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Ridge Runt Evo - Build Thread
- Thread starter Wayne
- Start date
We do have an error in the plans! Thank you for reminding me. Seems we imparted an error in wing length on the plan. I is about 1/8" too long so the rib spacing on the plans is off a little as you work your way out. We discovered this yesterday during the wing build. The last thing we had updated was the wing drawing, so looks like we imparted a little error.
OK - final bits of construction.
Lets sand the wing tips flush. I used a dremel drum sander to remove most of the extra carbon, then finished it off with the sanding block.
Then we can pop out the parts that make up the wing tips and start gluing them into place with thin CA.
I trimmed the top 2 pieces to save a little sanding time. We just want to match the height of the rib top.
Then use the plans to cut the trailing edge from the main aileron stock.
Same for the wing tips.
And glue into place with thing CA.
Locate the servo covers and fit them as shown. Minor sanding may be needed. When fit hold down flush on the building board as shown and glue into place with thin CA.
Lets tuck the servo wires through the wire pass through on the bottom of the wing while we have access.
Lets sand the wing tips flush. I used a dremel drum sander to remove most of the extra carbon, then finished it off with the sanding block.
Then we can pop out the parts that make up the wing tips and start gluing them into place with thin CA.
I trimmed the top 2 pieces to save a little sanding time. We just want to match the height of the rib top.
Then use the plans to cut the trailing edge from the main aileron stock.
Same for the wing tips.
And glue into place with thing CA.
Locate the servo covers and fit them as shown. Minor sanding may be needed. When fit hold down flush on the building board as shown and glue into place with thin CA.
Lets tuck the servo wires through the wire pass through on the bottom of the wing while we have access.
Mark the decking for the center of the wing and trim to fit.
Pop off the decking when you are happy with the fit and apply MEDIUM CA where the decking will make contact.
Carefully align decking and hold while glue cures, make sure you are pressing on the area of the spar.
Collect the parts for the horizontal tail.
Pop out the scrap from the horizontal and build yourself a mini glider! No really, this is an important step!
Refine and enjoy, it actually flies very well. LOL
Ok, back to the tail, some very light sanding and the inserts with cross grain pop right in. Secure them with a little thin CA. You can add the plywood doubler at this point if you like, or hold till after the tail is covered. You will want the doubler on the top. Hint: The top is the prettiest side.
Pop off the decking when you are happy with the fit and apply MEDIUM CA where the decking will make contact.
Carefully align decking and hold while glue cures, make sure you are pressing on the area of the spar.
Collect the parts for the horizontal tail.
Pop out the scrap from the horizontal and build yourself a mini glider! No really, this is an important step!
Refine and enjoy, it actually flies very well. LOL
Ok, back to the tail, some very light sanding and the inserts with cross grain pop right in. Secure them with a little thin CA. You can add the plywood doubler at this point if you like, or hold till after the tail is covered. You will want the doubler on the top. Hint: The top is the prettiest side.
Sanding
The sanding step is where I see ,many builds go wrong. Many new builders like to rush through the sanding and get the plane flying, but that is a real mistake. We have many benefits from a well sanded model. Sure, they look a LOT better, but they will also be lighter and perform better. Areas like the wings leading and trailing edges are of the most importance, you want them well shaped and smooth for the best flying qualities. Sanding time for the Ridge Runt is about 2 hours.If you can, do this outdoors, we will be making a lot of fine dust.
I like to use a brand new sheet of about 80 grit sandpaper. This will do 95% of the sanding on this model. We will start on the fuselage as this will warm us up and get us some practice before we jump into the wing.
For the Ridge Runt Evo I like to put a little masking tape at the bottom of the vertical fin to protect it from the sanding block.
The goal is to bring the beauty out of the "box" we have built. Lets start by simply sanding off any wood that is hanging over any edges. Go around and sand off anything hanging out. And we can sand off the sides of the nose block following the curved inner part as a guide. Wow that looks better already.
The next trick works really well for me. For years I just randomly sanded and always had a hard time with lumps and bumps until someone taught me to first sand all of the corners at about a 45 degree angle to a consistent depth. You can use the triangle stock as a guide to see if you are at the same depth as you sand. In the photo below you can see the front of the hatch is sanded a little deeper than the rear based on the amount of the triangle stock that is now exposed.
Go around the entire model doing this. A little less sanding in the tail area. The 80 grit should make quick work of this step. Here are a few photos for reference.
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For the base of the vertical you can use some paper around your finger, or something else round in shape if you like.
You can sand a lot of the fuselage tip down for a nice clean look. Think of the tail weight you are saving!
