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Old May 10, 2012, 11:31 PM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
Build Log
Another Tritle Dragon Rapide Build - and Maiden Flight

The Tritle Dragon Rapide is a wonderful design and a great kit.

There have been several really great build logs already for this design.
http://www.rcgroups.com/forums/showthread.php?t=1009606
http://www.rcgroups.com/forums/showthread.php?t=559571
http://www.rcgroups.com/forums/showt...t=dragon+rapid

Many RC Group threads show flawlessly excuted designs by master craftsmen. They are stunning and I love to read them. This is not one of those threads. I am charitably an intermediate builder and make a lot of mistakes. These are my own fault not the fault of the design. But I will share what I have learned. Perhaps it will help another flawed builder.

It has been a lot of fun and mistakes and all, I am very pleased with the result so far. Pat, thanks for a great design.

My build philosophy has been to try to be faithful to the design philosophy of light first, scale fidelity second.

Best,
Robert

Addendum as of February 8, 2014. Here is a component list. All of the equipment listed has worked flawlessly for two flying seasons with 31 logged flights and 140 minutes of air time:

Designer: Pat Tritle
Kit: Dumas
Battery: 1300 mah, 2S, lipo
Motors: brushless inrunner Feigao 1208436L x2
Gearbox: 2 IPS S-2 3.5:1 gear ration
Propellers: APC 7x6 Slo-Flyer propellers x 2
Speed controllers: BP Hobbies 10A Mk II brushless ESC x2
Wire from battery to speed controllers: 1.5 mm silicone insulated wire
Wire from speed controller to motors: 3 strand heavy duty servo wire.
Servos: 2 Tower Pro 9 gm servos for rudder and elevator, 2 Tower Pro 5 gm servos for ailerons
Receiver: Spektrum AR600x "Full Range Sport Receiver."
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Last edited by Robert R; Feb 08, 2014 at 01:42 AM. Reason: Added equipment used list.
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Old May 11, 2012, 12:10 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
Framing up the wings went well with only one problem. The spar on the wing where the aileron is to attach to the wing is to be doubled. However, I managed to double the leading edge of the aileron itself instead. Twice. The fix was to separate off the wrongly glued spar, put it in the right place on the wing and lots of sanding on the leading edge of the aileron. Unfortunately, that sanding made the anterior surface of the aileron flexible. When it came time to cover the aileron, even with Nelson Lite film, it bowed the aileron and I needed to redo the leading edge of the aileron.

Another thing I realized on the wing, when I shaped the leading edge, I sanded in too sharp a leading edge into the outer wing panels. It could have been more blunt and more stall resistant if I had thought about before I covered the wing.
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Old May 11, 2012, 12:36 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
I really enjoyed laminating the tail surfaces. I learned something here as well. Even when I soaked the sticks they tended to crack when I tried to bend them around the forms. A nice solution was to flex the sticks back and forth between my fingers before bending the sticks. It worked fine. Ammonia water would have also been a good thought.

I learned another thing. When I framed up the rudder I made the horizontal stick which fits over the top of the fin for the aerodynamic balance part of the rudder in two pieces. I should have made it in one piece. With two pieces it allowed the tip of the rudder to bend up when the covering was shrunk. The fix was to replace the piece and recover.

Best,
Robert
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Old May 11, 2012, 12:41 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
Framing up the fuselage sides is my favorite part of a build. It is totally relaxing. No mistakes here. The tool above the knife is a home made hinge slotter. It is a sharpened piece of brass attached to a dowel. Works great. It is a Pat Tritle idea.

Robert
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Old May 11, 2012, 01:15 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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When I glued the fuselage sides together there were more things to learn. Gluing the sides together nice and square in the center section of the cabin was easy. Gluing the tail post and aft section of the fuselage together squarely, no problem.

Getting the anterior section of the fuselage together squarely was a learning experience. I should have made a fixture the way Hammered did or use a big wood working clamp the way Jeffh did.

What I did was struggle and get things together with a bit of a curve limited to the anterior portion of the cabin and fuselage.

The fix was to use a temporary diagonal brace to square up the fuselage, then gussets to hold the shape and finally remove the braces.

Hammerd's and JeffH's way was more elegant.

Best,
Robert R
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Old May 11, 2012, 01:29 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
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All and all, I was very pleased with the framing up process.

What I don't like is systems installation.

