This set of pages document John Mitchell's assembly of his Carden 40% Extra 330S.
The Carden 40% EXTRA 330S
Construction Review by John Mitchell
This project actually started last year for me after losing my Carden 35% Extra 300S during an IMAC contest.
My 40% Carden CAP 232 was now my primary plane (at this point my only plane) and it was time for a new addition to the hangar.
I spoke with Dennis and asked what would be on the drawing board next.
When I found out it was going to be a bigger Extra 300S (which evolved into the 330S) and I was given the opportunity to be a part during the prototyping stage I was ready.
The great thing about this project is Dennis and Caroline from Carden Aircraft and Dave from Desert Aircraft are all just a phone call away and all patiently willing to go over details, questions, and concerns throughout the project.
Now for the plane specifications for my Extra 330S
Carden 40% scale Extra 330S
The Fuse
Fuse 1 Another tip I learned from Bob’s Edge540 Construction web page. There are two vertical braces fore and two more aft of the wing tube section. This area is where the 3/8-inch plywood anti-rotation plates glue to the inside of the fuselage. You will notice there is a 3/16-inch gap between the brace and the 3/8-ply block on each side. Do not glue the anti rotation blocks in. I opted to glue the rear vertical brace and using the ply blocks as spacer’s glue in the fore vertical brace. This will give more support to the anti-rotation blocks
Fuse2 The fore vertical brace glued in place using the braces as spacers
Fuse 3 The anti-rotation blocks removed. Do not glue them in at this time
Fuse 4 One side truss assembly complete. I placed the long straight edge along the bottom horizontal 3/8-inch piece for construction. It would have been better to place it along the top horizontal piece
Fuse 5 The fuse socket support being epoxied in place
Fuse 6 I placed the second truss assembly on top of the first, wth wax paper separating them, and glued on the other fuse socket support for the wings. Use a square and the wing tube to make sure everything is aligned. Also at this time make sure you are making a left and a right half!
Fuse 7 Both truss halves complete with sheeting applied
Fuse 8 Taping off and sanding of top hatch ¼ inch balsa plate
Fuse 9 Sanding down to the masking tape. Remove the tape and final sand the edge to shape
Fuse 10 Bottom Deck sheeted and trimmed
1Fuse 11 Top Deck sheeted and trimmed
Fuse 13 Instrument panel and bottom deck extensions sheeted
Fuse 14 The motor box sides have small marks showing the location of the center points for cutting the 4-inch lightening holes. I choose to only cut the top lightening holes because I will be installing KS pipes with the DA150 motor
Fuse 15 The 4-inch hole saw on the drill press
Fuse 16 Getting ready to install the ½ inch square ash to support F1 and the landing gear plate
Fuse 17 The ½ square ash epoxied and clamped in place. The 3/8-inch square balsa will support the floor that will separate the exhaust heat from the inside if the plane
Fuse 18 The motor box being epoxied and clamped together. I placed 3/8-inch square balsa braces to support F2 and F3 while glued. It also gives added strength to the glue joint against the motor box
Fuse 19 Another view showing all the clamps
Fuse 20 Starting to cut the top and bottom 3/8-inch cross braces. From Steve’s 330 page I borrowed the tip to cut and sand the top and bottom pairs so that each pair is exactly the same size
Fuse 21 After drilling the landing gear plate the ply and hardwood are taped for an 8-32 screw
Fuse 22 The firewall (F1), after being glued in place with epoxy, is pre-drilled to allow for 12 8-32 sheet metal screws adding to the structural support for the 150cc motor.
Fuse 23 As explained in the intro to my construction descriptions I am installing KS pipes on the DA150 for this plane. Looking over the Edge540 construction web page Bob Hudson has put together I have applied his method for having the air exit the pipe tunnel. Here I have installed a 1/32 inch plywood sheet with a nice tight radius to allow the air to exit smoothly.
Fuse 24 Another view of the front of the motor box with part of the sub-floor installed to separate the pipes from the inside of the plane and create a tunnel for cooling air to flow through. The balsa filler has also been added under F1 and sanded to shape.
Fuse 25 The truss sides have been joined to the motor box assembly and all cross and diagonal bracing has been added. I use standard builders triangles from Home Depot to help keep the structure square.
