"Sky Spy" Construction Progress

Sky Spy Construction Report

Sky Spy Construction Progress Report

The Sky Spy is coming along very slowly. It seems like every time I get back to it, I spend most of my time trying to figure out where it stands, and what I need to do next. Then, once I get to that point, it's time to do something completely unrelated. So, in effect, it goes nowhere.
I hoped to have this completed by the end of May, but I know that's not going to happen. There are just too many details that are left unexplained in the design (and a few problems with the design I have had to work to correct), and more steps to add to include my own modifications. Being that it is scratch-built, it tends to take a bit more head space than a kit does since all the pieces are not nicely cut out, much less arranged in a detailed instruction manual. All I have to go on are a set of plans, and two-pages of text to describe the general steps necessary to construct the beast.
Nevertheless, I intend to post its progress here, partly as motivation for me to continue to work on it...and (hopefully) eventually get it done.
It was never my intention to make this a night-flying aircraft, but I decided to go ahead and install a simple lighting system...just in case. I know I am going to do much experimentation with this aircraft (if I ever finish it), so I may as well make it visible in the dark.

February 10, 2002
Recently, I installed some LEDs in the wings. Since the outer-most rib section will be sheeted (top and bottom) I elected to add three LEDs to the three adjacent rib sections. My circuit will consist of three parallel LEDs in series with two other sets of three parallel LEDS, for a 3x3 series-parallel circuit. I actually have six LEDs in parallel, but three of them are wired in reverse polarity. That way, depending on the polarity of DC power that I apply to the circuit, I can turn on one set of three, or the other set of three.
This photo shows the LEDs installed in one wing tip:

Where is the sixth LED, you ask? Well, it's right here:

I mounted one LED, externally, on the leading edge so that I have a reference when making landing approaches. It has been my experience that the most difficult orientation to see a plane in at night is when it is coming straight at me. These LEDs will make it possible for me to see the wingtips on approach, making night landings a more pleasurable experience.
So, the wings have two of the three parallel circuits, which means I have one more to add... somewhere. I was originally going to put them in the tail, but then for safety reasons, I felt that would not be a good idea in case there was a failure in the circuit. I have decided to put the tail on a separate circuit so that if one circuit goes out, I don't lose sight of the whole plane. I'm only going to put three LEDs, total, in the tail. I want to keep the system simple, and reserve my power requirements for other on-board equipment. I won't have the option to reverse polarity in the tail section.

That's where the plane stands at the moment. I have spent a lot of time looking at the pieces and the plans and the work I have done so far, and I have come to realize that I have done all the easy work so far. Now the real "fun" begins.

The Checklist
I like checklists. They help me keep on track - especially with projects that keep getting interrupted...often.
The following is a checklist of what remains to be done on the wing. I haven't created a checklist for the rest of the plane, yet.
Checklist for the Wing:

Apply webbing between inner wing sections
Cut/drill holes in ribs for aileron linkage (will require some ingenuity - should have been done before building the wing!) - plans indicate holes that are too wide and too far to the rear, weakening the wing structure. Investigate alternatives to using bellcranks before punching holes in the ribs!
Install bellcranks for ailerons
Install servo mounts in wing for elevator and rudder servos
Apply bottom leading edge sheeting
Apply sheeting to bottom center section - cut or leave open area for rudder & elevator servos
Create servo mount in wing center for aileron servo - there are no guidelines in the plans.
Install aileron linkages (this should prove to be interesting...)
Install connector for lights through bottom center sheeting.
Install wires that will lead to connectors in tail booms
Apply top center sheeting - cut hole for connector wires
Apply wing tips
Add top and bottom sheeting to wing tips (outer rib section)
Install tail boom mounts on wing (lots of sanding and fitting work) - route wires through
Add connectors to wires
Apply cap strips to ribs
Collect tools, select an area (outdoors), and decide on a day that I can spend SANDING.
Sand wing contours (sheeting, LE, wing tips etc.) to shape. Be careful of external LEDs on LE - may prove to be a nusiance. Sanding the square edges down to meet the angle of the aileron stock may be a lengthy procedure.
Install ailerons TEMPORARILY
Apply MonoKote
Install ailerons PERMANENTLY

Notes:

Tail booms are removable. This means the linkages to the servos must be easily removed (i.e. use clevises, not z-bends). Also, an electrical connector must be installed to provide power to tail lights. Control rods will share space with electrical wires for the length of the booms - ensure they do not interfere with each other. Use twisted-pair wire.
I am concerned that the brass rods used as a power bus for the wing LEDs may cause problems with other RF equipment that the plane may carry in the future. Perhaps cut them short and run twisted pair wires out to them. This decision will need to be made SOON, while the rods are still accessible!

Copyright 2002

02/10/2002