Best,
Robert
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Old May 11, 2012, 02:19 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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Since I don't like systems, I took a little detour from systems and made a pilot figure.

I was not trying for an exact human likeness just the suggestion of a 1930-40 era British pilot. I call him Nigel. I got my inspiration for the flight suit from the chap in the blue, I got my inspiration for the face from what I imagined a happy Sir Hugh Dowding would look like.

I started with pictures of pilots in Dragon Rapide cockpits to help me size the pilot for my Rapide. I drew a pilot in a tracing of my Rapide cockpit then started carving blue foam. I started with four pieces: head, body and two arms. I added separate nose and sawed the arms in two at the elbow to allow more realistic positioning.

Craft store acrylic paints were used to color the figure.

One of the best tips I read on figure painting was regarding eyes. They said don't paint the whites white. Pain them ivory or gray. The pupils and iris should not be round but rectangular and take up most of the eye socket with just a bit of white showing.

My first attempts at face carving resulted in a cranky looking pilot. From looking at the pictures of the happy pilot in blue and Sir Hugh I realized, the more vertical the cheek creases are the crankier the pilot looks and the more horizontal the lower cheek crease/naso labial fold is the happier the pilot looks. Just pressing in a different cheek crease into the blue foam, I had a happy pilot. It took all of 15 seconds. Thanks for the lesson Sir Hugh and happy Rapide pilot.


The seat is made of balsa and file folder paper.

Best,
Robert
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Old May 11, 2012, 10:13 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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One more thing I learned about framing up the wing; when sanding the trailing edge to airfoil shape don't get the trailing edge too thin or even with mild shrinking Nelson lite film the strength of the pull of the film is enough to deform the trailing edge or even pull the TE off the aft end of the occasional rib.

What I learned.

1. Don't sand the TE too thin... but if you do
2. You can add the odd 1/32 gusset to the trailing edge/aft rib joint.
3. If you notice the problem after covering, It is possible to open the covering, repair the rib TE joint and recover. Lite film repairs are really almost invisible.

This picture doesn't really illustrate that problem too well. I will try to find a better one later.

Best,
Robert
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Old May 11, 2012, 10:30 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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Picking the color scheme was a lot of fun. I wanted to find a relatively simple color scheme that I had not seen modeled before. The Iberia Airlines Spanish registry EC-AAY looked like just the thing. It would be mostly unpainted silver Lite Film, to keep the weight down but with a bit of bright yellow and red. I had read great things about Callie Graphics so I figured the registration markings, the "Iberia" graphic and the lightning bolt would not be too difficult.

I tried several experiments to find a light yet opaque silver covering. I failed. The semi-translucent light film was the best method of carrying out the build philosophy of light weight first scale fidelity second.

I am really glad that I made that decision. The framework is so pretty, I really like being able to look at it. I also have had a bit of stick and tissue experience so the "Chinese lantern" of stick and tissue is esthetically pleasing in it's own right.

I would not change a thing in color scheme or covering choice. Even with this very light weight film I would occasionally have to deal with deforming the most fragile structures i,e. ailerons and wing trailing edges.

Best,
Robert
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Old May 11, 2012, 10:51 AM
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Albuquerque, NM USA
Joined Sep 2003
15,571 Posts
Nice work.

And congratulations on how you reworked the pieces that you had trouble with. Many of us (me most of all) will sometimes not take the time to remove, rebuild, and recover parts that aren't right.

charlie
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Old May 11, 2012, 11:29 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
Quote:
Originally Posted by portablevcb View Post
Nice work.

And congratulations on how you reworked the pieces that you had trouble with. Many of us (me most of all) will sometimes not take the time to remove, rebuild, and recover parts that aren't right.

charlie
Thanks Charlie,

Your Derek Micko/Manzano Laser Works Hurricane and Pat's much anticipated Song Bird are on my short list of to build next projects. I really appreciate what you and Pat do for this hobby.

Best,
Robert
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Old May 11, 2012, 12:38 PM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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For the system choices:

Receiver AR6100 - I may revisit this choice I have heard about "brown out" I don't know if I will swap out this receiver or not. My transmitter is a Jr 9503.

