Projects Canadair Ct114 Tutor Build

Some how all my text disappeared. Picture one is the Tutor as used in training. Pictures two and three are the Tutors in Snowbird colours. Picture four is the colours
mine will be in. Next post I'll start the build

Don
 
First some background. I started building rubber powered balsa models when I was 9 years old. I am now 74.
I have built a lot of kits and modified a lot of kits due to unscheduled landings. I'm not a master builder just a modeler
with a lot of build and repair experience.

First off I had to make a hot wire cutter. As this is to be a one time build, the cheaper the better. Home Depot had the non digital
light dimmer. A local electronics store had the rest of the parts. I had some 1/4 inch plywood for the box. See picture one.
Next I built the bow from some 1"x2" poplar I had. The bow is flimsy at best but as I said, it's a one shot deal. I made the bow
30" long. This works with my wing panels which ar 27" long.
The hot wire I got from China. It's .024 gauge for hot wire cutters. Thirty feet on a roll for $1.98 free shipping. See picture two.

From the plans, I cut out the patterns for the formers, the wing root and the wing tip. Then I glued each to 1/8" Masonite hardboard
and cut them out. See picture three. Now the Styrofoam. Pic 4. I cut 2 pieces 1"x12"x27" and glued them together . I used 3M 77 spray adhesive
throughout the build. Center lined the foam and attached the root and tip templates to the foam with drywall screws. Note that the wing tip
template is 1/4" up at the trailing edge. This for the washout. Pics 5+6. I built the fuselage in sections. Former 2 to three, former 3 to 4 etc.
Pic 7 shows the foam blocks ready for gluing and the templates. Pic 8 shows all the sections before shaping. Pic 9 is the f2-f3 station with
F2 template on the front and F3 template on the back ready for cutting. Pic 10 is the F5-F6 section cut to basic shape and hollowed out to leave
1/2" shell. Notice the holes left by the drywall screws. The one on the right has a 1/8" dowel in it. In the future both holes will have dowels in them for
alignment when glued together. Remember, contact adhesive gives you only one chance to get it right. Pic 11 is all the sections stood on end. It stayed standing.
so I guess the cuts are square. It's not glued together. Pic twelve is the right wing panel showing the 1/4" washout. Pic thirteen is the fuselage glued together.
It's in to pieces because I was going to mount the fan in the scale position. But. I decided against it and glued tihe two together.

Next up is the wing.

