(In no particular order, but basically as discovered or remembered)
Ribs and rib jig
~ Good place to start the Piet building process. ~ Don't over complicate the jib, the simpler the better. ~ T-88 doesn't stick to polypropelene (?) Those clear paper protector sheets. ~ Secure the jig pieces so they don't move. You want every rib an identical copy. ~ Steaming: 2-3" aluminum pipe from Home Depot and a Tea Kettle works great. Steam rule of thumb: 1hr per inch of wood thickness. Approximately 30 mins worked great for strips.
Helmet box / Turtleback front bulkhead. I built this so the side cover and met the fuselage longerons sides. I needed to build these to overhang the longerons by at least 1/2" on each side, to take into account the 1/4" x 1/2" spruce strips which I wanted to apply. Instead, I will have to transition the strips to be flush with the fuselage side as they go back to this bulkhead, and then use no strips for the rear part of the fuselage.
Sadly, I learned this many times. Metals parts cut to plans specifications "will not" fit. Every Piet is slightly different, and will require slightly different size parts. When possible, it is best to wait until the metal piece is ready to be made, then use a template out of cardboard, plastic, wood, or clear sheet (whatever is available) to make a practice piece as close as possible. Then transfer this to the metal material and cut it out. The piece will be unique to this piet.
Tools: Table saw "Metal Cut-Off" blade from HD works great (lots of sparks) Horizontal band saw from Harbor Freight, use in the vertical works great as a metal band saw. The "thicker" the metal, the better it works!! Blade tended to bit and jump of the wheel on thinner pieces.
Upper fuselage cross braces
I built the cross braces early, and according to plans (I thought). Later, when I needed to install the middle strut fittings, I had to "cut out" parts of the cross brace pieces. Upon much closer look of the long fuselage plans, it appears the cross braces do not include the pieces which would interfer with the struts. Regardless, it is probably a better idea to build and attached the struts, then build the cross braces later.
Engine mount braces
Minor point. I was hesitant with the motor mounts and building the firewall. Finally realized both are very straight forward. I built the motor mount braces to fit over the front lower cross brace. I removed these and glued on the firewall. Once dried, I cut out hole for the brackets. I had to make the top motor mounts slightly longer to extrude the 1"+ inches forward, and same with the lower ones. After I made the lowers, they looked a bit small, beacuse of the modification to go over the cross brace. I re-made two more and they came out much better.
Torque tube and control horns
Torque tube is very susceptible to heating and warping when using oxy/acet. I heated the opposite side to take out much of the warping, but left some in. This last amount was off set by the control horn when I welded it in place. Also, the aileron control horn warped quite a bit. I straightened in up as much as possible. I left a small difference between the alignment of the left and right side in order keep the aileron wires from rubbing.
Torque Tube Doesn't Fit....
Even though I built the torque tube, and front and rear seats according to the plans, and checked the fit often, I failed to check the fit after the aileron control horn was welded on. At this point, I realized it would not fit and there was no way to maneuver it through the front seat back opening. I felt the best way to rectify the situation, with the least amount of damage, was to cut a small slit in the rear seat, mount the torque tube, then fill in the rear seat with extra braces. It came out pretty good. ___________ Corollary I became necessary to remove the torque tube again to modify the pulley supports slightly. I decided to modify the rear seat permamently, so the torque tube could be removed easily at any time. I drilled out the small indentation in the front of the seat, and epoxied in several vertical supports under the seat. The seat is quite strong now, actually providing more support for when the pilt steps on the rear seat, entering the cockpit. The torque tube is easily removed.
Control sticks and connecting rod hit the sides (not enough throw)
The control sticks were made according to plans, however when installed, the connecting rod between the control sticks hit the side of the hole it went thru (the forward seat back support). This was because the connecting rod is offset to the one side (I may have cut the hole in the seat back too small as well, but I don't think so, because the "Vee" in the braces defines the actual hole size. Also, the connecting rod turned out to be a little "low" and it barely touched the rudder bar brace. So I decided to raise the connecting rod on the control sticks by about an inch to and inch and a half. This worked out great, and after installation, all seems to function good.
Bellcrank and elevator cables
Bellcrank- I built the bellcrank as close to plans as I coulld measure, however, two (2) problems materials. 1) The first was the geometriy of the cables and bellcrank. When the control stick cables were connected, it worked fine but the cables tightened up when the stick was neutral and loosened as it was moved fore AND aft. It flet like there was a ridge in the middle. What I determined, after many drawings and scratching of my head was this. The bellcrank needs to be though of as a wheel, with the pivot point perfectly in the center and the cables need to connect somewhere on the radius of the circle. I determined, to fix the cable tightening/loosening problem I needed to move the connecttions forward and down on the circle radius about one inch. I modified the bellcrank with two additional pieces at the top and bottom, which could be remove and changed if necessary. With the corrected hole placement, this worked great. 2) The second problem was that that the cable to the bottom of the bellcrank rubbed on the aft pulley I had installed behind the rear seat. I modified this pulley as high as I could, but the cable still barely touched. My options were to make a new bellcrank or modify the new pieces I had just made. I remade these, now with the necessary longer throws, adjusted the holes again as if on a circle radius and reattached the cables. The lower cable no longer touches and the binding issue is gone.
Engine mount pieces. "How to make a sewing bobbin"
Engine mount pieces: Entitled "SEC B-B". I totally got over zelous on getting started. I thought I'd looked over the mount prints pretty well, and decided to start with these attachment fittings. After I had made them (but before I drilled the bolt holes) it dawned on me I had miss-read the side view as representing the total piece. Oh well, I just had to laugh at this. I got some much need welding practice on this tubing, it was actually very valuable. And I can always use these for paper weights.
Do not make pieces like this one, these pieces are wrong of course!!
Engine mount side pieces. Make sure to leave room to fit inside the fuselage engine mount brackets.
Engine mount side bolt flanges. Interpreting the plans, it appeared the best way to weld the cross tube flanges (for the 3/8" bolts), would be to weld them to the ends of the 3/4" tubes, exactly in the middle. In other words, spaced so they extended an equal distance out from the 3/4" tubes on each side. Makes sense. However, you must take into account when the engine mount is fitted into the fuselage brackets, the inside fuselage bracket must have room, so as not to hit the engine mount bracket, which curves inward. I've attached a rough drawing, but study the plans, and realize how the engine mount will fit into the fuselage engine brackets. The when you go to weld the engine mount pieces and side support pieces, it might be worth offsetting these to ensure a proper fit.
Tail wire brackets:
lessons learned here. I made the brackets early on, and later when I
went to fit the support wires on, I discovered two issues, which I kind
of had a feeling was going to happen. The small brackets, all cut
exactly to plans do not allow the attaching bolt to fit threw and not
interfere with the cloth covering. This is probably because BHP did not
use modern turnbuckles or shackles, I'm not sure. Regardless, I will
have to remake these, extending them to allow for the bolt to stop above
the covering. It will take a few hours to remake these....8 of them,
the vertical stabilizer, for the single bracket the plans call out two
holes combined into one opening (looks like a "figure-8"). I opted to
make two separate holes to accommodate turnbuckles or shackles,
depending on which end I put which piece on. Well I guessed at the whole
separation (I did not have either shackles or turnbuckles at the time).
Now when I went to fit them on, what I thought would be plenty of room,
still was not enough. I had to remake these two brackets to fit the
turnbuckles. Not a big deal, only took an hour or so for these.