IS-4 Jastrzab

[Soarntz]

Looks VERY NICE

[mlachow]

5 hours of masking and sticking on paint masks. Two hours with the airbrush. Another hour of pulling off masking tape and paint mask......

I have a colorful fuselage.

[Soaranator]

Wow! That is beautiful!

[stevekremer]

The paint really makes it pop! Looks Great. Amazing how long that takes.

[mlachow]

Six paint masks. Stripe on fin, stripe on skid, side stripes that are also on rudder and top stripe that matches wing patters and red in front of canopy.. I also had to fix stab red stripping to properly match the final. More than the usual left side right side. A lot of work. Far from perfect but it is an old wood sailplane. Not some molded thing.

[mlachow]

Here are all the parts assembled. I still have work on hinging, control horrns, radio installation , canopy, interior.

[mlachow]

I did some gluing on the canopy. I checked the plastic and it was not affected by xylol or E6000. I thinned out the E6000 (which is usually thinner than Goop) so that I could apply a nice thin layer. The front window is the tricky one since the canopy material provided did not have the exact bow for the middle frame Between the screws on the bottom and some electrical tape I was able to get it shaped and attached all the way around. The thinned E6000 worked nicely since I was able to use a minimal amount and it levels itself pretty good when you smooth it onto the frame. That way there is minimal squeeze out when the canopy gets clamped to the frame to dry overnight.

After drying, I removed the screws and used a countersink to do a better job getting the screws flush with the surface of the canopy. I will apply some silver oracal over the edge to finish up the canopy. Maybe I'll add a sliding window sometime later.


On the fuselage the tow release was glued in and it was fun to get the servo screws installed up front. The screws I used have a hex key drive. I have some hex drive bits and some short ratcheting wrenches that can use the hex drive bits. Just enough space to get your hand in there and turn things in. I added two battery boxes one on each side for the 20700 two cell battery packs. There is still plenty of space above that where I can bolt in any additional ballast to finish balancing the model. Right now it looks like I'll need about 300-400gm ballast beyond what I glued into the nose block earlier.

[mlachow]

More finishing details.

I put a spring on the rear canopy latch. It is just a simple spring to provide a little force to make sure the rear pin stays in place. Friction is probably enough but the spring adds a little insurance.



The wire holder on the wing is mounted to the root rib. For the fuselage, the wire slides out to attach things. Some 1/2" rocket tube is just big enough to slide the servo connectors and wires through. But it is not large enough for a MPX connector. So even if he wire gets pushed into the fuselage, it will be easy to pull out with short pliers. The tube also supports the wires over the rudder pull-pull cables.

[mlachow]

I need to get this thing to the field. Time to cut two fuselage supports for the rack in the van. I used some tracings of some bulkheads to get the shape. Add 3/8" for a layer of EPE foam. Some bolt holes for the rack and cut. EPE foam is attached using E6000, aka Goop.

Right now things are loaded up to head north to Chenango Airport Aerotow tomorrow.

[Steve P]

Mike maidened the plane and more today at Chenango Bridge…

[mlachow]

The first flight was uneventful. It did require a little down trim in all flight modes. I wasn't expecting much with the weight of the model but it actually glides pretty well. It has a pretty low aspect ratio and the spoilers are a little less effective than I expected.

The second flight I had tweaked all the flight modes for elevator and adjusted the aileron to rudder mixes a little. Roll rate is pretty good and I could probably cut down elevator throw a little. The aileron to rudder mixes and differential some flight modes needed some more adjustment.

Flight three was a nice tow and time to try a few more aerobatics. This thing should be fun in Cumberland on a slope day. With the big fuselage and low aspect ratio it is no speed demon. But it definitely is different than your typical sailplane.

It wasn't a very good day to try out thermal soaring. I think it will be OK.

[stevekremer]

It looked very nice in the air!

[mlachow]

Thanks for the tow. I 'm only missing a photo from Jeff. He has managed to be there the days I had first flights on my Orlik, Pirat, Bocian, and Foka refresh.