My other learning plane.

To do the conversion, I decided to use the FrSky DIY Telemetry module (http://www.alofthobbies.com/diy-telemetry-module.html).  It had good reviews over on RCG, so I went with it.  It only needs three connections to work: 1) +voltage, 2) ground, and 3) a PPM signal.  I just had to figure out where on the circuit board the PPM signal came from.  Opening the transmitter showed this little circuit board:


I searched the internet for days looking for schematics for the Cadet III, but could find none.  I also couldn't find a good schematic of the OKI L9362 chip.  The only clear schematic on a L9362 didn't look like the one in the Cadet.   As a side note, the OKI L9362 is also used in the Cox Cobra radios. So, I spent a while searching other pages on doing a 2.4Ghz conversion, and found one that had data on the OKI chip.  The signal comes from pin 9 of the OKI chip. I marked the trace with a black pen mark.  Instead of soldering the signal wire at the OKI chip, I followed the trace up to what I figured was a better place to solder the lead.  You can see where I marked the trace, and where soldered the yellow signal lead in these pictures:

Most of the conversions I've seen have the power leads soldered to the circuit board somewhere, but I hate intricate soldering. I chose to take the + voltage directly off of the power switch, and the ground off of the power meter ground terminal. In the following photo, you can see the + voltage lead soldered to the top of the power switch, and the ground lead to the right side of the power meter. In the photo, you can also see how well the module fits into the right side of the transmitter, between the case and the throttle potentiometer. A nice snug fit.


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I trimmed off the housing for the old antenna from the top of the case and mounted the new antenna in the open hole.



The module has a small board that has a pushbutton for binding and a L.E.D. that needs to be mounted remotely.  I located and drilled a couple of holes for the button and light in the back of the transmitter.  I used a couple of bamboo skewers for mounting the board and glued them to the case, and then attached the remote board.  Here is how it looks from the inside and outside:

With the binding board mounted and all the wires routed, its ready to close up.  There's also a 3-way switch to toggle telemetry that needs to be mounted on the case, but since I'm using a receiver without data feedback, I just set it for no telemetry and stuffed it inside.  The last thing was to pull the AM crystal so that there was no chance of a weak signal being broadcast, even with no antenna.

Here it is ready to close:



And all buttoned up!  I was going to clean it up nice and pretty, but I changed my mind.  If I'm going for the retro thing, I figured I'd leave it with all it's battle scars and age marks, even if it does look rode hard and put away wet.  I left the Channel 54 sticker on the front, also.  Just looks right.




I bound the transmitter to the receiver and tested it.  It all worked, but I did have to spend some time modifying and re-positioning the throttle pot and lever.  Somehow the previous owner had rotated the pot in its mounting bracket and the servos would do strange things when the throttle lever was moved all the way down.  I also removed the ratchet, and the lever motion is smoother now.

So there you have it. A period Cox Cadet III radio brought up to modern standards.

The "Dragged Kicking and Screaming into the New Millenium" Mark

Very cool!

Okay, time to get the airframe going.  I started on the wing ribs this afternoon.  Boy, these ribs are stout!  I checked the plans three times, and each time it said to make the ribs from 3/32" balsa.  1/16" seems more natural, but I'll go by the plans.  I sorted through my wood and pulled the lightest 3/32" sheets I had. One sheet of 3"x36" is enough to make the ribs.  I made an extra pair of wing ribs, as I'm still debating adding an extra bay to each side of the wing since I'm going to use three channels for the plane, adding throttle for the engine.  With that 7" chord, though, it should be okay.  Here're the wing blanks cut to 1 1/2" by 6" stacked and ready to cut:



And cutting the ribs on the scroll saw.  I did it in two sets of 5 blanks to make it easier and smoother.


And the cut out ribs:



The Cuttin' Mark

Mark, you might try to run a couple pins up thru the bottom so the ribs don't shift while you're cutting them, cover the heads of pins with masking tape so they don't catch on jig saw.

I haven't mastered making accurate cuts with my scroll saw yet. So far, I haven't used it a lot for delicate parts though. Pretty soon I'll be cutting ribs too.

Rusty

i like to pin multiple parts, that way if you let go or change approach angle you can go right back to where you want to or stopped cutting, easy peasy.

Mark Boesen wrote:Mark, you might try to run a couple pins up thru the bottom so the ribs don't shift while you're cutting them, cover the heads of pins with masking tape so they don't catch on jig saw.

Mark, what I do when cutting the blanks is to put all the blanks on a piece of cardboard, then lightly dust them with 3M 77 spray adhesive. Then, stack them and press together. This keeps them tight together while going through saw, and then I just pass a blade between the ribs to separate them. That's the technique I've been using for the past 25 years. Never had a problem with shifting parts. I also use a light dusting of 3M 77 on wood to hold the plans to it while cutting. Then the paper just peels away after the parts have been cut and sanded.

I didn't even try the scroll saw with my flite streak double build ribs (on stunthanger, not here) maybe I should have.  I have used the scroll saw for all the plywood and the thicker balsa so far.  The 1/16 balsa made me shy away a little actually.

I need to get some spray glue and try it.

I have noticed that the blade quality affects how the cut tracks more than the saw itself.  Using a slightly more expensive bare end blade I get straighter cuts than with a cheaper bare or pin end blade.  I think the more expensive saw blade is sharpened and a proper kerf is set, instead of being merely stamped and left like the really cheap blades are.

