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Old Oct 11, 2011, 08:01 AM
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Fort Worth, TX USA
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Raise the wing tips 1 1/2 inch from the work surface. Use a small amount of weight over the spar to hold the wing center section flat against the table top. Block sand the spars and the sheeting at the root flush and 90 degrees to the bottom sheeting. Fit the spar joiners in-between the wing panel spars and bond them in place.
To fit the spar joiners; cut the width first, slide it in place, mark the point where the bottom of the top sheeting meets the spar joiner on both sides the cut between the marks. Don't forget to bond the gear plates in place first if you are going that way.
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Old Oct 11, 2011, 08:02 AM
RC 4 Life
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Fort Worth, TX USA
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After the joiners have dried; Repeat the sheeting steps used to bond the top sheeting in place for the top sheeting of the center section. Using a long razor will speed the trimming of the aileron torque rod supports.

note the center section has been designed with a slight taper so we can slide it back if the gap has been cut too narrow.

Next we fit the fuselage to the wing . . .. .
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Old Oct 18, 2011, 03:49 PM
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Fort Worth, TX USA
Joined Feb 2001
4,601 Posts
Cartoon P-40

Just a note to let you guys know that the Cartoon P-40 has flown and did very well.
I have neglected this thread concentrating on the project because so many have been waiting for it. sorry
I'll be back soon.

My Wife cautioned me not to make so many P-40 kits. I am any way
Within the next two days I'll have it on the site then start the thread later.
She'll see.

This one did so well that I did some leisurely flying with it despite forgetting the memory card for the camera.
Turns out that the video we shot on that stupid flip camera did not record.
Gotta remember to delete the stuff once it's on the computer.
The Cartoon Prop Balance thing I did earlier sucked up all the memory.
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Old Oct 18, 2011, 10:29 PM
Talk to me...
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Wow, that P-40 looks great!!! :-D
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Old Oct 20, 2011, 02:29 AM
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Fort Worth, TX USA
Joined Feb 2001
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Lessram . . .thanks for catching the screw up.
I have edited the U-tube comment and now it reads Cartoon Spitfire
Lots of copy and paste going on that day.
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Old Oct 20, 2011, 02:30 AM
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Fort Worth, TX USA
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Sorry duped post
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Last edited by sparks; Oct 20, 2011 at 02:46 AM. Reason: oops!
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Old Oct 20, 2011, 02:33 AM
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Fort Worth, TX USA
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Aileron servo.

This design has what I call a "lost servos" problem, that is to say the servos cannot be removed without damaging the plane. The thought here is that hatches cost weight and can always be installed if needed when a problem arises. Because of this, the aileron and elevator servos must be connected to the receiver and properly rigged to the control surfaces while we can. So, now is the time to rig the ailerons.

Find the center section center line and cut a hole just forward of the aft spar and cut a hole to fit your servo. note that a chunk of spar will have to be removed to clear the servo wire. (we need all the length we can get)
If you are going with no gear plate, the servo will fit against the bottom wing skin if the plate is in place you will need to cut and bond 6mm shims in place.
You can see that I screwed up and went with aft of the spar then found the wire was too short.
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Old Oct 20, 2011, 02:50 AM
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Fort Worth, TX USA
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ailerons

locate the two 6mm strips in the wing by holding it up to a bright light. Mark the half way point between the two. Use a saw to cut the ends of the aileron all the way through. (the dot is the halfway point and the line was taken from the plans.
While holding a hobby knife at a slight angle toward the trailing edge cut the ailerons free from the wing. The playing card shows the angle you need. it's a bad camera angle but the card leans aft.
Sand an equal angle into the ailerons bottom leading edge. This will allow the aileron to move downward after the hinges are in place. A small amount of sanding will be needed for the strip above the hinge line as well. The hinge line is easy to find, it is where the top sheeting and spar strip meets
If you used a dark highlight pen during the sanding step it should is easy to see.
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Old Oct 20, 2011, 02:52 AM
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Fort Worth, TX USA
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But before you hinge the ailerons . . . .

Bend music wire to make the aileron torque rods and don't forget to use a plastic tube bearing. A precise fit between the tube and wire is not necessary, it's primary job is to protect it from the glue used in the next step. Cut a groove in the wing so the aileron torque assembly can be installed with the wire parallel to the hinge line. If a heated wire is used, please practice first on scrap material.
Tape the assembly in place and use epoxy to lock it in place. A scrap piece of foam sheeting can be used to cover the installation. or you can fill the groove with epoxy.
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Old Oct 20, 2011, 02:57 AM
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Fort Worth, TX USA
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To connect my aileron servo to the torque arms I like to make my own hardware with aluminum tubing because it's easy and very cheap. I smash the aluminum tube then drill a small hole in the flat spot.
Next is to measure the length cut and fit . . . equal to the servo arm is a safe bet you will not over work the servo due to linkage.
I sand the steel wire to remove the anti rust coating and put CA adhesive or epoxy in the tube and slide it over the steel. Be sure to let it set up all the way and hold it upside-down to keep it in the tube while it does.
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Old Oct 20, 2011, 03:02 AM
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Fort Worth, TX USA
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Elevator servo and linkage

Drill a hole at the push rod exit then use the drill bit like a file to elongate the hole. On the servo end, plot the point the push rod should go through the bulkhead and make a hole. Use a piece of piano wire threaded through the turtle deck hole to puncher the formers . Do your best to aim the wire at the servo arm. Go ahead and connect the wire to the arm . The wire can be heated with a soldering iron to remove any foam preventing the most direct route. Thread small tubes over the wire and bond them on the enlarged holes to form a guide / bearing for the wire.
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Old Oct 20, 2011, 03:04 AM
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Fort Worth, TX USA
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Bind and set

Hook up your radio, bind it and make sure the servo arms are in their neutral positions.
Remove the bind plug and power it up again for a quick bind test.
Install the servo arm screws.
I found that the elevator plate is a bit thin so to be safe I added a 6mm strip as a stiffener.
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Old Oct 20, 2011, 12:49 PM
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Halifax, NS
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What material are you using to hinge the ailerons / elevator on these models?
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Old Oct 20, 2011, 01:54 PM
Watt Waster
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Joined Oct 2010
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Making a Hinge and ...

