Narfi's Life after EU: Chapter Five - CH750-SD 3 Place Aircraft

If you see the form blocks I have been making, there are 2 sets for each part, the bending formers, and the cutting templates. Each set is made up of 2 pieces of wood with matching tooling holes that I can bolt through.

I lay one piece of the cutting template over the sheet of aluminum and drill through the tooling holes through the aluminum.
Then I put the other cutting template piece underneath the aluminum sandwiching it between the two and bolt them together.
Then I run a hand held router with a 1/4" or 3/8" end bearing around it which cuts the aluminum exactly to the edge of my cutting templates. It makes a lot of metal shavings everywhere, but makes for a perfectly repeatable part with very smooth edges.

 

Still sore from our villages annual "Turkey Bowl" having lost so much weight this was my first year really running and catching instead of just playing on the line. Felt great but I'm guessing I'll never be young again :p

2hrs cleaning up the holes and 1 hour flanging all the holes.
The plywood separated on the smaller die, so epoxied it and have a few of those holes left but will be just 15min or so.

Landon came out to help but couldn't get enough oomph on the mallet so we tried a couple with clamps, learned about leverage on making handles longer but still not practical so he watched me beat the rest out with the mallet.

He likes visiting at work and trying out the different cockpits and getting ideas and dreaming.





Total time spent building: 63.5 hours
Total Cost: $8276
Airplane + consumables + project specific costs: $5340
Tools, etc.. I will keep for future projects: $2936

 

30min
Epoxied the male plug back together and flanged the last of the holes. Very last one and the plywood on the male plug failed in a new layer (not my epoxy joint)
Not sure if there is more flanging to do that size or not, but if there is I will probably make a new male piece from solid wood instead of plywood.

Called Roger this morning and he is still waiting on Rudder drawings for me, so I'm on hold for a little bit.






Total time spent building: 64 hours
Total Cost: $8276
Airplane + consumables + project specific costs: $5340
Tools, etc.. I will keep for future projects: $2936

 

I got the blueprints for the Rudder from Roger this week but in the middle of making a storage bed w/ bookshelves and secret cave for my son so probably cant start till next week.


Ordered the 3/4x3/4 angle I needed, just a few inches needed for the rudder but Roger told me I would need roughly 20ft for the entire project, I bought a 25ft stick cut in half. Also have some 1/8" aluminum coming, will need some for the rudder horn.

total for that order $275 (including $30 delivery)


Ordered Some aluminum prep and some primer = $252

I decided to just go with primer I know, PPG 910-704 Super Koropon, it sprays easy, goes on super thin, and produces a hard chemical resistant shell.


Total time spent building: 64 hours

Total Cost: $8803

Airplane + consumables + project specific costs: $5867

Tools, etc.. I will keep for future projects: $2936

 

Hehe.... I've been itching to get back to working on the plane, but have been building a fancy storage bed with bookshelves and a 'secret' cave for my sons new room. It is taking a lot longer than I expected but I think it is turning out pretty nice.

 

Finally got most of Landon's bed made, still waiting on some magnets and hinges, and will need to paint it (black then scuffed up and clear coated for the old distressed look) once reassembled in his room. For not knowing anything about carpentry and making it up as I went along I am pretty happy with it, just not with how long it took :p





Was able to start on the rudder yesterday, took about 5 hours to make 7 parts and decide that I needed more dimensions/info to make the rest.

Tapered spars are easy, just make them a few inches too long each direction and then cut out the right size from the middle when done.
I borrowed a neighbor's 12ft brake and it's got some quirks, not sure if it's just old or needs some adjusting, it bends sharper on the ends than the middle and doesn't clamp over center, the clamp arms need to be 'balanced' in the clamped position and it's a pain getting both clamped without one springing open.

I got pretty close on my angles for the spar and doublers and just tweaked it a little with the hand seamer back at the tent when done.
The hinge brackets were easy as was the little spar fairing and angle tab.

Was my first time cutting sheet metal with the ulfa knife and it worked really well, though took quite a few passes for the .040, the thinner sheet cut really easy.



I sent Roger an email listing the rest of the dimensions I need for the ribs and skins and horn. Will give him a call as well.

Total time spent building: 69 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

 

~8 hours over the last few days.
Built the rest of the rudder parts.
Tip rib, rear ribs and forward rib.
Going slow because they don't have the scratch built plans yet. Roger has been taking pictures of parts with the tape measure beside them. I'm sure he is getting tired of me calling

Last night I attached the ribs to the spar and everything looked good except the forward rib seemed too wide for where it attaches between rear ribs 2 and 3. It fit perfectly against rib 2 but after talking to Roger today my parts are the right demensions and it for sure goes a few inches further (narrower) up the spar. I will play with it tonight and probably just need to bend the flanges down a bit tighter.(I hope)

Then I will take it apart and put the spar doublers in place and the hinge brackets.
All of this is being done with a #40 drill bit for pilot holes and fitting. Once it's all cleaned up and fitted I am hoping Landon will want to do final drilling for size.

