IS-4 Jastrzab

[mlachow]

I painted all the screws black. That is definitely nicer than the silver. The 3D printed inserts go through the front, a layer of plastic behind the wood and finally the instrument pictures.

I will add one cross piece to the fuselage at the front of the cockpit. The panel will be screwed to that cross piece so that I can remove it to access the tow release servo and batteries. I still have to build two battery holders for the front for the 20700 battery packs. More than enough power for a weekend and I think I will still be able to slide them out easily to charge outside of the aircraft.




The next step is to build more stuff for the cockpit. I will make some fiberglass liners for the inside to cover the sides but still be easily removable. I also need to make a seat and various controls.

[mlachow]

I made some side panels for inside the cockpit with fiberglass. I gut some pieces of mylar a little longer than I needed. I used some old pieces of mylar from some wing I bagged long ago. The mylar was waxed with Meguirars Mold Release 8 and then a coat of primer. I guess Meguairs sold the #8 product to Stoner. I masked the side sides of the fuselage so that I could use that to hold the mylar and glass while the epoxy cures. It would be fuselage / tape / mylar / glass / release film for the layup. That way the smooth side off the mylar would be shaped for the inside of the cockpit. I used one layer of 1.4 glass, tjhen a layer of 2 oz glass and another one inch wide strip of 2 oz glass to apply to the top edge as well as a strip near the front and near the back to help the glass keep shape. The glass was wet out with MGS Epoxy and then I put a layer of release film over that. The release film lets you squeege the glass a little more while wet to work out any air bubbles. I trimmed this all down to the size of the mylar and then taped the mylar to the sides of the fuselage.


The basement is a little cool now so I left things on there for a day and a half. Normally the MGS 285 fast hardener is good after waiting overnight. I trimmed the top, then back and then front . I'll finish trim the bottom after I make the floor and seat.

[mlachow]

Just working on little stuff here and there. I built a seat out of balsa and liteply. The back edge sits on tip of the wheel support and the top will get two screws to attach it to the bulkhead. That way the entire seat is easily removable.


I also built a spoiler control for the side. It will attach to the side panel with some 2mm screws. The back has some balsa shaped to fit the panel curve. The only thing remaining is a control stick. I pulled my 1:3 pilot out of my Orlik to trial fit. It looks like a standard 1:3 pilot will fit. I still need to build two battery boxes on each side of the tow release servo. If I kneecap the pilot everything should fit and I think I will be able to pull out the batteries if I want to do that for charging.

[mlachow]

Starting to do some finishing work on the model. The fin and stab are fully sheeted. I don't really need to cover them with Koverall like the rudder and elevators. I decide to try out some water based stuff. I decided to try applying some light fiberglass cloth with water based polyurethane. I have a few yards of 0.50 oz fiberglass which should be more than enough. It looks pretty good at this point.

[mlachow]

The fuselage is going to get fiberglassed using epoxy. I like to put some carbon around the cockpit openings. I use some thin spreadtow carbon to do this. It still leaves a little ridge if I apply the carbon and fiberglass over it all at once. This time I decided to apply the carbon first and put some teflon coated glass cloth over it while it cured. I was able to squeege out more epoxy and the glass cloth smoothed out the edge of the carbon with some excess epoxy..


After it cures, the teflon coated glass is peeled off leaving a rough surface. Hopefully this should leave a smoother edge when it all gets fiberglassed.

[mlachow]

It has been pretty boring stuff. Just putting some fiberglass on the fuselage. Back end is 0.7, From behind the wing forward is 1.4oz S-glass with an extra layer on the wing fillets on the bias. There is also a second bias layer of 1.4 from mid-wing forward. I am still holding off on gluing the nose block and ballast in. Just a pain handling the fuse with all the nose weight added. I'll wait until the fuse is mostly primed and the tail is primed

I have also been trying out pilot and battery locations. The choice is low batteries left and right on top of the release servo tray. That choice leaves no space for pilots feet, The other option is to place the battery boxes up high in the nose. Then I will need to do something like a magnetic instrument panel holder to make it easy to pop out the instrument panel and pull out the batteries.

The other room in the shop has the EPP Swift build going.

[mlachow]

Not too much has been happening lately. It's winter and there has been plenty of snow. You can't do much painting then.

