It's somewhat sad that it took that long for the first "Beaver" comment! 
Scale Build Off - Ryan Navion from 1960's Control Line Plans
- Thread starter Joker 53150
- Start date
The balsa filler was dry, so time to sand it! The transition to the canopy really comes into shape with the excess removed. It's a little hard to see, but the lines of the Navion are really starting to show up.
An Orange 6 channel receiver was dropped inside the fuselage to give an idea of scale. Once those formers are removed there will be a lot of room for all of the electronics! I was planning to use a 1000mAh pack to keep weight down, but seeing this I might bump that to 1300 or 1500 depending on that final weight.
Tomorrow I'll start the tail feathers, and will possibly give the fuselage an overall coating of filler.
An Orange 6 channel receiver was dropped inside the fuselage to give an idea of scale. Once those formers are removed there will be a lot of room for all of the electronics! I was planning to use a 1000mAh pack to keep weight down, but seeing this I might bump that to 1300 or 1500 depending on that final weight.
Tomorrow I'll start the tail feathers, and will possibly give the fuselage an overall coating of filler.
roversgonemad
Member
It's somewhat sad that it took that long for the first "Beaver" comment!
Just trying to keep it family friendly
But man, two at once....
Looks like I'm going to try and use retracts, assuming I can get the nose gear to fit properly. Hobby King sells this set of 6, and the reviews are decent enough to risk buying 'em. I'll need to reverse the actuator lever on the nose-gear compared to how it's pictured, but supposedly it is easy to do. The wing gear should be much easier, as there is plenty of room in the wing to create the structure to hold everything. I wasn't going to do retracts until I saw some pictures of my contest Navion flying with gear up, and it just looks so much nicer I couldn't resist trying it again.
The tail surfaces were designed to be made from solid 1/4" sheet, but I want to shed a little weight from the tail so I'm doing built-up construction. I used the balsa stripper to cut a 3/16" plank into 3/16" and 1/4" sticks (much cheaper than buying them pre-made!). The original plan was copied and the new design was made. After the glue dries I'll remove the pins, do some trimming and sanding of the excess wood, and do a little creative strengthing in key areas as the butt-joints aren't strong enough as-is.
At the corners of the horizontal surfaces I've done some reinforcing. If this were a laser-cut kit the parts might interlock to create strength, but I'm going a different route. Once the glue was dry which butt-joined the pieces together I cut a 1/16" deep recess out of each corner. In that recess I glued in a 1/16" thick hard balsa filler, with grain running in a different angle. The pieces were clamped and left to dry. Then it's just trimming and sanding like normal, but with stronger corners.
The elevator got similar treatment, but due to the smaller size I did bracing on both sides. Front braces on one side and the rear braces on the other. The parts feel substantially stronger now. Next up, sanding and installing the control horn bracing.
A glamour shot is in order! The nose is looking a little flat, so I will probably do a little custom work to smooth it out.
The elevator got similar treatment, but due to the smaller size I did bracing on both sides. Front braces on one side and the rear braces on the other. The parts feel substantially stronger now. Next up, sanding and installing the control horn bracing.
A glamour shot is in order! The nose is looking a little flat, so I will probably do a little custom work to smooth it out.
Yeah, I'm not sure how I'm going to do it yet, but glassing over it will hide the ugly!
Waiting on wood - the problems of growing old!
To smooth out the curves on the nose I had two options. First was to just sand the existing structure to a curved shape. The problem is that I'd be sanding through all of the planks and the glue holding them in place, and would end up with some very thin material around the edges. The second option was to take a piece of 1/4" balsa and glue it to the nose. This would give me enough material to round nicely. It would also eventually push the motor forward slightly, hopefully avoiding any need for dead weight in the nose to hit the proper CoG. So I went with the extra piece of 1/4". The plans call for two pieces of 1/4" at the nose already, meaning I'll have a little carving to do inside once I get that far. But with that extra piece and some sanding the nose looks MUCH better. Not as tapered at the front as the original, but the original really gets small at the front which could cause problems making the motor fit.
On the topic of the Navion's nose, I'm still not completely sure how I'm going to handle motor installation, retract space, etc. I'll have to cut the nose off eventually, or create an access hatch of some type. I'm also considering making a fiberglass plug & mold for it. Maybe even trying my hand at vacuum forming...! The big advantage in either fiberglass or vacuum forming is that it opens up a lot more room inside the cowl, as there is a lot of balsa structure in there right now.