And then we simply round off those 45 degree bevels. This will go really fast as we are not sanding through the glue joints. So use less pressure as you sand as it will really eat the balsa fast. I like to stay with the 80 grit paper at this stage as it will still work on the CA joints when we run across them, if we jump to a finer grit paper it will have little effect on the CA and you will end up with ridges. It is also important to use a sanding block that is hard, not a padded block. This final rounding step goes pretty darn fast. Sight down the fuselage often to see if you have any high spots that need attention.
Now is a great time to put a little wood filler on the low spots and alignment pins. I like spackling compound as it is cheap, very light and sands great. You do not need much, and can skip this step if you don't have any.
I smear a bit on anything that is low, and some at the base of the vertical.
Then let it dry.
You can sand a lot of the fuselage tip down for a nice clean look. Think of the tail weight you are saving!
And then we simply round off those 45 degree bevels. This will go really fast as we are not sanding through the glue joints. So use less pressure as you sand as it will really eat the balsa fast. I like to stay with the 80 grit paper at this stage as it will still work on the CA joints when we run across them, if we jump to a finer grit paper it will have little effect on the CA and you will end up with ridges. It is also important to use a sanding block that is hard, not a padded block. This final rounding step goes pretty darn fast. Sight down the fuselage often to see if you have any high spots that need attention.
Now is a great time to put a little wood filler on the low spots and alignment pins. I like spackling compound as it is cheap, very light and sands great. You do not need much, and can skip this step if you don't have any.
I smear a bit on anything that is low, and some at the base of the vertical.
Then let it dry.
Ok - We are now sanding experts, lets tackle the wing. I start off with some masking tap around the ribs as shown to protect them from sanding the leading edges. I also popped some over the servos to keep them clean.
You may like to use a mini plane to shave off some of the wood, or just use the same sanding block with the 80 grit. At this point the fuselage should have taken some of the bite out of the 80 grit making it a little more gentle. For me I like the sanding block the most, some folks love the plane. Here is a plane at work.
I simply sand the leading edge, trailing edge and tips down so they match the ribs curves. My first pass I'm just rough sanding anything that is proud of the correct height. Then I come back around and fine toon until I'm just making contact with the tape. As you follow the rib curvature the leading edge should pretty much come to the correct shape, just needing a little rounding and smoothing.
Before you know it you will be done. Make sure to sight down the leading and trailing edges to make sure you are not creating lumps and bumps. You want them nice and straight.
Here is a little trick for sanding the ailerons. Use tape on the top of the ribs to protect them from the sanding block. I also used a strip of tape on the bottom of the aileron to secure it to the bottom of the wing. This holds it in place while sanding, but also lifts the aileron up the thickness of the tape, giving us a little better fit when we are done. This worked out well for me.
You may like to use a mini plane to shave off some of the wood, or just use the same sanding block with the 80 grit. At this point the fuselage should have taken some of the bite out of the 80 grit making it a little more gentle. For me I like the sanding block the most, some folks love the plane. Here is a plane at work.
I simply sand the leading edge, trailing edge and tips down so they match the ribs curves. My first pass I'm just rough sanding anything that is proud of the correct height. Then I come back around and fine toon until I'm just making contact with the tape. As you follow the rib curvature the leading edge should pretty much come to the correct shape, just needing a little rounding and smoothing.
Before you know it you will be done. Make sure to sight down the leading and trailing edges to make sure you are not creating lumps and bumps. You want them nice and straight.
Here is a little trick for sanding the ailerons. Use tape on the top of the ribs to protect them from the sanding block. I also used a strip of tape on the bottom of the aileron to secure it to the bottom of the wing. This holds it in place while sanding, but also lifts the aileron up the thickness of the tape, giving us a little better fit when we are done. This worked out well for me.
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We can do that. I have leadingedge templates. We could cut them into wood, or print them on the plans.
I will admit that I do not enjoy sanding wings. It was not bad at all, and following the rib curves resulted in the correct shape naturally. I now have more confidence in my wing sanding skills.
I will admit that I do not enjoy sanding wings. It was not bad at all, and following the rib curves resulted in the correct shape naturally. I now have more confidence in my wing sanding skills.
Final Sanding
Now is a good time to switch over to a finer sandpaper. 150 to 200 grit will work well. I like to use a block for this, but some like to use a sheet in their hand, or a foam sanding block. Go over the entire fuselage, if you notice any high spots, give them a little attention. You should not need to spend much time on the final sanding. Be careful around any CA joints as they will resist the finer sandpaper, but the nearby wood will sand lower and lower. This is why I like a hard block even for final sanding.Next we can turn out attention to the vertical fin. Sand off the filler and and gently rounder the leading edge and tapper the trailing edge. When tapering the trailing edge be careful not to sand into the pushrod housing. It should looking something like this: (click on photos to enlarge)
I forgot to show the wing tip shape earlier, here are a couple of photos. You are welcome to sand whatever shape you like. I find this simple style nice and robust.
