Model Airplane News "Build to Win" Contest, Build Thread

[Joker 53150]

There is something about the ammonia in the Windex which weakens the fibers in the balsa that makes it bend more easily, although it might prematurely weaken the balsa as well. This is all according to what I read on the internet, which by law has got to be the truth!

If I get bored I might try a side-by-side comparison to see if there is any appreciable difference.

 

[Joker 53150]

The discussion of water vs Windex for forming balsa had me wondering if there was much of a difference so I did a really basic experiment. Two pieces of balsa were cut from the same stock. One was soaked with water and the other Windex and they were left to sit and soak for a few minutes. They were then secured around identical shaped bottles and left to dry for a day. I purposely used an odd shape bottle instead of a round one to see if the shape would hold.




After a day the tape was removed and the balsa appeared to hold the shape well in both cases. But would either hold the shape better over time?




This morning I checked and they're pretty much identical still. As long as they would hold long enough for glue to dry I'd be happy, but I don't see any difference between them. This is FAR from an exhaustive testing! It's just a quick way to see if both methods would work. I should have tried a third piece that was not soaked at all to see what would have happened, but I ran out of stock and need to get some more today so maybe I'll try this again with tighter radius conditions.



So back to the contest plane! The horizontal tail surfaces were covered in white which is ultra boring. A little color will wake it up. On one of the first few pages of this thread I posted pictures of my inspiration for the design. It won't be a perfect re-creation, but the flavor will be there.

 

[Joker 53150]

The rest of the canopy sheeting is cut roughly to the right size, left large on most sizes so I can do the final trimming without the tape in the way. The wet balsa conformed pretty easily to the curves and I was able to glue everything in place from underneath. When the glue dries I can do the final trimming. There will be a lot of balsa filler needed to make a nice smooth canopy, and some extra bracing may be needed on the inside to keep the sheet from flexing too much. Sheeting is 1/32" thickness.





Ailerons have been started as well. These use torque tubes inset into the trailing edge of the wing, and both ailerons will be controlled by one 9 gram servo. The beautiful red one in the pictures is a salvaged piece I use for mock-ups.




There is a LOT of room for aileron movement as I didn't want to leave any chance for binding up.

 

[earthsciteach]

The discussion of water vs Windex for forming balsa had me wondering if there was much of a difference so I did a really basic experiment. Two pieces of balsa were cut from the same stock. One was soaked with water and the other Windex and they were left to sit and soak for a few minutes. They were then secured around identical shaped bottles and left to dry for a day. I purposely used an odd shape bottle instead of a round one to see if the shape would hold.

View attachment 14405


After a day the tape was removed and the balsa appeared to hold the shape well in both cases. But would either hold the shape better over time?

View attachment 14406


This morning I checked and they're pretty much identical still. As long as they would hold long enough for glue to dry I'd be happy, but I don't see any difference between them. This is FAR from an exhaustive testing! It's just a quick way to see if both methods would work. I should have tried a third piece that was not soaked at all to see what would have happened, but I ran out of stock and need to get some more today so maybe I'll try this again with tighter radius conditions.

View attachment 14407
So back to the contest plane! The horizontal tail surfaces were covered in white which is ultra boring. A little color will wake it up. On one of the first few pages of this thread I posted pictures of my inspiration for the design. It won't be a perfect re-creation, but the flavor will be there.

Great little test, Joker! Thank you for sharing!

 

[Joker 53150]

The aileron torque tubes are now both recessed into the wing bottom. It's a pretty simple system overall, similar to that found on a number of ARF kits.




It ain't pretty, but here are the pieces that the aileron servo will connect to. The throw on the ailerons will be directly related to how low I connect the servo to these arms. The lower they are connected, the more throw I can get on the ailerons.




Back to the canopy, all six pieces of the sheeting are now installed and trimmed. This REALLY ain't pretty, but I've got some stuff to help me hide the ugly.




I start off with some sanding to knock off the major extra balsa and then put on a layer of balsa filler. This first layer had two main goals - first is to fill in the cracks and help start the filling process and second was to help identify what areas need a lot more attention.