To smooth out the curves on the nose I had two options. First was to just sand the existing structure to a curved shape. The problem is that I'd be sanding through all of the planks and the glue holding them in place, and would end up with some very thin material around the edges. The second option was to take a piece of 1/4" balsa and glue it to the nose. This would give me enough material to round nicely. It would also eventually push the motor forward slightly, hopefully avoiding any need for dead weight in the nose to hit the proper CoG. So I went with the extra piece of 1/4". The plans call for two pieces of 1/4" at the nose already, meaning I'll have a little carving to do inside once I get that far. But with that extra piece and some sanding the nose looks MUCH better. Not as tapered at the front as the original, but the original really gets small at the front which could cause problems making the motor fit.
On the topic of the Navion's nose, I'm still not completely sure how I'm going to handle motor installation, retract space, etc. I'll have to cut the nose off eventually, or create an access hatch of some type. I'm also considering making a fiberglass plug & mold for it. Maybe even trying my hand at vacuum forming...! The big advantage in either fiberglass or vacuum forming is that it opens up a lot more room inside the cowl, as there is a lot of balsa structure in there right now.
Got a nice shout-out on the Crash Cast today, along with a picture of the Navion under construction. That was kind of fun.
The build has again moved into uncharted waters, adding ailerons where they previously didn't exist. How wide to make them, how long, etc. I'm going with the "that looks about right" method, making them bigger than scale, but not 3D big. This won't be an acrobatic bird so fingers are crossed I get good control while keeping a scale-ish look.
A mark was made across the ribs showing the cut-line and off comes the future aileron!
A piece was then cut from sheet stock to fill in the blank. I cut slots into the ribs with matching tabs on the filler so it would get a little more strength. Some fillets will be added as well.
With the pieces assembled it's starting to look like a typical wing construction. There should be plenty of room for a standard 9 gram servo in each wing to operate the ailerons.
A mark was made across the ribs showing the cut-line and off comes the future aileron!
A piece was then cut from sheet stock to fill in the blank. I cut slots into the ribs with matching tabs on the filler so it would get a little more strength. Some fillets will be added as well.
With the pieces assembled it's starting to look like a typical wing construction. There should be plenty of room for a standard 9 gram servo in each wing to operate the ailerons.
TLAR at its finest!!
I've been scratching my head for a while now trying to figure out how I should do the cowl so I had access to the motor, ESC, and nose gear. The plans call for the top of the cowl to be removable, but I didn't want the clean lines of the Navion cut up like that, plus that would make adding a retractable nose wheel difficult - assuming I go with a retract...
Instead, I made the bottom "chin" removable, and plan to make an internal structure to hold the motor and landing gear. The lower cowl will then simply attach around these pieces, and preserving as much as possible the clean lines.
First step was making some cuts. I didn't have a blade long enough to do it as well as I had hoped, but some balsa filler will hide the rough edges. This first pic is with a little filler added in to smooth things out before adding fiberglass. After the glass is done I'll remove and clean up the internal formers, but for now they're additional strength to keep everything aligned properly.
Test fitting of a motor I had for another plane getting some work shows me that I should have plenty of room. The nose is plenty thick and will need to be hogged out a bit. This should allow me to keep the prop and spinner close to the cowl easily. After this picture was taken I laid down some fiberglass on the inside of the nose planking. It needed a little extra support for final sanding of the exterior and it will help tie everything together for the eventual motor/gear mounts.
The chin is now covered with a very lightweight fiberglass and Z-Poxy finishing resin. I considered using water-based polyurethane but have concerns about it softening the balsa filler. It probably wouldn't be a problem, but I've used the Z-Poxy a little in the past and really like how well it works. With the finishing resin covering the balsa it really makes the balsa planking look nice, almost like an old wood-hulled ship. I could see doing some type of plane and just leaving it with this "natural" finish.
Instead, I made the bottom "chin" removable, and plan to make an internal structure to hold the motor and landing gear. The lower cowl will then simply attach around these pieces, and preserving as much as possible the clean lines.