Don


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Okay I'm back.
First thing I had to do was build a handheld hot wire cutter. As I said before, one time build keep the tools cheap. It's made from some 1/4" ply wood scraps
a couple of screws and wire from the roll I used for the bow. The cross piece is wide enough so that it sits on the foam beyond the width of the cavity. The hot wire is
shaped the width and the depth of the pocket and extends up to the wires from the power pack and is locked in place with the cross bar. Now mark out your pocket. Take
3/4 masking tape and tape along the lines. Now cut out the foam. Remove the cut out and you have a servo pocket or what ever you need. Pic 2 is the wing shape with the
leading edge glued on. Pic 3 is the wing tip balsa marked out and ready for gluing. Pic 4 is the tip clued in place. Oh, this also would be the time to install the
navigation light if you are using them. Pic 5. The leading edge and wing tip have been sanded to shape and the flap and aileron have been sanded in to the air foil shape.
Pic 6. A hole has been drilled in the wing tip and metal 1/4nc threads put in to accept the pitot tube. Pic 7. The real aircraft pitot tube. Fourty inches long . The model
will be 5" long. It has to come off and on for transport. As we all know if it's small and pointy it will get broken off first time out. Pic8. Flap and aileron cut out and
balsa added to the tailing edge and to the aileron for hinge attachment. Notice the two marks up on the wing. This happens when the wire cutter depth is just a shade too deep. Pic 9. Lots of cutting. Pockets for the aileron, flap, servoless retract, main gear strut, main wheel and servo that operates the in board door. Also trenches for the
wiring. 3/16" plywood added around the edge of the pockets so that screws can be used to attach the hatch covers. The flap and hinges are installed. The aircraft uses "slotted flaps". They rotate out and away from the trailing edge, leaving a slot between the flap and the trailing edge. Pic 10. Landing light installed and the balsa installed to the trailing edge for the hinges for the aileron. Pic 11. I cut a 1/16th shelf in to all the trenches. This allows for a 3/32" piece of balsa to glue to it and after sanding will be flush with the wing. Pic 12. Balsa strips have been glued onto the wiring troughs, and ready for sanding. Yes I did remember to lay in the wiring first. LoL. You can't see it because it comes out the top side center of the wing. The white piece where the flap mounts is a piece of .040 styrene plastic glued to the top of the trailing edge
of the wing to deflect air, coming through the slot when the flap is down, over and down the flap. Pic 13. The real aircraft, showing the flap down and the metal that deflects the air. Pic 14. The inboard door, showing the servo mounted to the hatch cover, linkage to the in board door and door hinges. Pic 15. Servo mounted to a hatch cover.
This works for flaps and ailerons. Pic 15. Main gear door. All the doors and covers are from 1/16" aircraft grade plywood. 2-56 screws and nuts and wire from the roll of hot wire. A flat was filed on the middle boss on the door side of the strut. A hole was drilled in the middle of the door between the screws and threaded with a 4-40 tap. Then
a 4-40 set screw was screwed tight to the gear strut. It didn't matter how tight the wire straps were tightened, the door would still rotate until the set screw was installed.
Pic 16. Main gear door. I'm underneath the wing and take a picture. Then I get my note book and tape measure, make a rough drawing and start adding measurements.
Pic 17. Now on my back for picture of the inboard door and measurements. Man are these aircraft low to the ground. Pic 18. Picture showing the slotted flap hinge detail.

Don







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Tony

Staff member
I love the fact that the paint codes are on the under side of the plane lol. How convenient. lol. Loving this build!
 
More on the wing. Making the pitot tube.
Parts 1, 1/4"nc bolt, 1/4" i.d. brass tubing, 1 1/4" dowel. Cut the pieces to length as per measurements and scale from real aircraft. Pic 3. Tools for the job.
The drill of course turns the dowel, the wood rasp turns the dowel down to the correct diameters, the calipers check each dimension as per my messy notes and
the caliper box helps support the dowel while it turns. Pic 4. Solder the threads from the bolt into the brass tubing. Shorten the dowel so that the total length including
the brass tubing is 5 inches and epoxy into the brass tubing.
Pic 5. The wing has been epoxied together. I added 1/4" alignment dowels to the left half and corresponding holes to the right side. This kept the two halves aligned
until the epoxy cured. Each wing tip was blocked up an inch and five eigths for correct dihedral. The wing has been covered with 3/4oz fiberglass cloth. Minwax
Polycrylic was used to glue it down. Pic 6. The landing gear doors and retract installed. Flap and aileron servos installed. Pic 7. The landing light with plastic cover
installed. The real bulb is 8" diameter. This one is 1" diameter and 3 watt. Real bright. Pic 8. The slotted flap, showing the slot when the flap moves down and back.
Also the styrene plastic strip that covers the slot. Pic 9. Shows the under side where the air flows up and over the flap. Also the pretty close to scale hinges.
Pc 10. The electronics for the wing. On the right is the landing gear and door controller. Just like a P51, inboard doors open, gear comes down, inboard doors close.
Second from right is the controller for the navigation lights and beacons. Third from right is the landing light switch that actuates when the gear is operated.
Pic 11. I make my own wire extensions custom to where they need to go. Pic 12. Eventually, all the wiring will be through these 35 pin connectors. One mounted to
a board in the fuse and the other on to the loose wiring on the wing. One plug does it all. Just plug the two together. Put the wing in place and bolt it down.
The wing is now ready for primer and paint. Now on to the fuselage and the air intakes.

