch more fabrication that needs to be done, but, for now, I just started the F-705G angles. These are made from 187 x 2 x 2-1/2 angle stock, and I only cut them to length tonight. Eventually, these angles will be the parts that the tip-up canopy latch to when the canopy is closed.
The F-705G angles have to be fabricated from the plans.
I used the bandsaw to cut the F-705G angles to the proper length.
That’s it for RV-7 construction in 2011. Happy New Year!
F-705 Bulkhead Started (12/30/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on December 30, 2011
2.0 Hours -
With the F-704 bulkhead more or less finished, it’s time to move on to the F-705 bulkhead. Right away, this one starts off with some fabrication. After finding the right parts and stock material, I had to cut the F-705B center section bar to length, cut the F-705C bar doublers to length, and make the F-705H spacers.
The F-705B center section bar was fairly simply. I only had to cut one end in order to make it the correct length, and then draw a line down the center of one side. Using the line, I positioned the bar on the F-705A rear spar attach bulkhead, and drilled the bar to the bulkhead using the holes in the bulkhead as a guide.
The F-705B center section bar has a line drawn down the center that is used to align it with F-705A for drilling.
I thought the F-705C doubler bars were going to be more complicated since they have a couple of bends in them. However, after finding the parts, I was happy to see that the factory already made those bends for me. With the bends already made, all I had to do was use the dimensions given on the plans to figure out where to cut the bars to make them the correct length. Once cut, I lined the bars up on the F-705B center section bar and match-drilled the doublers to the bar.
The F-705C bar doublers are bent at the factory, but they still need to be shortened on one end and tapered on the other.
Finally, I made the F-705H spacers. These small spacers will go between the F-705B bar and the F-705C doublers. The plans give the dimensions for the spacers, and, for the first time that I’ve seen, the plans specifically mention which direction the grain of the aluminum should be in the finished part. If Van’s takes the time to mention it here, it must be important. After making the spacers, I clamped them into place and drilled them to the bar and doublers.
The F-705H spacers are made from some bar stock. This is the only time I've seen the plans reference grain direction, so it must be important.
A completed F-705H spacer. The camera makes the small notch hard to see.
The center section bar, bar doubler, and spacer all aligned for drilling.
After drilling all the parts together, I tapered the end of the F-705C bar doublers.
Up next, I will drill the seat belt anchors to the F-705 assembly. However, I decided to call it a day at this point.
F-704 Bulkhead Finished For Now (12/29/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on December 29, 2011
4.3 Hours -
With just a few tasks left, I thought I was going to quickly finish the F-704 bulkhead today. However, those few tasks took a lot longer than I thought they would.
The first thing on the list was to finish the F-704M web stiffeners. I had already marked a line down the back of one side of the angle pieces, so all I had to do was line-up that line in the bulkhead’s holes and drill. I used the holes in the bulkhead to drill the #30 and #19 holes. Once those holes were drilled, I removed the stiffeners and used a nutplate as a guide for drilling the nutplate rivet holes. One of my nutplates got a little askew, but it really doesn’t matter since there is plenty of edge distance and the screw hole stayed aligned…cosmetics only. Since the stiffeners are made from angle (non-alclad), I decided that I would prime them. As soon as the primer was dry, I riveted the nutplates on.
The blue line is used to position the F-704M stiffeners for drilling.
After drilling the stiffeners, I primed them and installed nutplates. The nutplate on the left got a little crooked, but that doesn't matter.
The web stiffeners get riveted to the back side of the F-704A bulkhead with three flush rivets. The flush head of the rivet will be on the forward side of the bulkhead, so I had to countersink the bulkhead’s webbing appropriately. Once this was done, I riveted the stiffeners to the bulkhead.
The F-704M web stiffeners are riveted to the back of the F-704A bulkhead using flush rivets.
With the web stiffeners in place, the next task was to install the cover support ribs to the forward side of the F-704A bulkhead. These are attached using a combination of rivets, screws and bolts.
The cover support ribs and installed on the front of the F-704A bulkhead using a combination of rivets, screws, and bolts.
Next came the center section verticals and shear bars. As when I final-drilled these parts, I decided to partially insert the NAS1307 bolts prior to riveting to ensure that the alignment was perfect. I then squeezed as many rivets as I could reach with my longeron yoke, and then bucked/shot the rest. On the F-704B bulkhead, I also riveted the shear bars in place once the verticals were finished.
When installing the vertical center sections to the bulkheads, I squeezed all the rivets I could reach with my longeron yoke.
What I couldn't reach with my squeezer, I had to buck/shoot. All rivets turned out pretty good.
Now it was time to put everything together for a test fit. The plans call for fabrication of two F-904J center section spacers made from aluminum tubing. I started to search for the appropriate sized tubing when I remembered that there were some miscellaneous pieces of tubing and a few other things that came with the wing kit but never got used. When I located these parts, I found two pieces of tubing that were already cut to the perfect length. I’m assuming these are my spacers and the plans just haven’t been updated to let you know that they have already been made.