Fuse 26 Another view of the assembly with the wing tube slid in place to verify the phenolic tube is square in the structure
Fuse 27 The rudder servo control assembly is added at this point when I can still get to the cross bracing underneath to add some additional supports. I have designed this assembly so each servo is connected to and drives the bell-crank assembly. Installation is easy just epoxy onto the current cross bracing and clamp down. After the epoxy cures additional cross bracing will be added. I am considering kiting and selling the plywood structure if builders are interested. I will be starting a web page with more details very soon. If you are interested or have questions let me know. The hardware is Nelson and Hangar 9 with JR8411 servos.
Fuse 28 Another view of the assembly clamped in place.
Fuse 29 A closer view of the bell-crank assembly.
Fuse 30 Another view.
Fuse 31 The fuselage has been turned upside down and additional 3/8 square balsa cross bracing has been added to make the structure rigid.
See more pics and descriptions of John's system on his web pages.
Fuse 32 Another view of the additional bracing along with the antenna tubes installed.
Fuse 33 I drew on the planes the bell-crank location and rudder attachment crossing the pull-pull lines on the way back. I wanted to allow the wires to cross but not rub against each other so I installed a thin carbon fiber tube at the cross point at the proper height. Should work well and was very simple to do, You can also see the servo wire tube installed.
Fuse 35 Rudder servo control assembly with antenna tubes and the servo wire tube to the rear installed.
Fuse 36 Setting the wing incidence using the long robart bar and digital level accurate to a 10th of a degree. As you can see 0.0 incidence. Support the fuselage so it reads 0.0 or level before setting the wings to 0.0
Fuse 37 Another view setting the wings incidence
Fuse 38 Before going too much further with the fuselage construction I wanted to get the DA150 motor mounted and the KS pipes setup. This picture shows the motor standoff dowels cut to size and temporarily installed for motor and exhaust fitting.
Fuse 39 The pipes have been bolted on the motor and the cans installed for now just resting in place. From this setup I can work out the dimensions for making the canister mounts and the cutout required for the front of the motor box. I will be using the mounting method developed by Steve Johnston on his Carden Edge 540 . More info to follow
Fuse 40 Closer picture of the cans inside the fuselage.
Fuse 41 The picture shows how the canisters will exit behind the landing gear mount. Most of the area will eventually be covered over with ¼ inch balsa. The pipes have an offset because of the cylinder offset. You can also see the curved plywood that will form the air exit.
Fuse 42 Picture showing the header pipes and teflon couplers.
Fuse 43 Picture of the fuselage in the upright orientation. You can see the hatch area that is still uncovered as part of the air tunnel in the fuselage. This area will give access to remove the canister hold-downs if the exhaust system needs to be removed for any reason.
Fuse 44 Close-up front view of the DA-150 and pipes.
Fuse 45 Side view of the header pipes.
Fuse 46 Along with bolting the pipes on to the cylinders the canisters also need to be supported inside the air tunnel. Again borrowing some design from Steve Johnston’s Edge 540 construction information I made-up two mounts from ½ poplar that will be epoxied in place on the landing gear plate under the seam of the canisters. For a heat buffer silicon tubing will be cut in half and applied to the edge of the poplar holder.
Fuse 47 "AeroTrend" number 1061 silicon coupler is used.
Fuse 48 View of the canister mounts in place and the canisters resting in the saddles with the silicon buffer.
Fuse 49 Another view of the canister mounts.
Fuse 50 The bottom deck and front side extensions have been attached. The ¼ balsa cross sheeting with a cutout for the canister pipe exits has been put in place.
Fuse 51 Front view of fuselage. The air tunnel has been coated with a thinned mixture of epoxy and denatured alcohol.
Fuse 52 A top view of the bottom decks with a better view of the pipe exit hole.
Fuse 53 The bottom plate for the motor box has been installed with a large cutout for the pipes and canisters to be installed and removed for maintenance. It is also the air entrance for the tunnel to help cool the canisters and pipes.
Fuse 54 Following Bob Hudson’s Edge 540 construction I made the rear bottom deck extension into a hatch to have access to the servo wires and rudder pull-pull cable exits. ¼ inch dowel pins are used in the front with a recessed single socket head #6 screw in the rear.
Fuse 55 Another view of the bottom hatch in place.
Fuse 56 Close-up of rear mounting screw. I used ½ dowel with a 3/8-inch diameter recess for the washer, lock washer, and screw. In this shot the dowel has not been sanded flush to the surface of the hatch.
Fuse 58 The fuselage is upside down and the view shows the pull-pull cable exit points.