Cool conversion, and nice looking plane.

Phil

...with the pins theres no glue needed, less mess and probably faster.

We have a tool store nearby, for contractors and goofballs like me too. I should stop in and talk to someone there about my saw blades.

Rusty

make sure they're fine tooth blades, you want 20 TPI at least, teeth per inch.

Started the wing.  I went ahead and left the wing at 36".  I printed off right and left wing sheets and taped them together. I pinned the right wing plan  on my board under some Glad cling wrap.  Then pinned the ribs, spar, and trailing edge in place.


Ribs, L.E, and T.E. glued up.  The L.E. was a pain since it's just 1/4" spruce carved to shape.  I know my razor plane is somewhere within a 10' radius of me as I type this, but for the life of me I can't find it.  I just had to use an X-Acto knife to carve it to shape.


And most of the 1/16" center sheeting in place.  I didn't cover that last little bit because I have one leftover piece of 1/16 that I'm using for both sides, and I'll wait until I cover the other side also to see what I have for scraps to fill in the open sections.


And the underside. I'll clean up the joints and sand just before joining the two wing halves:



And now on to the left wing panel.  I just LOVE CA glue.  Building just screams along with CA and accelerator.  Unfortunately, I didn't have one complete 36" piece of 1" trailing edge in the wood box.  I had one that was long enough to do the right wing, but I had to join a couple of left over pieces to make the left wing.  Ah, well.  I'm going to cover it with opaque Monokote anyway, so it won't be noticeable.  Pics of pinning in place and with the ribs glued to the T.E. and spar.  It's a little late, so I will tackle carving the L.E.  and sheeting tomorrow.



More to come,

The Up Past His Bedtime Mark

Well, I was able to get back to the Q-Tee this evening.  I finished up the wing panels.  I'll sand and join the wing halves this weekend when I have more time to take it slow with the alignment of the center joiner.  Here's the upper and lower sheeting finished, and the cabane cutouts done:




And on to the tail surfaces.  Man!  This thing is built like a tank!  The fin is 1/8" sheet.  Making the fin from one rectangular piece of balsa:





And framing up the stab.  The plans call for making it from 3/16" sheet and sticks!    That seems WAY too thick.  I went ahead and dropped down to 1/8" sheet and sticks to frame up the stab, and even then it seems very stout.





And the stab all glued up and pins removed.  Did I mention I love CA glue?



The fin and stab together.  I really like how the fin actually slides down in between the center of the stab sheeting instead of just gluing on top of the stab.  I'll have to be sure to do that with all my other models in the future.




I'll final sand once I make the elevator and rudder.  But it's again past my bedtime.  Work in 7 hours.

The Drowsy Mark

Well, I've been procrastinating on finishing this model, hoping that I'd be inspired and create a "Super, Gee-Whiz" paint scheme, but nothing's come to me.  So, I figured I'd just go ahead and finish it in the standard Batjac Aeroworks© color scheme and get it done.  I went with a simple Monokote finish, as painting is still out due to the rain.  The first things covered were the wing and fuselage.  Sorry, I didn't take pictures as I was covering, but it's just a straight forward cover job.  The tail surfaces took a little more time, as I chose to use my favorite Monokote hinges.  I know a lot of people like the Monokote hinges where your create a seam with the top and bottom Monokote sealed together to make the hinge.  Personally, I like my Monokote hinges more like the old cloth hinges.  Works the same, but better.

First, I cut a strip of my base color Monokote 1/2" wide.  Then I cut 3/4" pieces off, and iron them face to face to create the hinges.






Then, I take another piece of base color Monokote and put a strip along the mating surfaces of each tail surface.  Then, iron on the hinges the same as you would glue cloth hinges.



When you're done, iron on the finish pieces of Monokote on your tail surfaces.  With this type of hinge, there's almost no gap, but the tail surfaces can be folded over on themselves easily.  



And, no matter what angle the surface is moved to, these is still no gap between the tail surfaces.

And, with the tail surfaces glued in place, motor mounted, and radio equipment installed, it's ready for a good flying day for her maiden.



I'm trying out Bernie's throttle for a Reedie.



The Uninspired Mark

Hi,

What is the all up weight please ? please share video how it fly if possible ;-)

Beautiful work Mark. Let us know how it flies.

Very nice work. When I have time this evening I'll read all about it more closely.

Rusty

Really nice work, ought to be a real fun flier.  

Nice thing about Q-Tee is that it has generous wing area, so it flies on its wings, but is aerodynamically clean enough that it has good penetration.

Back in the 1990's, I flew one at 6,500 feet (1,981 meters) elevation in Gallup, New Mexico. Due to the different in atmospheric air pressure, 11.5 PSIA (0.78 Atm) versus 14.7 PSIA (1.0 Atm) at sea level, there is a loss in horsepower of about 20 to 25 percent.

Normally one would upgrade the engine to an AME or Tee Dee .049 or Thunder Tiger .07 (back then, I don't think the TT GP-07 was out yet). I could still fly my Q-Tee with Cox .049 Black Widow engine, because of its generous wing area.

Have fun with your Q-Tee and throttled .049 Sure Start. We'll need a flight report and photos or video if possible.  

For George Hostler.....Welcome to the forum sir!