This is a continuation of the Yak54 build. Use the above mini-menu to see all aspects of this build. The components list is here.

I basically just followed the manual, so I'm only going into detail on items that were additional or contrary to it.
 

Ignition Kill Switch:

I used a EMS/Jomar Opto-Isolated Switch for an ignition kill switch. The found the written directions a little mis-leading (refering to the part about positive and negative solder terminals and the need to possibily reverse the wires) but the picture diagrams were clear. Basically, it's like a SPST switch that's either open or closed. I used it to break the positive line. Since I needed both a male and female Futaba J connectors, I just used a spare 12" 20-22 gauge extension cable (the white wire is not actually connected to anything).

The wiring goes: 4.8v battery, manual switch (plane-mounted emergency kill and battery charge), Jomar-Opto Switch, and finally the DL-Ignition module. If it works backwards on the transmitter switch you assign it to, simply "reverse" it in the radio's programming.

I mounted it next the the front of the gas tank (closer to the ignition than the receiver). Apart from the obvious security it provides, it won't allow you to start the engine if the receiver is off. Also, if the receiver battery dies in flight, the motor should stop.

Choke Servo:

I installed another Futaba 3010 for the choke. Same setup as the throttle (2-56 ball-links on both ends, nylon pushrod, vertical plywood brace, etc.) The differences are that the engine's choke lever wasn't extended (didn't really see an easy way to do it anyway). Also, the choke's hole through the firewall is larger (to allow the ball-link to slide partially in without touching). Therefore, the last place the choke pushrod is attached/braced is at the plywood former around the fuel tank (see below).

GraphTech CF Gear Install

Due to the weight of the 50cc engine, and the need to use a 22" prop. I decided to swap out the stock aluminum gear for GraphTech carbon-fiber (#237 v.4d). It's about an inch taller and doesn't flex as much as the stock gear (and of course, it won't bend :-). However, they are designed and bent a little different than the stock gear, so you can't really just use the old ones to transpose the holes to the new ones.

Install the stock gear and use card stock to create 2 small templates of the outer 2 holes (on both sides). Mark the template and fuse. where it lines up. Make a larger one for the inner 2 holes under the fuel tank. It should touch the sides and be about 1-1/2" wide. This will be used to create a reinforcing brace (from ply or hardwood ... since it's 2 piece gear) and also as a guide to find the 2 holes underneath in the next step.

Create the wooden brace from the template (with 5/32" holes for 6-32 screws), and bolt it down to the stock gear. Mark the fuselage on both sides where it touches. Remove the stock gear.

Enlarge the slots on both sides so that the new CF gear just fits into place, but snuggly (use Dremel cutting tooltip #561). I propped the plane up so that the fuselage (not the engine) was perpendicular and parallel on a small table. Adjust Landing Gear so that both sides are equal in every way:

• Inserted the same amount (measure distance to middle of fuselage).
• Bottom (where axle will attach) is even or maybe just 1 degree of toe-in.
• Bottom is same distance away from edge of table.

Drop the new wooden brace in place and line up the marks on both sides. Use something sharp to etch where the inner holes go (one 5/32" hole in each piece of LG). Remove LG and drill holes. Reinstall both pieces of LG with the brace and longer 1"x6-32 screws. Be sure they will screw down tight.

Check all your measurements again and align both sides of the gear (if you loosen the screws they both should be able to pivot a little at this point) Tighten them down. Using the smaller templates you made earlier, tape them to the fuse. frame and LG on the sides (lining up each template's marks). Etch the 4 holes, remove both, drill and reinstall. If everything went as planned, everything should line up.

To finish, I reinforced the upper mount with some 5/16" Basswood. Make it shorter on one side so the center brace can still be removed. Before you epoxy it in, lay a piece of wax paper on the center brace so it does not get glued in.

These are the actual templates I used, but unlike pictured, used inside the plane instead.