Fuse 59 View of turtle deck being glued and taped in place. The 3/8 square blocks were tack glued in place to half on the fuse to define an edge for the turtle deck to follow.
Fuse 60 Another view of the turtle deck glued in place.
Fuse 61 Front view of the turtle deck.
Fuse 62 ¼ balsa cross grain glued in place for the vertical fin-mounting platform.
Fuse 63 Side view of the fuselage taking shape.
Fuse 64 Another view of the fuselage taking shape.
Fuse 65 Fuselage again.
Fuse 66 Front view of the top hatch and fuselage side rounding for a smooth transition.
Fuse 67 Vertical fin being glued in position.
Fuse 68 Rudder and fin in position. Notice the cutout for the Nelson rudder control arm.
Fuse 69 Close-up of vertical fin in position and rear capping of the turtle deck. I use ¼ balsa to cap off the turtle deck because I place a padded tie-down strap over this area when hauling the plane in the trailer.
Fuse 70 Instrument dash mount being put in place. Notice the hatch area in the cockpit that allows me to remove the Patty doll and also have access in the cockpit area after the canopy has been glued in place.
Fuse 71 Cockpit area
Fuse 72 Starting to mount the cowl. Notice the balsa spacers taped in place for an equal gap around the rear of the cowl.
Fuse 73 Lower cowl being fitted
Fuse 74 Lower cowl in place with DA150 and pipes in place
Fuse 75 Another view of the lower cowl. Front air intake was also cut out. After talking to Dennis when the cowl is completed I will block the area with a screen with balsa backing painted flat black. The opening can cause too much airflow over the carb resulting in carb adjustment problems
Fuse 76 Top and bottom cowl pieces taped in place
Fuse 77 KS Canister tie-downs. Heavy Duty ½ wide cable tie-wraps cut to size with .06 aluminum simple l-brackets and back plate
Fuse 78 Close-up of mounting ends for the tie-downs
Fuse 79 Opposite side of mounting ends with #4 screws to hold it together
Fuse 80 Inside fuselage mounting of canister hold-downs. Number 8 sheet metal screws into the hard ash and number 8 flat-head
screws through the landing gear plate from the underside
Fuse 81 Canisters and pipes assembled
Fuse 82 Smoke tubing attached to the header pipe
Fuse 83 Pipes and canisters installed. Breather tube attached to the carb and the smoke tubing attached to the “T” fitting. The
overflow / vent for the smoke and gas tank are visible with silicon protective sleeves attached to protect them from the heat of the
canisters.
Fuse 84 Another view of the smoke lines going into the pipes
Fuse 85 Number 8 screw up through the landing gear plate to lock-down the canisters
Fuse 86 Top view of the access area for the canister mounts
Fuse 87 Another view of the rudder control assembly with the pull-pull cables attached
Fuse 88 Rudder view of the pull-pull cable attachment
Fuse 89 Top view into the motor box – on the right is the smoke servo, smoke valve, and throttle servo. On the left is the B&B smoke pump
Fuse 90 Another view of the front end and looking back a little more to see the 50oz gas tank and the 40oz smoke tank standing on its side. Everything fits perfect just remember to setup your vent tube on the smoke tank for this orientation
Fuse 91 Another angle of the front-end
Fuse 92 Mounting of the two receivers
The Stabs & Elevators
Elevator 1 Using a builder’s angle to transfer the hinge line to the foam core
Elevator 2 I have found there is no substitute for drawing the control linkage on the planes with measurements so when it comes time cut out the servo bays in the sheeting no mistakes are made
Elevator 3 Servo supports glued in and taken to the root for added strength
Elevator 4 Another view
Elevator 5 The horizontal stabilizer cores have been sheeted using Pro-Bond glue
Elevator 6 The sheeted cores have had the leading and trailing edges trimmed
Elevator 7 The horizontal stabilizer halves with balsa leading and trailing edges installed. I use Elmers Outdoor wood glue and several tape strips to hold everything in place. The rudder is being done at the same time
Elevator 8 The next step with the horizontal stabilizers is to get them ready for mounting on the fuselage and setting the incidence to zero. Here the forward mounting bracket hard-point is being readied for installation.