Today I did do some covering on the tail surfaces. I covered the elevators and rudder with Sig Koverall. It is attached using Stewart Systems EkoBond. I tried out the linen color. It works the same as the regular stuff except for the fact that the cloth areas with EkoBond on it looks wood colored.

[mlachow]

The project has been sitting around some for a while. I did pick up a pilot. Tonight I covered the ailerons. For the rest of the wing panels, they are fully sheeted. They are getting some light fiberglass applied. One panel is covered. The other needed some rework on the sheeting on the bottom center section. One of the sheets probably had some funky stresses in it and sitting around in the shop it got really wavy between the ribs. It was on the bottom near the TE. The rib spacing is really wide so anything funny in the sheet shows up. Hopefully I can get some primer on in the next few days.

[mlachow]

The wing is painted white now. It's time to sort out the masking for the other color. After some experiments with string I cut some paper outlines to see what things might look like. This layout seems pretty good. It looks similar to the one top picture I have of SP-1383.

[mlachow]

Time to create all the wiring for the servos. Multiplex 6-pin connector for the wing. 26-guage connection for a standard MKS 6110HV servo for the spoilers and a 22 guage connection for the two aileron servos JR NX3421's on JR XBus. The elevators are JR DS189HV, one each side and the rudder is a NX8431+ on XBus and the release servo is also XBus.

[Steve P]

So nice! This is going to be another beautiful sailplane — can’t wait to see it at an event.

I see you’re mixing the wire weights and gauges. Apologies for what she may seem like a bit of a commercial…. A number of us have become really impressed with the PowerBox wire and it’s two size offerings. Its thin fireproof covering instead of the thick PVC means less weight. Also the signal wire is slightly smaller since it doesn’t carry an amp load. It is also a stiffer and easier to run. And, a bit pricier. YMMV.

[mlachow]

When I want top quality wire for my F3b models, I make my own. I use an even thinner PFTE insulation and for power, the wire is silver plated so it has a lower resistance than standard copper wire. And when I use 28 gauge for the signal lead I have to add some heat shrink to it so the crimp will hold. Unfortunately at today's price in a scale ship, things would be insanely expensive. A lot of the twisted wire I have seen from Europe has insanely thick insulation. Only the wire that comes from Samba in their models is nice quality. The ..3mm2 is between 22 and 24 gauge wire.

My actual wire choice was partly based on what happens to be in the shop and what will work.

[mlachow]

I thought I had enough reducer for the KlassKote but as I am planning to put the final primer on the fuselage I notice I don't have another can of reducer and the open one is almost empty. I guess I won't get the fuselage painting done this weekend. I can still finish up the radio install and hinging for the wings and elevators.

I also have to figure out how I want to latch the canopy.

[mlachow]

The front of the canopy can be some pins. I glued in two 3/32 dowel pins into the fuselage. The frame can be tilted to slide onto the pins.

[mlachow]

I decided to assemble things to see how things are looking. Servos are installed in one wing panel. The spoiler servo is in the other but I haven't glued the hinges yet since I need to touch up some areas of the paint on that wing. Elevator servo frames are in but it still needs wiring and linkages to be added. The fuselage is just in primer at this point. I'm waiting for more klasskote reducer to finish up the painting.

[Steve P]

Bee you tee full !!!

[mlachow]

Reducer delivery scheduled for Friday. I get to finish painting next week.

[mlachow]

The canopy itself is a little different from normaL. The plastic does not fit over the frame in one piece. You actually have to cut it up into two pieces and fit them to the frame.

The first thing I did was figure out roughly where the pieces could be cut from the canopy that was provided. This gave me a front and rear part.

The next thing I did was fit the front of the windscreen. I used a bunch of plastic spring clamps to hold the plastic against the frame. ONe side was drilled and screwed first. Then I reclamped the plastic tight against the frame to drill and screw the other side. It is attached to the canopy frame with four screws. I use some small flat head screws. I'll countersink the holes in the plastic just before putting them in for the last time. After that I trimmed the rear of it to match the center line of the frame. The front just overlaps a little and the sides overlap the bottom of the frame and the fuselage about 3mm.

The next step was to trim the edge of the rear part of the canopy to align with the front piece. Similar steps of screwing in one side, reclamp and screw in the other side. Then trim the sides and rear down to the desired overlaps. This is definitely one of the stranger canopy setups. It would have been nicer if they molded the actual shape in one piece. I'll cover the edges and frame area with some oracal