VS

Inserted the VS skeleton into the jig again. It is ready for riveting

Tail wheel rating and boat

Got my tail wheel rating yesterday. It took 5 h and 10 min with a total of 53 landings! 49 of those were done yesterday during 3 1/2 hours. It was done in a Piper Cub where I have a chare (actually it is a "loan" to keep it operational, because the airplane is no less than a flying museum artifact belonging to Bodø Aircraft Museum). The Cub is an old Army Cub from 1954 used by the Military, an PA-18 Super Cub with 90 HP Continental engine. They say only 4 of these were built. Starting is by hand. I had my first solo ride in it this evening. All my flying from now on will be in this cub untill my -4 is finished. After having flown advanced aerodynamic shaped carbon fibre aircraft (The Atec Zephyr), it is almost unbelievable how extremely good this Cub is, a 80+ year old design.

Three weeks ago I also purchased an old boat. A 22' "snekke" (I have no idea what the english term for this boat class is, but the closest is probably a "positive displacement" cabin cruiser). It weighs 2 tons, has a 15 HP Yanmar diesel, and is perfect for cruising around in the fjord at sunny days. The boat is a homebuilt from the late 70s. Cruise speed (and max speed) is around 6 knots. The cruise speed of my RV-4 will be 30 times that! The pictures are with two of my sons today, and with Olaug last weekend where we went to Tautra, an island in the fjord with a 12 century monestary.

Rudder, leading edge

Finished the leading edge of the rudder. Need to debur and prime before riveting.

Riveted on the rudder skin

The rudder skin is riveted on the rudder skeleton. I used Cherrymax rivets on the control horn. I need to get a pipe wrench tomorrow to bend the leading edge into shape. I thought I could do it by hand, but it is way too strong and I just can't get a good grip on the pipe.

Stiffeners elevator, Rudder

Finished drilling and deburring the stiffeners on the left elevator. Started again on the rudder. The skin has to be riveted on to free up some clamps that is on the rudder jig before doing anything else.

Left elevator stiffeners

Drilled on the stiffeners on the upper surface. Had a visit from the controller yesterday. Everything was OK, and the books signed.

elevator stiffeners

Did some more trimming of the stiffeners and marked the rivet holes.

Trimmed the stiffeners

Finished the stiffeners for the left elevator.

Cut out the elevator trim

Cut out the elevator skin and made the stiffeners. Have to trim and deburr the stiffeners.

Marked up the left elevator

Measured and marked up the left elevator including the trim tab.

Riveted right elevator skeleton, started on left

Riveted together the the tip ribs on the right elevator. Had some primer left in the gun, so I primed the pop rivets in the rudder skeleton as well. Started on the left elevator, simply studying the drawings and parts trying to figure out how this all fit together.

More priming

Did some more priming. Riveted on the brackets for the elevator hinges and the hinge nut.

Priming elevator parts

Primed some elevator parts. Ordered a bunch of vareous CherryMax rivets after looking at some videos at EAA "Hints for Homebuilders". Replaced the sole 4/32 solid rivet with a 5/32 rivet in the R-410. It simply looked way too strange with three different kind of rivets there.

Rudder and elevator

I was going to prime, but run out of gloves. Have to put pop rivets (LP4-3) in R-410 because none of my tools fit inside, and I have already riveted the assembly together. Due to some drilling difficulties, I will have one 4/32 and one 5/32 solid rivet, and two LP4-3 rivets. This looks strange, but is perfectly OK.

Drilled holes in elevator hinge plate

Drilled the holes in the attachment plates for the elevator hinge. Then I did a cleanup of the whole shop (long overdue). Wrote into the build logbook all the things done last year(copyed from this blog). This logbook will follow the airplane throughout its lifetime.

Elevator hinges and horn

Drilled the tip ribs of the right elevator spar together. Drilled it to the spar with the angle. Position the horn and drilled it to the spar, then made holes for the hinge bolts and started fine adjusting the elevator in to its proper position on the HS.

Details on elevator

Couldn't figure out how to position the bend on the lower flange on E-404 to mate with the spar. Instead I made an angle that I will rivet on to the spar and E-404. Marked rivets and fluted the elevator ribs.

elevator stiffeners and horn

Riveted on the stiffeners to the right elevator skin.




Started fitting the elevator horn and went straight into problems again. The elevator horn has pre punched holes. The problem is that the inner most holes are punched at least 3-4/16 too far in, so they interfere with flange of the E-409 rib. I didn't notice that before the spar and rib already was riveted together. Had to drill the rivets out and file 3/16 off the flange, and rivet together again. From the drawings and manual it is obvious that the horn originally was not pre-punched. Not a big deal, but still.

Elevator skeleton and priming

Made the skeleton for the right elevator. Primed the skin, stiffeners, skeleton and the rest of the bits for the rudder.

Elevator skin ready for priming and dimpling

Finished the right elevator skin and all the stiffeners. Drilled all the holes and deburred. It is now ready for priming and dimpling.

Elevator and rudder

Finished the rudder. Deburring and dimpling and fine trimming. My controller has to come and look at the rudder and VS before I rivet on the skin.

Started on the right elevator. Measured up and fabricated the stiffeners.

Deburring and dimpling

Dimpeld the rudder skin and skeleton and deburred them.

Drilling the rudder

Marked all lines and holes and drilled the rudder skin to the skeleton. Also made the strips to fasten the fiberglass trimming and details.

Fixing rudder

Finished trimming the rudder skin. Cut out the slots for the hinges. Used cutters for a rough cut, then a dremel for the rounded corner and a file to get straight edges.

Fighters, another look

Digged out an old SOM software that I made some 10 years ago. SOM = Self Organizing Map, and is a kind of artificial neural network that maps multidimensional vectors on to a 2D map according to a highly non-linear algorithm. On this map, similar vectors become clustered together, while non similar vectors are far apart or have "mountains" between them. It is used for instance in match-making software, image analysis, pattern recognition and so on. A SOM will only show the relative differences, nothing more.

The basic data for an airplane is a typical vector. So I simply feed the SOM with airplane data (several T/W and wing loading data and some other stuff), and let the artificial neurons do their job making some maps.

On the first picture, the map became devided in two distinct regions. "Real" fighters are on the left, while more fighter bomber planes are on the right. The Gripen and the Rafale are also somewhat isolated from the rest of the fighters. The F-35 is very similar to the F-18E. So, the F-35 is for all practical purposes (practical in a T/W ratio, wing loading sence :-) ; a stealthy F-18E. If this is good or bad, I don't know, but the F-35 is certainly no real fighter in a "classical" sense relative to the fighter bunch.

On the other picture I have "hard wired" a mystery plane in the middle and let the SOM work to see the similarities with the others. Clarly the mystery plane is very different from the rest, probably much better looking :-) But, it has to be built...

Trimming rudder

Started trimming the rudder for hinge points etc.

R-410

Time to do some work again. Started with cutting and filing R-410 into shape. Spent some time studying how to cut/trim the rudder, but I'm still not completely sure in which sequence this should be done.