SZD-9 Bocian 1E

[mlachow]

SZD-9 Bocian 1E

Wingspan 4.5m

Length 2m

Weight 6kg (Ha. Mine with pilot and all is more. just over 9kg after repairs. The 1c build on rcgroups was 8.7kg.)

Root chord 415mm

Manufacturer - Oldgliders.com

Web Site - https://oldgliders.com/en/offer/szd-9-bocian-kit-14/

Main Wings - Two Piece

Main Wing Materials - Balsa / Ply / Pine / CF Joiner

Airfoil HQ

Fuselage Single piece, single wheel

Tail Removable stab, Balsa, Ply, Pine

Control Surfaces Ailerons(2), Spoilers (2) Rudder, Elevator(2), Tow Release



This was built starting late November 2019 and mostly framed by February 2020. It was covered in March and there was enough good weather to do painting in March. I was rushing to hopefully get it ready for spring Cumberland 2020. You know what happened next. First flights were at Muncy in June.

There is a build log of the 1C variant in RC Groups Blogs.

https://www.rcgroups.com/forums/show...n-1c-scale-1-4

RC-network.de

https://www.rc-network.de/threads/bo...tausch.326734/

[mlachow]

Starting the next box on the shelf. When I picked up my Pirat kit, I also bought a Bocian kit. It makes sense to ship a few kits at the same time since shipping doesn't change that much. I ordered the 1E variation. They also have a 1C version which has the more rounded tail. In addition to the kit, I ordered the carbon wing joiner, spoilers, and "Amortized landing gear with wheel (wheel with shock absorber). I also ordered the set of balsa planks. They didn't offer the pine strips at that time. I will make those on my table saw and I will use aircraft spruce for the spar.

The Oldgliders kits are all routed parts. That means they are going to need a little sanding and a lot of corners need to be filed to make them square. The box is full of parts, mostly mixed up. In some ways that is annoying but it also protects the parts in shipping. They seem to ship better and rarely do you find a damaged part. My Pirat had none. The Bocian had one fuselage former that was broken.

The plans have limited detail on them. Just a few balsa sizes are listed, not much else. I had a minor printing error on one part of the plan. One of the printers ink colors was running out so some of the text was in a very light yellow. They probably ran out of blue ink when printing. There are no written instructions. You just get a DVD with a while bunch of pictures of the assembly. One of the images is a note on where the CG goes and on control throws. A few other ones have very important information on shim sizes for the ribs when building.

Ordering the balsa planks make things a little easier. The kit is designed with metric balsa. You can substitute the fractional sizes that are close if you have a good stock of balsa. I did that back when I built my Orlik. But you will have to figure out where to use the wood. You get enough wood, but it is not always obvious how to use the wood. The wood I received was very nice wood.

So the first order is to sort out all the parts into the wing panels, stab, rudder, and fuselage. Remember these are routed parts so nothing gets labeled. The only labels are on the aileron parts which get hand numbered, 1 through 25. I sorted all the pieces. I also looked at all the fuselage parts to figure out where they fit A DVD of the build is provided with the kit. That helps to figure out where some of the remaining parts might fit if they are not obvious on the plans. There are a few pieces around the nose and at the back of the canopy opening that are not obvious on the plans.

Fuselage parts. Canopy frame, outline of the fuselage, wing root parts, formers for the front, middle, back of the fuselage and the fin.


Wing parts sorted. The aileron parts were hand numbered, 1 to 25. Nothing sanded at this point, but if you look at the stacks of ribs, you can see where the router started and stopped on the outline. There is a little bump that will need to be sanded.


Parts for the rudder.








Parts for the stab and elevators. It is set up for two elevator servos. The outlines and ribs interlock which is nice but also means more corners to square up where the parts fit together.

