Update: July 4, 2009: Wing shortening is almost completed.

meintalley at yahoo dot com

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I have almost finished the wing shortening. Two bays were removed from the outboard ends of each wing. This should change the wing span from about 33 feet to about 26 feet.

I finally decided to remount the HKS 700E onto the Tandem airframe. There will be a lot of refinements to the design while reassembling the Tandem. Brakes are needed at the paved airport for one.

Much closer to a finished mount. Gussets done and trigear mounts finish welded.

I'm back working on the Pulsar XP engine mount. This was actually fun tonight. Kelli helped so I wasn't working alone. That was nice. I ran out of argon/CO mix so we'll have to go shopping tomorrow. I also need a shock mount from a mountainbike to replace the solid forward link as designed originally. Also notice in the last photo that I have "upgraded" to the larger fork for a 5/500 front tire. We mounted it to the trigear leg after this photo.

This month's Tandem progress relates to tidying up the engine and engine accessories installations. Here you see a new mount for the pulse fuel pump. Aluminum must be bonded with an appropriate epoxy after careful preparation. Here 80 grit sandpaper was used to remove oxidation and provide "tooth" followed by MEK wipe and a minute or so for evaporation of the solvent and then immediate coating of both sides of the bond mating surfaces to avoid reoxidation which would cause bond line failure. I mounted the bolt upside down to allow easy preflight on the nut.

Because I want a cleaner more professional engine compartment I am redoing my battery box. My design evolved from a one piece box to a three piece box. Originally I was to use "C" shaped sides but went with a "Z" shaped side in the final box as shown. Structural epoxy from AeroPoxy was used after appropriate aluminum prep. The clecos just hold the box together while curing.

The ply box is the old battery box. It is gone now for good.

After three years delay I have finally fixed those broken tubes. They ain't the prettiest welds but I did the best I could welding relatively upside down.

After three years delay I am finally ready to weld those broken tubes.

I don't like drilling holes in the spar but that's what the build manual says to do.

Henry, Hope these photos help.

Henry, I'm sorry I don't seem to have any photos of the underside where the stick and torque tube connect. I'll try to get some this week for you and post them.

It's been a slow process getting these brackets on. I drilled the rivet holes approximately in the middle of the angle leg and presto, the rivet tool would not fit. It took a few days to figure out how to fix this. I could have used solid rivets if I had those kind of tools but I don't. So I ground the side of the rivet tool off so it would fit. The rivet tool is used with opened side down but shown up for illustration of the tools modification.

I'm working on these rivet backing strips. I flipped the first one over to show what the aluminum looks like prior to sandblasting. It is definately an adventure to get these strips coated with adhesive quickly after blasting and wiping with MEK to clean up dust residue.

Here are a few more detail photos from the second flap install today. I was too chicken to do both flaps yesterday. I "broke" the first set of hinges free today with a flat head screw driver, small hammer, and patience. I put a bit of flox in the structural adhesive to help with sagging during curing. I precoated the hinge legs with pure micro first. Then I mixed in the flox.

So here is my drawing from my manual. It does not show the foam in between the hinge legs used to apply pressure during the initial structural adhesive curing of the free hinge leg to aft spar. Thus my confusion. It does show setting the flat bottomed wing (which Pulsar's don't have) on a flat surface to align the flap bottom when bonding. This won't work for me anyway because my wing isn't being built in Autocad so the height accuracy of my homemade aft spars aren't exactly what they need to be. Without any dimensions in the manual to guide me in cutting my aft spar, I just copied the height of the aft ribs. I'll need to adjust this aft spar height after installation of the flaps and ailerons so both the top and the bottom of each wing are flush with all control surfaces.

For now, I have mounted my flaps to be flush on the upper surface as is desireable. I sand blasted the hinge contact surface and sand got under the tape so I might as well have left it off and simply blown the hinges clean with an airgun.

I used some scrap aluminum and a few clamps to make a shelf to align the upper flap and wing surfaces. I also placed very thin ply spacers to help keep the hinge from riding up the skin when clamped. Notice I did not clamp the two middle hinges to the aft spar. These middle hinges should float so as to not overcompress the bed of structural adhesive/flox they are bonding in. To do otherwise would likely result in hingeline misalignment. See aft spar overheight in photos 8 and 9 below.