Elevator 9 The backside of the hard-point has a blind-nut installed and two wood dowels to help anchor it into the foam
Elevator 10 The parting lines need to be drawn on the surface for the elevators
Elevator 11 Here the stabilizers root and tips are being installed. I prefer installing them now and cutting the elevators free afterward. By doing it in this order the leading and trailing edges that will be installed will run the full length which makes it easy to bevel with the micro-plan
Elevator 12 The elevators are installed on the fuselage and the incidence set
Elevator 13 The incidence must be set at 0.0 degrees
Elevator 14 I tack glue a small piece of balsa in place setting the incidence at 0.0. This makes it easy to install the L-bracket on the front of the stabilizer to hold the incidence
Elevator 15 Front L-bracket in place. I recessed it into the balsa side against the hardwood mount in the fuselage
Elevator 16 Elevators in place on the fuselage
Elevator 17 Along with the L-bracket in front the stabilizer tube is also held in place with a screw through the tube and a hard-point. A ½ diameter hole needs to be cut through to the tube. I used a brass tube to cleanly make the cut
Elevator 18 The hard-point for the tube is a ½ diameter dowel with a blind-nut on the side to go against the tube and I counter-bore the other side so the socket head screw is recessed
Elevator 19 The underside of the stabilizer with the L-bracket installed and the tube screw hard-point in place. It still needs to be sanded flush to the surface
The Wings
The wings and tail feathers follow a Carden standard of solid foam core with balsa sheeting.
The first step of the process is to join all the balsa sheeting with an aliphatic glue (Elmer’s wood glue) to make the large sheeting panels for each wing panel and the horizontal and vertical stabilizers.
I use the aliphatic glue because it sands uniform where using a CA type glue would be faster it would not sand as smooth. To keep everything flat while the glue is drying I placed wax paper over the taped panels and laid a complete volume of encyclopedias with yearbooks over the entire surface.
After the panels were all dry and the tape removed I sanded each surface with an electric palm sander down to 220 grit. It is definitely worth the time at this step to sand everything smooth because after assembly onto the wing cores all that is left is final sanding. I also prefer sanding a flat surface than a curved surface.
Wear a dust mask and have a shop-vac ready because it is amazing how much sanding dust is made sanding four wing panel sheets inside and outside and six tail surface sheets inside and outside.
The next step is to install the wing tubes and cut the openings for the servo bays and servo extension wires.
Working with the sheeting and the wing foam wing cores is where you can start seeing the attention to detail and quality of product Carden Aircraft puts into their designs and kit.
The foam cores were perfect. I use a soldering iron and bent wire template heated to cut the shapes for the servo bays and the long center wing channel for the servo wire extensions. Lightly sand the foam cores and vacuum them off to get them ready for sheeting.
I use Elmer’s Pro Bond Polyurethane glue to bond the foam cores to the balsa sheeting. The key here is to make sure you do this on a very flat surface so you don’t build in any warps to the surfaces and pile on the weight to force the glue into the foam core of the wing. I use 300 pounds of weight on each wing panel – as the picture shows including the kitchen sink – toolbox.
After the glue has cured (over night) the weight is removed and the leading and trailing edge surfaces are trimmed and trued.
The leading and trailing edges for the wings and tail surfaces were glued on and shaped. Using very long sanding bars and again a lot of tape makes this process fairly easy.
I lay several rows of masking tape down on the surfaces next to the edge being shaped and using a razor plane and sanding bar bring the edge to shape.
The masking tape prevents the sanding bar from biting into the balsa sheeting surface and causing gouges. The masking tape is then removed and the last little trimming is made for the edge.
