computer anywhere on the vehicle so long as these numbers are exactly in line with
each other.
6. Make your drills on both guides first - these are all for the M3.5 screws. Drill directly in
the center of each red dot, through the airframe. If you’re using a cardboard or a
somewhat flexible airframe, I recommend drilling holes at 2.5 or 3mm, so that the hole
taps itself when the screw is inserted. Otherwise, do not drill larger than 3.5 mm.
7. Cut on the red lines with a sharp hobby knife.
a. On the TVC guide, red lines outline the minimum required cut out area, mostly for
the TVC servos and pushrods.
b. On the flight computer guide, these are simply suggested cut out areas, and are
not completely needed. The cutouts allow you to insert and remove the Micro SD
card, turn the computer on and off, and observe the LED clearly without removing
the computer from the rocket. If you prefer not having a hole in the side of your
rocket, you can cover this up by making a removable door.
8. If you’re building a vehicle with multiple airframe sections, it can be useful to label each
“side” on the inside of the airframe; 1, 2, 34. This can help you line up the different
sections during assembly, and is vital if the computer and TVC mount are in different
sections.
9. That’s it! Your rocket is now ready for assembly!
8. Assembly notes
Before putting all these parts together, there are a few things to note.
● By nature, in comparison with traditional model rockets, TVC rockets will be heavy for
their thrust. This means they’ll have a more energetic impact on landing, which could
damage some parts of the rocket. Because of this, I recommend reinforcing the airframe
around the TVC mount/bottom of the rocket.
○ To do this, you can use an extra body tube. Cut out sections of the tube to fit
around the outside of the bottom of the vehicle. Very generously use epoxy, CA,
or a strong hobby glue to secure this tubing to the outside of the airframe.
Contrary to most cases, the more glue - the better!
● You are welcome to cover up the TVC servos with your own 3d printed or handmade
parts! So long as you are careful not to restrict any of their motion, placing objects or
covers over them is just fine.
● The same goes for the flight computer cutouts. The barometer just needs to sense the
outside air-pressure. So long as your rocket has a few holes to ensure that happens,
covering up the flight computer access hatch is no problem.
● You can paint the TVC mount - if you’re painting your rocket and want to disguise your
the TVC cutouts, you can paint the rocket while the TVC mount is inside. The paint will
have little or no effect on its ability to gimbal the motor.
● You cannot paint the flight computer - doing so will cover up the state indication LED,
and may damage some of the sensors or screw terminals.
Copyright © 2019 Barnard Propulsion Systems, LLC
Version 1.8, Jan 1, 2019
