Monthly Archives: September 2013

Bonsai Maiden Flights/Crashes

Brought the new wing out to a field and gave it a go; seems to fly well! I moved the servo arms back one notch from neutral as the flaps seemed too low and I couldn’t trim enough to eliminate the problem. I also adjusted to 30% D/R on the remote which helped a lot in the later flights.

Wing took the crashes amazingly well on the whole though the final crash resulted in the battery pulling out the piece of wood its glued too. I imagine I can just switch to strapping all the way through the wing to fix it though.

Hobbyking Bonsai – Assembly

Assembling the Bonsai with the parts I selected required a few tweaks.

Servos

Servo

First off, I had to enlarge the servo holes. I left the outside and forward edges of the stock holes alone, taking material off the other two sides to make room. I left the holes ~1/8″ undersized to ensure a snug fit which seemed to work well. I used the third hole from the inside on the servo and the top hole on the flap. According to flite test you want 15mm of flap movement for high rates and 8mm for low rates; the positions I used provide ~25mm at full range so I will have to program the controller down to achieve the targets. Using closer hole son the servo looked like it would start to interfere mechanically.

I did have to slightly enlarge both the holes with a small drill bit to get the pusher rods in.

When using the heatshrink to connect the carbonfiber rod to the Z bends, I added a little superglue as otherwise they seemed apt to come apart.

Motor

Motor Mount HolesEnlarging for Motor

The stock pre-drilled holes for the motor mount were not spaced appropriately for my motor. I used the motor’s mounting plate as a template and, using a very small drill bit, drilled new holes. The nut securing the motor shaft seemed to poke a bit too far back; to provide it some clearance I drilled a hole from the top then enlarged it slightly with a file.

Also, the bullet connectors I purchased were the correct diameter but not deep enough to fully seat the motor’s connectors. I simply resoldered the new connectors onto the motor so everything mated well.

Winglets

Glueing Winglets

My patience is pretty short and the super glue pretty slow to set so I propped the wing up on 2×4’s and used some weights to hold the winglets in place while the glue sets. Given the slight texture on the foam I’m not sure superglue will hold that well (doesn’t like to bridge gaps) but I started with it and will use the same setup to gorilla glue it should they break off.

Receiver

The 8 channel receiver I purchased is notably too large for the application. I stripped the case off of it which seems to get a decent fit. As it filled the compartment out I did have to cut a small notch to provide clearance to actually plugin the servo’s and ESC.

Looking at the back of the plane, the left servo is connect to Channel 1, the right servo to Channel 2 and the ESC/throttle to Channel 3. I followed this youtube video for setting up Elevon Mixing:

RC Flying Wing

I decided to add an RC plane to my flying collection. After a bit of research I settled on the Hobbyking Bonsai.

Based on others success/recommendations I went with a slightly larger motor, battery and servos than the hobbyking recommendations.

Installing the servos actually required enlarging the stock holes. I used an exacto knife to enlarge the holes but kept them ~1/8″ narrower and shorter than the actual servo to ensure a snug fit. I kept the outside and forward edges in the stock location removing material on the inside and back edge.

Installing the motor similarly required drilling fresh holes as the stock ones were not correctly spaced.

Flite test recommends smearing shoe glue onto the leading edge to make it a bit more robust which I have done. I went with a pretty thin layer that extends back ~1/2″ to 3/4″.

The full list of parts purchased was: