Dedicated to the Promotion of Electric Propulsion in all types of Aeromodeling

The Next Big Thing-Step 10


See that bear?  Yes, THAT is the arrow shaft I am using for this tricopter !
Honestly, this is THE place to get graphite arrow shafts of ANY type. Just to
see this place and the indoor range and the trophies EVERYWHERE  is worth
the drive! But, I digress…

I have now made a new airframe with flight proven electronics. It is almost like the
first airframe although with modifications based upon “experience” .

The first task is a more robust tail servo mechanism based upon AlexinParis’ quick and dirty concept.
The helicopter blade holder is also just too fragile


This is actually very quick to fabricate and is of very low friction. The pieces of tube that are
wrapped with thread are just extra graphite tube cut-offs. The thread is just button thread
cyano’d on. The trick is, I used some 1/4″ polyethylene water tubing jammed into the graphite
tube cut-offs. I then drilled out the center of the green tubing to make a nice bushing for the aluminum tube
(that holds the motor mount) to pivot on.  The motor mount is made of plywood and while it is hard to
see in the picture, it has some fiberglass cloth re-inforcing the mounting to the aluminum tube pivot
that rides on plastic bushings that cost 1/4 cent. The servo mount is also fiberglass re-inforced to
the graphite shaft. This works really well, no slop, no friction, light weight, easy, cheap, fast.
What more do you want? ( Did I hear some joker say, “for someone else to do it”  ? )
Check out the undermount servo. Totally covered by the motor, no drag.


This is slick and light and after all is said and done, I don’t think I would do it like this again.
I mean look at it. Even though I am going to put a bumper on it, it IS vulnerable to a hit.
You have to remember that the airflow into and out of a propeller is pretty much  80% of the
flow is through the outside 20% of the propellers’ span.  So mounting the servo on TOP of
the boom next to the motor would probably have a minimal impact on the total lift and a BIG
improvement on the rugged-ness  ( is that a word?) of the airframe. Hey, next time. In the mean time
here are some more pictures of my tail servo set-up.




Next month we will delve into the upgraded power distribution network .

Stay tuned!

Rocket Bob Kreutzer