Quote:
Originally Posted by karlpenney View Post
What material are you using to hinge the ailerons / elevator on these models?
Wow, not sure what sparks is using, but there are a lot of options to keep the weight down and save a few coins on hinges. One of the old standbys is medical tape, the cloth type that is said to be water and sweat proof. It is said to stay put even if you shower or take a bath. Sometimes it is called athletic tape. To use it as a hinge you double it back on itself, sticky side to sticky side. You can also use a low heat trim, or plastic film iron to warm the glue a bit after making the joining. While the glue is still warm inside the sandwich, you use a roller to press the two parts together even more. I have read some go another step and clamp the sandwich between two thick pieces of plate steel (around 2"x3") and really screw down hard with clamps while the glue is warm. Since the glue is on the inside and the cloth is on the outside there is little risk of having a hard time removing the cloth hinge later. Even so, it is a common practice to put the hinge inside a wax paper "taco", or fold. By doing so, it makes the clamping pressure all that much greater on the cloth tape hinge.

The final product is a cloth hinge that has been crushed very, very flat, is around 3/4"-1" wide and as long as you think best. Since the tape comes in various widths, it is your call which you will purchase. Another common detail is a small hole punch is used to make a hole near the ends of the hinge, and using a very sharp knife, a strip is cut out of the center. What you end up with is a hinge with a center section removed, which is said to make it much more difficult to pull out once the glue gets into the slot. After installation, what you see is two closely spaced cloth strips in the gap. When I purchased an F-15 foamie from Yardbird, it came with hinges made in this way, and they also nipped the corners. I think the reason the corners were nipped was to make it a little easier to install the hinges into the foam after a sharp knife was used to make slots in the center of the foam edges.

Another old method is to use the mylar material from the 5.25" old diskettes made for floopy disk drive. I suppose the mylar in the 3.5" diskettes is the same, but recently I got on the Internet and ordered a box of 100 of the older, surplus 5.25" floppy diskettes. It came out to around 3 cents each with shipping included and each diskette makes enough 1/2"-3/4" wide hinges for two standard sized park flyers. It is a common practice to punch a few small holes with a needle, or sharp, thin finishing nail in the mylar before installing so the glue can get into them and act like pins/nails that prevent the mylar from pulling out. I suppose the mylar hinge is about as easy as it gets and since the diskette material is thicker than other options and very flexible, it is one tuff hinge that resist twisting or stretching in park flyers. If you want to use the material in a larger, heavier RC model, it is wise to double the mylar, often as a folded hinge that has been glued together in a fashion similar to the above medical/athletic tape hinge.

I am sure you know of the other, more expensive plastic hinges made by Dupro and others. Also keep in mind many of the same suppliers of plastic hinges sell hinge tape/strips. Sometimes the hinge tape/strips are very much like the medical/athletic tape that comes in a roll and other times the material is a flexible plastic. If you do an Internet search for "RC model hinge", there is no telling what else you might find. You can also do the same search in the Hobby shops on line. There are only a few that don't offer parts and pieces for park sized flyers and that is true of the suppliers of foam board for scratch building foam flyers. If you have the time, you can spend hours on video sites like Youtube learning how others build their foam RC flyers and pick up all sorts of clever ideas and methods. Some even tell you how they make cheap as dirt hinges for their speed demons. Some of these methods are chemical hinges, meaning a glue is used as a hinge material. Welder's glue is one favorite for all sorts of park flyers, including racers and combat wing builders. Others use hot glue and stretch the stringy glue while it is still warm. I am including a few Youtube video examples of various methods. Enjoy.


Welders Glue Hinge Flexibility (1 min 20 sec)


welders hinge (1 min 16 sec)


The Welders Glue Hinge (3 min 0 sec)


Hot Melt Hinges for EPP Airplanes (6 min 53 sec)


installing RC airplane hinges (5 min 50 sec)


RC Plane Bamboo & Thread Hinge Technique (8 min 25 sec)
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Old Oct 20, 2011, 02:37 PM
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Fort Worth, TX USA
Joined Feb 2001
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OMG, never seen so much material on hinges.

I buy the fuzzy sheets that Great planes sell.
No worry about it not sticking
More flexible than all the others
and you can cut it to any width you want.

I go with 1/8 to 3/16; that way all I have to do to make the hinge slot is push the hobby knife in once.
Next would be to rock it around a little bit to compress the foam and form a wedge shaped hole.
Dip the hinge strip in a small puddle of epoxy and shove it in the hole.
wipe any excess epoxy away. and let it set up.

When the surface is installed the steps are the same but I flex the surface and run a brush down the gap to smear the excess epoxy .. . .both sides.
after it all sets up I flex the surface to break any little bonds that might have been made to keep the servo from doing the work.
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