Lets sand the horizontal stabilizer and elevator. You can use a little tape to connect the elevator to the stab for a little easier handling. (hint I have more tape on the other side and will move it around as I sand.)
Start by rounding the tips and the leading edge. (Hard to see in the photo.)
Then sand in a taper on the trailing edge. Holding the sanding block at about a 5 degree angle sand until you have reached half way through the wood thickness, then flip it over and do the same on the other side.
Now we want to sand in an angle to the elevator to allow the elevator to hinge up and down. I start by taping the elevator over onto the stab like this:
Then I sand a gentle angle into both the elevator and the stab as shown. We do not need much of an angle here, maybe 7 degrees. be careful not to sand the outer edges more than the center as this will result in a curved hinge line. Un tape the two and check to make sure they still mate up without any gaps. If you have a gap, just sand the gap free areas to close up the gap. A tiny bit goes a long way.
You can see I have a little gap near the camera. You can also see that the elevator can freely drop about 15 degrees.
You can see I have a little gap near the camera. You can also see that the elevator can freely drop about 15 degrees.
Electric Conversion
If you are building as both a pure glider and as an electric, you can remove the nose. (did you screw it on?) In this case I had used a drop of CA on either side, so a little xacto knife cutting and she pops off.A little light sanding on the firewall and we can see 2 interesting things. How little triangle stock is left, and how far that one drop of thin CA penetrated.
Lets mount the motor. Yep, a snug fit, but not touching. (Note: we have flipped the shaft orientation on this motor, we will include details on this a bit later.)
And here is the real surprise, a 40mm spinner fits really well! (Note: Spinner was not fully seated against yoke, it actually is better than shown.) A little wide on the sides but near perfect on the top and bottom. I did not expect it to be this good with all of the sanding for the glider nose.
If building just an electric, then get the 45mm spinner and sand to it's profile. This should fit even better and you will have more wood upfront too. Here it is with our 7x4 blades.
Correct, both will be installed after we cover. You could slip the wing pin in now if you like. Chances are it will be a little too long, and I like to put a small curve on the front of the pin so it aligns into the bulkhead easily. To do this I put the carbon in a drill and spin the carbon on some sandpaper to get a nice curve.
Before covering the tail, please test fit the upper tail mount. Due to wood tolerances, you may need to lightly sand the top of the vertical to get a nice tight fit. We want it snug here, but not super TIGHT. We do not need to cover the area below the upper mount as we do want some glue contact with the wood. There are nuts already captured inside the upper tail mount, so it is good to go.
Before covering the tail, please test fit the upper tail mount. Due to wood tolerances, you may need to lightly sand the top of the vertical to get a nice tight fit. We want it snug here, but not super TIGHT. We do not need to cover the area below the upper mount as we do want some glue contact with the wood. There are nuts already captured inside the upper tail mount, so it is good to go.
I'm not going to explain covering all of the ins and outs of covering a model as I honestly am not the best at this art. There are some great youtube videos that do a great job. I'll see if I can find some links for the manual.
For now I decided to start with the canopy. Oddly enough, this is probably the hardest part to cover on this model, so you may want to hold off if this is your first covering job. As you can see I have a couple of wrinkles in the corners, but can probably work those out a bit later. I started off be checking my gaps were even all the way around the canopy. Light sanding to make them even. If you have any big gaps, you can glue in some balsa scraps and fine tune. I like to have about 1 mm of gap prior to covering.
The Ridge Runt does not have much curve on the bottom of the fuselage, so I used a single piece of film that covers the bottom and both sides. Fully sealing all edges with a covering iron before using a heat gun to shrink down the middle. Then I covered the top areas.
Next I will test fit my upper tail mount to make sure it is fitting onto the balsa well. This is keyed to only fit in one direction. If it will not go on, then lightly sand the top of the vertical. We want a nice snug fit. You may prefer to install the top mount prior to covering, or after. I have not yet tried covering first.. I'll report back if it works or not. LOL
For now I decided to start with the canopy. Oddly enough, this is probably the hardest part to cover on this model, so you may want to hold off if this is your first covering job. As you can see I have a couple of wrinkles in the corners, but can probably work those out a bit later. I started off be checking my gaps were even all the way around the canopy. Light sanding to make them even. If you have any big gaps, you can glue in some balsa scraps and fine tune. I like to have about 1 mm of gap prior to covering.
The Ridge Runt does not have much curve on the bottom of the fuselage, so I used a single piece of film that covers the bottom and both sides. Fully sealing all edges with a covering iron before using a heat gun to shrink down the middle. Then I covered the top areas.
Next I will test fit my upper tail mount to make sure it is fitting onto the balsa well. This is keyed to only fit in one direction. If it will not go on, then lightly sand the top of the vertical. We want a nice snug fit. You may prefer to install the top mount prior to covering, or after. I have not yet tried covering first.. I'll report back if it works or not. LOL
