Sub Micro (Spy) Blimp Building with Hacked Servos

Step 5 Balloon Attachment and Trimming

The assembly from the previous step is put on the balloon as shown. Two 4 cm pieces of tape should suffice. You might have to carefully shift it backwards or forward to have the blimp hang in the air with the rod more or less horizontally.

Final trimming is done with putty. The amount should be just enough to have the blimp slowly float down when no power is applied. The place you put the putty should help the final trim to have it hang horizontally.

When flying in high halls you should take in account that higher up and in warmer areas a blimp can have tendency to increase its buoyancy. So it is better to trim it a little heavier. The battery will run down a somewhat faster as you will need more power “up”, but it is better to be safe than sorry.

One advantage of using a latex balloon is that it will lose helium noticeably within hours and come down. When using a foil balloon you should take more care in trimming, as coming down can take days. A spare balloon on a string and double sided tape on top can be a real saver by allowing for some “inverted fishing”.