[mlachow]

I had a few mystery parts. There were three and one appeared missing. When I went back to the original kit box I was able to locate one more part. The extra four pieces ended up being stuff to build the basic shape of the instrument panel at the front of the cockpit. The plans show an outline so they have added parts to build the instrument panel. I didn't see any of this in the provided photos


Next thing to look at is the stack of balsa sheets. All the sheet wood is 100mm wide, and 1 meter long. There are two sheets of 10mm, one sheet of 6mm and one sheet of 3mm. The thicker sheets are all used as strips for things like the leading edges of the control surfaces. The 6mm and 3mm are the wing leading edge. I went and weighed all the pieces. Most of the wood is in the 6 to 8 lb/ft3 range. The leading edge sheets were heavier, in the 9 to 10 lb range which is nice for the wing LE.

There are 10 sheets of 2.5mm balsa. All of that goes into the fuselage. The lightest sheet will go into the fin sheeting. The one sheet is actually around 5.5, reallly light stuff. The fuselage shape isn't that complex so you can attach pretty large pieces of sheet at one time to the fuselage. I'll use the lighter sheets at the rear and save the heaviest sheets for around the wing and the nose of the fuselage.

The wing is a bigger challenge with 25 sheets. At least two are needed for the horizontal stab. I will select the lightest, two to use for the stab. But since I have to split the sheeting for elevator servo access on the bottom, I'll probably pick a heavier piece of sheet for the bottom middle of the stab.

There was one really heavy hard piece, 12lb stuff. I'll throw that at the spar webs in the center section up to the spoilers. Four more pieces between 10 and 11 lbs will get used as part of the sheeting at the thickest part of the wing in the center. The wing panels are about 2.2 meters long so it takes more than one splice to make a sheet long enough for the wing panel. The next heaviests wood will go into webs and the leading edge sheeting closer to the root. The lighter pieces go into sheeting further out on the wing.

I will sketch out how the tapered pieces will be trimmed from the sheets. They get used to make the wider tapered sheets that are needed. The webs consume quite a bit of sheet too. The least of my worries are the capstrips. Those will come from whatever is left around and most of those are short anyway.

In general the sheets of wood are pretty flat. One sheet had some kind of damage to it in one spot. Another had one spot where the grain was bad. Both easy to work around using the sheets for smaller pieces. There was heavier wood available for where it could be put to best use. And enough light wood for the tips and tail.



If you want it, you have to order the hardware in addition to the kit. The spoilers are TopModel. Landing gear are nice. The wing joiner is a rectangular carbon rod. It may need a little sanding to true it up. The joiner boxes seem like they are a loose fit but in reality when you glue it all together they fit fine. The joiner tube looks like carbon but it is not. I'm not sure what they did to make the fiberglass look black.

[mlachow]

The outlines and sheeting matches up with the various three views and pictures and other plans I can find on the Internet. There are a few minor details that could be added. One obvious item is the elevator trim tab. This will require a few extra pieces to frame out on the left elevator. Basically the leading edge of the trim tab and the one rib in the middle of the trim tab.


The rudder only needs one minor tweak. An extra diagonal at the top.

[mlachow]

The kit is designed with a single aileron. The Bocian is a really large aileron so it actually is split. The kit is designed for a single aileron servo. Looking at the ribs, they are plenty thick to add a second 12 or 13mm servo out where the real second aileron control horn exists. Looking at the rib, a JR DS390HV or MKS HV6130H will fit mounted through the rib.



The only constraint would be the shear webs. it with a 14mmx5mm spar all the way out there, there really is no need for a shear web front and backl 4 ribs from the tip. The plans all for top hinging the ailerons. The actual ailerons are slotted, and the hinge pin is at the bottom surface. That would take some custom hinges to implement. That just looks too ugly for the mode airfoil performance. I like to fly.


The rib where a second aileron servo would have to go could hold a 12 or 13mm thick servo. Just have to watch the mounting tab and the shear web on the spar.



Root sheeting ends in an open area. I'll add a balsa rib to support the sheeting here.





The wing panel is long. Looks like I need 85 inches on the building board. So that will be my flat board plus some of the dihedral extension.

