SZD-22 Mucha 1/4

[mlachow]

Finishing up the wing root on the fuselage. The remainder was sheeted and blocks added at the LE. Then things were shaped to match the wing panels.

[mlachow]

Other little stuff up front. Time to assemble dash panel. You can still access the back of the panel from the bottom to insert the clear plastic and instrument print out.

[mlachow]

Almost all of the fuselage sheeting is now done. There is just the front section by the motor. I have been looking for what to do with a tow release. I did find room to stick in a standard Topmodel release. Just enough clearance on the motor and the sheeting for the pushrod. I have also rough checked the CG. Things should be in the ballpark with no weight needed.

[mlachow]

The nose is now all closed up. The last of the front sheeting has been added and sanded.

The tow release does not make it all the way out so I glued in a piece of fiberglass tubing cut on an angle to protect the balsa from the tow line.

A short section of brass tubing was added to the nose block. It's not a glass fuselage so the tubing provides a hard edge on the hole for the prop hub. The other piece of tubing is just to make sure there is clearance when inserting the motor.

[mlachow]

The front of the fuselage originally had a ply tray that linked the first few bulkheads and also provided a place to mount the tow release servo. This piece was only used to align things when building the fuselage. It is in the way of the motor and access to the motor and tow release.

A wing servo was mounted to the fuselage side down low for the new lower nose tow release. It still makes sense to tie together some of these formers. Two pieces were fabricated that go between the three formers. They extend all the way to the fuselage sides. Enough space remains to access the motor. The pieces will also be used to bolt a front equipment tray in the fuselage if the motor battery ends up mounted up front for balance. The Zugvogel had the battery mounted under the wing. But that model has a much lighter tail and smaller tail and lighter fuselage. The Mucha probably needs the battery weight up front. The battery can sit down low or up on a bolt in tray.

The rudder servo will sit behind the cockpit area.

[mlachow]

Some work on the back end of the model. The stab mount needed some more work. The balsa filler under the stabilizer was added. The part of the fin in front of the stab was also sheeted. There is a hole drilled though there so the elevator servo could be plugged in through the top of the stab. That will make assembly much easier This is possible because there is a removable fairing above the stab.

Here is where things go.


Balsa work underneath.




And the faring marked up but not yet cut.




The carry bar for moving the sailplane is being omitted. That front balsa piece should actually have a cut in it and a dowel or something. But it adds tail weight.

[mlachow]

8 months later, the project is still alive. I finally put servo mounts in the stab for the elevators and now the stab and elevators are covered.

Final wing standing and then covering is up next.

[mlachow]

Some progress on covering the wing and the tail. White Oratex. Now the wing and stab are ready for hinging and servo installations.

[mlachow]

Wing surfaces and elevators are now all hinged. Servo mounts are there but the servos aren't mounted.

The fuselage is almost covered. Just one side up front, the skids, and some trim color on the fuselage remain. I have to rebuilds the instrument panel, it was flipped over for the instrument graphics I have. But that can wait.

[mlachow]

Covering and radio install was completed. CG around 120mm. The instructions called for 11 to 12cm.

The first flights were off winch launch.

I run the winch enough to get things up in the air from the aerotow connection. After releasing, the motor provided more than enough power. Initially there was a 14x10 on the front end. At full charge in the cooler temps, it peaked at 59 amps. So in warmer weather it would probably go over 60 amps. The climb was pretty good so after the first two days in Cumberland, I switched to the 13x10 white blade. That dropped things down to 55 amps.



Some lettering and logos are still needed. After the initial launches, I added a red stripe on the bottom. That did help in visibility at Cumberland. I think I will remove that red and put on several stripes in the mid section and at the tip. The rudder and fin also needs some red trim.

[mlachow]

Since the Castle controller isn't compatible with JR Telemetry, I put in a SM-Modellbau Unisense. This goes inline between the battery and the speed controller. It provides flight pack voltage, current, and an altimeter. Control Hobbies handles them in the US. They work with a pretty wide variety of radios.

I used a Zepsus dual battery switch so that I could use both the ESC BEC as well as a LiFe battery to provide redundant flight packs. The nice part is I can also alarm on zero voltage from the motor pack as a reminder to connect the second battery pack.

For the prop, I used a 6mm Torcam hub. This makes it easy to remove the prop when attaching the tow release or carrying the airplane with the radio on.


I used a Hacker A40 glider version in my Zugvogel. That provided more than enough power. I put another A40-10L V4 14 pole kv500 motor in the Mucha. It just needs to be the regular motor when using the Torcman system. The A40 is good for 1100W which is enough for a 5kg model. With the 6S battery my setup is a little hot but I don't need to use full throttle The 3300mah battery is good for four climb outs to decent altitude.

[mlachow]

At Cumberland I had just finished the Mucha enough for flying. It was still missing graphics. Time for a trip to the local Makerspace at my library. They have Some Cricut Maker 3's there. I did have to pick up some 12 by 24 cutting mats for the machines to handle longer lettering with Oracal outdoor vinyl. I used my CNC router software to clean up some scans of pictures of the Mucha logos for the side of the fuselage. Exported the SVG files and then imported into the Cricut software. Cutting vinyl was pretty simple.

I had one other challenge I wanted to try. The fin/rudder of Mucha's usually has the Mucha swoosh. So I put some of my Oratex on a fabric mat for the Cricut. Loaded in a rotary cutter blade. It cut things just fine. I did stick the Oratex on the tacky cutting mat with the color down, and backing facing out while cutting. It's not something you want to do with really small graphics since you don't have the transfer tape you use with sign vinyl.

[stevekremer]

Looks good Mike.