After the first layer dried and was sanded I could much more easily tell where the low spots were. I was also able to clean up the transition from the canopy to fuselage. I applied it at first with a paint stick, but then moved to a putty squeegee for automotive Bondo. This squeegee is flexible enough to get a smooth application around the curves. I found that there were more low spots than I had hoped for, but this filler is pretty light so it shouldn't be a big problem using a fair amount of it. Once it's finished I'll cover it with the rest of the fuselage and add details to represent glass and panel lines.

 

[Johan]

Thanks Joker,

I'm learning so much from yours posts in this thread!

That is going to be a very nice canopy

 

[.XxBensterxX.]

Looks great guys... wish I could build like that.

 

[Joker 53150]

The canopy is one big curve with very little flat area, so I didn't want to use my sanding bar to sand the filler. I could probably go out and buy something, but I have what I think is a perfect way to make my own. We had a pool a few years ago and had some foam floaties. Many have seen the big round pool "noodles", but there are also flat versions of a flexible foam. I simply cut one to size, stuck some sandpaper to it, and went at it! I did cut some relief cuts in the back to allow it to flex more easily. This material will conform to most curves now without a problem.




Looking at the canopy from the inside you can easily see where the thin areas are. One or two spots are only held together by the Tite Bond II glue! I'm going to add a little extra sheeting on the inside to support these areas now that the canopy is sanded.




Speaking of the canopy, the last picture is the finished piece. It took a few days to do it, most of which was just waiting for the balsa filler to dry, but I'm happy with the results. Before covering the fuselage I'll go through and do a little touch-up on it, add a little sheet to the inside, etc.

 

[jrbemis]

Awesome build in balsa

 

[Joker 53150]

I need to finish up the wing before I finish the fuselage details because I'm worried about getting the center of gravity correct. The retracts really throw a curve at things, especially the nose wheel. That is why I'm trying to get the rudder and elevator servos as far back as possible in the tail. Any little bit of weight to offset the gear helps! So I'm working on finishing the covering, aileron linkages, and landing gear on the wing which should be done in the next few days. The covering isn't perfect, but if I make the pictures just out of focus enough nobody will notice. For anybody that has noticed that both ailerons are raised in the first picture, it's because the rods inside are currently too long and are forced forward.




The nose doesn't scream "NAVION" like I had hoped it would, but it isn't bad. Everything is a tight fit and to get the motor installed I need to remove the front retract. There is then just enough room to get a screwdriver in to tighten the top two screws. The motor is still installed with the nylon screws and spacers so I'll need to update that to something slightly stronger. I'll also shorten the spacer length. This will put the prop closer to the cowl for a better look and will move the motor weight back slightly. Again, any little bit of weight helps me out.

 

[xuzme720]

The covering isn't perfect, but if I make the pictures just out of focus enough nobody will notice.

View attachment 14557

Covering looks fine, I don't know what you mean!

 

[Joker 53150]

Covering looks fine, I don't know what you mean!

Mainly the wingtips aren't that good. I need to convince my wife to help me out when I re-cover the tips with the red trim color. I'm using standard weight covering on this plane, and quite honestly I don't like it compared to the lightweight stuff. That seems to be the opposite of what other people say as many really hate the lightweight stuff.

 

[Joker 53150]

Rolling right along, the wing is 95% done now. Landing gear is installed, the trim is done, and ailerons are installed and working. Work can now focus on the fuselage.




The aileron linkage is in and everything works fine. The only things I need to swap out still are the balljoint piece as they are designed to work with thicker wire. I had to sneak in a little extra wire to fill the gap for now until I get the pieces replaced.

 

[xuzme720]

Just a thought, since heavier wire will mean disassembling the torque rods, how about a tight wrapped layer of light gauge wire to boost the torque rod thickness so the ball joints can grab. A quick shot of solder to make it all one piece, and it will be all done, neat and secure

 

[Joker 53150]

Plenty of work accomplished for the day, so it's time to kick back with my old friend the Captain. But first, pics and info on what is accomplished. I got most of the work done on the elevator and rudder/steering servos. Pushrods are mostly done with only fine adjustments needed before I start covering. The servos were put in the tail of the plane to push the weight behind the CoG as I think I'll be a little nose-heavy. I didn't really come up with anything I particularly like for the placement, but it works. The servo to the right is for the rudder and steering which explains the two pushrods attached to it. Access to the servos will be through the bottom of the plane. Part of the bottom rear end of the fuselage will have sheeting permanently attached while access to the servos will be done through a hatch.




