When demonstrating my Raptor last week, I noticed some resonance in the body just before reaching my normal flying RPM. I only noticed it briefly during the spool-up, once the rotor reached its normal speed of ~1700rpm the vibrations where gone. This called for a checkup of the rotor balance, which is what I’ve done this weekend. I used the page over at Raptor Technique to guide me through the process.

The blades seemed to be fine; their Center of gravity matches almost perfectly (less than 3mm difference). Their weight also looks fairly identical, as I could balance them on the (blunt) edge of a knife (1.5mm wide).

Next up was the flybar. I noticed that both paddles are not aligned as it should be. After some tweaking, this is the result:
Raptor 50 Flybar
Which seems a lot better than before!

All that’s left is give it a test-flight and see if it’s better; but with the current weather, it will have to wait a few days.


  1. Christophe Vandeplas says:

    Where are the pictures of your baby flying ?

  2. Niobos says:

    They are right here

  3. Long-term Memory » Blog Archive » Flight log 2008-06-09 - Follow up says:

    […] reported in my previous post, I needed to re-balance the rotor-blades. Again… Also, the glowplug needed a […]