The plans say to make the F-904J spacers. However, I found these in some misc. parts that came in the wing kit. The size is perfect, so I'm assuming they are the F-904Js.
I also started to make some wood spacers for the bulkhead assembly, but then I realized that these are just going to get set aside for a while and I stopped. Two spacers are already made, and I’ll need two more…I’ll make them some other time or I’ll find a better solution than sections of 2 x 4. For now, I just assembled the bulkheads with two bolts just so I could see what the finished assembly would look like. After taking a couple of pictures, it came right back apart and will be stored for a short time.
The F-704 bulkhead is temporarily assembled. This thing is heavier than it looks.
Another view of the completed F-704 bulkhead. The spacing is only approximate at this point.
Misc. F-704 Bulkhead Work (12/28/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on December 28, 2011
2.8 Hours -
There’s still a lot of little things that need to be finished on the F-704 bulkheads before I can start riveting things together. The first thing I did today was to drill and countersink the top flanges of the F-704A/B bulkheads for nutplates. Once everything was drilled, countersunk, deburred, etc, I went ahead and riveted all the nutplates on.
The top flange of the F-704A/B bulkheads has to be countersunk for some nutplates.
Next, I dug through the parts crate to find the four cover support ribs. Once located, these were match-drilled to the F-704A bulkhead.
The cover support ribs are match-drilled to the forward bulkhead.
After match-drilling, the cover support ribs were removed so that I could enlarge three holes in each rib for snap bushings. Each of the three holes is a different diameter, so I had to pay close attention to the plans to make sure I was making the correct sized hole in the correct location. The holes were enlarged using a unibit. After enlarging, I went ahead and deburred the edges of both the parts and the new holes.
Several big holes have to be made in the cover support ribs to accommodate snap bushings.
The last bit of work to do on the cover support ribs was to drill for and install several nutplates. Since the flange supporting the nutplates is a little narrow, I opted to use NAS1097 “oops” rivets for nutplate installation instead of trying to do a full countersink.
The cover support ribs also need some nutplates installed.
With the support ribs complete, the next task is to fabricate the F-704M web stiffeners. These are made from some .063 x 3/4 x 3/4 angle, cut to fit between the stiffener bars on the F-704A bulkhead. For today, I only made it as far as cutting the stiffeners to length and marking a center line on one side for alignment. Tomorrow, I’ll match drill these to the F-704A using the bulkhead as a drill guide.
The F-704M web stiffeners have to be fabricated. For today, I just cut them to length.
F-704 Bulkhead and Control Column Work (12/27/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Fuselage on December 27, 2011
3.7 Hours -
Since I didn’t spend an hour making a new workbench today, I actually made descent progress on the airplane project. Of course, I haven’t even made a dent in the fuselage parts crate yet!
The first thing I did today was to match-drill the F-704C center sections to the F-704A forward bulkhead. Since this bulkhead is a critical component of the plane for stress distribution, the parts have to be in absolutely perfect alignment before drilling. To get the alignment just right, the big NAS1307 wing bolts are partially inserted before clecoing anything together. The NAS1307 bolts are close tolerance bolts, so they are very difficult to insert. I put a couple drops of air tool oil on the ends to make insertion a bit easier, and I only inserted them a little bit since there’s no need to put them all the way in (they’re about 4 inches long). Once the bolts were in (one on top and one on bottom), I put a few clecoes in and started drilling.
The big NAS1307 wing bolts are used to make sure the F-704C & D center sections are in perfect alignment with the bulkheads for final-drilling. They only need to go in a little bit at this stage, which is good because these suckers are tight!
Once the forward bulkhead was done, the F-704D center sections had to be match-drilled to the F-704B aft bulkhead. The F-704 shear bars also have to be drilled to the aft bulkhead, making it a little more involved than the forward bulkhead. To align the shear bars, I pulled out a couple more long bolts, inserted them through the shear bar and bulkhead, and then used a big clamp to lock the shear bar in position. Once the bar was clamped, I started drilling.
On the aft F-704B bulkhead, the shear bars are aligned with bolts and clamped in place for match-drilling.
An F-704G shear bar after drilling.
After match-drilling the shear bars, they are removed and the rivet holes are countersunk on the forward side. Since my countersink cage was already set up with a #30 cutter from the other day, countersinking four holes was pretty easy.
The F-704G shear bars are countersunk for a flush rivet on the forward side.
On to the control column. The F-633 control column mounts need a little fabrication work, so I located them in the parts bin and started marking out the location of the top hole. Once the top hole is drilled in the mount, they are bolted to the F-704B aft bulkhead, squared, and the bottom hole is back-drilled using the bulkhead as a guide. So far so good.
The F-633 control column mounts need some fabrication, They arrive from the factory zip-tied together through the bearing.
The top hole on the F-633 control column mounts is located and drilled.
The F-633 control column mounts are bolted to the bulkhead through the top hole, squared, and then the bottom hole is drilled using the bulkhead as a guide.