Don







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Tony

Staff member
There is some awesome ingenuity in this build! Making that speed probe without a lathe takes some skill! Well done. And using a serial cable is an awesome idea! I can't want to see this thing done lol.
 
Tony. Thanks for the input. After the next post on the fuselage build, we're up to date on the build. I haven't done anything on the Tutor for about three months.
Home maintenance has to be done when the weather is good. Also taking time out to repair my FMS 1400mm Cessna 182. That might be another project on
repairing EPO foam.
 

D.O.G.

Goblin 380 Supporter
wasfixedwing that's some awesome talent and patience you have. I'm enjoying your pics. of your build. Keep them coming and thanks for sharing :).
 
Now the fuselage. Pic 1. All the work stations are glued together, the wing saddle cut out, wing bolt blocks installed, and blocks installed for the leading edge dowels.
Hot dog! The wing fits and it's square. Alot of hours put in to find out that there is something wrong. Pic 2. Using the nose wheel for the size of the opening. Pic 3. Nose gear opening traced out and you can see the lines for the hatch cover for the receiver and servos. Pic 4. Tail section lined out where the vertical fin will be. Pic 5. Making the fan mount. 1/8 aircraft grade ply is used . There are no plans for the mounts. Remember, this is scratch build. Pic 6. Trial and error is done and the mounts are ready to install.
Pic 7. A second piece of 1/8 ply is added to the top side to allow enough depth to use 4-40 blind nuts. Pic 8. Fan mounts epoxied in place. Pic 9. The tail feathers. The horizontal stabilizer and elevator are from 1/4 inch balsa. The vertical fin and rudder is 1/4 inch balsa with 1/8 balsa lamenated to it and then sanded to profile. The hole in the stabalizer is for the push rod for the elevator. Notice the rod between the elevators. That used to be a stock item and various sizes at the local hobby shop. Not any more.
Piece of 1/16 brass flat bar, a length of 4-40 rod, a trusty wire bender and we're off to the races. I used a control horn to get the length for the brass bar. Drilled the bar to take the 4-40 rod. Cut the rod to length including enough for bending a 90 degree 1/2" on each end. Drilled three 1/16" holes in the brass bar for the push rod clevis.
Pushed the bar onto the rod, bent 1/2" 90's on each end, soldered the bar to the center of the rod and epoxied into the elevators. Pic 10. The reason for the laminated fin, is for the elevator push rod and the wiring for the rear light. I used my Dremel to make two 1/8" deep, 1/8" wide channels. Put the wire in one and the push rod in the other.
Glued the 1/8" balsa on to the 1/4" making sure no glue got in to the channels. This allows the wire and the push rod to be moved up and down to get the right length.
Pic 11. Is the completed fin and rudder. All hinges in the elevator, rudder, and ailerons are Robart 1/8" pin hinges. Pic 12 is the finished stabilizer and elevator.
Now the part that hurts. Pic 13. The wiring, elevator push rod, and the rudder push rod are inside the fusalage. The only way to get there is to split the fuselage.
This is the left half with the rudder push rod installed. Pic 14. This is the right half gluing in the vertical fin. Using 30 minute epoxy. Also a 4s battery makes a good weight untill the epoxy sets. Pic 15. Both halves of the fuselage with control rods,wiring, wing bolt blocks, fan mounts, leading edge dowel blocks, and fin glued in place.
I used two sided tape to hod the rods and wire in place. Also, I used epoxy on top of the tape, as insurance for longevity. Notice the black dots on the fuselage edge. Again the left side will be alignment dowels and corresponding holes on the right side. Pics 16,17,18. Different views of the fan and thrust tube. The Tutor requires a thrust tube.
You have to make it. Staples is the best place to buy the plastic. It is a plastic cover for a desk blotter. It is quite thin, about .015". You need it thin so that you roll it into a cylinder. Best part is, it's cheap. Pic 19. The fuselage pushed together but not glued. Pic 20. The fuselage with stabilizer and elevator sitting on top of the fin. Pic 21. The fuselage glued back together. The nose gear installed, servo rails installed and the piece of ply in the center of the rails is for the receiver. Pic 22. The fan unit with it's thrust tube installed.