It took me a while to figure out what the purpose of the 3/8" by 1/4" foam tape was. I could not buy this type and size so I compromised and custom cut what I could get at Wally World. Bill, did your fast build wing come with flaps and ailerons installed or did you have to do these tasks?

I love finding a use for tools that are 15 years old. The upper wing shin needed trimming to one sixteenth inch overhang. I used a flush cut bit in this laminate trimmer and used a 1/16th" ply shim under the bearing.

It has taken a lot out of me to figure out how to build these flaps. The drawing in the book is not to scale, one of my flaps is used and therefore already drilled, and it took me a while to figure out how to rivet that actuation tube in place with my nonexistent shims and arms too large to hold the tube in place from the end rib opening.

I finally just used adhesive to bond some 1/8" thick aluminum on top of the actuation tubes so it couldn't move while drilling. I was proud of my first flap building results until I realized the reason this flap had been rejected by its previous owner was because he placed the middle two hinges in the wrong place by measuring from the wrong end of the flap. This would not be hard to do since the drawing is so bad. Even after realizing I must have rebuilt the flap incorrectly, I was doing mental gymnastics in my head to make sure I was right that it was wrong. Got that??? Forth photo shows how I had to mark hinges to match existing holes in flap.

I'll just have to drill out ten rivets, move the middle hinges to where they are supposed to be (see white tape in 5th photo below), and have ten extra unfilled rivet holes in my flap. No wonder I get so little done on this project.

Second flap finished shown in photo 8. Bad flap fixed shown in photo 9.

I had really wondered how I was going to bevel this aft spar. I used a black Sharpie to place a line on the forward edge so I would know if I had taken the height down. Then the belt sander with a pretty coarse belt worked great playing the trigger on and off to keep the belt speed low. A vacuum later and all is well.

I had hoped to bond on the outboard lower wing skins today until I thankfully realized I need to mount the aileron hinges first. Only problem is I am missing one folded aileron skin. I called a friend in Kansas to ask him whether his brake will bend 5 feet long metal. I sure hope it will.

The thing that drives me most crazy about Pulsar XP construction is almost everything is so serial. You have to build part A before you can build part B since you use it to locate the hinges in this case. There has to be a better way.

I have my upper fillets and glass tape in here but I don't know how to do a good job on the other side. Maybe if I were 1 inch tall?

I finally decided to install the in-wing flap accuation torque tubes for good. I think the tubes turned more freely before greasing their bearings during installation. The tubes mainly just wiped the grease during insertion. I guess that is why bearings generally have grease fittings that force the grease in from the middle of the bearing out over the captive tube.

The grease wiping that occured during this process is exactly like what happened to the horizontal stabilizer tube to stabilizer shell bond that failed after repair leaving the joint epoxy starved and then causing Mark Brown to parachute out of one of his customers Star-Lites before it crashed.

I was very happy that I had figured the proper angle for the spring pin through the main spar along time ago. I would have been so mad had that hole been aligned improperly. As it was it took some head scratching to figure out how to put the parts together in a way that worked. I still don't know if I am supposed to rivit those thrust bearings in place or just let them float?

Every small bit of progress counts right? I'll glass tape the aileron box after it cures in place. I hope to do lower outer wings skins this week sometime since I need to move the wings to the garage to fit the forward spar plates, aft spar plates, and mark the correct location of the plastic aileron bushing in ribs number 1 on each wing. Lower photos show wing skin splice glass tapes over doubled ribs.

My kit was missing the NACA ducts so I'm gonna make my own. I haven't quite figured out how to transition to the eyeball vent yet. I'm definately getting aluminum eyeball vents though because they are awesome blowing in your face when you start feeling airsick. This was the first time I have tried Gorrilla Glue. You wet one side and put the adhesive on the other. Poof! It foams up and cures in an hour. Nice for non airplane stuff.

Yippee, I'm almost ready to leave for Sun N Fun. Just bolt the wings on and go right? Guess what. I'm almost out of epoxy again. Where does this stuff go?