Servos 2 Tower Pro 9 gm servos for rudder and elevator, 2 Tower Pro 5 gm servos for ailerons

Power system - this was confusing. In several good threads there was so much back and forth about various options it was difficult to tell what the final choice was. My final decision was: Gear box IPS S-2 3.5:1 ratio x2 with Feigao 1208436L 12x30 mm brushless motor x 2, GWS prop adapter set ADC001, APC 7x6 Slo-Flyer propeller x 2, BP Hobbies 10A Mk II brushless ESC x2, heavy duty servo extension wire was used to run from the ESC to the motors,1.5 mm silicone insulated wire was used to wire the battery to the two ESCs, a 1300 mah 2 cell lipo battery will be mounted to the lower surface of a Lite Ply a battery tray which was placed just behind the cockpit bulkhead in a horizontal position just below the side window structure.The ESCs were placed on the forward portion of interior surface of the lower wing mount plates, the receiver was placed on the posterior interior surface of the lower wing mounting plate. The electronic components were attached with hook and loop fasteners

I spent several evenings constructing home made a "Y" adapter of just the right length to go from the receiver to the ESCs, another Y from the battery to the ESCs and shortening and adjusting various servo leads and motor power wires so that they were an appropriate length for this application. I didn't want it to look like a spaghetti dinner inside.
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Old May 11, 2012, 01:24 PM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
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After the systems were installed I went to my second favorite part of a build - covering. It seems like there is so much obvious progress during the covering stage.

Knowing that glossy silver is a very unforgiving finish, I sanded a lot; too much in some places like the trailing edges of ailerons and wings. I learned to not thin down the trailing edges too much and to use a very light weight covering. Lite film.

Read the instructions. Realize this is a low heat covering. When covering with Litefilm it is very helpful to use a powder on the stickey side of the film to keep it from sticking to itself during application. It does not seem to decrease adhesion to the framework. The procedure is to put the covering stick side up/backing side up. Start removing the clear backing little by little and as you go apply a powder lightly on the adhesive side of the covering. Apply covering, shrink and trim with a brand new #11 blade. What powder should be used? Unscented talc is recommended. I could not find any. I used scented talc ie baby powder and was happy with the results. Others have used corn starch.

When my Callie graphics arrived a day or so after I got finished covering, in a fit of enthusiasm, I installed them all in a single 1-2 hour sitting. Her graphics are quite simple to install and BEAUTIFUL. I ended up with a few bubbles which were easily fixed with a very fine pin prick and another rub down and the bubbles were gone. Callie did a wonderful, economical and very speedy job on the graphics. She also sent me some sign makers silver vinyl which I cut into strips to simulate the cockpit windshield framework and to help fair in in the windshield and nose piece.

The reason that there are no post-covering, pre-marking photos was that once the markings arrived, I couldn't wait to see what they looked like in place.

This brings us to where the build is to date. It will now proceed in real time rather than fast forward.

Pat Tritle was very generous with his help regarding wiring and avoiding several of my initially poor choices regarding systems. Pat, thanks for a great design and for your help. This build has been an advanced course in beautiful, light, strong building techniques.

In the back ground of the second picture is a solid foam carved Boeing 247 fuselage (see my avatar). It is awaiting much design head scratching on my part. I need to decide if I will build it of hollow foam covered with paper or fiberglass, Warren truss box-frame with formers or keel and formers. One reason for doing this build was to learn Pat's design techniques and shamelessly copy them.

Best,
Robert
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Old May 13, 2012, 12:53 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
Side cabin window tip

One build thread told how difficult it was to install the cabin side windows after the fuselage was covered. Forewarned, I covered the sides and bottom of the fuselage, installed the side windows, then covered the top of the fuselage. It worked very well. No headaches at all that way.

Best, Robert
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Old May 21, 2012, 12:49 AM
This is a fine fiddly business
Robert R's Avatar
United States, WA, Marysville
Joined May 2009
1,302 Posts
The Pull Pull System

A few more points on the learning curve.

The pull pull system.

Reasoning that silk is very strong, I initially installed the rudder pull pull system with heavy gray silk beading thread from the craft store. The problem was that it was too stretchy.

So I went to the local sporting goods store to look for Kevlar fishing line but I found only Spectra. A little research reveals that Spectra is ultra-high-molecular weight-polyethylene and is used in body armor and prosthetic human joints. Further it has very low stretch and high tensile strength. Out came the silk and in went the Spectra. While I was at it I added Dubro mini ez connectors and short lengths of wire to serve as tension and centering adjustments for the pull pull system.

Best,
Robert
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