Okay. Now you are caught up to me.

Don







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More on the fuselage. I'll go to the air intakes because they are part of the fuselage. When you first look at the Tutor, it looks like it is twin engine. Its not. It is one single engine drawing air from an inlet on each wing. The engine is 8 times the size of the fan unit in the model. Tutor 20" fan, model 2.5" fan, Tutor 40" long, model 5" long.
Model fan can't touch the Tutor weight. 12oz vs 431lb. The first 6 pics are for reference, along with my drawings and measurements, to help with sanding the block to shape. Pic 7 is 2" thick block of foam 15" long. The template is just a piece of cereal bock cardboard. Pic 8. After the hot wire cutter got at the block. It's not pretty but with the amount of foam that's going to come off, it doesn't matter. At it's thickest point it will be 1.25" and 14" long. Pic 9. After some aggressive sanding with #80 paper there is a basic shape. Pic 10. After more sanding with #100 and#220 paper The final shape is starting to appear. The filler is drywall compound. After another sanding with #220 there is hardly any compound left and all the divots and scratches are filled. Pics 11, 12. Test fit to wing and fuse. And more sanding and filling to get best possible fit. Pic. 13. The hot wire cutter again and the inlet is cut out. I added a balsa ring to the inlet for added strength. The inlet is sanded and fiberglass cloth added. Pic. 14. I have no idea what this is called. What it does is, it helps to smooth out turbulence that would build up in front of the inlet and provide a smoother air flow into the inlet. Pic. 15. The part glued to the inlet. Pic.16. The intake test fit on the fuselage. Pic. 17. When the intake was on the fuselage I took a pencil and traced the inside of the inlet for the position of the opening into the fuselage. Notice that the opening is slanted to the rear. To help direct air flow to the fan unit. Pic.18. The opening has been sanded smooth and fiberglass cloth applied. Pic.19. The opening is painted. Pic. 20. The air intakes also painted white. Pic. 21. Showing detail of the shimming so that there is a flush fit with the fuselage. I'm using water based contact cement and it requires a flat surface for best results. The last 5 pics are the intakes cemented on and ready for paint prep. It's starting to look more like a Tutor every day.

Thanks for viewing.
Don



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Tony

Staff member
You know it's coming along when you start putting the intake ducts on it. Coming along very nicely!
 
Thanks Keith. Only 5 things left before paint prep. Nose gear doors, Servo hatch cover, Elevator and rudder control rods, Cock pit. I have a fellow vacuum forming a canopy, so, I've been waiting. As the price is low ( $0.0 ) I can't be pushy. The work left could take two weeks or two months. You have the same job I have. We do what we want, when we want, if we want.
Again thanks for the comment and thanks for viewing.

Don
 

Tony

Staff member
We don't allow html (the iframe tag you were trying to use) on this site. It is a Major security risk to allow html. All you need to do is copy the video url up in the url bar of your web browser and paste that link in a reply here on the site. It will auto embed it into your post like you see in your post above. I went ahead and edited that post so that the video would show up properly. Trust me, for about a year after moving to this site I was still trying to use the embed tags for videos lol. It's a hard habit to break.
 

Tony

Staff member
Watching the video and you are doing an amazing job! I do have one question though that you didn't show in the video. When you put the gear up, does it disable the steering servo? I'm sure it does, but would hate to have this plane go in the air and burn up the servo trying to push on something that doesn't move, then not have steering when you land.

Keep up the great work! This is an amazing project! Definitely enjoyed watching the video and hope you make more in the future.
 
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