More small progress. Concerned that I might die and someone else finish my plane and not put in those airholes that came standard in the dissolvable blue foam ribs I decided to protect my reputation and drill some foam. If these seatbelt attach points end up being too far forward I'll just have the world's strongest headset hangers. While it is spring up here in Canada, it is still cool enough that I have been greatful for my forced air electric resistance heater in my garage.

I am so happy to finally have this horizontal stabilizer aft spar pin in place. Because my stabilizers were built in place it was much more difficult to properly place these pins but I was sitting at the computer today and it just occurred to me how to accomplish this task. I cut the opening and progressively drilled through the fuselage from the outside using the longest bits I had to keep the angle shallow. Then I used the 1/4" diameter bit turned by hand in that adapter from the inside to align the hole in the fuselage parallel to the aft spar. The whole relieved area was then filled with flox and covered in two layers of 9 oz glass cloth. The oval part of the hole in the fuselage was then packed with flox from the inside to make a concentric fit.

It's hard to see but I have four 1" wide three wrap bearings on this tube now. Once they green cure I'll bond them into the fuselage.

All three new ribs are in now. They are the ones without drips running down their sides. Yea! Now I won't fall out of the sky.

Well isn't this fun? Breaking these tubes out of their wax prisons was the sacriest thing. It took a lot of force on that screw driver. Yes, I know the manual told me to use only 1 1/4" wide tape and that would have been easier to break out (compared to the full 2" width), but then centering the bearings would have been even harder.

I'm getting ready to bond these boxes into the wings but I needed to do inside fillets and tapes first. I also needed to bond a ply spacer onto one end of one box since it was a little short. I'll flip each box and do the opposite side inside tapes tomorrow morning.

I have finally decided to get at fixing those three broken ribs and I want to take this time to clear up some misconceptions. First, if you haven't tried to nail the skin blocks down to a composite spar that is going on 15 years old, you won't have any appreciation for why I built that exoskeleton. Second, if you think I broke ribs because I didn't wet my plywood before bonding it to the ribs, you obviously don't realize that the plywood will flat wrap the ribs with gravity alone, the clamp blocks are only necessary because we have to uniformly compress the viscous micro until cured. Thus, the reason my three ribs broke was that the clamping method I used was so tight against the main spar, and the 1/4" thick strips so unbending on the short outboard ribs, that it pushed them down until they broke. My broken ribs had nothing to do with my safe wire tie downs which simply aligned the wing for proper washout until the wing skins cured. When the skins were cured, the wing stayed in place after the wire was cut. The second wing which used thinner strips on the outboard short ribs did not have any broken ribs and it also maintained proper washout when the wire was cut.

Ribs 15 and 11 will be replaced one by one as the previous new rib has fully cured.

Well here we have it. I'm still wondering how one puts glass tape on the bearings if they protrude only 1/8" past the ribs on each side. I did the best I can. I know this isn't good enough for some of my readers but for the rest of you, I hope you learn from my honesty and forthrightness.

I'm sure I'll be criticized once more for failing to follow plans that don't make sense to me (maybe I'm stupid) but I'm working on my flap torque tubes and I'm going to install them per my plans (after much confusion, controversy, and criticism of my asking questions that led to a lot of Mark Brown worshipping and no real answers based in science) with the torque tube parallel to the main spar which makes the flap actuation pushrod nonlinear to the direction of bellcrank rotation. But hey, I'm just a stupid airplane builder, what do I know.

In any event, the instructions on page 48 of my circa 1992 plans have 7 steps (paragraphs) titled "FLAP CONTROLS" and none of those paragraphs say anything about a "double layer glass pad around each bearing (9 oz) (4"x6") shown in the drawing on page 49. Instead step 2. refers me to the tree saving "standard procedures section." The standard procedure section doesn't show it or talk about it. So is the 4x6 in place of the 2 inch tape lapped 1/2" onto the rib or is it in addition to this? Well I went ahead and put the 4x6 double layer pad on first only to figure out later that this made drilling the hole saw holes in ribs 1 and 3 by hand very difficult. So, my point of this rant is that I can't be perfect when building according to imperfect plans.

Congratulations to all those builders who are perfect. Keep up your great work and learn to be a little bit more supportive and a little less ready to condemn everyone who thinks about problem solving differently than you.

Tandem Airbike's First Flight

Robert