Wing 1 My first step with the wing core is to cut the servo bays, servo support notches, and servo wire exit slot. I have made templates from lite ply and hot wire cutting tools from 12 gauge copper wire. I place wheel collars on the wires and use them to set the depth of cut. Using a soldering iron with the copper wires I first cut the servo supports slots then the servo bays. I then use a long straight edge and cut the servo wire exit slot. Accurate measurements are critical to make the servo bay cut outs after sheeting
Wing 2 Hot wire cutting complete
Wing 3 Servo mounts epoxied in place
Wing 4 Servo wire exit slots
Wing 5 Wing phenolic tube with balsa end cap in place and trial fit of the socket support plate
Wing 6 Wing tube socket support scribed to sand to shape
Wing 7 This tip comes from Bob’s Edge 540 construction web page. I will be using Pro Bond to glue the phenolic tube into the cores. With a ¼ inch drill make a few small funnels in the top of the wing core along the hot wire groove. This makes it easier to get the Pro Bond down in the tube slot
Wing 8 I still choose to glue all the sheeting together. This makes large sheets that can then be cut to size. A lot of encyclopedias work well on a flat table to keep the sheeting flat while it dries
Wing 9 The big sheets being cut into wing panels. Invest in 3M stock before starting this project because you will be using a lot of masking tape
Wing 10 Place the phenolic tube into its slot up to the first funnel and squeeze Pro Bond down the funnel. Slide the phenolic in and out twisting it and working your way down the slot. Make sure the tube is well coated and finally fill the hot wire slot. Tape over the slot and tape the tube socket in place. Place the wings in their cradles and weight them down for the glue to cure
Wing 11 I prefer gluing the sheeting together first because it allows me to pre-sand both sides on a flat surface with a palm sander and long sanding bar
Wing 12 Sanding wing cores prior to sheeting. Notice the Pro Bond filling the hot-wire groove
Wing 13 Bottom of the wing panel ready for sheeting. Notice the servo bay support slots have been filled in with scarp foam pieces
Wing 14 not used
Wing 15 Wing panel after sheeting and trimming
Wing 16 Wing panels with leading and trailing edges being glued and held in place with masking tape
Wing 17 Using a micro plane remove the majority of the excess leading and trailing edge balsa
Wing 19 When the plane brings the excess balsa down close to the surface lay on 3 to 4 layers of masking tape to protect the surface from gauges while sanding the rough shape. Remove the masking tape and use the sanding bar to bring the leading and trailing edges down to the wing skin surface
Wing 20 The wing with the servo bays cut-out, leading and trailing edges installed and trimmed but the leading edge not sanded to shape. The ailerons have been cut free and all edges have been trimmed out. The bevel on the leading edge of the aileron and trailing edge of the wing assembly have not been done.
Wing 21 The wing tips installed and sanded to shape.
Wing 22 A view of the wing root with the wing tube sanded flush.
Wing 23 Top view of the wing panel.
Wing 24 Another view of the top of the wing panel and aileron.
Wing 25 The hinge centerlines have been marked and the hinge points located. The aileron has been taped against the wing panel for proper alignment of the hinge point locations on each half
Wing 26 Another picture of the wing with aileron taped in place
Wing 27 The hinge locations have been drilled and the aileron leading edge and wing trailing edge have been beveled and shaped
Wing 29 Wing tip with aileron installed showing the beveling of both surfaces
The wings have been prepped and sanded for covering. The covering has been applied to both wing panels with graphics to follow
Wing 30 Bottom view of the wing covered with servo bays opened and aileron in place with hard points installed.
Wing 31 View of the rocket city hard point installed on the ailerons. The same has been done on the elevator halves
Wing 32
The
wings finally covered with the graphics and gold pin stripe that cannot be seen in the picture.
Wing 33
The bottom
of the wings with graphics.
The Fin & Rudder
Rudder 0 Foam core for the rudder after having the balsa sheeting glued using Pro-Bond. All edges have been trimmed
Rudder 1 The rudder has been marked for parting from the fin.
Rudder 2 The rudder and fin have been cut and are ready for the leading and trailing edges to be installed.
Rudder 3 Vertical
fin glued in place.
Rudder 4
Nelson
hardware installed in the rudder and covering completed.
Rudder 5
Picture
of the tail of the plane
Rudder 6 Close-up
of the rudder counter balance with the checkerboard and gold pin stripe complete.
The KS Canister System
See more pics and descriptions of John's system on his web pages.
The plane is finished!
The CG was setup 5 ¼ back from the leading edge at the tips.
The battery packs were used for balancing and ended up under the rear of the canopy.
Painting was done using the PPG OMNI basecoat clear coat method that turned out great.
The checkerboard on the cowl and swirl on the spinner were a bit of a challenge but worth the effort.
The clear coat also seals the thin gold pin stripe on the cowl that makes clean up a lot easier.
The 40% Patty Wagstaff doll looks great in the cockpit and the plane looks and flies outstanding.
Another success from Carden Aircraft. A special thanks to Dennis and Caroline.
I would also like to thank Dave from Desert Aircraft for his support with the motor and pipe setup.
See
pictures of the finished plane in my Gallery at Carden Aircraft
.
last update Aug 16, 2001
These methods and techniques are neither supported nor promoted by Carden Aircraft, this webmaster, nor the contributors to this site. They are merely the methods used by the contributors and are solely here to display the contributors methods in how they are building their model aircraft.
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