After the bolt holes are drilled on the F-633 control column mounts, Van’s suggests removing some material for weight savings. The amount of material to be removed is clearly laid out in the plans, so I marked the area to be removed and then made a rough cut with my band saw. By the time I got to the second mount, my band saw blade had had enough and was no longer cutting well, making the second mount much more challenging than the first. Looks like I’ll have to make a Home Depot run for a new blade before the band saw is used again.
Van's suggests removing material from the F-633 control column mounts for weight savings. The one on the left has been rough cut, while the one on the right has only been marked.
As usual, after the rough cuts were made, I used files, my belt sander, and the Scotchbrite wheel, to finish the edges of the mounts. This was no easy task since the mounts are made from some really thick aluminum. However, the finished product looked pretty good.
The F-633 control column mounts are finished. My band saw blade needs to be replaced after working on these!
Next, the F-633 control column mounts were re-bolted to the F-704B bulkhead, and the control column was installed. The instructions aren’t very clear about washer placement for the control column…they basically say to use enough for a tight fit, but not so many that movement of the column is stiff. The washer wrenches sure helped with washer placement here!
The control column base installed on the F-633 control column mounts.
After the control column was installed, I pulled out the control stick bases. These needed a little work before they could be installed. The brass bushings had to be removed, and the I.D. had to be enlarged to 1/4″ in order to accommodate an AN4 bolt. To open up the I.D. of the bushings, I made a small clamp out of a piece of 2 x 4. With the bushing held in the clamp, I could then use my drill press to open up the hole.
The hole in the center of the control stick brass bushings needs to be enlarged to 1/4". I made a wood clamp to hold the bushing while my drill press did it's thing.
Even after opening up the bushings, a little more work had to be done. The bushings were a little to long for the control column base, so I shortened them with a couple quick passes on the belt sander. Once shortened, they were still tight in the control column, but I could squeeze them into place. Before re-inserting the bushings in the control stick bases, I made sure everything was clean and then applied a little grease to the outside of the bushing.
With the bushings finished, I could finally install the control stick bases. Nothing complicated here…a bolt, washer, and castle nut, for each side. For now, I’m not installing the cotter pins since I know these will be removed more than a few times later down the road.
The control sticks are installed on the base and bulkhead. Now that it's assembled, it has to come off...but I'll leave it like this for tonight.
The plans say to remove the control column and stick bases as a unit, but leave the control column mounts installed on the bulkhead. Since I’ve read in a few places that the mounts have to come off eventually too, I’ll remove the whole assembly as a unit. It’s pretty obvious that the mounts are going to be in the way anyways. However, all of this is going to wait for another day.
Firewall Finished, F-704 Bulkhead Started (12/26/11)
Posted by Ethan Jacoby in Bulkheads, Construction, Firewall, Fuselage on December 26, 2011
2.5 Hours -
Before I got too far along on the fuselage, I wanted to build another workbench that is bigger than my other ones. I also wanted another bench so that I wouldn’t have to keep moving things around in the garage. I knew that I would also need sawhorses eventually, so off to Home Depot for supplies. I ended up buying two FatMax sawhorses and some wood. The FatMax sawhorses have slots for 2x4s in their tops, so I decided to construct a table top and use the sawhorses to hold it. The nice thing is that I can easily take the top off for storage if I need to free up space. As much as I hate working with wood, this actually turned out pretty good.
All it takes to make a nice 4ft square table is two FatMax sawhorses, a couple of pieces of MDF, some 2 x 4s, and about an hour.
Once the table was built, it was time to focus on airplane construction again. I set up my back-rivet plate under the firewall. The firewall flange is slightly taller than my back-rivet plate, so I ended up putting my back-rivet plate on a piece of 2×4 and then made some blocks for leveling the rest of the firewall. Once all of this was set-up, the actual back-riveting was simple and quick. However, I did run into one issue when I got to some of the weldment rivets…the rivets called for in the plans were too short, and I ended up having to go up one size in these areas.
The areas of the firewall that couldn't be squeezed got back-riveted. I had to put my back-rivet plate on some blocks to account for the firewall flange.
The forward side of the finished firewall.
The aft side of the finished firewall.
After finishing the firewall, it was time to move on to the F-704 bulkhead. The F-704 bulkhead parts were delivered a long time ago with the wing kit. When I received the wings, these parts got stored under one of my workbenches, and they didn’t come back out until now.
The F-704 bulkhead parts haven't been touched since I got the wing kit.
The first thing the plans tell you to do with the F-704 parts is to drill a bunch of 5/8″ holes for snap-bushings. You know these parts are crucial when Van’s sends them partially assembled with a gold anodized finish, so it is almost painful to have to drill big holes right from the start. Fortunately, the plans are very clear where the holes go, so I didn’t stress over it for very long before attacking the parts with a unibit. It didn’t take long before I had made/enlarged four holes in each of F-704A&B, and one hole in each of the F-704C&Ds. After deburring all of these new holes, I decided to call it a day.
The first thing done to these very important parts is to drill a bunch of 5/8" holes.
All snap-bushing holes drilled in F-704A&B...4 holes in each part.
One snap-bushing hole is drilled in each F-704C&D. These will be used for the rudder cables.
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