Testing the fit of the spar tunnel z parts
Assembly Test Turtle Deck
Dan assembled the turtle deck to check the fit. Looks Great! Check out those rib rivet hole lines.
Turtle Deck Ribs Finshed
Dan finished up the turtle deck ribs. Some of the flutes are hard to get right. They need to be in the right location to avoid the rivets yet deep enough to make the part flat and the flange at the right angle. The smallest rib, F20-04, was tricky. We have the large red fluting pliers and the smaller style. I want to ask our Tech Councilor about this the next time he stops by.
Dan broke out the “Big Bend” brake for all the fuselage parts.
Turtle Deck Ribs
3_16_2014
Fuselage status
After completing cutting and drilling the larger sheet parts for the fuselage over the last few weeks I started working on the turtle deck rib formers. We had purchased the rib forming block kit long ago and the fuselage ribs were the only ones that had not been converted to parts (although to be fair, the only other ribs other than one fire wall rib former were for the wings).
So I finished making copies of the rib formers for the fuselage (yes, and the one for the fire wall). The #1 fuse rib is part number F20-01 (R and L). I had set aside a piece of 032 for these two pieces and through the course of the day was able to finish one of the two. When I laid it up along the turtle deck skin and bent the skin around the rib it seemed to follow the edge of the cut skin quite well. These complex edge cuts of the skins make me a little nervous as they are laid out as a table in the drawings and you need to “connect the dots” and generate a smooth curve to cut them. I must be getting better at it because the wing tips did not appear to really follow the layout (despite the fact that we generated a CAD plot of the complex shape). For the wings I cut the skin long and trimmed to fit the tip (a method I would recommend) but for the turtle deck (which is quite a bit more straight forward) I simply marked it on the aluminum and cut to the smooth curve I generated from the points.
Another 4 hours and I should have all the turtle deck parts (ribs) formed. Then it will be on to bending some of the other parts with the brake for all the cross members within the fuselage and then I am expecting to start building the numerous angle pieces as they are needed.
One of the distractions today was a trip over to a friend of Tim and mine from work. Eric Hokenson. Eric is a rod builder (and quite a good one at that). Eric has a shop that is the envy of many a handy man. There are few tools he does not have, English wheels, band saws, brakes, shears, end mills….where do I stop? Not only does Eric have a lot of tools but he knows how to use most far better than 95% of the craftsman owning the same tools. Anyway, Eric has a collection of tubing benders and one of the issues Tim and I have been struggling with is the canopy. We have imagined building a gull wing canopy but recently I started getting cold feet as the details started to worry me.
One of the suggestions Tim made that I (at first) discarded was beefing up the front wind screen bow by substituting 4130 for the existing aluminum ½” tubing. The advantage is that 4130 is significantly stronger and it can be welded, so a center overhead section could be easily attached to it. Well, Eric has a couple nice tubing benders and I am thinking that maybe using 4130 and Eric’s tubing bender could maybe get me back on track with the center overhead section necessary for a gull wing canopy. We’ll see if I can talk myself back into this again ‘cause I sure don’t like the current design of the side opening canopy the Sonex has.
Turtle Deck Skins Match Drill
Dan had the good idea of match drilling the center seam of the turtle deck skins on the bench.
Glare Shield + Rear Fuselage Bottom Skin
Since we are trying to make the best use of the aluminum sheets we continue to cut out the largest parts first. Here is the glare shield, F07-01. We are not sure if we want the sloped instrument panel or a vertical one so we added material on that end. We can decide later.
The rear fuselage bottom is the next large part. Dan used the side of the aluminum sheet but gave a little offset. (Using the electric shears.)
Here is the finished tail end of the bottom skin:
Turtle Deck Cut Out + Seat Sling
February 23, 2014
Turtle Deck Cut Out & Seat Sling
The turtle deck sections were marked and cut without incident last week. The only issue I had at all was that the power went out do to a massively wet and heavy snow storm on Thursday night. The total snowfall was only 12 or 14 inches but it started as a rain and snow mix and by the time the air cooled and the snow really began to accumulate the trees and power lines were loaded with ice and snow.
The plans do not mention it but I am planning on match drilling the seam at the top of the turtle deck with the two sections laid flat to insure the holes line up. It seems obvious as I write this but the plans show two halves being drilled as separate pieces and only later laid flat to be riveted with the seam channel. The two sections I am referring to are F20-06 (R and L) and the seam channel is F20-07.
After the turtle deck sections the next largest uncut fuse piece was the cockpit floor, F16-01. This was to be cut from 0.032″ but there were two more pieces needed at 0.025″, the aft bottom skin (that needed to wait until we picked up one more sheet) and then the seat sling. We were planning on installing the sport trainer controls (center brake, flaps, throttle, etc.) and the lowered seat option. Together these two options required we follow C06 through C09.
There a bunch of changes and substitutions related to these four sheets and it is best to carefully read and then review the implications of the sheets. Tim and I are slowly getting up to speed with these sheets and I’m sure by the time we’re done it will seem very straight forward but for now it is often confusing.
I finished the modified seat sling cut out tonight. I then moved the last full 4’x12′ sheet of 0.032″ sheet aluminum to the table to be cut into the lower side panels, F13-01, lower cockpit skin, F16-01, glare shield and control panel. We need to be sure we have a large enough piece for the control panel to add a few inches to the bottom as others builders have done for a little more instrument room.
Rear Fuselage Side Panels
2/8/2014
Starting the layout of fuselage parts. The plans has the side panels as the highest numbered sheets. Tim and are expecting that we will be at least one sheet of 0.025″ aluminum short. This is due to (likely) some careless cutting on my part, way back when we were fabricating the control surfaces. At that point it appeared as though we had at least one sheet of 0.025″ surplus and when I was cutting out the control surfaces I simply continued cutting them in sequence from a single sheet. The general rule of thumb for consuming sheet goods for best material use is to cut (or lay out) the largest pieces first and to nest the next smaller sized pieces within those larger cut outs. By ignoring this rule and in addition, having to recut one aileron due to a mishap during trimming (grrrrr) I likely set the stage for needing to make another trip to the local aluminum vendor. Lucky for us there is a local vendor for 6061 or I would be paying for shipping.
So Tim and I laid out the large pieces for the fuselage and it is clear we are at least one short. I would say that the fuse parts require the same level of attention to the plans as all the rest. I read through the F26-01 skin multiple times before I realized I missed the detail at the skins are mirror images except for the inspection hole AND the hole for the rudder control slot. I have the two skins stacked to lay them out for drilling and fortunately caught this difference before I drilled any holes.
I think the best procedure is to cut out and complete fabrication and drilling of all the major fuselage skins before heading out to pick up the needed additional sheet as there is little room for error on the large parts before we would need to add to our order. Hopefully that will not be necessary.