The skin is going to be interesting as there are no pre punched holes for aligning the ribs. But I think once I actually fit it together it won't be too big a deal to get lined up. I have the angles the ribs are supposed to sit from the spar.


Total time spent building: 77 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

 

~6hrs
Bent the trailing edge skin.
Drew out the angles of all the ribs from the spar on a sheet of plywood with centerlines extending beyond the edges.
Layed out the skin on the drawing and drilled the trailing edge pilot hole for each rib.
Drew centerlines on all the ribs and inserted the skeleton into the skin.
With the spar and trailing edge blocked for jigging. Clamped the skin to the spar where I had marked it belonged and lined up the ribs till I could see the center lines through the pilot holes, drilled and clecoed.
Drilled a pilot hole in line with the rib centerlines at each intersection on the spar and then used a rivet spacer fan(not sure proper name) drilled along each rib all the pilot holes pitch 40 or less.
Flipped it, rejigged it, and did the same on the other side.
Using the river spacer drilled all the holes along the spar spaced evenly between all the ribs on both sides.
Made the lower splice plates and drilled and clecoed them in place. I bent my rear skin square with a full width 48" sheet and it ended up a little shorter than the plans, I'm guessing they bend at an angle to get a little longer or something. No big issue, my splice plates
just look a little different.
Removed the clecos where the lower forward fairing attaches and slid it between the skins and spar. Marked a line on each side so I would know how far to slide it in, then drilled through the pre existing akin holes and clecoed it in place.

Next up I need to form the leading edge and fit it. Then will drill all the holes to final size and clean it all up for priming and final assembly.




Total time spent building: 83 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

 

They are a temporary spring fastener that holds everything aligned together before final assembly.

Most of the rivets we will assemble the plane with are a more expensive version but works the same as demonstrated in this video,

There are also solid driven rivets which I use mostly at work on commercial aircraft, and there will be some on this one I will use as well. I picked this plane because it is designed to be assembled with 'pop rivets' and that will be easier for my son to do in a repeatable manner that is harder to make mistakes with.

 

Well we moved back up to the top floor this weekend.

Landon's room is done and everything else nearly done, still waiting on the black iron for the rails on the stairs and a few touch up spots here and there but close enough to move back in. Hope to get back to working on the airplane in a few days, still need to do alot of sorting and putting stuff away.


I am pretty happy with the way the bed turned out, spent half a day putting all the hardware on, but it really makes it imo.

 

~5hrs
Landon helped me cut a piece of aluminum for the rudder leading edge and vacume form the radius before the sounds of kids in the neighborhood distracted him.

I got it fitted in place sandwiched between the spar and rear skin to drill all the pilot holes to the spar.
Got the lower rib aligned and drilled. Dinged the leading edge a little with the squared off front of the rib sliding it back and forth, but not bad enough to need to redo it all. Lesson learned though, I should have left the skin looser right there.
I need to call Roger and find out the shape and dimensions to trim the lower section of the skin, the drawings show it curved up, but looking at some recent assembly videos online it looks straight.... Is it trimmed to fit after installing on the tail? Or is that supposed to be done now?

Next up will be shaping the rudder horn, I already have it rough cut and bent, just need to grind down the final shape and fit it to the lower rib.

This weekend I hope to get Landons help redrilling all the holes to final size and cleaning up for priming. Will see how timing goes around the house

Been snowing, and as we all know, that means it's warm enough to comfortably work out in the tent for longer periods again




Total time spent building: 88 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

 

~1.5hrs
Landon started drilling out the holes to final size. I had it all drilled out with a #40 and alternating holes with silver clecos. He drilled up to a #30 and put in the copper clecos then removed the silver and drilled them out as well. He did most of one side, I'll probably finish up tonight.
While he was doing that I finished shaping the control horn and fitted it.



Total time spent building: 89.5 hours
Total Cost: $8803
Airplane + consumables + project specific costs: $5867
Tools, etc.. I will keep for future projects: $2936

 

hehe, I just posted on that same image somewhere else.....

 

~8hrs
Did the final trim along spar rivet line of the leading edge skin.

Drilled out the hinge holes on the brackets. Debuted all edges and holes.

Hauled everything over to the hanger I work at and prepped for priming and primed.

Put the extra mixed primer in the freezer to keep it from kicking.

Went back the next day and wrapped everything in towels and brought home.

We riveted the skeleton together and then the skins and control horn. We brushed primer on both sides of every joint and seam before assembly and riveted together "wet."

A few weeks ago I had Landon working on a practice sheetmetal project with solid driven rivets. His comment yesterday was "this is a LOT easier." ...... I agree with him, pulled rivets feels like a cheat code for assembly. No stress and much quicker.

Once done brought the finished rudder inside over night for the primer in the seams to cure. Was fun waking up this morning to a nicely finished part to greet me.