The airfoil on this thing looks like an HQ airfoil. The site says HQ 2/11 but that is not possible. It is more like 13 to 14% thick. The thickness runs all the way to the tip, it does not get thinner out there. The wing also needs tapered shims for supporting the TE stock. Kind of what you would expect with a HQ airfoil.

The tip plate is kind of odd. I don't think that is scale.

[mlachow]

The next bit of work is making all the pine strips for the aircraft. I have some spruce that I will use for the spars and all the other strips will be pine. I picked up a bunch of really nice pine boards a number of years ago. The first step is to get the table saw ready for all of this. Splitter, featherboards, rippping jig, etc. But the most important first step is to clean the saw blade. Noting cuts like some nice, clean, carbide. Laundry detergent makes a really good blade cleaning solution. It is amazing how well it cleans up the blade. For the wing TE, you need 1mm strips. The spar is 7mm by 12mm. I have used a nice long board so the spar will be one piece. Then you need lots of 5 by 5 strips for the fuselage and a few places in the wing.


Once the spars are cut the other thing to cut are a bunch of tapered shims to build the wing. The spar itself is shimmed 2mm full length. But you also need tapered ones for the trailing edge, and the aileron . The info on what the shims looks like comes from a few of the photos on the disk with the kit.



Building is typical oldgliders construction. I did add some wraps to the spar






.


The wing is sheeted on the front part and only cap stripped in the back third.

[mlachow]

The fuselage needs some stuff to support things for the build. I had some 80-20 aluminum that I used as a frame to clamp the top and bottom ply pieces. It is a simple fuselage shape and there is a nice straight bottom.


I got the nicer landing gear with shocks that they sell for the model. The same as in my Orlik. I did reinforce the mounting ply for this part. I laminated the lite ply with carbon.



All the bulkheads are added and all the stringers are added. Once in place, I did trim down the vertical supports for the fuselage. You can also see the landing gear sitting on the bench and the wonderful box of clamps....





The root rib is not glued on yet.. It is just place there to see what things look like. It is easier to complete the planking with the rib off.

[mlachow]

I did the planking on top first.



And also completed the fin.




After that it is time to remove from the building fixture and complete the bottom of the fuselage.



And to check the landing gear installation. The forward part keys into some hardwood/plywood. And in the middle there are some screws to hold it in place.

[mlachow]

Nothing special on the tail construction. The stab is straight and it is set up to have two elevator servos installed in the stab.

The lite ply sometimes requires some extra clamping and alignment when you have long strips like the elevator hinge line. Most of the time the ply is fine.





I modified the elevator to add the trim tab. Not functional.



Completed with sheeting and cap strips.

[mlachow]

For the covering I used Sig Koverall applied with EkoBond. That is a separate topic.

https://forum.scalesoaring.com/forum...g-with-ekobond

The fuselage was fiberglassed and I did use some carbon around the canopy area.

[mlachow]

I picked the colors of HA-3933. There are quire a few photos on the Internet. It is unique. I figured it was some RAL color so my best guess was Blue Lilac. This color looks different depending on lighting and angles. The KlassKote folks will do custom colors if you want. I had them mix up a quart of this color.

After that I added the red trim using Red KlassKote. The white strips are OraCal striping and the lettering is from Callie.

[mlachow]

Radio Installation

Transmitter JR T14X4
Receiver (2) JR RG613BX
Power/Redundancy JR XB2-CHB

Aileron 1 (2) JR NX3421
Aileron 2 (2) JR DS189HV
Spoilers (2) MKS HV6110


The 3421 is on XBUs, the other aileron and spoiler connect to a 2-port xbus adapter in the wing.
Elevator (2) MKS 6130HV
Two port xbus converter used for the two MKS servos. Servos are installed in the stab.
Rudder JR NX8931
Tow Release JR NX588


Flight Packs (2) 2 cell 21700 battery packs
Orbtronic is a good source of cells.

[mlachow]

Videos
Bocian is around 4:01 on the ground. Really nice landing shot at 4:30.
https://vimeo.com/showcase/9316114/video/584609783


Another landing 5:01
https://vimeo.com/showcase/9316114/video/584399404