The horizontal stabilizer is attached to the fuselage finally, so I can turn attention to the vertical stabilizer.




There is a gap between the horizontal stab and the top decking on the fuselage that needs to be filled. As I was building I didn't know exactly how these pieces were going to come together so I left the space open. The stock stab that came with the kit would have extended further forward, but I didn't use that stab at all. I'll probably use some soft balsa block to fill the gap, and carve/sand it to shape. I can then extend the vertical stab forward onto the rear decking to get the correct look of the Ryan Navion. Maybe this thing will be done and flyable by the contest deadline after all!

 

[earthsciteach]

Beautiful work, joker! You are definitely doing justice to the Navion.

 

[Joker 53150]

The filler block between the rear turtle deck and horizontal stab was super simple. A couple pieces of soft balsa glued in place and then carved & sanded to shape. A little bit of balsa filler will be added after the sanding (see 2nd picture) and it's done.




Along with the canopy I find the vertical surfaces on the Navion a defining part of the design. I ended up re-cutting the pieces because the original ones I made were a little too thin in my opinion. They'd have been strong enough, but just looked a little skinny. I did the same thing with the horizontal surfaces so now both pieces match in size/scale. The pieces are now glued and drying so I'm almost done with the bulk of the fuselage exterior short of covering. A little gusset creation is needed where the vertical meets the fuselage to smooth it out a bit. I should have plenty of room for the control horn on the elevator, but I might need to get a little creative for the rudder.

 

[Joker 53150]

It's time to start something I both love and hate - covering the fuselage. I love how it FINALLY makes the plane look finished, but hate how it isn't perfect (I'm my own worst critic). If you jump back to the beginning of this thread I posted a few images that I wanted to use as my inspiration, so here goes...!

I normally cover from the bottom to the top, but in this case I have red and white covering and didn't want to put white over red so I'm doing it backwards. The sides were easy, but the canopy was very tough and has a lot more wrinkles in it than these pictures show. The whole canopy area isn't that strong so I didn't want to force things too much.




With the top done I added a swoop to the red lower fuselage and a quick outline for the canopy.




Some silver SoLite covering was used to make the windows. After looking at this picture I changed the design of the big side windows a little as here it looks a little blocky. I also added some yellow pinstripe to the sides. As it sits now the bird feels like it might be a little tail-heavy, but it's hard to tell without the motor, ESC, RX, and battery installed. My plan was to use a 1000mAh battery instead of the recommended 1300 to help offset some of the extra weight I added with the retracts, but I'll switch back to a heavier battery before I stick any dead weight in it to get correct CoG. Still to go: the tail needs covering, the electronics need to be installed, servos connected, and a number of other small items. But it's close!

 

[Joker 53150]

Externally the Navion is finished! Mostly, at least. Control horns are still needed on the elevator and rudder, and correct mounting screws are needed for the nose gear, but otherwise she's ready for the internals. The Park 450 1050kv motor appears to have enough power with the 8x6 prop (neon orange was the only color I had - yuck!). I like the color scheme, although I can't take credit for the design. The covering job is what I'd call a 10' job - it looks good from 10' away.






I'm happy with the profile, and think it matches the lines of the Navion pretty well. The canopy is a just a touch too big and the silver to mimic glass on the sides doesn't make me too happy, but I'll live with it for now.




Switching to the bottom of the plane I've added the red trim to connect the front and rear red sections. The nose will be left open as it is now for two reasons - it gives plenty of room for the retract and it's also how I'll get the battery in/out. Once all the pushrods are installed, the RX is mounted, etc I'll figure out where the battery needs to be and will create a mounting tray with hold-down strap for it. I'm still not sure if the 1000mAh will be big enough or if I'll need to go with the 1300, but either way shouldn't be a big deal as long as I don't need to add extra dead weight to get the balance correct.

 

[earthsciteach]

Congrats. She is a beauty! Best of luck with the maiden!