First step was making some cuts. I didn't have a blade long enough to do it as well as I had hoped, but some balsa filler will hide the rough edges. This first pic is with a little filler added in to smooth things out before adding fiberglass. After the glass is done I'll remove and clean up the internal formers, but for now they're additional strength to keep everything aligned properly.
Test fitting of a motor I had for another plane getting some work shows me that I should have plenty of room. The nose is plenty thick and will need to be hogged out a bit. This should allow me to keep the prop and spinner close to the cowl easily. After this picture was taken I laid down some fiberglass on the inside of the nose planking. It needed a little extra support for final sanding of the exterior and it will help tie everything together for the eventual motor/gear mounts.
The chin is now covered with a very lightweight fiberglass and Z-Poxy finishing resin. I considered using water-based polyurethane but have concerns about it softening the balsa filler. It probably wouldn't be a problem, but I've used the Z-Poxy a little in the past and really like how well it works. With the finishing resin covering the balsa it really makes the balsa planking look nice, almost like an old wood-hulled ship. I could see doing some type of plane and just leaving it with this "natural" finish.
The natural finish does look pretty good on the cowling, but it's not exactly scale. Speaking of which, are you doing a military or civilian pain scheme?
No idea yet. Probably civilian but the Coast Guard version looks very nice.
These next few steps were mentally difficult for me, since I really like the natural look of the balsa. But it was time to do some more work prepping the chin. A lot of work is being done on it right now so I can be comfortable with the process when I start on the fuselage. I'd much rather have to re-do the chin than the entire fuselage!
I gave the 'glassed chin a good sanding and then took standard Bondo glazing/spot putty and gave the chin a good coating to fill in any low spots. The yellow block next to the chin is a section of a flat "pool noodle". One side has fine sandpaper stuck to it, and the flexible noodle allows the sandpaper to conform well to the curve of the chin. Using a sanding block would have resulted in very uneven sanding.
When the putty was dry it was sanded down, leaving only a small fraction of what I started with. I've read about thinning the putty to a pancake batter consistency and then brushing it on, but I didn't have the right thinning agent to try it. I can see how that would go on much better than trying to work a thicker putty into compound curves so I'll try it when I move on to the fuselage.
With the putty sanded a coat of filler/primer was sprayed on. This too will be sanded until it's almost all gone, and the priming/sanding process will eventually be repeated until I'm happy with a smooth finish. That won't happen right now as this is mainly a test of the process, and I still have to cut out for the motor, landing gear, and magnets to hold the chin in place. But I'm happy with how it's turning out at least.
While paint dries I finally remembered to test-fit the 9 gram servo in the wing. There will be plenty of room for them, so I can start deciding on what kind of structure will be needed to hold them.
I gave the 'glassed chin a good sanding and then took standard Bondo glazing/spot putty and gave the chin a good coating to fill in any low spots. The yellow block next to the chin is a section of a flat "pool noodle". One side has fine sandpaper stuck to it, and the flexible noodle allows the sandpaper to conform well to the curve of the chin. Using a sanding block would have resulted in very uneven sanding.
When the putty was dry it was sanded down, leaving only a small fraction of what I started with. I've read about thinning the putty to a pancake batter consistency and then brushing it on, but I didn't have the right thinning agent to try it. I can see how that would go on much better than trying to work a thicker putty into compound curves so I'll try it when I move on to the fuselage.
With the putty sanded a coat of filler/primer was sprayed on. This too will be sanded until it's almost all gone, and the priming/sanding process will eventually be repeated until I'm happy with a smooth finish. That won't happen right now as this is mainly a test of the process, and I still have to cut out for the motor, landing gear, and magnets to hold the chin in place. But I'm happy with how it's turning out at least.
While paint dries I finally remembered to test-fit the 9 gram servo in the wing. There will be plenty of room for them, so I can start deciding on what kind of structure will be needed to hold them.
Progress on the wing continues. Since this was a control line plan there were no provisions shown for ailerons or servo mounting. I'm doing a pretty typical installation here, with the servo mounted to a hatch. The hatch is secured to the wing via 4 screws. I ran some lengths of birch between the ribs which the hatch will be screwed to. Some extra bracing will be installed to make sure this isn't a weak-spot in the wing, since I did cut two holes into two different ribs. losing a wingtip mid-flight would suck!
